«MHh g a M M a « MM P B a iB Wgi*g w Book . S s. . CopghtN" COPYRIGHT DEPOSm v-m fiWx m-M--^ INSECTS INJURIOUS TO STAPLE CROPS. / BY E. DWIGHT SANDERSON, B S.Agr, u ENTOMOLOGIST, DELAWARE COLLEGE AGRICULTURAL EXPERIMENT STATION; ASSOCIATE PROFESSOR OF ZOOLOGY, DELAWARE COLLEGE. FIRST EDITIOR. FIRST THOUSAND. > J ) } > > i I M^' \^ >''' 'j' '' Ur ^.^ NEW YOEK : JOHN WILEY & SONS. London- CHAPMAN & HALL. Limited. 1902. THE LIBRARY OF 0ONG??ESS. Two COfMES Received JAN. 14 1902 COPYSIQMT ENTRV CLASS ««^XXo. NO. COPY 8. Copyrigrht, 1902, BY E. D. SAiNDERSON, • • • ••• ccc t ••• c»» .*» I c * t»*tC 'c* ROBERT DRUMMON'D, PRINTER, NEW YORK. PREFACE. The sources of information concerning the insects affecting our staple crops are widely scattered throughout tlie bulletins of the State Agricultural Experiment Stations and of the United States Department of Agriculture, a few books on Economic Entomology, and various other publica- tions. Few men but the entomologist have the desire or ability to glean an account of any given insect from the first-mentioned publications, if they know of the existence of others than those published by their own State station. The few books which have been written upon American Economic Entomology usually give but a brief and sum- mary account of any given insect, too brief — it seems to the writer — to give a very clear understanding of the matter. In preparing the following pages the author has been more and more impressed by the fact that for the control of most of the worst insect 2:)ests of our staple crops, the farmer must depend very largely upon general methods of farm practice. This being tlie case, it is essential that he have a correct knowledge of the pest to be combated ; such a knowledge of its life-history as will nuike plain the reason for the effect of any given procedure against it. Thus the better class of farmers may find a work in which each Yl PREFACE. insect is treated somewhat comjireliensively as to life- history, habits, and remedies, yet without being exhaustive or technical, to be of considerable service to them. To furnish such a guide to the more intelligent class of prac- tical farmers has been the aim of the writer, who trusts that the following pages will be read as such and not as in any way a contribution to science. The author wishes most uiu'eservedly to disclaim any originality for the contents of the work, and to state that unless otherwise noted all the facts are merely comjoilcd from the writings of others. Free use has been made of the writings of all the most prominent American ento- mologists. Where the treatment of a group of insects has been largely drawn from one or two sources, they will often be indicated by quotations in tlie text. Many of the following chapters or parts of them have previously appeared in various agricultural journals during the past three or four years, to the editors of which the author desires to express his thanks for their courtesy in allowing him to here republish them; namely. The Country Gentleman, The Farmers' Review, Farm and Fireside, Farm News, The National Eural, Texas Farm and Ranch, The American Agriculturist, The National Stockman and Farmer, and The Practical Farmer. The author is particularly indebted to Prof. M. V. Slingerland, of Cornell University, for kindly reading portions of the manuscript and for several suggestions of value; to Dr. L. 0. Howard for assistance in part of Chap- ter X; and to his wife, Anna Cecilia Sanderson, for a large amount of clerical assistance. E. DwiuHT Sandkhson". Newark, Dkl., February, 1901. SOURCES OF ILLUSTRATIONS. Electrotypes of the following figures were purchased, being secured through the kindness of the parties named : Fig. 9, from Houghton, Mifflin & Co. ; Fig. 102, from the Iowa Ag. Exp. Sta., through Prof. H. E. Summers; Figs. 7, 136, and 137, from Dr. J. B. Smith; Figs. 51, 52, 60, 84, and 85, from Cornell Univ. Ag. Exp. Sta., through Prof. M. V. Slingerland; Figs. 25 and 28, from The Farmers' Eeview, Chicago; Figs. 74, 75, 76, 77, and 78, from Dr. S. A. Forbes; Figs. 71 and 72, from The Country Gentleman, for which they were originally redrawn by the author; Fig. 53, from the Xebr. Agr. Exp. Sta., through Prof. L. Bruner; and Figs. 11, 24, 31, 50, 59, 61, 62, 64, 66, 67, 68, 79, 80, 81, 82, 83, 88, 89, 90, 91, 92, 93, 94, 97, 104, 105, 106, 107, 108, 109, 111, 112, 113, 114, 116, 117, 118, 119, 120, 121, 122, 123, 124, 126, 127, 128, 129, 131, 134, 135, 136, 143, 146, 154, 155, 156, 157, 158, 159, 160, 161, 162, from the United States Department of Agriculture, through the kindness of Dr. L. 0. Howard and Mr. F. H. Chittenden, of the Division of Entomology and the Division of Publications, to which gentlemen we are under especial obligation. The following figures were kindly loanerl by the parties named: Figs. 29, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, vii Vlll SOURCES OF ILLUSTRATIONS, 41, 42, 44, 45, 46, 47, 48, 110, and 150, from the Md. Agr. Exp. Sta., through Prof. A. L. Quaiiitance, these having been first used by the author iu The Farmers' Eeview; Figs. 65, 132, and 133, from the Ky. Agr. Exp. Sta., through Prof. H. Garman; Fig. 125, from the Fhi. Agr. Exp. Sta., through Prof. H. A. Gossard; Figs. 54, 55, 56, 57, 58, 63, 70, 96, 98, 101, and 103, from the Ohio Agr. Exp. Sta., through Prof. F. M. Webster; Fig. 49, from the Minn. Agr. Exp. Sta., through Director W. M. Liggett; Figs. 12 and 95, from the Del. Coll. Agr. Exp. Sta.; Fig. 151, from the Peninsula Horticultural Society, through Prof. Wesley Webb. Figs. 19, 20, 21, 66, 138, 139, 140, 141, 144, and 147 were loaned by the author. Figs. 13, 14, 15, 16, 17, 18, 23, 26, 27, 99, 115, 145, 149, 152, and 153 were copied from prints. Figs. 1, 4, 5, 6, 8, and 10, and Figs. 2, 3, 22, 86, 87, and 100 and frontispiece are original from photos by the author, the photos of the latter numbers being loaned by the Del. Coll. Agr. Exp. Sta. TABLE OF CONTENTS. PAGE Preface v Sources op Illustrations vii CHAPTER I. Injury done Staple Crops by Insect Pests 1 CHAPTER II. Structure and Development of Insects » « 6 CHAPTER III. General Farm Practice against Injurious Insects 20 CHAPTER IV. Beneficial Insects 30 CHAPTER V. Insects Injurious to Grains and Grasses 44 CHAPTER VI. Insects Injurious to Wheat 90 CHAPTER VII. Insects Injurious to Indian Corn 125 CHAPTER VIII. " Weevil " in Grain ....,, 155 ix X TABLE OF CONTENTS. CHAPTER IX. PAGE Insects Injurious to Clover 172 CHAPTER X. Insects Injurious to Cotton 188 CHAPTER XL Insects Injurious to Tobacco 214 CHAPTER XII. Insects Injurious to the Potato 239 CHAPTER XIII. Insects Injurious to the Sugar-beet 252 CHAPTER XIV. Insects Injurious to the Hop-plant 269 CHAPTER XV. Insecticides 284 INSECTS INJUKIOUS TO STAPLE CROPS. CHAPTER I. INJURY DONE STAPLE CROPS BY INSECT PESTS. Ever since the plague of locusts in the time of the Pharaohs, insects have maintained a continual opposition to agriculture. History is replete with accounts of insect scourges and the enormous losses occasioned by them. And instead of diminishing with the advancement in agri- cultural methods, injurious insects have undoubtedly be- come both more numerous and more destructive in modern times. Every now and then we hear of communities assembling for prayer and fasting to appease the Almighty, whose wrath has hurled a new insect plague against them. But a little reflection will show that tlieee scourges are entirely due to natural causes. In fact such injuries are very largely due to man himself, who, in trying to subdue Nature by the clearing and cultivation of the land, has deprived the insects of their natural food. Thus they must needs feed upon that which is substituted by him, and as it is less abundant than the former wild vegetation, the number of insects and the injuries they inflict are more Z INSECTS INJURIOUS TO STAPLE CKOPS. apparent. But the native insects are by no means entirely- responsible for this condition. Foreign insects are con- stantly being imported in one way or another, sometimes already being established pests in other lands and some- times only becoming so under their new surroundings. These are even more injurious than those native, for whereas many of our native birds, insects, and diseases constantly prey upon native insects and thus keep their numbers in check, the enemies of imported pests rarely accompany them, and they thus increase at an alarming rate and do enormous damage before they are attacked by the natural enemies of similar native pests. American farmers have learned from sad experience of the severe losses occasioned by insects, but few realize their enormity when considered as a whole. Several cal- culations of these losses have been made by competent authorities, who practically agree that one-tenth of the total agricultural product of the United States, or 1300,- 000,000, is but a conservative estimate of the loss annually sustained by this country. But when this statement has occasionally been made by the author it has been met with a look of incredulity which very plainly indicated that he was thought to have a very elastic imagination. A careful collection of such data as may be confided in as accurate shows that the above estimate is entirely correct. Con- siderably over one-half of this loss is upon the staple crops, the remainder being uj)on truck crops, fruits, domestic animals, and timber. Growing Cereals. — Probably no other insect does so wide-spread damage as the Hessian Fly, attacking our chief staple, wheat, as well as rye and" barley. One-tenth of the whole crop, valued at 'ii>40,000,000, is generally con- INJURY DONE STAPLE CROPS BY IKSFCT PESTS. 3 ceded to be destroyed by this pest every year, and in certain sections the loss often amounts to from 30 to 50 per cent. If the loss to rye and barley be put at one- fourth the loss of wheat, it amounts to about $1,000,000. From various estimates made at different times during that period. Prof. F. M. Webster states that 1330,000,000 represents the loss from the depredations of the Chinch- bug since 1850, or 17,000,000 per annum, whicli has been largely confined to the States of the Mississip^^i Valley. Corn has a host of insect enemies. Frequently the Corn Eoot-worm has damaged the crop to the extent of 10 to 20 per cent in many of the largest corn-growing States. The annual loss on this cro23 due to insects is certainly not under 5 per cent, or 137,000,000. Thus with only the above figures we see an annual loss of $85,000,000 u23on growing cereals. Stored Grain. — But stored grain has its insect pests also, which are especially injurious in the South. Mr. F. H. Chittenden, of the U. S. Department of Agriculture, places the loss on stored corn in the seven Grulf States at $20,000,000, or 20 per cent of their crop. If only one- fourth of this amount, or 5 per cent, of the rest of the country's stored corn were thus lost, it would amount to $40,000,000. Twenty million dollars, or 3 per cent of the value of all other stored grain, certainly no more than cover the loss sustained upon it and other stored products subject to insect pests, which gives an aj^proximate total of $60,000,000 damage to stored products. Grass and Hay. — A host of grass and clover insects damage the hay crop. Half a million dollars have fre- quently been given as the loss sustained from the Army- worm alone in individual States. Five per cent of the 4 INSECTS INJURIOUS TO STAPLE CROPS. hay crop, or -^20. 000, 000, fairly represents the loss upon this cro]) and pasture-lands due to insects. Cotton. — The cotton-plant has a number of serious enemies, of which the Cotton-worm, Boll-worm, and Boll- weevil are the worst. In 1880 the United States Ento- mological Commission valued the annual ravages of the Cotton-worm at 130,000,000, but, thanks to their careful study of the pest, the damage done by it has been greatly lessened in recent years. But the Boll-weevil has now presented itself in Texas. In 1894 it damaged the Texas crop to the extent of '$8, 000, 000, and its injuries are not reported as having diminished, Thus $15,000,000 must be a low estimate for the insect de^^tredations upon cotton. Tobacco. — The tobacco crop, valued at $25,000,000, has a horde of insect enemies at all stages of its existence, which will easily consume 8 per cent of it, or $2,000,000. Potatoes. — The Colorado Potato-beetle does not do that crop so serious an injury as formerly, but some new enemies to it have ap^^eared, and a loss of $10,000,000, or about 6 per cent of the value of that crop, is un- doubtedly caused by our six-legged foes. Surely, when we include the injury done to fruits, truck crops, domestic animals, and timber, $300,000,000 is a conservative estimate of the price these aj^parently insig- nificant little insects are annually costing this country. Yet there is another aspect to the matter. '' One man's loss is another man's gain '' is never more true than as regards these losses occasioned by insects. For, through wide-spread injury by them, prices rise; while if these injuries were not done and correspondingly large crops were placed upon the market, prices must surely fall. INJURY DONE STAPLE CJIOPS BY INSECT PESTS. 5 These estimates of losses due to insects are then very largely comparative. Yet, to a large extent, they are still real losses, the same as are those occasioned by fire and storm. For though a small crop may bring better prices, it is usually at the expense of individuals or communities which have sustained exceptionally heavy losses. Were these losses evenly distributed among all those producing a given crop, there would be no real hardship to them; but such is by no means the case. All this, then, goes to emphasize the fact that the suc- cessful farmer — as the successful man in any other trade or profession — is the one Avho is able to overcome obstacles which, though possibly ruining his neighbor, are making a good market for his special crop. And these insect pests can be largely overcome. The millennium will doubt- less come before the farmer will be able to stop fighting them, but a large part of the damage by them can be pre- vented at a cost which renders it profitable. Rational methods of general farm practice with the proper use of apparatus and insecticides, even such as are now known, and in which improvements are being constantly made, if intelligently used by American farmers, would save to them fully two-thirds of this enormous loss. CHAPTER II. STRUCTURE AND DEVELOPMENT OF INSECTS. The more experience the farmer has with insect pests, the more he comes to realize that if he would successfully combat them, he must have a certain amount of necessary- knowledge concerning their structure and growth. In general, the artificial means which may be effectually used to combat an insect pest will very largely depend upon the anatomical structure of the insect, while control by general methods of culture will depend upon a knowl- edge of the peculiarities of its life-history. The value of a proper understanding of these important factors in insect control is therefore apparent. General Structure of an Insect. The body of an insect is composed of three separate parts, the head, thorax, and abdomen (Pig. 1), each of which is composed of several rings or segments. To the head are attached the jointed antennae, or feelers, the compound eyes, and the mouth-parts, which are described below. Each of the three segments of the thorax bears a pair of legs, and adult insects usually possess one or two pairs of wings upon the last two segments of the thorax. The abdomen is composed of nine or ten segments, but 6 STRUCTUKE AND DEVELOPMENT OF INSECTS. 7 bears no appendages save the ovipositor of the females of certain orders. Harvest-mites, or ^^daddy-long-legs/' sow-bugs, thou- sand-legged worms, and similar vermin are often popularly called insects, but all of them can readily be distinguished from true insects by their possessing more than six legs, Fig. 1. — Honey-bee, showing three principal regions of the body of an insect : — 1i, head; th., thorax; ahd., abdomen. (Original.) the harvest-mites and spiders having eight and the others many more. How Insects Grow. With rare exceptions insects hatch from eggs laid by the adult females. Upon hatching they are but little larger than the eggs, and often bear but little resemblance to their parents. Thus the young caterpillar would never be recognized as the immature stage of the butterfly by one unfamiliar with its transformations. Grasshoppers and some other insects, however, upon hatching from the Qgg bear a marked resemblance to the adult form, except that they lack wings. 8 INSECTS INJURIOUS TO STAPLE CROPS. Complete Met amor pilosis. — But let us return to the cater- pillar and follow it through its short but interesting life. Upon hatching from the egg it at once commences to feed and grows very rapidly. But before long an obstacle to further growth arises. Unlike higher animals, insects possess no internal skeleton or framework for the organs of the body, but the outer skin becomes hardened and to it the muscles and ligaments are attached. This harden- ing of the skin is best seen in the horuy wing-covers of the beetles and is due to the secretion of a hard substance called chitin. This chitin is secreted by all parts of the skin in greater or less degree, and thus forms a sort of shell for the whole body. Though this hardening is not so apparent in larvae as in adult insects, it is always present, and it is for this reason that when the young- caterpillar has made a certain growth it is forced to shed its skin, which refuses to expand further, in order to develop more fully. Thus the skins of insects are shed several times (see Fig. 2, h), — usually five or six, but sometimes as many as twenty, — this process being known as ^^ molting." During its life as a caterpillar, which is called the "larval stage," and during which it is called a "larva," it is an elongate, worm-like creature, with six short, jointed legs on the three thoracic segments, a pair of fleshy false legs or jiro-legs on the last abdominal seg- ment, and probably several pairs of pro-legs between these and the true legs. No traces of wings can be seen, but the body is often covered vvith hairs, spines, or warty tubercles. But with the next molt the insect changes in appearance most radically, becoming a pupa, or chrysalis as this stage is termed for butterflies. Duriug the pupal stage the insect remains dormant either in a small cell slightly under STRUCTURE AND DIOVELOTMENT OF INSECTS. D the surface of the earth, or in a silken cocoon spun by the caterpiHar, or merely attached to the food-plant by a Fig. 2. — Complete Metamorphosis. The different stages of the Corn Ear-worm {Heliotliis armiger Hiibn.X a, eggs on corn- silk; h, the first three larval stages; c, pupa from below; d, same from above; e, adult moth — all enlarged; 5, about twice natu- ral size. (Original.) strand of silk or the cast larval skin. In many of the Diptera, — the order including flies, mosquitoe's, gnats, etc., — however, the last larval skin is not shed, but hardens and forms a case — called a puparium — within which the pupal stage is passed. 10 INSECTS INJURIOUS TO STAPLE CROPS. The typical pupa (Fig. 2, c, d) of a butterfly or moth is of a more or less oval shape, rather resembling the adult insect than the larva, with the wings and antennae tightly folded at the sides, the legs drawn up snugly together under them, and the head and mouth-parts bent upon the breast, or sternum. But all of these parts are not always recog- nizable, the legs and mouth-parts being sometimes lacking. Gradually the adult insect develops, and at last the pupal skin is broken open and the airy butterfly emerges to enjoy a short life and perpetuate the species. Such a series of transformations is that commonly found among butter- flies and moths (Lepidoptera), beetles (Coleoptera), flies (Diptera), and bees (Ilymenoptera), and is known as a complete metamorpliosis. All of these insects normally pass through four stages, the Qgg, larva, pupa, and aduit. Incomplete MettDnorpliosis. — In contrast to this mode of development is that of the grasshoppers (Orthoptera), bugs (Hemiptera), and some other insects. As already stated these are much like the adult upon emerging from the Q-gg. With each molt they become larger and small wing- like pads gradually appear on the sides of the thorax. There is no dormant or pupal stage, the adult insect differing from the previous stages in having fully developed wings, being larger, and often by an accompanying change of markings. The immature stages of such insects are called nympJiSy and this development an incomplete meta- vwrpJwsis, having but three stages, the egg, nymph, and adult (Fig. 3). The time occupied by the complete life-cycle of an insect varies from a week or ten daj^s for the plant-lice to thirteen or seventeen years for some Cicadas, and is entirely dependent upon the habit of the species and the climate. STRUCTURE AND DEVELOPMENT OF INSECTS. 11 A correct knowledge of the exact time and conditions under which the transformations occur for each individual Fig. 3. — Incomplete Metamorphosis of a Bug (Brachymena Ji-'puatu- laia). a, eggs; h, adult bug; c, different stages of young bugs or nymphs. (Original.) insect pest is therefore often most essential when seeking- means for its control. How Insects Feed. The material to be used in cumhating a given insect is almost entirely dependent upon the structure of its mouth- 12 INSECTS INJURIOUS TO STAPLE CROPS. parts. Much Paris green is wasted upon insects unable to eat it and which it will, therefore, never kill. Insects may be rouglily divided into two classes, those which bite and those which suck their food. Among the former are the beetles, grasshoppers, the larva? of butter- flies and moths, and the larva? of saw-flies; and among tl:e Fig. 4. — Front- view Face of Grasshopper {Schiztocerca americana). ant., an'^enna; oc, ocellus; ey., eye; cL, clypeus; Ibr., labrum, or upper lip; mx.p., maxillary palpus; lab. p., la'oial palpus; g<(l., galea, lobe of maxilla; lab., labium, or uuder lip. (Original.) latter are butterflies, flies, bees, and bugs, while the ]arva3 of most flies and bees do not possess mouth-parts homol- ogous with those of the above. Biting Mouth-parts. — Mouth-parts typical of those of biting insects are easily seen in the grasshopper (Figs. 4, 5, and 6). In brief, they consist of an upper and a lower lip, between which are two pairs of jaws which work trans- versely. The upper pair of jaws, or mandiJjhs (md.), are stout, sliort, and horny, usually sharpened at the tip, STRUCTURE AND DEVELOPMENT OF INSECTS. 13 slightly serrated at the margins, and flattened at the base. The lower pair of jaws, or maxillce {mx.), are longer, not so strong, and to each of them is attached an accessory lobe, and a jointed style called a palpus or feeler. At each Fig. 5. — Mouth-parts of Grasshopper, separated to show position and relation, a, from above the mouth; b, lookiuo; into the month; c. from below tlie month. Ihr., labrum, or upper lip; md., man- dible or biting-jaw; mx., maxilla, or second jaw; lab , labium, or under lip: hyp., hypopharynx, or tongue; mx.j)., maxillary palpus. (Original.) side of the lower lip is another palpus, these palpi being- sensory organs. Sucking Moidli-parts. — In the sucking insects these mouth-parts are prolonged into a tube through which the juices of the food plant — or animal — are sucked. In the plant-lice and other bugs the lower lip is elongated so that it forms a tube, and the maxillae and mandibles consist of long hair-like bristles, or seta?, enclosed within this tube (Fig. 7). The tip of this beak is rested upon the surface of a leaf into which the set^ are thrust, lacerating the tissue, and by a pumping process of the mouth the juices are sucked up through the beak. The structure of the mouth-parts of the various orders of sucking insects varies 14 INSECTS INJURIOUS TO STAPLE CROPS. considerably, but all agree in that their food must be sucked up in a liquid state. Any application of a poison - Fig. 6. — Cicada, showing Mouth-parts of a Bug, a Sucking Insect. a, seen from below, beak or rostrum {ro. G. ) reposing between forelegs; b, head removed; e, eye; lb7\, labrum; md., man- dible-setae; mx., maxillary setae ; lab., labium. (Original.) ous spray to the surface of foliage will be of no avail against them, though sure death to most biting insects STRUCTURE AND DEVELOPMENT OF INSECTS. 15 wliich chew the leaves, and sucking insects must therefore be killed by other means. How Insects Breathe. In the side of one thoracic segment and each abdominal segment except the last, of a caterpillar or larva, is a small Fig. 7. — Mouth-parts of a Plant-louse; a, the jointed beak; h, the lancets, much enlarged; c, antenna; d, foot. (After J. B. Smith. ) oval spot, in the centre of which is a slit closed by two membranous lips. These apertures are called sj^iracles or stigmata (Fig. 8, st^-st^^), and are the openings of the respiratory system. Similar openings are to be found in all insects, though not so easily seen in the adults. Con- necting these spiracles is a pair of tubes on each side of the body, throughout its length, from which branch off IG INSECTS INJURIOUS TO STAPLE CROPS. smaller tubes to all of its organs and tissues. Fresh air is thus inhaled to all parts of the body through these tubes (Fig. 8, tr). \%T^ ^ \ i\\h> I lmC)°' /^^^^^ ^^^^^^^^' f^'^w^^Sk 1 1 wsy Fig 8, — Diagram of tracheal or breathing system of an Insect. .s-^j-6'^jQ, the ten pairs of spiracles; A, head; B^_^, the three seg- ments of the thorax; 7V., the two main tracheal trunks; trs., trachea leading from the main trunk to the spiracle; ti^u., tra- chea connecting the two main trachea; tri., visceral trachea; tro., ventral trachea; t7\, the anterior termination of the tra- chea; g.-g., nerve-cord with ganglia to which go branches of the visceral trachea; au., eyes; a, antennae; p, palpi; 7n, man- dibles; Pi-p^, bases of the legs. (After Kolbe.) The blood of insects does not circulate through any system of tubes as it does in the higher animals. Along STRUCTURE AND DEVELOPMENT OF INSECTS. 17 the middle of the back, above the alimentary canal, is a long tube po^Kilarly called the heart (Fig. 9, Ir, Fig. 10, dr). This heart is composed of a number of chambers each of which is funished with side valves for admitting blood from the body-cavity. The blood coming into the heart from the body- cavity is propelled forward toward the head, where it again flows into the body-cavity. Thus various currents of blood are maintained throughout the Fig. 9. — Ideal section througli an insect, a, alimentary canal; h, heart; n, nerve-cord; s, stigmata: t, tracheal tubes; I, legs; w, wings. (From Riverside Nat. History.) body, but other than the heart there is no system of blood- vessels, the blood merely filling the body- cavity around and through the various organs and tissues. Constantly flowing around the respiratory tubes or tracheae, the blood is quickly and thoroughly purified, though the exact manner in which this is done is not definitely known. The respiratory system has absolutely no connection with the mouth or pharynx (Fig. 10, ^j/i), as have the lungs of the higher animals, and if an insect is to be suffocated, it must be done by closing the spiracles. It is in this way 18 INSECTS INJURIOUS TO STAPLE CROPS. that tobacco-dust, lime, ^^yrethruni, and similar insecti- cides kill sucking insects by penetrating the spiracles and choking the tracheal system. Whale-oil soap, kerosene emulsion, and the other ^'contact" insecticides, or *^ irri- tants,'* may also stop u}) the spiracles and thus cause death, but they act chiefly as "irritants,'' penetrating the Fig. 10. — Internal Anatomy of Silkworm. A, the upper, or dorsal, body-wall seen from within; B, the back of the silkworm re- moved, showing alimentary canal; C, alimentary canal removed, showing nervous system and tracheal trimks; t?'., trachea; d.v., dorsal vessel or heart; p7i., pharynx or mouth; su., supra- cesophageal ganglion; sp. sp., spiracles or breathing-pores; n, nerve-cord; ^?\<., tracheal trunk; (?6S., oesophagus or throat; C7\, crop; s.g., silk-gland; pro., proventriculus or grinding-stomach ; St., stomach ; h.L, hind-intestine. (Photo, by author from Azoux model.) skin and thus killing the insect. When insects are killed by means of a gas such as carbon bisulfide or hydrocyanic acid gas, they are truly asphyxiated by a substitution of these gases for air, the same as are higher animals by the use of anaesthetics, STRUCTURE AND DEVELOPMENT OF INSECTS. 19 Though arsenical poisons are generally used as sprays for biting insects, soft-bodied caterpillars and similar larvae are often killed by the use of contact insecticides, which affect them the same as sucking insects. The reader will observe that, almost without exception, the remedies advised for different insect pests in the fol- lowing pages are determined by some peculiarity, either of structure or development, of the insect to be combated. CHAPTER III. GENERAL FARM METHODS AGAIjNST INSECT PESTS. In the following pages artificial means of combating insect pests, such as spraying with insecticides, are not as often the remedies or preventives given as those which consist of some method of general farm practice. That such should be the case is but natural, for the staple crops, being cultivated in large areas, can hardly be treated with sprays or mechanical devices, in many instances, with any degree of profit. The best methods to employ against most of the insects affecting the staple crops are what might be termed cultural methods, consisting of some mode of culture or handling the crop which fatally inter- feres with the develoj^ment of a given insect pest. Such treatment is far less simple in many instances, however, than the use of a spray-pumj) or powder-gun. In the latter case the farmer merely waits until he observes a crop being injured and then with a liberal a2:>plication of poison destroys his insect enemies; but in using the former method he must have a more or less accurate knowledge of the life-history of the insect which he wishes to combat. It will also be necessary for him to observe or ascertain the usual dates of the transformations of various insects for his particular locality, as they vary considerablv for different latitudes and altitudes, and to make due allow- 20 GENERAL FAUM METHODS AGAINST INSECT PESTS. 21 auce for any variation of these dates on account of the peculiarities of the individual season. Looking Ahead. — Few farmers, in planning the manage- ment of their land and crops for the coming season, con- sider the effect which any given procedure will have upon the injurious insects with which they may have to contend. A field which has for several years been in wheat, corn, or tobacco may be sown with some other crop for the sake of soil improvement, or may even be favored with a green- manuring of rye, crimson clover, or cow-peas; but how often is it considered necessary to rotate crops in order to lessen insect pests ? In most cases the answer would doubtless be, " Not until some noticeable loss has been suffered from their injuries." That this is a mistake may be seen from a brief survey of the best methods for com- bating our worst insect pests. For this purpose let us take the list of sixty-three insects given in the Year Book of the United States Department of Agriculture for 1898 as a basis, it being carefully com- piled by experienced entomologists. But in passing, though foreign to our theme, it may be interesting to note that of these sixty-three insects twenty- seven have been imported from foreign climes, thirty-one are native, and four are of doubtful origin, so that we can correctly say that fully one-half of our worst insect 23ests are imported. Among those native to the United States are the Chinch-bug, Corn Root-worm, Cutworms, Locusts, and Colorado Potato- beetle: while among those imported are the Angumois Grain-moth, Gypsy Moth, Codling- moth, Cotton- worm, Sugar-cane Borer, Grain Weevils, Hessian Fly, and San Jose Scale. Of these sixty-three pests eight infest stored grains and 22 INSECTS INJURIOUS TO STAPLE CROPS. liouseliold goods, and may be exterminated by the fumes of carbon bisulfide; and five are insects affecting cattle, and are combated with various washes. Thus only fifty are really to be considered insects of the farm crops. Of these, three are controlled by '- ditching," three by mechanical means or devices, and for two of them hydrocyanic acid gas is sure death, while a spray of whale- oil soap is advisable for two others, a spray of kerosene emulsion for six, and of Paris green or London purple for fifteen, these sprays, etc. , being used largely for orchard pests, which comprise eighteen of the fifty. But for the control of many of the insect pests affecting the staple crops, and which are, therefore, of the greatest economic importance, we have so far been unable to devise anything better than a judicious manipulation of purely natural agents, and for the control of twenty-three of the fifty farm insects listed, or nearly one-half, and 75 per cent of those outside the orchard, such methods must be mainly relied upon. Clean Farming. After a crop has been harvested, there is usually some portion of it which is allowed to remain on the land. In this refuse the insects peculiar to the crop often go on multiplying until winter, and greater damage to the crop in the following year is therefore probable. Thus the Wheat Joint-worm and the Corn Stalk-borer both winter in the stubble of those crops, the Potato Stalk-borer remains for some time in the vines, and numerous other cases might be cited. It is therefore of importance in our war- fare against insect pests that the remains of a crop, stubble, vines, leaves, or stumps, as it may be, should be GENERAL FARM METHODS AGAINST INSECT PESTS. 23 removed from the field as soon after it is harvested as possible. Such material allowed to remain in the field also furnishes the adult insects an excellent place in which to hibernate over winter. Much can be done to rid a field of insects by cleaning it so thoroughly as to deprive them of shelter during the winter, during which time they hibernate under all sorts of rubbish, grass, and weeds, in fence-rails, loose bark of trees, etc. This fact may also often be utilized by first carefully cleaning a field and then leaving one or two piles of rubbish in which various insects will assemble during the winter, when they can be easily caught by burning the whole. Such a trap will be more effectual in catching the insects affecting truck crops than those of the staple crops. Weeds. But even when all the piles of litter and rubbish have been carefully cleared up many of our native insects will merely leave them for some common Aveed upon which they will feed and breed during the season, and, if it should be earlier than the cultivated crop, will continue upon it the following spring until the cultivated croj^ is to be secured for food. '• Volunteer '' plants should be included with weeds in this connection, as they frequently serve the same purpose. Thus the Cotton Boll-weevil feeds upon volunteer cotton during the spring, and the Hessian Fly on the volunteer wheat during late summer, while the Corn Root-louse lives on the roots of the smart-weed until corn is out of the ground. Then, too, many in- jurious insects feed in the larval or adult stage upon some common weed, while in the other stage they are injurious to a cultivated crop. The flea-beetles thus feed upon the 24 INSECTS INJURIOUS TO STAPLE CKOl'S. roots of Solonaceous weeds during the larval stage, and attack all sorts of garden and truck crops as adults; one of the Corn Bill-bugs lives in the roots of a wild grass as a larva, but is injurious to corn as a beetle. The weeder can, therefore, be occasionally used as an insecticide as effectually as the spray-jmmp. Burning. To start a prairie fire in order to destroy all the insect life of the plain might prove to be poor policy, but the careful use of the torch has a distinct place upon the farm in controlling its insect foes. The burning over of stubble and grass land will very largely aid in or secure the entire extermination of Army-worms, Chinch-bugs, Locusts, and Wheat Joint- worms. Raking up and burning the vines will be excellent practice against the 8quash-borer, Squash-bug, Potato Stalk-borer, and Hop Plant-louse, while the removal and burning of all wild plum-trees in their vicinity will greatly lessen the damage to hops by the latter pest. Deep Fall Plowing. Deep fall plowing is being increasingly recommended for the reduction of many pests, and will be found to be of advantage for the Corn Stalk-borer, Corn Ear-worm, Cutworms, Locusts, and Wireworms. In both burning and fall plowing the object is to kill that stage in which the insect passes the winter. But this method does not affect all of these insects in the same manner. Some insects will be destroyed by having the cells in which they have gone to pass the winter broken up, and being thrown up to the surface, they will GENERAL FARM METHODS AGAINST INSECT PP:STS. 25 be killed by the weather before they again provide them- selves with winter quarters. Among these are those which hibernate over winter as larvae, and those which pass it in the pupal stage. Among the former may be mentioned the Cutworms and the Corn Stalk=^ or Sugar-cane=borer larvas. Of those passing the winter as pupge, the Corn Ear-worm is a good example. It goes into the pupal stage in the fall, and this method of breaking up the pupal cells is practically the only way of combating it upon corn land. But whereas some insects are destroyed by exposing them on the surface, others may be literally buried alive and thus killed. One of the best instances of the value of fall plowing in this way is in the destruction of grass- hoppers' eggs. If they be turned under to the depth of five or six inches after they are laid in the fall, the young hat(5hing from them in the spring will be utterly unable to regain the surface and will thus be smothered to death. Other insects which pass the winter in the pupal stage, but wiiose pup^e are encased in a tough cell not easily broken open, may also be killed by being turned under in this manner. In fact, even adult insects may be so handled. After the plants are all thrown out of the ground in November the adults of the Mexican Cotton Boll-w^eevil can be readily caught in this w^ay and plowed under so deeply that they can never regain the surface. Young grasshoppers are also destroyed in a similar manner just after they have emerged from the eggs in the spring. It is a homely, common-sense method, but with a correct understanding of their life-histories it may be used to good advantage against many of our most common and injurious insects. 26 INSECTS INJURIOUS TO STAPLK CROPS, Drainage. The Eice-weevil can be largely controlled by proper drainage, and the Corn Bill-bugs are usually injurious only on land adjacent to or recently reclaimed from swamp land, and disappear with the introduction of proper drainage. Fertilizers. In general, land covered with barnyard manure presents more favorable conditions for the development of insects than that fertilized with mineral fertilizers, sometimes furnishing them food and always affording a good shelter for the cold of winter. On the other hand, it is claimed that kainit, lime, and nitrate of soda are often of consider- able value in controlling, driving out, or preventing the attacks of insects. A liberal application of fertilizers in any form will always be of great value in preventing loss from root-feeding insects by enabling the plant to outgrow the injury and mature fruit in spite of it. Poultry. A flock of chickens or turkeys following the plow will pick up a great many White Grubs and Cutworms and can readily be trained to this — for them — rather pleasant task. In many tobacco-growing sections large flocks of turkeys are raised especially for destroying the Tobacco Horn- worm and are slowly driven through the tobacco-fields several times a day. Trap Crops. Doubtless the reason that trap crops are not more in favor v/ith the farmer is because their successful use requires more or less of a knowledge of the life-history and habits of the pest to be caught; yet this is easily acquired by a little observation and reading, and the men who combat these pests successfully are those wiio have such a knowledge of them. Let us consider, then, one or two of the more important cases where this principle may be used to advantage. The Harlequin Cabbage-bug is a southern insect, but it has recently been found in southern Pennsylvania and seems to be gradually working northward. When this insect has succeeded in reaching the cabbage-field it is an exceedingly difficult matter to prevent serious injury by it. If, however, a crop of early kale is planted the previous fall, the bugs which hibernate over winter will attack it in the spring, and may then be killed by spraying them with pure kerosene, and the danger to the cabbage crop be thus largely averted. The Corn Ear-worm, Tomato-worm, Tobacco Bud- worm, or Cotton Boll -worm, as it is variously known in different sections of the country, according to the crop which it most commonly infests, is one which must be treated almost entirely by means of a trap crop of corn. Unfortunately for that plant, however, this method can- not, of course, be of use in protecting the corn-field, where it must be controlled as best it may by breaking up the cells of the hibernating pui^a? by late fall plowing. But as corn is the favorite food of the worms, and the moths will invariably deposit their eggs in its silk, tobacco, cotton, and possibly tomatoes may be largely protected by a proper handling of the corn crop. By planting an early crop of corn, the moths will deposit their eggs in the silk; and before the worms have become full g-rown it 28 INSECTS INJURIOUS TO STAPLK CROPS. should be cut and fed to stock. Another crop shoukl have been 2^ hinted near by, or in alternate rows with the previous one, so as to mature a little later, and it should be handled in the same manner. Even a third will prove to be of considerable value. In this way the worms will be trapped in the corn, and the more valuable crop pro- tected. Sweet corn is the best to use, and a few strips will often be found to be of great value when properly used. Xumerous other instances of the successful ai323lication of this principle might be cited, and several are mentioned under the discussion of individual insects. With a correct knowledge of the habits of a given pest, the ingenious farmer will often find the method one of great value. Time of Planting. The proper time of planting is of imj^ortance in the protection of many crops from insect attacks. Late-sown wheat is usually exempt from the attack of the Hessian Fly. Late-planted corn is much less affected by the Stalk-borer than that planted earlier in the season. Rotation. A very imj^ortant, if not indeed the most important, factor in insect control is the rotation of crops in such a manner that no single crop shall be continuously grown on the same land, or any two crops nearly related botani- cally. Allowing land to remain in meadow for some time forms a breeding-ground for White Grubs, Cutworms, and Wireworms, and if it is then desirable to cultivate the land, it should be planted in potatoes or some such crop unrelated to the grasses. It may then be planted with small grains, and then with corn; for if the number of GENERAL FARM METHODS AGAINST INSECT PESTS. 29 these insects in tlio grass laud be at once concentrated upon the comparatively few corn plants, the in jnry will be much more severe than if the change be a gradual one, with first a crop not of the grass family which would be largely immune from their attacks, and then a small grain. The value of rotation is possibly best illustrated in the case of the Western Corn Koot-worm, which is never injurious to corn after the land has been in a small grain or clover. The Hessian Fly, Wheat Isosoma, Wheat Plant-louse, Wireworms, and many other of our worst pests may be largely controlled by a rapid rotation, and their increase and consequent depredations are very often due almost entirely to a lack of such practice, which is also of the utmost importance in preventing soil depletion. Thus a proper urderstanding of the pests with which he has to deal and a timely consideration and application of these homely methods may be of the greatest value, and indeed often the only available means for the control of the larger part of the insect enemies of the general farmer. CHAPTER IV. BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC. Ladybird-beetles. Aftp:u his strawberries have been ruined by the Straw- berry-weevil, the garden truck by Cutworms, the wheat despoiled by the Hessian Fly, the melon-patch fallen a prey to plant-lice, and the fruit crop has been a failure on account of the Codling-moth, Plum Curculio, and San Jose Scale, it is scarcely surprising that the farmer does as one of my acquaintances did and '^ orders the hands to kill everything that crawls/' But such would be entirely too heroic a measure, and if strictly adhered to the remedy would be as bad as the disease, for it would mean not only useless labor, but the destruction of the most effective means whereby insect pests are held in check. We pride ourselves — and justly — that with our Paris green and kerosene sprays and gas tent most of the crops can be effectually protected; but were it not for those other insects which feed upon these injurious forms, what an enormous and, in some instances, almost futile task it would bs! Among these beneficial insects the little Ladybird- beetles of the family CocciiieUidm are entitled to be in the first rank. Almost all the beetles and larva? feed upon BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC. 31 plant-lice and scale insects. Of such value are those feeding uj^on scale insects that not many years ago a large number of Australian species were imported into California that they might prey upon the San Jose and other scales. One of these was eminently successful and almost com- pletely destroyed the Cottony Cushion-scale. Of those feeding upon plant-lice, one of the most common is the Mne-spotted Ladybird [Coccinella novem- notdta). This beetle is about one-fourth of an inch long, with black head and body. The wing-covers are orange- yellow marked with nine black spots — four on each side and one on the central suture. The larva has been fancied to resemble a miniature alligator; it is nearly twice as long as wide, almost black, marked with bluish and orange spots, and has long legs, which carry it around quite rapidly. The beetles hibernate during the winter and come forth in the spring and lay their eggs wherever the young will be able to find food when they hatch. When the larva has satisfied its ravenous appetite and become full grown it fastens itself to the food-plant — seemingly by its tail, if such a term might be allowed, — transforms to the pupa, and in a week or ten days the adult beetle emerges from the pupal skin. This life- cycle is repeated several times during the summer season, before the fall brood turns into winter quarters. Another very common form among plant-lice on garden truck is the little Adalia hipunctata, or Two-spotted Lady- bird. It is slightly smaller than the preceding, and with only one black spot on each wing-cover (Fig, 11). Several other species in the genus Hippodamia are very useful, and among them the Convergent Ladybird {Hip2)odamia convergens) is one of the best known. Its 32 INSECTS INJURIOUS TO STAPLE CROPS. iRimo is received from two white dashes on tlie black thorax, which converge posteriorly. The thorax has also a white margin, and there are thirteen black dots on its orange wing-covers. These larva3 and l)eetles are very common among the plant-lice on melon-vines, and are an important factor in their extermination. They have also BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 33 been noted for eating the Black Peach Aphis and many other plant-lice. A form which is often very abnndant among lice on corn Fig 12.— 1, the Fifteen- spotted Ladybh d : a, larva eating plant- louse; b, pupa; d, beetle. 2, the Convergent Ladybird {Hippo- damia converg6ns\ larva, pupa, and beetle. 3, the Nine- spotted Ladybird {Coccinella 0-notata). 4, Megilla maculaia. (After Riley.) is Megilla maculata. The head, thorax, and wing-covers are a dark pink, with two black spots on the thorax and ten on the wing-covers. Snch immbers of these little fellows have freqnently been found huddled together un- der the rubbish at the base of some tree in a last year's cornfield that they might be fuVon n-i^ l->Ar fbo bQi-,/i-Pni ^^^- 1^- — The TwicB-stabbed tdken up by the iiandtul Ladybird {ChUocorus Umilne- without difficulty. Many 'rus). a, beetle; b, larva. (After other species leed upon plant-lice, but the above are the most common, and all bear a resemblance to one another, being generally orange or red with black spots, and of a characteristic round or 34 INSECTS INJURIOUS TO STAPLE CROPS. oval form, flattened below, so that the legs may be drawn in under the wing-covers. Those Ladybirds which feed upon scales are much smaller and black, though sometimes spotted with red or orange. As far as known, there is no way in which these useful allies may be encouraged or increased in numbers, but it is trusted that the above may give such a brief view of their habits that fewer may be killed through ignorance concerning their true worth. Syrphus-flies. Besides the little beetles described above there is a family of flies, the SyrphidcB, many of whose laiva3 feed upon plant-lice. This family is a very large one, and thus the luibits of its different members vary considerably. One of them so closely resembles a honey-bee as to be almost indistinguishable from it. The larva of this fly [Eristalis tenax) is one of the common Rat-tailed Maggots which is found in putrid nuitter. It is thought that the old '' bugonia '' superstition of the ancients that bees came from maggots in dead animals, etc., was due to the con- fusion of this fly with the honey-bee. In another group of the family, the adult flies of which also quite closely resemble bees, the larvee are parasitic in the nests of honey- and bumble-bees, feeding upon their larvae. But the larv^ of possibly the most typical portion of the family, embracing the genus Sifvplius and its near allies, are entirely predaceous upon plant-lice. Rarely can a colony of plant-lice be found without some of these little enemies hard after them. BENEFICIAL INSECTS, PKEDACKOUS AND PAKASITIC. 35 The acUilt syrplics-fly is a very striking insect, with its dark green metallic thorax, and abdomen variously banded with yellow and black. The female fly lays her eggs upon some plant bearing plant lice. The 1 a r v ge which hatch from these are elongate, flattened mag- /^ " - ^^ gots,about one half an incli long, with hardly a trace Fig of a head, but with four small hooks, which serve as jaws, projecting from the more pointed end of the body. These maggots are often of a light green color, and so like the color of the plants as to render them most difficult to be recognized. The young larv« at once commence crawling over the plant in search of the ajohids, and as soon as ihey come in contact with one it is firmly clasped by the small booklets until the juices are sucked from its body. In this manner very 14. — Byvplius ribesii. (Au- thor's illustration. ) Fig. 15. — The Hoot -louse Syrphus-fly {Pipiza radicans). got; h, puparium; c, fly. (After Riley.) a, mag- large numbers are destroyed, a single maggot of the American Syrphus-fly (Syrplnis americanus) having been observed to eat twenty-five Apple Plant-lice {Aj^Jiis mali) 36 INSECTS INJURIOUS TO STAPLE CROPS. in as many minutes. When the larva is ready to pupate it attaches itself to a leaf, and the larval skin dries up and forms a case or puparium inside of which the pupa remains until it transforms to the adult fly. Though most of these larva? feed upon plant-lice upon the leaves, one of them, the Koot - louse Syrphus - fly {Pipiza radicans), lives entirely underground during that stage, aud feeds upon the root-lice of the apple and the grape. None of tliis family are injurious, and as a large portion of them are so beneficial as to frequently destroy whole broods of plant-lice, they should not be disturbed in their good work if possible to avoid it. The Ground-beetles. If, as you scrape away the loose chips at the base of a tree in your door-yard, turn over an old log in the wood- land, or pick up a fallen fence-rail, you will scrutinize the inhabitants under these shelters, a number of shining black beetles varying in length from one-fourth to one and one-half inches will usually be noticed. If the city reader be not so fortunate as to be familiar with or have access to these hiding-places, he may find large numbers of the beetles under any electric arc light during the warm summer evenings; for there they are having a sumptuous banquet upon the small flies and moths attracted by the glare. They are rarely seen at large during the day, as they are almost exclusively nocturnal insects, and from their habit of remaining almost entirely in or on the ground they are usually known as ''Ground-beetles." As might therefore be inferred, they are exceedingly valuable to the farmer by destroying large numbers of noxious insects which pass a part or all of their existence BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC. 37 in the soil. Besides tlie gloss}^ black forms which are most commonly seen, man}^ are brilliantly marked with gold, green, purple, and iridescent tints. The Fiery Ground-beetle (Calosoma calidun)), so called on account of the wing-covers being dotted with bright gold, has many times been of great assistance in helping to rid. a corn-field of Cutworms. The larv^ of this insect Fig. 16.— The Fiery Ground- beetle {Calosoma calidum). a, beetle; h, larva. (After Riley.) Fig. 17. -''The Searcher" {Ca- losoma scrutator). (After Ri- ley.) are about one inch in length, of a dark brown color, with the skin of a hard, horny texture like that of the beetle. They have strong, prominent jaws, and at the j^osterior end of the body is a forked aj^pendage looking much like another pair of jaws. It is not only surprising that these larvae will eat so large a number of cutworms, as they have frequently been known to do, but also that they will dare to attack such a formidable creature fully three or four times as large as themselves. But their assault is sharp and vigorous, and a single larva has often been seen 38 INSECTS INJURIOUS TO STAPLE CHOPS. to kill and eat in a short time several full-grown cntworms. Many instances of the good work of this beetle are on record, among which one by the late Prof. J. A. Lintner might be cited, where he found them eating large numbers of the Corn-crambus — sometimes locally known as the Corn Bud-worm, Another somewhat larger beetle, called by Prof. J. H. Comstock '' the Searcher" [Ccdosoma scrtt- t(itor), and in fact one of the largest of the family, is a brilliant metallic green, bordered with a dark purplish blue, and has the good quality of having a very particular appetite, causing it to kill large numbers of caterpillars, but eating only part of each, While in the earth as pup^ large numbers of the Colo- rado Potato-beetles are destroyed by members of this family, and one species, Lehia grandis, which is peculiar Fig. is.— Lehia grandis. Riley.) lAftcr Fk;. 19.— The Murky Grcnmd ])eetle [ILirpalus cuUginosiu, . (xifter Riley.) in that the wing-covers are somewl:iat abbreviated, thus leaving the tip of the abdomen exposed, has been noticed on the plants eating the eggs and young larvae of this old potato pest. Another valuable species is one called l)y Dr. Riley the BENEFICIAL INSECTS, PllEDACEOUS AND PARASITIC. 39 Murky Ground-beetle (Ilarpalus caligiiiosvs). Its larva is of considerable assistance to fruit-growers by eating large numbers of Curculio larvge, which it secures from the plums after they have fallen to the earth. From a glance Fig. 20.—^, larva of Murky Ground-beetle; B head of same; G , mandible. at its formidable jaws, Fig. 20, l-c, it is easy to conjec- ture the fate of many a curculio grub. Thus here again are found some " bugs ^' that are friends and not foes, worthy of all the protection that can be afforded them, and well repaying such carefal observation of their habits as may be bestowed upon them. Insect Parasites. Though large numbers of injurious insects are annually destroyed by those which are purely predaceous upon them, many more succumb to those minute forms which live parasitically within them. A few of these parasites belong to the order Dipfera, or true flies, but most of them are classed in the order Hymenoptera, in which order are also included the saw-flies, ants, wasps, and bees. Of the half-dozen families of hymenopterous j)arasites one of the largest and most beneficifil is that of the Ichneumon-flies. The illustrations will best shoAv the form and structure of these insects, which the casual 40 INSECTS INJURTOUS TO STAPLE CROPS. observer will Imrclly be able to dibtinguisli from other fiimilies of the group. But it will be noticed that the fine veins of the wings vary considerably in the difPerent para- sites figured, and it is by these that the entomologist is enabled to separate the different groups and often to identify the species at a glance. Both this and the fol- lowing family are peculiar in having an exceedingly long Fin. 21. — A Plant-louse Parasite {Aphidius granariapJiis), showing above the parasitized louse from which it has issued. (Copied from J. B. Smith ) ovipositor or egg-tube, of which it will be seen that they make a very good use. It is with this extensile tube that the female deftly punctures the skin of some unsuspecting caterpillar, and under it inserts her eggs. In a few days there hatch from these a host of young grubs, which feed upon the juices and tissues of the caterpillar, but are seemingly careful to avoid injuring any of its vital organs, for as soon as the caterpillar readies its full growth it r.ENEFICTAL INSECTS, PREDATEOUS AND PARASITIC. 41 changes to a pupa, apparently unaffected. But now the maggots have reached their full size, and each spins wp a small silken cocoon inside the pupa, entirely filling np its now dead shell, and instead of a beautiful moth ai3pearing in the spring, from a round hole in the side of the pupa, or cocoon, a horde of small flies are seen to emerge. Thus large numbers of such pests as the Apple-tree Tent-caterpillar {CUsiocampa americana), Bag-worms Fig. 22. — Maggots of rimpht utquisitor, a parasitic Icbnenmon- fly, feeding on a caterpillar wliich had spun its cocoon and was ready to pupate. (Original.) [Tltyridopteryx epliemercefoiDiis), caterpillars of the swal- low-tailed butterflies which feed upon parsley, carrots, etc., and a host of others, are consumed by members of this family. Those belonging to the genus Opliion are partial to the large American silkworms which produce some of our largest and most beautiful moths, and difficulty is fre- quently experienced in rearing a desired number of moths on account of the large per cent of cocoons parasitized. The species of the family Braconidce are very similar to those of the preceding one, and contain some equaHy 42 INSECTS INJrilTOrS TO STAPLE riJOPS. beneficial insects, feeding ;is they do 14)011 i'wvh pests as the Codling-motli, Web-worms, riiini-eiirciilio grub, Thmt- lice, etc. Some of the more common forms of this family belong to the genus Micrcgasto', and their small white cocoons may frequently be seen almost covering one of our large tomato- or tobacco-worms (see page 237), the Fig. 23. — The Long-tailed 0\i\\ioii [Opliion mnerxirum). «, adult; h, maggot. (After Riley.) pupae of which are often known as *' horn-blowers." Many mistake these cocoons for the eggs of the worms, and there- fore destroy some of their best friends. Though some thus spin their cocoons on the outside of the host, others remain inside of the parasitized insect until the adult fly emerges. Thus dead plant-lice may often be found with a large round hole in the abdomen — the only evidence of I3ENKF1CIAL INSECTS, PUEDACEOUS AM) PARASITIC. 43 where one of these j^arasites has emerged. For this reason as a general rule dry, shrunken plant-lice should never be destroyed. The Chalcis-flies, which comprise another closely re- lated family, are exceedingly minnte insects, sometimes not over one one-hnndredth of an inch long. They are generally of a metallic black color, and the usual veins of the wings are almost entirely absent. Many of these flies are parasitic upon plant-lice, while a large number of their larvae live and mature in the eggs of other insects. Very similar to the Chalcis-flies in their habits of infest- ing plant-lice and insect eggs are some even smaller insects — in fact the smallest known, the largest being rarely over one twenty-fifth and the smallest only six or seven one- thousandths of an inch in length — with a corresjoondingly tremendous and unpronounceable name, known to science as the Proctotryjjidce. But enough has been said to indicate the important part which the immense hordes of these apparently insignificant insects play in the economy of Nature, by often clearing off a most dreaded insect pest in a few days almost as if by miracle. CHAPTER V. mSECTS INJURIOUS TO THE GRAINS AND GRASSES. Under the above head several common insects which are injurions to almost all of the grains and grasses may be conveniently gronped, thus distinguishing them from those which affect a few or an individual species. White Grubs {Lachnosterna spp.). Of all the insects attacking cereal crops none are better known than the so-called ''white grubs/^ I say " so-called," for the Englishman has styled this larva the "cockchafer grub," the Frenchman calls it " ver blanc," and the German has named it the "engerling," while here in America the adult beetles are known both as May- beetles, June-bugs, and dor-bugs, and when flying in the windows and buzzing around the ceilings are often termed " pinching-bugs." In Euro2:>e white grubs have long been recognized as one of the agriculturist's worst insect foes, and their depredations were noted in this country as early as the middle of the seventeenth century. Life-history. — As for most of our grain insects, grass land is their favorite haunt, and the female beetle usually lays her eggs in old meadows, though not infrequently in corn land. The eggs, which are glossy white, about one 44 INSECTS INJUinOUS TO THE GRAINS AND GRASSES. 45 eighth of an inch long, and broadly oval, are laid early in June and hatch in from 11 to 13 days. The grubs hatch- ing from these feed upon the plant-roots, growing but slowly, as they require a bout two years to become full- grown. Meanwhile, however, each grub does its full share of damage, especially to corn and grass, and often to the smaller grains. Its attacks have also long been feared by the growers of strawberries, potatoes, and garden truck. 46 INSECTS INJURIOUS TO STAPLE CROPS. as well as by nurserymen and greenhouse florists. The grub becomes full-grown in the summer of the second year after hatching from the egg. It then forms a small oval cell from three to ten inches below the surface of the soil, and here changes to the pupa. The pupal stage lasts slightly over three weeks. Late in August or early in September another transforma- tion takes place and the adult beetle wriggles out of the pupal skin, but remains m the earthen cell until the fol- lowing spring, when it comes forth fully hardened m May or June. The beetles at once pair, and the females deposit their eggs and soon die. Thus three full years are consumed in the complete life-cycle of each brood. Injury. — Ha\'ing seemingly formed a dislike to the light of day from their long subterranean existence, the adult beetles feed and pair entirely at night. The foliage of almost all of the common forest- and shade- and occa- sionally fruit-trees suffers from their attacks. Injury to maple-trees has been specially observed. About 9 p.m. of an evening early in June, thirty-five beetles were once taken by the writer from a small silver-maple tree about eight feet in height, and they were equally numerous on all of a long row of these trees. But the grubs and beetles are too common to need description and may be recognized from the figures. It may not, however, be known that the term ^^ white grubs ^' is generally applied to the larva? of many distinct species of the genus Lachnosterna and one of Cijclocephala, which so far as known have practically the same habits, except that the larva? of the latter genus remain over winter as dormant larva? and pupate in May. By cutting off the ta])-root and feeding roots of corn, INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 47 white grubs have often been responsible for the total or partial failure of large areas of corn land. In 1895 the grubs so injured one twenty -year-old meadow of 250 acres in Illinois that the sod could be rolled up like a carpet over the entire field. Bemedies. — Unfortunately, as regards remedies for this pest little is known. Though eaten by various birds and parasitized by a half-dozen or so insects, yet these natural enemies seem to^e of little value for holding the grubs in check. Leaving land in meadow for several years is undoubtedly conducive to their rapid increase; and hence a short rotation in which clover follows grass and which is in turn followed by the small grains before corn will very largely prevent serious damage to the latter crop. Poisoned bran mash such as used for cutworms (see page 217) is reported as having been used successfully against the grubs by scattering it over infested land. If turned loose in infested grass land, swine will fairly gorge themselves on the grubs, and, prior to plowing grass land for corn, this will be found to be one of the best means for ridding it of grubs. The hogs will also feed as freely upon the beetles which drop to the ground from the trees and hide during the day, and hence they may be of considerable benelit in woodland adjoining infested fields. A flock of chickens or turkeys following the plow or culti- vator will also be found to consume not a few of the grubs. In Europe the beetles are systematically jarred from the trees in the early morning by organized bands composed mostly of women and boys, in much the same manner as we '* jar" for the Plum-curculio. But such methods, as well as spraying seem hardly practicable in our larger (Country, except possibly for young orchard -trees, which are often 48 INSECTS INJURIOUS TO STAPLE CROPS. seriously defoluited. As the booties renuiin in the pupal cells over winter and are still tender, not fully hardened, deep fall plowing will destroy a large number of them by breaking open the pupal cells and exposing them to the weather, and by burying or crushing them. But possibly the best method of preventing serious injury by white grubs, and one which will not only be of benefit in securing immunity from the attacks of this as v\^ell as many other insect pests, but will also cause less drain upon the soil, is a judicious rotation of crops, avoiding a continual growth of grass in any one field. Wireworms {Elaferidm). Injury. — The soil has been properly prepared and the field carefully planted. Day after day the anxious farmer awaits the sprouting of the young shoots of grain. But all in vain ! Still no signs of growth appear. So, appre- hensive that he lose the use of the land, he removes the earth from some of the seed and there finds the kernels of corn or wheat either with a small round hole drilled through them or some ''hard, smooth, shining, reddish or yellowish-brown, slender, cylindrical, six-legged larvae " still devouring the seeds, with their heads firmly embedded in them. If he be a man of any experience, he at once recognizes the work of wireworms and wastes no time in reseeding his field, for of all the insects attacking grain in the seed, these are the most common and destructive. If later on the resown seed secures a start, its growth is exceedingly liable to be stunted by the worms attacking the smaller roots, and it may even ])e killed when several inches high by their boring through the underground INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 49 stalk. All the grains are attacked by wireworms, Dat wheat and corn suffer most, as well as potatoes, turnips, and many garden croj^s. 7)e5cr/);//:oy^— Wireworms, which are the young of a number of beetles, which, from their habit of snapping Fig. 25. The Corn Wireworm {Melanotus The AYireworm of Drasterius ele- crihulosus), enlarged 4^ diam- gn7is, enlarged seven diam- eters. (After Forbes.) eters. (After Forbes.) their bodies up in the air, are known as "click-beetles,'' are all more or less like Fig. 25 in general appearance. Althouofh th e common wirewoi 'ms are usually supposed to be of but one kind, upon examination several species will 50 INSEC^rS IXJUKIOUS TO STAPLIi CUOl'S. often be found which may be distinguished by a compari- son of the caudal segment with the illustrations (Figs. 27 and 28). The adult beetles are mostly about one-half to three-fourths of an inch long, decidedly flattened, of a dark brown coJor, with short heads and shield-shaped thoraxes, as in Fig. 26. LIfe-hisfory. — Land which has been in grass for several years is their native breeding-ground, and here the eggs Fig. 26.— J., Beetle of Wheat Wire worm; B, Bmsterius elegans, both enlarged about 4 diameters. (After Forbes.) are deposited. Much concerning the life-histories of these important pests is still unknown, but it seems safe to assert that the larva3 require from three to five years to become full-grown. Thus the second year after grass land has ])een planted in grain is that in which the worst injury occurs, and this is especially true with corn, which covers the ground less completely than do the smaller grains, The larvae become full-grown iu midsummer, form a small earthen cell, and there transform to the pupa3. Three or four weeks later the jidiilt l)eet]es shed the })U})al skin, l)ut only a few of them make their w^ay to the surface during INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 51 the fall, the most of the brood remaining in the pupal cells as partially hardened beetles until the following sj^ring. Means of Coin'b((t'nig. — Remedies galore have been advised for these insects, almost every farmer having his Fig. 27. — A, last segment of Melnnotus communis, dorsal view. (After Forbes.) B, the Wheat AVireworra. Agriotes munrm. a, b, r, d, details of mouth-parts, enlarge>l. (After Slinger- land.) favorite expedient, but in recent years a careful testing has shown that a satisfactory remedy or preventive for wire- worms is vet to be discovered. Professors Comstock and Fig. 28. — G, caudal segment of the Wireworm of Drasterius elegam D, caudal segment of the Wireworm of AsapJies decolovatm much enlarged. (After Forbes.) Slingerland performed extensive experiments for nearly three years in attempting to successfully combat these insects by (1) the prote(;tion of the seed, and (2) the destruction of the larvae by (r^) starvation in clear fallow 53 INSECTS INJURIOUS TO STAPLE CROPS. and supposedly immune crops, and {b) ])y the use of in- secticides and fertilizers. But all the remedies or pre- ventives tested resulted in failure, and this has been the experience of several other leading entomologists. It was ascertained, however, that they may be more or less checked by destroying the beetles. This can be done both by fall plowing or by trapping. By plowing late in sum- mer and keeping the earth stirred for a period of a month or so, large numbers of the newly transformed beetles which do not become fully hardened until spring, and pupae, will be destroyed. When the wireworms are numerous in re- stricted areas, as they often are on spots of low moist land, they may be effectually trapped with but little labor by placing under boards bunches of clover, or sweetened corn meal poisoned with Paris green. A short rotation of crops, in which land is never allowed to remain in grass for any length of time, will undoubtedly secure comparative immunity from serious attack. The Chinch-bug {BUssus leucopterns Say).* Though individually insignificant, when assembled in countless myriads Chinch-bugs have doubtless been of greater injury to the farmers of the Mississippi Valley than any other insect attacking grain crops, and are responsible for hundreds of millions of dollars' loss. Distrihntion. — This insect may be found over all the eastern United States to the Rockies, and in restricted *See "The Chinch-bug," F. M. Webster, Bulletin 15, n. s., Div. Eut., U. S. Dept. Ag. ; Dr. S. A. Forbes, 12th, 16th, and 20th Repts. St. Ent. Illinois. INSECTS INJURIOUS TO THP: GRAINS AND GRASSES. 53 localities in Cuba, Central America, Panama, Lower and Central California; but the area in which it has been most injnrions lies in the Central and North Central States. Daring the last fire years, however, its attacks have been increasingly wide-spread in Ohio and Kentnck}^ and in August, 1898, some damage was done by it in Pennsyl- vania and New York. De.^crijjticm. — The adult bug is about one-fifth of an inch long, with a black body. Its wdiite wings lie folded over Fig. 29.— The Adult Fig. 30.— a, h, eggs magnified and natural GhinQh-hngiBlissus size; c, young nymph; e, second stage of leui-opterus Say) nymph; /, third stage; g^ full-grown enlarged. (After nymph or pupa; d, h, j, legs; //beak Riley.) through which the bug sucks its food. (After Riley.) each other on the back of the abdomen, and are marked by a small black triangle on their outer margins, while the bases of the antennae, or feelers, and the legs are red. The young bugs are mostly red, but vary in the different stages. Life-liistory. — During the winter the bugs hibernate in clumps of grass and under boards and rubbish. With the first warm days of spring they come forth and spread about the neighboring wheat-fields, but there do little harm. V^ery soon they pair, and the females, each of which is 54 INSKOTS INJURIOUS TO STAPLE (JKOPS, Fm. 81.— Corn-plant two feet tall infested with Chincli biio-s. (After Webster, Bull. 15, n. s., Div. Ent., U. S. Dept. Agr.) INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 55 capable of laying 150 eggs, commence to deposit tliem either upon the roots or bases of the stalks. This occurs from the middle of April until the first of June, depend- ing upon the latitude and weather, and the eggs hatch in from two to three weeks. The nymphs often severely injure the small grains, and are full-grown about the time of harvest. As the wheat is harvested they spread to oats and soon to corn, but, curiously enough, though the adults have wings they prefer to travel from field to field on foot, much like Army-worms, and were it not for this fact we would be at a loss how to cope with them. Another lot of eggs are now laid under the unfolding leaves of the corn, and the young nymphs emerge in about ten days. This brood lives upon corn, and when full-grown is that which hibernates over winter. South of the latitude of southern Illinois there is often an unimportant third brood. The most extensive injury is done by the mature nymphs and adult bugs of the first brood. Though no means is known for preventing the ravages of this brood in the small grains, every effort should be made to defend the young corn from its attacks, for, with the innumer- able little beaks of the adult insects sucking out its life, it soon succumbs when they are reinforced by the largely multiplied numbers of the second brood. Methods of Prevention and Destruction. — During the migration from the small grains to corn seems to be prac- tically the only time when this pest may be successfully combated. Just before harvest a narrow strip should be plowed around the corn-field and this thoroughly pulver- ized by harrowing and rolling, and then reduced to as fine a dust as possible by dragging over it a brush composed of dead limbs, or whatever contrivance is most convenient. 56 INSECTS INJURIOUS TO STAPLE CROPS. A log or block should now be dragged through this strip in such a manner as to form a deep furrow, with tlie incli- nation of its side next the corn as steep as possible. In attempting to climb this barrier, the dust will slide from under the bugs and large numbers of them will accumulate in the furrow, where, on a clear day, they will soon be killed by the heat if the temperature of the air be over 88 degrees Fahrenheit (the soil wiJl then be 110 degrees Fahr.). The furrow may be kept clean by redragging the log through it as often as necessary. If the weather be cooler, the bugs should be further trapjDed by sinking holes with a post-hole digger about one foot deep every ten or twelve feet in the furrow. Large quantities will soon accumulate in the holes, and may be there crushed or killed with coal-tar or kerosene. Of course a sudden dash of rain will destroy such a furrow, and the bugs will then at once march on to the corn-field. In such an emergency a narrow strip of coal- tar, about the size of one's finger, should be run around the field a few feet inside the former furrow, with post- holes dug as before upon the outside of the line. Dislik- ing the smell of the tar, the bugs will again fall into the trajjs and may then be destroyed. As many stri2:)s may be made along the outer rows of corn as seem necessary to prevent their further progress. These strips of tar should be freshened whenever dust, straw, or rubbish has crossed them at any point. In this manner one Illinois farmer protected over 300 rods with less than a barrel of tar. That this method is practicable and efficient was thoroughly demonstrated by Prof. W. Gr. Johnson in a series of experiments in Illinois, in the report of whose work Prof. Forbes says: ''In short, the success of this INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 57 field experiment, tried under very difficult conditions, was substantially complete, and the value of this method of contest with the Chinch-bug seems established beyond controversy." Extensive experiments have been made in Illinois and Kansas in the use of the Muscardine fungus — Sporotrichiwi gloluliferum, — against the Chinch-bug. Though the re- sults have often seemed to indicate its use to be profit- able, yet it has never so commended itself — even to ento- mologists — as of sufficient value to be brought into general use, and its value must still be considered as largely problematical. If the bugs have already become numerous in the outer rows of corn, most of them may be destroyed by a spray of kerosene, which, with a tar strip, will effectually pro- tect the remainder of the field. Such a spray may be either (1) in the form of an emulsion, composed of a ^' stock solution" of one pound of soap, one gallon of water, and two gallons of kerosene, prepared in the usual manner, and diluted with fifteen quarts of water; or (2) may be merely a mechanical mixture of about one part kerosene to four parts of water (20 per cent), which can be formed only by pumps with a special kerosene attachment, and which are now very largely doing away with the use of the soap emulsion. About a teacupful of this spray to a hill will be ample, and at this rate an acre will require about 60 gallons at a cost of about one dollar. In case of serious attack by the Chinch-bug the farmer must at once prepare to devote to combating it the time of as many hands as his interests may require; for the above methods require constant and personal supervision, but, where carefully tested by practical farmers, have been 58 INSECTS INJURIOUS TO STAPLE CROPS. found to be the best and only means of preventing the loss of their crops. Locusts {Acrid idee). Plagues of destructive locusts — or what the American farmer terms grasshoppers — have been recorded since the dawn of history. In Anicrica the worst devastation has been done by flights of the Rocky Mountain or Migratory Locust (Mekt)Wpli(-s spretns Thos.), which swooped down upon the States of the western part of the Mississippi Valley in the years 1873-70 like a veritable horde of mountain robbers. Since then they have several times done considerable injury in restricted localities, but never in such numbers or so generally as to cause apprehension of another ^'grasshopper plague.^' Concerning their recent distribution, numbers, and destructiveness, Mr. W. D. Hunter reported after the season of 1897 : " There was, this season, a general activity of this species throughout the permanent breeding region greater than at any time in many years. This was brought about by a series of dry years, which have resulted in the abandonment of farms in many places. It is, of course, well understood that the absence of serious damage since 187G has been partially due to the settling u}) of valleys in the permanent region. I wish to make it clear, how- ever, that the dryness is the primary and the abandoning a secondary cause. ^' The Rocky Mountain Locust. Let us first consider this the most injurious species, as the other locusts differ from it in but few essential points other than in being non-migratory. INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 59 To correctly nnclerstancl its habits the reader should first divide the area which this species affects into three parts. Of these the (1) '' Permaneut Region, including the highlands of Montana, Wyoming, and Colorado, forms the native breeding-grounds, where the species is always Fig. 32. — Rocky Mountain Locust. found in greater or less abundance/^ * (2) The Sub- permanent Region, including Manitoba, the Dakotas, and western Kansas, is frequently invaded. Here the species may perpetuate itself for several years, but disapj^ears from it in time. (3) The Temporary Region, including the States bordering the Mississippi River on the west, is that only periodically visited and from which the species generally disappears within a year. Spread. — When for various reasons the locusts become excessively abundant in the Permanent Region they spread to the Subpermanent Region, and from there migrate to the Temporary feeding-grounds. It is the latter area which suffers most severely from their attacks, but, for- tunately, they generally do not do serious injury the next year after a general migration. In the Subpermanent Region their injuries are more frequent than in the Tem- porary, but hardly as severe or sudden as farther east. Immigrating from their native haunts, flights of the grass- hoppers usually reach southern Dakota in early summer, Colorado, I^ebraska, Minnesota, Iowa, and western Kansas *Bull. 25, U. S. Dept. Ag., Div. Entomology. C. V. Riley. GO INSECTS INJURIOUS TO STAPLIC CROPS. daring midsummer, and southeastern Kansas and Missouri during late summer, appearing at Dallas, Texas, in 1874, Fig. 33. — Rocky Mountain Locust. Different stages of growth of young, about the middle of October, and even later in 1876. As thus indicated, the flights are in a general south to south- FiG. 34.— Rocky Mountain Locusts, a, a, a, females indifferent positions, ovipositing; b, egg-pod extracted from ground, with end broken open; c, a few eggs lying loose on ground; d, e, show the earth partially removed, to illustrate an egg- mass already in place and one being placed ; / shows where such an egg-mass has been covered up. (After Riley.) easterly direction, while west of the Rockies they descend to the more fertile valleys and plains, but without any such regularity as east. While the rate of these flights is INSECTS INJURIOUS TO THE GRAINS AND GRASSES. CI variable and entirely dependent upon local weather condi- tions, twenty miles a day may be considered a fair average. The flights are more rapid and more distance is covered in the early part of the season, when, while crossing the dry prairies, a good wind will often enable them to cover 200 to 300 miles in a day. As they first commence to alight in their new feeding-grounds their stay is limited to but two or three days, but later in the season it is considerably lengthened, and, after being once visited, in an infested country swarms will be seen to be constantly rising and dropping during the middle of the day. Life-lmtory. — Over all the infested area, and while still sweeping it bare of crops and vegetation, the females com- mence to lay their eggs, and continue to deposit them from the middle of August until frost. For this purpose '' bare sandy places, especially on high, dry ground, which is tolerably compact and not loose,'' are preferred. " Meadows and pastures where the grass is closely grazed are much used, while moist or wet ground is generally avoided.'' In such places the female deposits her eggs in masses of about thirty. These are placed about an inch below the surface in a pod-like cavity, which is lined, and the eggs covered by a mucous fluid excreted during oviposition. From two to five hours are required for this operation, and an average of three of these masses is deposited during a period of from six to eight weeks. As the time of ovipositing varies with the latitude, so the hatching of the eggs occurs from the middle or last of March in Texas till the middle of May or first of June in Minnesota and Manitoba. Until after the molt of the first skin, and often till after the second or third molt, the young nymphs are content to feed in the immediate 02 INSECTS INJURIOUS TO STAPLE CROPS. vicinity of their birth. But upon such food becoming scarce they congregate together and in solid bodies, some- times as much as a mile wide, march across the country, devonring every green crop and weed as they go. During cold or damp weather and at night they collect under rubbish, in stools of grass, etc., and at such times almost ['eem to have disappeared; but a few hours of sunshine brings them forth, as voracious as ever. When, on account of the immense numbers assembled together, it becomes impossible for all to obtain green food, the unfortunate ones first clean out the underbrush and then feed upon the dead leaves and bark of timber lands, and have often been known to gnaw fences and frame buildings. Stories of their incredible appetites are legion ; a friend informs me that he still possesses a rawhide whip which they had quite noticeably gnawed in a single night! By mathematical computation it has been shown that such a swarm could not reacli a point over thirty miles from its birthplace, and as a matter of fact they have never been known to joroceed over ten miles. As the nymphs become full-grown they are increasingly subject to the attacks of predaceous birds and insects, insect parasites, fungous and bacterial diseases, as well as being largely reduced by the cannibalistic appetites of their own numbers. When the mature nymphs transform to adult grasshoppers and thus become winged, large swarms are seen rising from the fields and flying toward their native home in the Northwest. This usually takes place during June and early July in the North, and as early as April in Texas, so that it is frequently impossible to distinguish the broods of the temporary region from the incoming brood which has migrated from the perma- INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 63 neiit region. Although the eggs for a second brood are sometimes laid, these seldom come to maturity, and the species is essentially single-brooded. Enemies. — As before mentioned, large numbers of the nymphs are destroyed before reaching maturity by their natural enemies. Among these a minute fungus un- doubtedly kills many of those already somewhat exhausted, especially during damp weather. Almost all of our com- FiG. 35. — Anthomyia, egg-parasite, a, fly; h, puparium; c, larva; d, bead of larva. (After Riley.) mon birds, as well as many of the smaller mammals, are known to feed quite largely upon them. A small red mite [Tromhidium locustarum Riley), some- what resembling the common Red Spider infesting green- houses, is often of great value not only in killing the nymphs by great numbers of them sucking out the life- juices of the young hopper, but also in greedily feeding upon the eggs. The maggots of several species of Tachina-flies are of considerable value in ^parasitizing both nymphs and adult locusts. Their eggs are laid on the neck of a locust, and. 64 INSECTS INJUltlOUS TO STAPLE CROPS. upon hatching, the maggots pierce the skin and live inside by absorbing its juices and tissues. When full-grown the maggots leave the locust, descend into the earth, and there transform to pupa3 inside of their cast skins, and from the pupae the adult flies emerge in due time. The maggots of one of the Bee-flies (Systceclius oreas) feed upon grasshopper-eggs, but their life-history is not INSECTS INJURIOUS TO THE GRAINS AND GRASSES. G5 fully known. The common Flesh-fly (Sarcophaga car- naria Linn.), Fig. 39, is also very destructive, though largely a scavenger. Fig. 37.— Tachlna-fly. {Exo- rista leucanim Kirk). (After Riley.) Fig. 38. — Tachina-fly. [E. flitmcauda Riley). (Alter Riley.) Fig. 39. — Common Flesh-fly {Sarcophaga carnaria Linn.), a, larva; b, pupa; c, fly. Hair-lines show natural size. (After Riley.) Fig. 40. — Various stages of a Blister-beetle {Epicauta mttata). (After Riley. ) But of all the insects attacking locusts, the Blister- beetles, which, unfortunately, are often known to us as very injurious to various garden crops, are probably of the 66 INSECTS INJURIOUS TO STAPLE CROPS. most value. The feninle beetle deposits from four to five hundred of her yellowish eggs in irregular masses in loose ground, and in about ten days there hatch from these eggs some " very active, long-legged larvae, with huge heads and strong jaws, which run about everywhere seeking the eggs of locusts.'' Each of these ]arva3 will consume one of the masses or about thirty eggs. The subsequent life-history of these insects is very complicated on account of their peculiar habits, but the various stages are shown in Fig. 40. The Lesser Migratory Locust. Besides the Rocky Mountain Locust there is only one other species that truly possesses the habit of migrating, though to a far lesser extent, and which is therefore known as the Lesser Migratory Locust (Mela)ioplus atltmtis Riley). It is considerably smaller than its western relative and somewhat resembles the Red-legged Locust both in size and appearance. The species of very widely dis- tributed, occurring from Florida to the Arctic Circle east of the Mississippi, and on the Pacific slope north of the 40th parallel to the Yukon. The habits and life-history of the species are in all essentials practically the same as of the former species except that they have no particular breeding-grounds. Injuries by this grasshopper were first noticed in 1743, almost seventy-five years before the first record of the Rocky Mountain Locust, and since then they have done more or less serious damage in some part of the territory inhabited every few years. Non- migratory Locusts. There are several species of locusts which, though lack- ing the migratory habit, and thus being more easily con- trolled, often become so numerous as to do serious damage INSECTS INJURIOUS TO THE GHAlNS AND GRASSES. 67 Fig. 41. — The Two-striped Locust (MelnnojJlus hMttatus Scud.). (After Riley.) Fig. 42. — The Differential Locust {Melanoplus cUjferentialis Thos.; (After Riley.) Fig. 43. — The American Acridium (Schistocerca americana Scud.). (After Riley.) Fig. 44. —Red-legged Locust (Melanoplus femur-ruhrum Harr.). (After Riley.) 68 INSECTS IN.TUKIOUS TO STAPLE CROPS. over limited areas. Both as regards the regions inhahited, its habits, and life -history, the common Red-legged Locust (Melanoplas feDiur-ruhriim Har.) hardly differs from the last species and is often found m company with it. It is non-migratory, however, and though its injuries are thus entirely local, they are often of considerable importance. Records of locust-plagues in California date back as far as 1722. Many of them were doubtless due to the Cali- FiG. 45. — The Pellucid Locust {Gi. — One of the methods most extensively tried Tor the destruction of the n^miphs upon small or young crops is by the use of crude kerosene or coal-tar in one of the so-called ^' hopperdozers." '^The main idea embodied in these contrivances is that of a shallow recep- tacle of any convenient size, provided with high back and sides, mounted either on wheels or runners. If the pan is larger than, say, three feet square, it is provided with transverse partitions, v/hich serve to prevent any slopping of the contents (in case water and oil are used) when the device is subject to any irregular motion. On puphing these pans, supplied with oil, over the infested fields, and manipulating the shafts or handles so as to elevate or depress the front edge of the pan, as may be desired, the locusts are startled and spring into the tar or oil, when they are either entangled in the tar and die slowly, or, coming in contact with the more active portion of the oil, expire almost immediately. A good cheap pan is made of ordinary sheet iron, eight feet long, eleven inches wide at the bottom, and turned up a foot high at the back and an inch high in the front. A runner at each end, extend- ing some distance behind, and a cord attached to each front corner, complete the pan at a cost of about $!l.50 (Fig. 47). We have known of from seven to ten bushels of young locusts caught with one such pan in an afternoon. It is easily pulled by two boys, and by running several together in a row, one boy to each rope, and one to each contiguous pair, the best work is performed with the least labor." Larger pans may be drawn by horses. The oil is best used on the surface of water, from which the insects are removed with a wire strainer. Various modifications of this apparatus have been devised, but the more simple INSECTS INJUlllOUS TO THE GRAINS AND GRASSES. 77 ones seem to be fnlly as effective as those more complicated for which fancy prices are charged for royalty. Destroying tJie Adults. — The destruction of the winged insects is an entirely hopeless task, for, though even large numbers are caught, so many will remain that the damage done the crops would be but very slightly diminished. One of the most promising means for averting the swarms of v/inged migratory locusts from alighting in the fields is by a dense smudge, in which some foul smelling substances are placed. Where strictly attended, and with favorable winds, this has often proved highly successful. To accomplish the best results farmers over an extensive area should combine in its use, Tlie South African Fungus. — In 1900 Prof. Morgan made a test of a fungous disease which had been found to destroy large numbers of grasshoppers in South Africa, to determine whether, after starting it by artificial projm- gation, it would spread sufficiently to destroy any consider- able number of locusts. The weather was favorable, rains being frequent. Early in August it was found that " over the areas where the liquid infection was spread diseased hoppers were abundant." '^^ As many as a dozen dead grasshoppers could be found upon a single plant, and some upon nearly every weed on ditch-banks where grasshoppers were numerous. From the centres of infection great areas had become inoculated, spreading even beyond the planta- tions first infected.^' The property upon which it was placed became thoroughly infected with the fungus. Strangely, though many other species of grasshoppers were abundant, only the Differential \\^as killed by it. Dr. Howard states that this disease has also spread and done effective work in Colorado, 78 INSECTS INJURIOUS TO STAPLE CROPS. Poi.soning. — A mash composed of bran, molasses, water, and arsenic or Paris green, which has been extensively used for cutworms, was found to be quite successful in the experiments of Mr. D. W. Coquillet in the San Joaquin Valle}^ California, during 1885, for protecting orcliards, vineyards, gardens, etc., and might even be of some value for grain crops. Two pounds of Paris green, twenty- five pounds of bran, barely moistened with water and cheap molasses, will be about the correct proportion. It should be placed in the fields, a tablespoonful to each plant or vine. At this rate the cost per acre of vineyard, including labor, will not exceed fifty cents. The 2)oison acts slowly^ but if judiciously used will be found very effective, especially for the non-migratory forms. In Texas the mash has been found satisfactory in destroying the grass- hoppers attacking cotton. One planter* writes: "We are successfully using arsenic (for grasshoppers) at the following rates: 10 pounds of wheat bran, 1^^ gallons sorghum molasses, 1 pound arsenic. Make a thick mash, sow broadcast on infected ground, and it will surely kill them. I used 40 pounds last year and made 49 bales ol cotton. My neighbors did not do anything and entirely lost their crop." However, Prof. M^organ concluded that "the mash cannot be relied upon in severe outbreaks, such as occurred in the delta, but may be used in limited attacks where the area affected would not warrant the more aggressive methods.'' * S. D. Harwell, Putnam, Callahan Co., Tex., Bull 30, n. s., Div. Ent., U. S. Dept. Agr., p. 06. INSECTS IN J bilious TO THE GRAINS AND GRASSES. 79 The Army-worm (Leucania unipunda Haworth). Almost every year from some portion of this large country reports are received of the ravages of armies of worms sweeping over the grain-fields, like a horde of Vandals. Invariably, also, there has not been a single attack in the infested locality for a number of years, so that the farmer is at a loss to do anything to protect his crops, and by the time information can be received from an entomologist a large portion of them will already have been destroyed. Thus previous knowledge of the habits and remedies for these insects may be of value to him when injury by them is threatened. Being a sj)ecies native to this country, these worms may almost always be found east of the Rockies in low, rank growths of grass, which form their habitual breeding- grounds. Yet, though the moth is widely distributed, its chief injuries have been in belts from eastern Iowa to Maine, from northern Texas to northern Alabama, and east of the Blue Ridge Mountains to northern North Carolina. Even in these regions, however, the worms have never been recorded as injurious for tAvo successive years, and the only recent wide-spread outbreaks have been in 1861, 1875, 1880, and 1896, though serious injury is almost annually done in restricted localities. Only when their usual feeding-places are exhausted, or when through favorable climatic conditions or the destruction of large numbers of the parasites which hold them in check, they increase in abnormal numbers, do they assume the march- ing habit and mass in armies. Life-Mstory. — In the North there are usually three broods each season, and the insects pass the winter as half- 80 INSECTS INJURIOUS TO STAPLE CROPS. grown caterpillars; but in the South there may be as many as six broods, and the moths often hibernate over winter, layhig eggs early in the S23ring. In the Northern States these young worms mature, change to pupa3, and from them the adult moths appear early in June, the May broods rarely doing serious injury. The female moths now lay their small yellowish eggs in rows of from ten to Fig. 50 — Army- worm Moth (Leucania unipuncta), pupa, and eggs iu natural position in a grass-leaf. Natural size. (After Comstock.) fifty, inserting theui in the unfolded bases of the grass- leaves, and covering them with a thin layer of glue. Over seven hundred may be deposited by one female, and thus it is that the myriads of young worms appear when they hatch in about ten days, and form the destructive army of early July. The worms usually feed entirely at night, and thus whole fields will often be ruined before they are discovered, though a few generally feed during the day, as they all do during cloudy weather. The leaves and stalks of the grains and grasses form their favorite food, the heads usually lacing cut off, but various garden crops have frequeutly been seriously injured. As a rule clover INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 81 is untouched, but even that is not always exempt. In from three to four weeks the worms become mature and are then about one and one-half inches long, of a dark-gray or dingy-black color, with three narrow, yellowish stripes above, and a slightly broader and darker one on each side, altogether much resembling catworms, to which they are nearly allied. They now enter the earth and there trans- form to pnpfe, from which the adult moths come forth in about two weeks. These again lay eggs for a brood of worms which appear in September, but are rarely very injurious. The moths developing from this last brood either hibernate over winter or deposit eggs, the larvae from which become partially grown before cold weather sets in. The moths very often fly in windows to lights, and are very plain little " millers " The front wings are of a clay or faAvn color, specked with black scales, marked with a darker shade or stripe at the tips, and a distinct white spot at the centre — on account of which they were given the specific name unipunda. The hind wings are some- what lighter, with blackish veins and darker margins. Enemies.— V^QV^ it not for other insects which prey upon the worms, the army habit would undoubtedly be assumed much more often; but ordinarily these very efficiently reduce their number, and Dr. L. 0. Howard has recorded two instances in which armies of worms were practically destroyed by them. Large numbers are always destroyed by the predaceous ground-beetles and their larvae, but their most deadly enemies are two small Tachina-flies. These lay from half a dozen to fifty eggs upon a worm, and the maggots from them enter the body of the worm and there absorl) its juices and tissues, thus 82 INSECTS INJURIOUS TO STAPLE CROPS. soon killing it. Ordinarily, when feeding at night, the worms are free from these parasites, but when the march- ing habit is assumed these little flies swarm around them on cloudy days, and before the next year will again have the voracious army under subjection. Thus worms with eggs upon them should never be destroyed if avoidable. Fig. 52. — The Farmer's Friend, the Red-tailed Tachina fly ( Win- themi)( 4.-pustul(it((). a, natural size; h, much eohirged; c, army- worm on which fly has hiid eggs, natural size; d, same, much enlarged. (After Sliugeiland.) Remedies. — ^When detected, all efforts shoidd be centred on keeping the worms out of crops not yet attacked and confining their injury to one point. As a barrier, there is nothing better than a steep ditch with the side next to the crop to be protected as nearly vertical as possible. In the bottom of this dig some deep holes every ten feet, Not being able to easily scale the steep wall, the worms will look for some easier ascent, and become accumulated in large numbers in the holes, where tliey may be destroyed Fig. 51. — Arm^'-VNorms at work vn Coiii-plaiit. (After Slingerland.) 83 84 INSECTS INJURIOUS TO STAPLE CROPS. 1)Y kerosene or l)y burning straw on them. S(;vei'al deep parallel farrows will act in the same way, and if a series are properly made, they will also be found efficient. If it be possible to turn w^ater in the ditches, or if they become filled by rains, the addition of a little kerosene, so as to form a thin scum over the surface, v^'ill soon kill the caterpillars. By thoroughly spraying or, perhaps better, dusting a small strip of the crop in advance of the worms with Paris green, and liberally distributing poisoned bran mash (com- posed of fifty pounds of bran and one pound of Paris green with about enough molasses and water to sweeten it) large numl)ers may be destroyed. But be careful not to pasture cattle in a field so poisoned until rain has thoroughly washed it. A flock of poultry will also do good service in consuming them. Burning stubble, grass land, and rubbish is also of considerable importance for this as well as all similar insects, But whatever is done to combat the Army-worm must be done quickly and at once, for a single day's delay may often mean the ruin of a valuable crop. Deep fall plowing followed by a thorough harrowing or rolling will do much to destroy the hibernating larva3 and thus prevent their attack the next season. The Fall Army-worm {LajJiyym a frvgiperda S. & A.). Descrij^ttion. — Very similar in its destructive habits to the true Army-worm is the Fall Army-worm or Grass- worm. At first glance the worms have much the same general appearance, bat upon close examination consider- able difference in the markings is noticeable. Along each side of the body is a longitudinal pitch-colored stripe, and in the middle — between them — is a yellowish-gray stripe about twice as wide, which includes four black dots INSECTS TNJUIilOUS TO THE GRAINTS AND GRASSES. S5 arranged in pairs. These worms assume the habit of working in armies', but usually do not feed in such large bodies as those of the true Army-worm and are thus even more difficult to combat. They appear later in the season, the other species rarely being destructive after August first, and have thus been termed the Fall Army-worm. The Army-woroi proper rarely feeds upon anything but grasses and cereals, while the Fall Army-worm feeds upon a large variety of cultivated crops, including sugar-beets, cow-peas, sweet-potato vines, millet, and many other general and truck crops. In Nebraska it has developed a peculiar fondness for alfalfa and has there been styled the Alfalfa-worm. It is also sometimes very destructive to city law^ns, as it was in Chicago during 1899. Indeed, that season witnessed an unusual outbreak of this species in widely distant localities, it having been exceptionally destructive in the Carolinas and Virginia, Illinois, and Nebraska, as well as other districts. The insect is more of a native of the Southern States, but occurs from Canada and Maine south to the Gulf States and west to Colorado and Montana. Life-history . — The life-history of this insect differs from that of the true Army-worm in that it passes the winter in the pupal stage. The pupa? are about one-half an inch long and may be found in small cells from one-half to one and one-quarter inches beneath the surface of the soil. The exact time of the emergence of the moths in the spring has not been definitely observed, but the first gen- eration of worms appears in May or June. The moths deposit their eggs on blades of grass, in clusters of 50, 60, or more, each mass being covered with mouse-colored down from the body of the moth. The eggs hatch in insp:cts injurious to staple crops. about ten days. The exact time required for the growth of the larva or the time occupied in the pupal stage does not seem to have been definitely observed. ''Present knowledge indicates that the number of generations that are normally produced each year is two in the most northern range of the species (in years when it develops northward), three for central localities like central ar.d southern Illinois and the District of Columbia, and prob- ably four for the extreme South. We know, however. Fig. 53. — Fall Army-worm {Lnphygma frugiperda S. & A.). 1, 2, moth; 3, pupa; 4, 5, larva. (After W. D. Hunter.) practically nothing of the development of this species in the Gulf States."* Prof. Morgan states that this insect often makes its appearance in damaging numbers in the States around the Mississippi Delta, in sections behind the levees immediately after an overflow or crevasse. This seems to be largely due to the predaceous ground-beetles (see page 36), which usually prey upon the army-worms in such numbers as to *F. H. Chittenden, "The Fall Army-worm," Bulletin 29, n. s., Div. Ent , U. S. Dept. Agr. INSECTS INJURIOUS TO THE GRAINS AND GRASSES. 87 hold them in check, being destroyed or carried to other places by the rush of water. The i)arent moth is very dissimilar from that of the Army-worm. It is of a ''general yellowish, ash-gray color, with the second pair of wings almost transparent, but with a purplish reflection. In extent of wings it measures about one and one-quarter inches, and when these are closed the length of the insect is about three-quarters of an inch. The front wings are mottled or marbled, especially near the central area, and usually there is visible a fine white line a short distance from the edge and parallel to it. The hind wings have a fringe of darker hair as well as veins that contrast somewhat with the lighter portion."* Remedies. — As before stated, this species is even more difficult to combat than the true Army-worm on account of the fact that its attacks are scattered over a wider area, the individuals being of more solitary habits. The same methods of combating it will be found profitable, however, and especially that of deep fall plowing and harrowing, which in this case will break up the pupal cells and prevent the development of the moths. '' In the case of perennial crops fall plowing is not practicable. For alfalfa Mr. Hunter has recommended that the field should be thoroughly ' disked,^ or cultivated with a disk-harrow, giving practically the same results as 23lowing other fields. For lawns a thorough going over with a long-toothed steel rake is the treatment recommended.'^ "In fields of young grain and on lawns many of the worms may be killed by rolling with a heavy roller, prefer- ably when the insects are at work early in the morning or * Press Bulletin No. 2, Nebr. Ag. Exp. Sta., "The Fall Array Worm." W. D. Hunter. 88 INSECTS INJURIOUS TO STAPLE CROPS. late in the afternoon. In pasture-lands and in fields that are injured beyond recovery, sheep or cattle could be turned in in numbers with benefit, as they will crush the larvae by trampling upon them.^' The worms may often be destroyed, when not occurring in too large numbers and especially while young, by spray- ing the food with Paris green or other arsenicals, and when present in only ordinary numbers like cutworms they may be killed with poisoned bran mash as advised for the latter on page 217. " Lawns can be freed from the insects by the application of kerosene emulsion, followed with as copious a drench- ing of water as possible from a hose. This remedy should not be employed in bright sunlight or on a hot day, but preferably toward sundown." When the worms occur in armies they may be combated in the same way as the true Army-worm. But too much emphasis cannot be placed upon the im- portance of cleaji cultural iiiethocls and the rotation of crops in the control of both this and the true Army-worm. This has been well expressed by Mr. Chittenden (1. c.) as follows : " Rotation of crops should always be practiced, as well as the burning over of fields in the fall, when they are too badly infested to recover from injury. Above all other precautions which it is necessary to take to secure immunity from attack is that of keeping the fields free from volunteer grain and wild grasses, since experience shows that these are the favorite breeding-grounds of the insect; in other words, they attract the female moths for the deposition of their eggs, and when the larvae hatching from these eggs have devoured the grain and grasses which grow in batches they are driven to cultivated fields for INSECrS INJURIOUS TO THE GRAINS AND GRASSES. 89 food. One of the most important sources of injury is the rotation of one cereal crop with another or with grasses, and the planting of crops in fields that have been allowed to run waste to wild grasses and weeds. As grasses and cereals are the crops most affected by the Fall Army- worm, the soil should always be very thoroughly plowed before planting to any crop, particularly a similar one, and it is inadvisable (not alone on account of the Fall Army-worm, but on account of the numerous other common cutworms, wireworms, and white grubs) to j)lant wheat, corn, or any other cereal in pasture-land unless a crop which is not so subject to infestation by this insect intervenes." CHAPTER VI. INSECTS INJURIOUS TO WHEAT. INJURING THE ROOTS. Meadow-maggots or Leather-jackets {TipulidcB). Several instances have been recorded in which serious injury has been done to wheat,, clover, timothy, and Wue grass by the larva? of Crane-flies. These insects are never so injurious in this country as in Europe, where they are known as " Daddy-long-legs,^' the common name of our harvest-spiders, though doubtless injury done by them is often attributed to other insects. The farmer usually declares the work to be that of wireworms or cutworms, the adults often being known as '' cutworm-flies," unless the maggots are so abundant as to attract his attention. When the maggots are abundant enough to do much injury, they usually occur in very large numbers, but ordinarily, though common everywhere, they occur in such small numbers as to escape notice. Several species {Tipula hicornis Loew, T. cost alls Say, and PachyrrJiinis sp.?) have at various times done con- siderable damage in localities in Ohio, Indiana, Illinois, and elsewhere. Life-history. — So far as studied, the life-histories of these species seem to be much the same. The larvae 90 IX SECTS INJURIOUS TO WHEAT 91 remain dormant over winter, but evidently commence feeding again very early in the spring, a wheat-field havino- shown the effects of their injuries from February first to Fig. 54.— a Crane-fly {Tipula hebes Loew). a, larva: h puna- r male adult. (After Weed.) ' i p . , April first. The hxrva? become full-grown from the latter part of April until the middle of May, depending upon the species and season. The full-grown maggots are about an inch long, of a dirty-grayish color, and of a tough 93 INSECTS INJURIOUS TO STAPLE CliOl'S, leathery texture. They are nearly cylindrical, somewhat tapering in front and terminating bluntly behind. Legs are entirely wanting, but at the blunt end are a few fleshy processes and a pair of small, horny hooks. The larvae seem to prefer low, moist ground, and will live for some time on land entirely flooded or in a ditch. They feed very largely on dead vegetable matter, but when excessively abundant they attack the roots of wheat, grass, and clover, so weakening them near the surface that the plants, deprived of proper nourishment, are killed and loosened from the ground. Pup^ may be found during the latter part of May, occupying small cells near the surface of the soil in a vertical position. Prior to emerging the adult pushes from one-half to two-thirds of the body above the surface and remains in this pose for several hours. The males usually emerge first, as their assistance is required by the females, which are loaded down with eggs, to extricate themselves from the pupal skins. The sexes pair imme- diately, there being many more males than females — one observer states one hundred to one — and the females deposit their eggs upon grass and clover lands, to the number of three hundred each. Eggs are laid for another brood in Sejotember, the maggots from which live over winter. Remedies. — Injury to wheat land may be Lirgely pre- vented by plowing early in September. No satisfactory remedy for the maggots is known when injuring clover, timothy, or grass, although large numbers have been known to be destroyed by driving a flock of sheep over infested land. Dr. S. A. Forbes states that ' ' close trampling of the earth by the slow passage of a INSECTS IXJL'KIUUS TO WHEAT. 93 drove of pigs would doubtless answer the same purpose, which is that of destroying the larvae lying free upon the surface or barely embedded among the roots of the grass." Several of our common birds feed upon the maggots and flies as well as a number of ground-beetles. The maggots are also sometimes attacked by a fungous disease which in tlie damp soil in which they live would doubtless grow and spread rapidly. Altogether these different enemies keep them so well in check that they rarely become of importance. Wheat Joint-worms {Isosoma spp.). Injury. — During midsummer, shortly before harvest, many of the ripening ears of wheat are seen to topple over and fall to the ground, owing to the breaking of the stalk, which has been weakened at one of the joints. Upon examination several small gall-like cavities will be found fractured at the broken joint, and at other joints will be found small round holes leading to some of these empty cells. Xow and then one will be found occupied by a small larva or pupa, the cause of all the mischief. Very often this injury becomes quite serious, affecting the crop much as does that of the Hessian Fly, though late in the season, and is often mistaken for the w^ork of that species. The Joint-worms, however, are larv^ of small hymen- opterous insects which were at first supposed to be parasitic upon the Hessian Fly, as they belong to a family, the ClialcididcB, most of the members of which are parasites of other insects. They differ from the flies in having four wings instead of two, and in many other structural points, as shown by the illustration, belonging to the same order as the bees, ants, and wasps. 94 INSECTS INJURIOUS TO STAPLE CliOPS. Two species are commonly injurious, the Wheat Joint- worm {Iso.soDia tritici Fitch) and another species of the same genus, more popuhirly known as the Wheat Straw- worm {hosoma grande Riley). The adults of 1. tritici are small black flies from an eighth to three -sixteenths of an inch in length, and with wings expanding about one fourth of an inch. The larvae are yellowish-white with the tips of the jaws brown, of about the same length as the fly, and of the form shown in the figure. Life-history, — The larvae of /. grande are much the same; but while the former species has but a single brood each season, this is double-brooded. The summer brood m I Fig. 55.—*^/, Wheat -straw affected by Joint- worm; h, adult as seen from above. (After Riley.) is similar to that of tritici, but the spring brood is peculiar in that the females are much smaller and almost wingless, so that the pest is spread only by the later brood. The larvae of tritici hibernate over winter in the wheat-stubble, coming to maturity in June, and the next brood feeds upon volunteer wheat and the fall planting. /. grande, however, passes the winter in the pupal state, also in the INSECTS INJURIOUS TO WHEAT. 95 stubble. From them the wingless females emerge in early spring and j^hice their eggs npon the young wheat, usually on or near the growing head. These become mature in June, and from them the winged females develop. Singu- larly, there are no males in this brood, they appearing only in the spring, while in the summer brood the females are so large and robust that they were at first mistaken for a Fig. 56. — Adult of Joint-worm {Isosoimi trltiei Harr.). a, female; h, male; c, d, antennae of same; e, f, abdomens of same. (After Kiley.) separate species. ^' These deposit their eggs in or near the joints of the straw, more frequently the second below the head," becoming full-grown by fall, and ])assing the winter in the stubble as 2)upa3. The two species may also be separated by their manner of injuring the straw. The Joint-worm {tritici) makes more or less apparent galls in the walls of the culm, while the Straw-worm {gr ancle) forms no galls and but fewer individuals infest a straw. Owing to their small size and retiring habits these little parasites of the wheat-plant — and they also infest barley 96 INSECTS INJUIilUUS TO STAPLE CROPS. and rye — are not often observed, or tlieir injnries are charL>-ed against the Hessian Fly, and not nntil they do Fig. 57. — Wheat straw Worm {Isosomn gr.mde Riley\ a, ventral view; 6, .side view of larva; c, aiitenua3; d, mandible; e, anal segment, ventral view;/, adult female; g, forewing; h, hind- wing; i, aborted wing. (After Kiley.) Fig. 5S.—Isoso7n(i givmde. Female of summer brood. (After Riley.) unusual and severe injury is the difference in the method of their attack from that of the " fly " noticed. INSECTS INJURIOUS TO WHEAT. 97 Remedies. — Owing to the fact that the Straw-worin is spread only by the summer brood, a simple rotation of the crop will keep them largely under control. However, as both species pass the winter in the stubble, most of them may be killed by burning the stubble in fall and winter. The Wheat Saw-fly Borer {Ceplius injgmcmLS Linn.). The " Corn Saw-fly" has been a well-known wheat-pest for many years throughout England, France, and the Continent, but was not noted as injurious in this country till 1889, when Prof. J. H. Comstock published * a very complete account of its injuries upon the University Farm at Ithaca, N. Y., where it had done more or less damage for two years, though Mr. F. H. Chittenden states that he collected a single adult at Ithaca in the early ^80's. Specimens were also collected at Ottawa, Canada, and Buffalo, N. Y., in 1887 and 1888, these being the only other references to its occurrence in this country. The following is gleaned from Prof. Comstock's interest- ing account. Injury. — No external indications of injury to the plant can be seen until the larva within has almost completely tunneled the stalk, at which time there is a discoloration just below the injured joints. Thus damage by this insect is not readily noticed, it merely dwarfing and stunt- ing the growth of the plant by boring in the stem. '^If infested straws be examined a week or ten days before the ripening of the wheat, the cause of this injury can be found at work within them. It is at that time a yellowish, milky-white worm, varying in size from one-fifth * Bulletin 11, Cornell Univ. Ag. Exp. Station. 98 INSECTS INJURIOUS TO STAPLE CROPS. to one-half an inch in length. The smaller ones may not have bored through a single joint ; while the larger ones will have tunneled all of them, except, perhaps, the one next to the ground. Life-history. — '^As the grain becomes ripe the larva works its way toward the ground; and at the time of Fig. 59. — The Wheat Saw-fly Borer [CepMis pygm(fus Linn.), a, outline of larva, natural size; b, larva, enlarged; c, larva in wheat stalk, natural size; d, frass; e, adult female;/, Paehyo- nerus calcitrest, to which we are in- debted for much of the above, advises as follows: ''Thresh as soon after harvest as possible, and bulk in tight bins or in good sacks. [By ''tight bins" are meant those which will not per- mit the entrance or exit of the moths. ] If the grain is dry when Jiii|i|>v-.ir % (I O «^ o )Q 100 IKSECTR TXJITRTOUS TO STAPLE CROPS. harvested, it may be threshed at once; if not, as soon as it is in good condition. If the sacked grain is infested, there will not be wormy kernels sufficient to heat the grain. The moths cannot make their way out and are stifled. Nothing can come in from outside and the grain remains safe. The threshing itself kills many of the insects and jars and rubs off many of the eggs. If binned, the bins should be tight and the grain should be tested occasionally for any appreciable heating. If it heats perceptibly, it indicates considerable infestation, and it should be treated with carbon bisulfide at once, used at the rate of one drachm per cubic foot, or one pound for 250 cubic feet bin-space.^' We have sometimes found two or three pounds for 100 bushels of grain necessary, though one or one and one-half pounds for 100 bushels has been often recommended. The bisulfide should be placed in shallow plates or pans on top of the grain, preferably not over a ponnd in a vessel, and the bin should then be covered with boards, canvas, or olankets, and allowed to remain at least twenty-four hours. If to be- used for seed, it should not be left for over thirty-six hours; but if not, leave it forty-eight hours, wliich will do it no injury for food. After treating keep the grain covered to prevent reinfestation. Those having wheat unthreshed, whether in stack or mow, should thresh at once, and treat as above directed, except that if much of it is noticed to be wormy, it should be treated with carbon bisulfide at once, as soon as threshed, which if done thoroughly will prevent any farther infestation this year. Barns and storehouses should be cleaned up and freed from all loose and scattered grain — chickens will help in this — before April 1st, so that no moths will be allowed to '' weevil" in grain. 167 develop and infest the grain in the field. Places where grain has been in shock the previous season should be cleaned up by the aid of chickens. Thus if there is any probability of grain being infested, it should be kept tightly covered in the spring so as not to permit the spread of the moths to the fields. Prevention of'^ Weevil.'' — Undoubtedly grain-insects can usually be more successfully combated by a proper housing of the grain. No matter how often the insects in a granary are destroyed, if the remainder of the barn is full of dust, sweepings, and refuse, as it generally is, on which the beetles can feed and in which they will breed, and if the granary is not absolutely tight, as soon as the gas passes off the insects from the barn will again enter the granary, and soon it will be as badly infested as ever. Cleanliness. — ^' Cleanliness will accomplish much toward the prevention of injury from these pests, the cause of a great proportion of injuries in granaries, mills, elevators, and other structures where grain and feed are stored being directly traceable to a disregard of neatness. Dust, dirt, rubbish, and refuse material containing sweepings of grain, flour, and meal are too frequently permitted to accumulate and serve as breeding-places for a multitude of injurious insects. "The floors or corners and walls of the barn or store- house should be frequently swept, and all material that has no commercial value burned.'' The Granary. — " The ideal farmer's granary, from the standpoint of insect ravages, should be built at some dis- tance from other buildings, and the rooms constructed of matched flooring so as to be as near vermin-proof as possi- ble. The doors should fit tightly, closing upon a rabbet, 108 INSECTS INJURIOUS TO STAPLE CROPS. which may be covered with felt or packing, and the windows covered with frames of wire gauze to prevent the passage of insects. The floor, walls, and ceilings should be smooth, so as not to afford any lurking-places for the insects, and it would be well to have them oiled, painted, or whitewashed for further security. A coating of coal- tar has been strongly recommended for the latter pur- pose.^'' '^'The value of a cool place as a repository of grain has been known of old, and a building in which any artificial heat is employed is undesirable for grain storage. The 'heating' and fermentation of grain, as is well known, is productive of ' weevil,' and this should be prevented by avoiding moisture and by ventilation. ^'Tlte storage of grain in large hulk is to be com- mended, as the surface layers only are exposed to infesta- tion. This practice is particularly valuable against the moths, which do not penetrate far beneath the surface. Frequent agitation of the grain is also destructive to the moths, as they are unable to extricate themselves from a large mass, a]id perish in the attempt. The true granary- weevils (small dark-brown beetles with long curved snouts, similar to the pea-weevil), however, penetrate more deeply, and although bulking is of value against them, it is not advisable to stir the grain, as it merely distributes them more thoroughly through the mass." Destruction of " Weevil." Carhon Bisidjide. — '-The simplest, most effective, and most inexj)ensive remedy for all insects that affect stored grain and other stored products is the bisulfide of carbon, a colorless liquid, with a strong disagreeable odor, which, 'MVEEYIL ' T^^ GRAIX. IGO however, soon passes away."' At ordinary temperature it vaporizes rapidly, forming a heavy gas, which is highly inflammable and a powerful poison. Application. — It may be applied directly to the infested grain or seed without injury to its edible or germinative principles by sj^raying with an ordinary watering-can having a fine rose nozzle. In moderately tight bins it is more effective, however, evaporating more slowly and diffusing more evenly, if placed in shallow dishes or pans, or on bits of cloth or cotton waste distributed about on the surface of the grain or infested material. The liquid volatilizes rapidly, and, being heavier than air, descends and permeates the mass of grain, killing all insects and other vermin present. Amount to Use. — The bisulfide is usually evaporated in vessels containing one-fourth or one-half of a pound each, and is applied in tight bins at the rate of one to three pounds to 100 bushels of grain, and in more open bins a larger quantity is used. For smaller masses of grain or other material an ounce is evaporated to every 100 pounds of the infested matter. Bins may be rendered nearly air-tight by covering with cloths, blankets, or canvas. The amount of bisulfide to be used depends very largely upon the shape of the space to be fumigated. If the grain is in approximately a cubical form, the above amounts will be sufficient; but if spread out with but little depth, two to four or five times as much will be found necessary. Time to Fumigate. — '^Infested grain is generally sub- jected to the bisulfide treatment for twenty-four hours, but may be exposed much longer without harming it for mill- ing purposes. If not exposed for more than thirty-six 170 INSECTS INJURIOUS TO STAPLE CROPS. honrs, its germinating power will be unimpaired. In open cribs and badly infested buildings it may sometimes be necessary to use a double quantity of the reagent and repeat treatment at intervals of about six weeks during tlie warmest weather." When possible it is always desirable to fan the grain immediately after fumination, thus removing the dead insects, and to thoroughly clean the granary before refill- ing it. " Mills and other buildings, when fonnd to be infested throughout, may be thoroughly fumigated and rid of insects by a liberal use of the same chemical. A good time for this work is during daylight on a Saturday afternoon or early Sunday morning, closing the doors and windows as tightly as possible and observing the precaution of stationing a watchman without to prevent any one from entering. It is best to begin in the lower story and work upward to escape the settling gas. The building should then be thoroughly aired, and the grain stirred early Monday morning. " For the fumigation of a building or a reasonably close room it is customary to evaporate a pound of bisulfide for every thousand feet of cubic space. In comparatively empty rooms, and in such as do not admit of being tightly closed, two or three times the above quantity of the chem- ical is sometimes necessary. Cauiiou. — " Certain precautions should always be observed. The vapor of bisulfide is deadly to all forms of animal life if inhaled in sufficient quantity, but there is no danger in inhaling a small amount. The vapor is highly inflammable, but with proper care that no fire of any kind, as, for example, a lighted cigar, lantern, or liglit of any '^weevil'' in^ grain. 171 kind, be brought into the vicinity until the fumes have entirely passed away, no trouble will be experienced/' Cost. — Carbon bisulfide may be secured through any retail or wholesale druggist in cans of various sizes. In considerable quantities it may usually be secured from wholesale houses and manufacturers at from 8 to 10 cents per pound, and in smaller quantities from retailers at 15 or 20 cents. CHAPTER IX. INSECTS INJURIOUS TO CLOVER. Both for its value as forage and as a fertilizer, clover holds a peculiar place among our crops. In the Mississippi Valley and the Eastern States we have nothing to occupy its place, and without it the farmer would be at a loss to make a suitable rotation of crops. Some eighty-two insects have been noted as doing more or less injury to the clover-plant, but hardly a dozen of these can be considered as serious pests. The insects doing the most injury to clover have so far not become widely spread and are largely confined to certain States and latitudes. But in these sections they have often been exceedingly destructive, and they seem to be constantly spreading. INJURING THE ROOT. The Clover Root-borer {Hylastes obscurus Marsh). This is the only serious pest preying upon the roots, but on account of the difficulty with which it is fought makes a formidable opposition to the successful growth of the crop. Thus in the southern part of Michigan hardly one- half a crop was secured in 1894 on account of its ravages. Though the beetles have been well known in Europe for over a century, their habits there seem to be but little INSECTS INJURIOUS TO CLOVER. 173 understood. In this country the pest has been noticed since 1876, when it was first found in three counties in western New York. Since then it has been noted as doing injury on Long Island and in several parts of Canada. Some ten years later it appeared in Michigan, and in 1894 was found in northwestern Ohio. Thus it has not become very generally distributed, and seems to be confined to the Northern States. Life-Mstory. — If one tears open a ch)ver-root in an infested field during the winter, he will usually find the beetles hibernating iji the burrows. They will not be readily distinguished, as they are scarcely an eighth of an inch long and are of a reddish -l^rown color much like that of the burrow. With the warmer weather of spring they commence burrowing and feeding in the roots, and during the latter part of May the females deposit their eggs along the sides of the tunnels. The eggs are shining white, and are placed in the sides of the galleries and then covered and packed with refuse, so as to separate them from the rest of the burrow. In a few days the eggs hatch, and the small white grubs emerge and continue the attack upon the roots. Here they grow fat during the summer months and ultimately transform to pupas, which again change to beetles during the early fall. This life-history varies con- siderably, and the grubs are often found much earlier and the beetles much later than usual. The spread of the insect occurs very largely in the spring when the beetles fiy from field to field, seeking uninfested plants in which to perpetuate their kind. Their entrance is usually made below the surface of the ground, though sometimes the burrow is started from the crown of the plant. It has been observed that alsike clover is not so badly 174 INSECTS INJURIOUS TO STAPLE CROPS. injured as the mammoth and common red, on account of its fibrous roots and the tendency of its tap-root to divide. Fig. 96.— The Clover Root-borer [Hylastes ohscurus Marsh), a, adult beetle; b. larva; c, pupae; d, egg; e, f, showing appear- ance of infested roots. (After Webster.) llemedics. — On account of its underground life this pest is not readily combated. The only remedy known is that INSECTS INJURIOUS TO CLOVER. 175 suggested by Prof. F. M. Webster, who advises ^^ plowing the infested fields as soon as the hay crop is removed and Fig. 96.~Contmued. before the larvae have advanced to the pupal stage. If the roots are thrown up to the hot sun and dry winds at this time, they will dry out and thus starve the young larvae, 170 INSECTS INJURIOUS TO STAPLE CROPS. thereby preventing their developing and migrating to other fields." A more frequent and thorough rotation of the crop will thus be of value. Meadow-maggots. (See page 90.) INJURING THE STEM. The Clover Stem-borer [Lanyuria mozardi Fab.). Early in June one frequently finds the beetles of the Clover Stem-borer here and there in the clover-field. They are slender, shining beetles, about one- third of an inch long, with red head and thorax and bluish-black Fig. 97, — Clover Stem-borer {Languria mozardi). Shows the eggs natural size and magnified, the beetle, larva, and pupa much enlarged, and above, a clover-stem with the larva at work in it. (After Comstock.) wing-covers. The beetles themselves seem to do little or no harm. Hibernating over winter, they lay the eggs in the pith of the stems early in June, and the larva? emerg- ing from these feed upon the pith of the stem, often verj- seriously weakening or killing it. The larvae become full- grown in a short time, transform to pupa3, and the beetles appear by August. Clover is only one of a dozen food-plants of this insect, which is widely distributed. It rarely does any consider- INSECTS INJURIOUS TO CLOVER. 177 able injury where clover is regularly cut in early summer and fall, and need not be feared when this is not neglected. INJURING THE LEAVES. The Clover Leaf- weevil {Pkytonomus punctatus Fab.). The Clover Leaf -weevil is also a native of Europe, and made its first appearance in this country in the same sec- FiG. 98.— Clover Leaf-weevil iPhytono7nus punctatus Fabr.). a, egg magnified and natural size ; h b h b, larvae ; c, recently hatched larva ;^ d, head of larva; e, jaws of the same; /, cocoon; g, same magnified to show the meshes; 7i, pupa; ^, weevil, natural size; j, the same magnified; k, top view of the beetle; I, tarsus and claws of the beetle; m, antenna of the beetle. (After Eiley.) tion of western New York as the root-borer, in 1881. Its injuries during that and the following year seem to have been the worst on record, Since then it has spread east 178 INSECTS INJURIOUS TO STAPLE CHOPS. into Connecticut, south to Mn,ryla.nd and West Virginia and as far west as Ohio and Micliigan. Every few years the weevils and larva3 destroy much of the foliage, but rarely are as bad the next season. The weevil is about one-third of an inch long, of a stout, oval form, with a long, thick snout. It is of a brown color, with several narrow gray lines above and broad gray stripes on each side, and with twenty rows of small, deep punctures on the wing-covers. Life-liistory. — In early fall the females lay their eggs in crevices among the stems near the base of the plant. The young larva? emerging from them are without legs, but manage to climb quite well by means of the prominent tubercles on the lower surface of the body. They are light yellowish green, which usually becomes deeper green as they grow older. The larv^ become partially grown before winter sets in, when they go into a dormant stage, hiding in rubbish or under the soil till spring, when they continue to feed upon the foliage and become full-grown in May and June. The larvae feed mostly at night and will not be noticed during the day, when they lie protected around the base of the plant. The injury done to the foliage is very characteristic, the edges of the leaves being eaten in a very regular manner as shown in the illustration. Before transforming to the pupa the larva constructs a very deli- cate cocoon of a greenish-yellow color, which is left on the surface of the ground. In this the pupal stage is passed, occupying about a month, the beetles being most common in July and August. The damage which the beetles do to the second crop of clover is fully equal that done by the larva3 to the first, and is more apparent, l)ecause the soil is then dry and the plant makes a slower growth. In INSECTS INJURIOUS TO CLOVER. 179 some cases the beetles have been known to hibernate ovei winter, when the larvse would occur correspondingly earlier. Enemies. — The reason that this insect has not become a more serious pest is, that as often as it becomes excessively abundant the larvae are attacked by a fungous disease which carries them off by the millions. When affected by this they climb to the top of a blade of grass, curl tightly around the tip, and soon die, first becoming covered with a white mold and then turning to a jelly-like mass. The spores of the fungus become scattered to healthy indi- viduals, which soon succumb. Larvae affected in this manner may be easily recognized, and when diseased larv?e are found in any quantity care should be taken not to pasture cattle on land infested with them, as instances are on record in which there seems little doubt that cattle have been seriously poisoned by eating these diseased larvae. The Clover-mite (BryoUa j^ratensis). The S23 raying of fruit-trees for various insect-pests in winter has been found to be one of the best means of keeping in control those which hibernate or whose eggs are on the trees during that season. One of these is the Clover-mite (Bryohia jjratensis), an insect Avidely dis- tributed and of most variable habits. As its name indicates, this insect is nearly related to the common red spider of greenhouses, belonging to the family of vegetable-feeding mites [TetranycMclcB), and with which it is often confused. It is, however, about twice the size of the red spider, being fully three-tenths of an inch long. Though knov/n as the Clover-mite, on account of its feeding upon that plant, 3^et this insect was first known 180 INSECTS INJURIOUS TO STAPLE CROPS. as, and is still, an important enemy of fruit-trees, more especially on the Pacific coast and in the Western States, but also in other sections of the country. The most injury seems to have been done to clover in the Central States as far south as Tennessee, though it has suffered somewhat even in the East. When attacked by the mite the leaves of the clover or fruit-trees become yellow and have a sickly appearance, as Fig. 99. — The Clover-mite {Bryohia pratensis). if affected with a fungous disease. Especially upon the upper sides of the tender leaves of clover the juices are extracted over irregular areas, looking more or less like the burrows of some leaf -mining larvse. Owing to the small size of the mites they may be doing considerable damage to the foliage and yet remain unnoticed; but in the egg stage the pest is much more readily detected and INSECTS INJURIOUS TO rLOYER. 181 attacked. In the more northern States the eggs are laid in the fall, and do not hatch until the next spring. Further south, however, the adult mites hibernate over winter. The eggs are of a reddish color, laid upon the bark of trees, especially in the crotches, and in the West are sometimes so thickly placed as to cover considerable areas two or three layers deep. When the adult mites leave the clover-fields in the fall to fiiul hibernating quar- ters upon fruit-trees for the winter, they often become quite a nuisance by invading dwelling-houses which are in their path. This is more particularly the case throughout the Mississippi Valley. liemedics. — When swarming into a house their j^rogress may be arrested by sjoraying the lower part of the building, walls, etc., with pure kerosene as often as necessary. Inside the house they may be destroyed by the use of P5^rethrum powder (Persian insect-powder), bnrning brim- stone, or spraying Avith benzine, care being taken not to brino- the latter substance near the fire. The only practical way of protecting clover from the mite is by destroying the eggs and hibernating mites upon the fruit-trees in winter. This may be done by burning all the prunings and thoroughly spraying the trees with kerosene emulsion diluted with five parts of water, or with a mechanical mixture of twenty or twenty-five per cent kerosene and water. Such a spraying will also protect the fruit-trees from the mite, and will also destroy numerous other insects, such as the pear-leaf blister-mite, which hibernates upon the trees. Such small insects, so minute as to usually escape notice, are often resj^onsible for a poor growth, and should be jiroperly checked whenever known to be injurious. 182 INSECTS INJURIOUS TO STAPLE CROPS. The Destructive Pea-louse or "Green Dolphin" (Nectaro- pho7'a 2^isi Kalt. ). Considerable injury was done to l)oth red and scarlet clover by this pest in the spring of 1900 in Virginia, Dela- ware, and Maryland, and to crimson clover in Delaware in 1890. In Europe the ^' Green Dolj^hin '^ has been known as one of the worst pests of peas, vetches, and clovers for the past century. The aphids leave the clover about May 1st in the above States, and feed upon peas during the early summer, practically destroying the crop of late peas in 1899 and 1900. During October and November they return to the clover and pass the winter upon it. Many predaceous and parasitic insects prey uj^on this pest, but it is held in check, especially on clover, chiefly by a fungous disease (Empusa aphidis). This disease is prevented by dry weather, and hence the pest is most injurious in dry seasons. As yet no remedy for the pest on clover or means for prevention of injury are known.* INJURING THE SEED. The Clover-seed Midge [Cecidomyia leguminicola Lint.). This is also a native of western New York, where its first injuries were recorded in 1878, but since then it has spread to almost every section where clover is grown, and is so serious a pest that it has become quite an art to raise a crop of clover-seed. The parent of all this trouble is a *See Bull. XLIX, Del. Agr. Exp. Sta., "The Pea-louse," E. D. Sanderson; and Circular 43, 2d Ser., Dlv. Ent., U. S. Dept. Agr., F. II. Chittenden. Fig. 100. — The Pea-louse {Nectarophora pisi Kalt.). p, pupa; wg., winged viviparous female; apt., wingless, or apterous, vivip- arous female and newly born young, all enlarged. (Author's illustration in Bulletin 49, Del. Coll. Agr. Exp. Sta.) 183 184 IKSECTS INJURIOUS TO STAPLE CROPS. little fly, resembling a mosquito, but only about one-tenth as large; so small, in fact, that it is rarely noticed. Life-history. — The eggs are laid among the hairy spines of the clover-head or beneath the bracts around the head. They are of a reddish color and scarcely one-tenth of an inch long. When the maggots emerge from them they Fig. 101. -The Clover Seed-midge {Gecidomyia leguminicola). a, fly; h, larva, enlarged. (After Riley.) enter the undeveloped florets, which they often prevent from flowering. In this case some of the flowers in the head will bloom, but the field as a whole does not blossom as usual. Once inside the floret the maggots feed on the developing seed. They are of a dark-red color, of a plump, oval form, and without feet. When full-grown they leave the florets and drop to the ground, into which they enter and form a little, tough, pa^oery cocoon, just under the surface. In it they transform to the pupa, which ulti- mately transforms to the adult fly. In the North two broods of the midge occur each year. The maggots of the first and principal brood become full- grown about the middle of June, and those of a smaller INSECTS INJURIOUS TO CLOVER. 185 one following during July and August. White and alsike clover have not been molested by tlie midge to any extent, but good judgment and a knowledge of the habits of the insect are needed to harvest a crop of seed from the red or mammoth. Iieuiedies.— Two methods are in practice for controlling this pest. The first, well adapted for dairy farms, consists in pasturing the clover until the 10th or 15th of June, and then securing a late crop of seed. The other method is to cut the clover for hay before the maggots have become full-grown and left the flowers, and then harvest a late crop of seed. Usually for red clover this will be any time during the latter part of June, and some two weeks earlier for the mammoth, as the latter will not mature a crop of seed if left later. But the exact time for cutting must depend upon the latitude and season, and to secure success will need good Judgment on the part of the farmer. A good rule for red clover is to start the seed crops a few days before timothy-heads appear. The Clover-seed Caterpillar (GrapJwHtha interstinctana Clem.). The larva of a small moth known as the Clover-seed Caterpillar {Grai^holitha interstinctana Clem.) has also done serious damage to the seed in Iowa and is common in clover-fields elsewhere. The greenish-white larvae are about one-fourth of an inch long, and destroy the seed by gnawing through the florets at the base. The larv^ pupate in thin cocoons spun in the clover-head, and from them emerge the small brown moths, which lay eggs for another brood at the base of the head. Three broods occur in Iowa; in June, August, and September. 18(3 INSECTS INJURIOUS TO STAPLE CROPS. Tlie remedies advised for the midge have also been found satisfactory for this pest. Fig. 102. — Clover Seeci-caterpillar [GrapJiolitha inter stinHana^. a, caterpillar; h. pupa; e, moth, all much enlarged; d, moth natural size. (After Osborn.) Fig. 103. — Clover Hay-worm (Pyra^w ^os^nf^/s). 1 and 2 show larvae suspended by threads; 3 represents the cocoon; 4, the pupa; 5 and 6, the moths; and 7, larva in a case which it has spun; all natural size. (After Riley.) INJURING THE HAY. The Clover-hay Worm {Pyralis cost alls Fab.). Even after all the above pests have been successfully combated, another insect, known as the Clover-hay Worm, INSECTS INJURIOUS TO CLOVER. 187 often does clover-hay considerable injury in the mow or stack. The caterpillars will usually be noticed toward the bottom of tlie stack if that part be searched in March or April. They are shown natural size in the illustration, and are of a dark-brown color, each segment being ringed with a band of darker brown. Hay infested by them has a moldy appearance from the numerous fine silken threads which they spin through it, often forming Avebs, and is so badly chewed and covered with webs as to unfit it for stock. Life-liistory. — The laiv^ form small silken cocoons in the cracks and crevices of the barn, from which the moths emerge early in June. As soon as the females find some clover-hay they deposit their eggs upon it, and from these the Avorms emerge and continue the destruction. Usually no serious injury is done except w^here clover-hay is kept over the second year or longer. When it is fed out each spring, before the next crop is harvested, there is no food for the young caterpillars, and they perish before the new crop comes in. Ilcmedies. — Thus these worms may be easily controlled by: 1. Xever stacking clover-hay two successive seasons in the same place. 2. Cleaning the mow out each sj^ring so that no old clover will be left over in the barn until the new comes. 3. Never putting new clover-hay on top of old, in stack or mow. Though the clover-2:)lant has numerous and serious enemies, almost all of them may be controlled by sim^^le means, the successful use of which depends almost entirely upon a thorough understanding of the habits of the insect to be fought. CHAPTER X. INSECTS INJURIOUS TO COTTON. INJURING THE LEAVES. The Cotton-worm {AUtia xylina Say). Best known of all the insect enemies of the cotton-plant is the Cotton-worm. Though the subject of numerous extensive investigations, it is such an ever-present pest that practical information concerning those habits which must be considered in successfully combating it is always perti- nent. Let us commence, then, with the new year, and follow the species through the season. Life-history. — During the winter months the adult moths hibernate in the most southern portion of the cotton belt, principally Florida and Texas, in the rank wire-grass occurring in the more thickly timbered regions. Only a few of these survive, but they are very capable ancestors, and in early March lay their eggs upon ratoon cotton where it is only an inch or two high. The eggs are laid singly, usually upon the under surface of the leaves, preferably near the top of the plant, and about five hundred are laid by each female moth. They are of a flattened convex shape, bluish green in color, and with a number of prominent ridges converging to the apex. In midsummer the eggs hatch in three or four days, but in the spring and autumn a much longer period is required. 188 INSECTS II^JUKIOUS TO COTTON, 189 When first emerged from the eggs the young larvae are of a pale yellow color, but soon assume a greenish tmge, and are marked with dark spots, which become more dis- tinct after the first molt. Thev then become marked as Fig. 104.— Egg of Cotton Worm- moth. «, top view; h, side view; greatly enlarged . ( From Fourth Kept. U. S. Entom. Comm. ) (X b Fig. 105. — Cotton-caterpillar. a, from side; h, from above — t wice natural size. (Fourtli Rept. U. S. Entom. Comm.) when adult, being more or less striped with black and are distinctly greenish. During the early season the green worms are the more common, while later the black forms predominate. The appetites of these caterpillars are only too well known to the cotton-grower. At first they are content with eating only the under surfaces of the leaves, occasionally piercing through. Then the leaves commence 190 IKSECT8 INJURIOUS TO STAPLE CROPS. t') look ragged, and when these become scarce the tender twigs and buds are attacked. When excessively abundant, like the Boll-worm, the larger larvae develop cannibalistic Fig. 106. — Plmi^la conquisitor, one of the principal Parasites of the Cotton-caterpillar, a, larvae, enlarged; b, head of same still more enlarged; c, pupa; d, adult female enlarged; e, /, end of abdomen of adult male, still more enlarged. (From Fourth Rept. U. S. Entom. Comm.) Fig. 107.— Cotton Worm-moth, a, with wings expanded in flight; h, wings closed, at rest — natural size. (After Kiley.) tendencies and often feed upon the weaker caterpillars. It requires from one to three weeks for the larvae to become full-grown, during whi(di time it is necessary for them to shed their skins some five times. The caterpillar now crawls into a folded leaf, which INSECTS IN^JURIOUS TO COTTOX. 191 sometimes is eaten away so that the pupa hangs exposed, and there sj^ius around it a silken cocoon and transforms to the clirysalis or pupa. In this stage the insect remains dormant for from one week to a month, when the adult moth emerges. The imago is of a dull olive-gray color with a wing- ex^^anse of about one and one-third inches, with wings marked as shown in Fig. 107, and sometimes with a j)urplish lustre. Like most of its relatives of the Noctuidm^ or "night-flying moths,'^ it flies only after sunset, but, unlike them, it is not confined to the nectar of flowers for foe 3, PS its mouth is peculiarly adapted to piercing the skin ol ripe fruit and feeding upon its tissues. They are strong flyers, the moths of the later broods frequently flying as far north as Canada. At such times they have been known to do serious damage to peaches in Kansas, and to cantaloups in Wisconsin. The first two broods develop rapidly, and in the extreme South and by early April the moths emerge and are carried northward by the prevailing winds. Eggs deposited by them develop into moths, which, in turn, fly further northward, and thus the worms are gradually found throughout the whole cotton belt, though with a consider- able confusion between the various broods. At least seven broods occur in the far South and three at the northern limit of the species range. With this number of genera- tions, it is readily perceived, considering the number of eggs laid by each female, how such great numbers of the caterpillars may arise by the latter part of the season, in a region where practically none remain over winter. The progeny of a single motli after four generations would amount to over 300,000,000,000 individuals, or, if placed 192 INSECTS INJURIOUS TO STAPLE CROPS. end to end, at the end of the third brood there would be enough to encircle the earth at the equator over four times. Eyiemies. — It is thus very fortunate that the cotton- worms have many deadly enemies which commence their warfare upon them as soon as the first appearance of spring, and continue it with increasing ardor throughout Fig, 108. — Cotton-worm ^gg-^fivdi^ite {Tricliogramma pretiosa). a, adult female, greatly enlarged; h, ovipositor; c, female antenna; d, male antenna. (From "Fourth Rept. U. S. Entomoloi,ical Commission.) the season. A little insect which lives inside of the eggs and is known to science as Tricliogramma pretiosa is one of the most efficient of these. Mr. Hubbard once observed in Florida that from 75 to 90 per cent of the fourth brood of eggs and 90 per cent of the fifth were destroyed by this parasite, while only three or four eggs in a hundred escaped in the sixth brood. One of the most useful parasites of the caterpillar was noticed to destroy nearly all of the chrysalids of the last i:n^sects injurious to cotton. 193 brood as early as 1847. The eggs of these insects are laid upon the caterpillars, and the maggots hatching from them bore into the worm and there feed upon its tissues. It transforms to a pupa as usual, but the pupa soon dies, and large numbers are thus killed. Several similar parasites j)rey upon the cotton-worm, among the more im2)ortant of which may be mentioned EuiAedrus comstocMi. It is to be regretted that we have no way of encouraging the good work of these valuable parasites. Bat the common insec- tivorous birds which eat large numbers of the worms, especially when they are yet scarce in early spring, may and should be protected by enacting and enforcing the most stringent laws against their wanton destruction. Remedies. — Paris green is an effectual and now widely used remedy for this pest. AVhen the United States Entomological Commission made their extensive investi- gations of remedies for cotton-insects in the early 80's, they devised some very tremendous appliances for spraying this upon as many as sixteen rows at once. But such machines have not proved practical, and it was found useless to attempt spraying over four rows at once. In fact they have never been used throughout the South in other than in an experimental capacity. Besides the general use of the dry Paris green by dust- ing it upon the plants as described below there have been several important factors which have so worked against the cotton-worm that the problem of keeping it in check is now considered ^practically solved by many authorities. The most important of these, and a most beneficial change as regarded from other than an entomological standpoint, is the diversification and rotation of crops, now coming to be more and more widely practiced by the 194 INSECTS INJURIOUS TO STAPLE CROPS. progressive agriculturist of the South. This alone has been very largely responsible for checking the rapid spread of the pest. Now that the seed has l)econie such a valuable product of the cotton-plant, smaller varieties with many seeds and a short fibre are being grown, in contrast with the rank- growing, long-fibre sorts formerly preferred. Thus the rows are more open, the work of the worms is more readily detected, and remedies more easy of application. With these advantages in their favor, the more southern jilanters have come to realize the importance of destroying the early broods, and by doing so have been able to keep them in a state of comparative subjection. For many years the most commonly used and. experience has shown, effective remedy is the use of the dry Paris green. It is usually dusted upon two rows of plants, from bags fastened at the ends of a pole, and carried by a man on horseback, who can thus poison from 15 to 20 acres per day. These sacks are about ten inches long by four inches in diameter, open the whole length of one side and firmly sewed at the ends. Eight-ounce Osnaburg is the best cloth for the purpose. A strip of oak or strong wood about one and one-half by two inches, and five feet long, has a one-inch hole bored through it at five inches from each end, and to this the sack is tacked, fastening one of the edges of the opening to each of the narrow sides of the pole. The sacks are filled through the holes in the pole. When freshly filled a slight jarring will shake out a sufficient amount of the j^oison, but when nearly empty the pole should be frequently and sharply struck with a short stick, or s^^aces in the rows will be missed. The poison has been found most effective without the admix- INSECTS IXJURIOUS TO COTTO:??. 195 ture of flour. If that be added, lighter cloth should be used for the sacks. The remedy for the cotton -worm is simple and effective. It simply needs careful watching, especially upon the part of the southernmost planters, and prompt work immedi- ately upon its apjDearance. Cutworms. For very few plants could a list of their insect-pests be made without mentioning the destructive cutworms (see page 214 to 217), and cotton is no exception. Their char- acteristic manner of cutting off the young plants at the surface of the soil is so familiar to every j^lanter and trucker that no discussion of their life-history and habits is here necessary. The best method for their destruction is by distributing through the field bunches of clover or grass poisoned with Paris green. This may be best done by spraying a patch of grass or clover with the poison, then cutting it, loading it on a wagon, and scattering bunches over the field with a fork. For best results such traps should be spread over the field just as the plants are appearing above ground, or even a day or two before; some care is necessary in so doing this that it will not result in injuring the young leaves. Grasshoppers. A much similar treatment will prove effectual for grass- hoppers, which frequently do considerable damage to the foliage. Twenty-five pounds of bran, one pound of white arsenic, mixed dry and then slightly moistened with water and cheap molasses, will form an excellent '^ mash "for their destruction, by placing a teaspoonful at the base of 196 INSECTS INJURIOUS TO STAPLE CROPS. each plant. Some fourteen different kinds of grasshoppers have been known to injure cotton, but of these the Ameri- can Acridium (Schistocerca americana) and the Differential Locust (see page 69) are the most injurious. Fig. 109. — Granulated Cut-worm {Agrotis nnnexa). n, larva; /, pupa; h, adult— natural size. (After Howard, U. S Dept. Agr. ) Fig. 110. — The American Acridium [Schistocerca americana Scud.). (After Riley.) Caterpillars. Many species of Lepidopterous larva3 occasionally defoli- ate the cotton-plant, among the most common being the Bag-worm {Tliyridopteryx ejjhemerceformis), Fall Army- worm {Laphygma frxigiperda) (see page 84), Garden Web- worm (Loxostege swiilalis) (see page 260), and the Leaf- roller {Caccecia rosaceana). Any of these may be destroyed INSECTS INJURIOUS TO COTTON. 197 by applying Paris green in a spiay or dust, as for the cotton-worms. Ftg. 111. — Garden Web-worm {Loxostege similalis). r^ larva, en- larged; b, side view of abdominal segment of same; c, dorsal view of anal segment; d. pupa; /, moth, enlarged. (After Riley, U. S. Dept. Agr.) Plant-lice {ApMclcB). The plant-louse which is most frequently found injuring the leaves of the cotton-plant is the same as the melon- louse {Aphis gossypii). As upon melons, its worst injury is done while the jDlants are yet young, and in such cases the best practice is to destroy the infested plants and replant in their place. A spray of kerosene emulsion and water or similar irritant will kill them, and sometimes may be used to advantage; but owing to the rapid and hardy growth of the plant, and the fact that large numbers of them are consumed by their insect enemies, plant-lice are seldom of any great importance. INJURING THE STALK. If it escapes the cutworms, the stalk of the plant will not be troubled further with insects, as long as it is in a healthy condition. Occasionally plant-bugs i^uncture the new growth, but such damage is rarely of importance. One of the boring-beetles, known as Ataxia crypt a (Fig. 112), has been supposed to injure the stalk by boring in 198 INSECTS INJURIOUS TO STAPLE CROPS. it, but investigation shows that its eggs are hiid only upon stalks which have already been damaged in some other manner. Fig. 112. — Cotton Stalk borer (At ixi i crypta). a, larva from above; b, larva from side; e, tunneled cotton-stalk showing exit-hole; d, adult beetle — all enlarged except c. (After Howard, U. S. Dept. Agr.) INJURING THE BOLL. Sharpshooters. Bolls are frequently damaged by leaf-hoppers, known to scien(3e as Homnlodisca coagtdata, which injury is termed "Sharpshooter work" by the planters. Usually they do not make their appearance till after the first of June. Before that they prefer the foliage of poplar and other shade trees near the cotton-field. Where the injuries are of annual occurrence it would be well to ascertain the trees npon which the insects are feeding, early in the season, and give them and neighboring nndergrowth a INSECTS INJURIOUS TO COTTON. 199 thorough spraying with strong kerosene emulsion during May. Fig. 113. — Houmdodisca coagulata. a, adult female seen from above; b, same, side view. (After Howard, U. S. Dept. Agr.) "Cotton-stainer." The Red Bug or Cotton-stainer [Dysdercns S7iturelhis) once did considerable damage to the bolls in Florida, Georgia, and neighboring parts of Alabama and South Carolina, but of late years has devoted most of its atten- tion to oranges. Early in the season they stunted the bolls and made them abortive by sucking the sap; but the most serious damage was done later, when they entered the open bolls, *' puncturing the seed and damaging the 200 INSECTS INJURIOUS TO STAPLE CROPS. fibre " by their yellowish excrement. This indelible stain greatly depreciated the market valne of the fibre, and was a vexing loss. Thongli never of commerical impor- tance, it was found by experiments that a rich orange dye could be made from these insects, which could be easily Fig. 114. — The Red Bug or Cotton-stainer {Dysdercus suturellus) enlarged. «, nymph; h, adult. (From "Insect Life.") fixed upon silks and woolens by an alum mordant. In winter these insects congregate in heaps of cotton-seeds, and by using these as traps the insects may be killed with hot water. Several other insects attack the bolls, but never very extensively. Among them is a weevil {Aroecerus fascicu- latus) often mistaken for the Mexican Boll-weevil and which closelv resembles that insect. It is a '^ cosmonolitan ^2s^. % S; 2 — Jll 5r^iio2"^^ c X a t^ ^ .9 =^ s =i « X ,, .9 ^ ^ g '-5 ^ t; u S > Q -13 >~ -^ a C .= .t -. t; -* ^ ^ "^ :^ -^ P r^'^^ 2 2 I , • _ o^ aj^iil 5i)2 Sh^ II^SECTS IXJURIOrS TO rOTTO>s". 201 insect living in the pods of various j^lants, among others in those of the coffee-plant in Brazil, but is never shown to attack healthy plants." Various leaf-eating caterpillars often gnaw the bolls, but will be destroyed by poisoning the foliage as previously described. If the Paris green be applied for the Cotton-worm, and the general methods advised for the control of the Boll- worm and Mexican Boll-weevil be followed out, little fear need be had of these minor insects, though a knowledge of the best remedies for them is always desirable in case of their apppearing in unusual numbers. The Cotton Boll-worm {Heliothis armiger Hubn.). The Cotton Boll-worm is one of the pests most widely dreaded by the cotton-grower, and differs from the Cotton- w^orm in that it is found in other parts of the world as well as America, and is not restricted to a single plant-food. Tlie Moth. — The adult moth is about the same size as the Cotton-worm moth, but has a larger body and a greater variety of markings. AVhen at rest the fore wings of the Cotton Boll-worm moth are slightly parted, while in the Cotton-worm moth they are closed. The Boll-worm moth varies much in color; both wings are bordered with dark bands, the wing-veins are black, and there are other black spots upon the fore wings. It may generally be seen about dark, and hides itself during the day in cow-peas and clover, sipping the honey from the blossoms of these and other honey-secreting plants, but does not, like the Cotton- worm moth, feed upon fruit. Li fe-histor I/.— It deposits its yellowish-white eggs uj^on all parts of the cotton-plant, but prefers the silk and g02 INSECTS INJURIOUS TO STAPLE CROPS. tassels of corn. If hatched on the cotton-plant, the worms attack the young buds or bolls, rapidly destroying them. The young worms resemble the cotton-worms, and walk like the familiar measuring- worms, but are darker in color. With age the worms exhibit great variety in appearance, from light green to dark brown or rose, and may be either striped or spotted or perfectly plain. The life of the insect from egg to adult averages about thirty-eight days, and there are usually five generations each year. The worms of the first brood, as a rule, appear about the first of May, and feed almost entirely upon the young leaves and buds of the corn; the second brood, appearing in early June, eat the tassels and forming ears of corn; the third brood, in July, attack the hardening ears. The fourth and fifth broods, appearing successively in August and September, appreciate the cotton as food, the corn having become too hard. About the middle of October the worms of the last brood descend into the earth to pupate, which state lasts from one to four weeks. Food. — The worm is known by various names according to the plant upon which it feeds, as, for instance, the Cotton Boll-worm, the Corn Ear-worm (see page 151), and the Tomato Fruit-worm. It is also foujid upon peas, beans, tobacco, pumpkins, squash, and many flowering plants. A strange but mitigating characteristic of this pest is its tendency to feed upon its kind, especially if large numbers are crowded together, thus materially reducing its own numbers. Iiemedies. — Poisoning the young worms by spraying with arsenic was a method formerly used, but as it proved only partially successful, and as another and better method has been discovered, it is now comparatively little used. IJ^SECTS INJURIOUS TO COTTON. 203 The more effective method of keeping the insect in con- trol is the result of practical experience, aud consists in tlio wise use of what are known as trap crops. Let five acres be planted with cotton and corn alternately with every seventy-five or one hundred acres of cotton, or in the same relative proportion for smaller areas. Of tlie five acres, for every twenty-five rows of cotton let five rows be left vacant. In these five vacant rows plant, as early as possi- ble, one row of an early-maturing sweet corn, planted sparsely, as only a small number of plants are desired. During the silking jjeriod let frequent search be made for the yellowish-white eggs, and when fresh eggs can no longer be found let the silk ends of the corn covered with eggs and young worms be cut off and destroyed by burn- ing or feeding to stock; or better still, to insure perfect safety, let the entire plant be destroyed. Let three other rows be planted with dent corn so as to bring the silking 2:>eriod about tlie first of July. The larger number of eggs which will be laid on these three rows should be allowed to mature for the preservation of the natural enemies which parasitize the eggs and young worms. The crowded condition of the worms in these rows will result in a large amount of cannibalism, so that only a small number will reach maturity, recompense for which will be found in the parasites. But to entrap these individuals, let the fifth row be planted so as to reach the silking period about August first, and let this row be cut and destroyed as soon as the laying of eggs upon it ceases. It has been found that the corn produced from the second planting will generally pay for the expense of cultivation and the sacri- fice of the five rows of corn. In many cases, if the other two be properly cared for, the third planting will not be 204 INSECTS INJURIOUS TO STAPLE CROPS. 5 ACRES CORN AND COTTON *^ o 05 P 5 ACRES CORN AND COTTON P§P o r Is ii 5 ACRFS CORN AND COTTON o8 rr i?; oi Q O H <1 O g o m Jz; o O < Q lO o cc ^ 03 O o C_( < Q o O !z; 03 o o Eh ir^ O cc !z; O 03 O Q anica. (After Riley.) appears again much like the second stage, but does not eat much, and soon goes into the pupal stage from which emerges the adult beetle. Altogether the life-history is one of the most peculiar and complicated among insects. Thus the Blister-beetles are one of the most important factors in holding the grasshoppers in check, Bemedies. — However, when they swarm into the beet- fields, potato- or garden-patches, one cannot afford to allov/ them to consume one crop for the good they may do in saving anotlier from still another insect scourge. "A bird in the hand is worth two in the bush," is equally true of insects. So l)e ready for them on their first appearance; give the plants a thorough spraying with Paris green, ut the rate of one pound and one pound of lime to 125 gallons 268 INSECTS INJURIOUS TO STAPLE CROPS. of water, aud when sprayed, it would be well to spray it with Bordeaux mixture, which will prevent various fun- gous diseases, and with which Paris green can be used much stronger without danger of burning the foliage; or it may be applied dry by mixing with from ten to twenty parts of flour or plaster, dusting it on in early morning, while the dew is still on the plants. Any other arsenical poison will prove equally effective, if used at the proper strength. CHAPTER XIV. INSECTS INJURIOUS TO THE HOP-PLANT. IXJURIN'G THE STALK. The Hop-plant Borer [Hydrcecia immanis Grt.). The Hop-plant Borer is sometimes the occasion of a considerable loss to the hop indnstry, Mr. Chas. R. Dodge having estimated upon the basis of the census of 1879 that it annually amounts to 1600,000 in New York State alone. The moths have been taken from Ontario and New Eng- land south to the District of Columbia, and west to Wisconsin, and also from Colorado and Washington, but the larvae have never become injurious in the hop-fields of the Pacific Coast. *^It is probable that it is a northern form, and confined, as it seems to be, to a single food- plant, it will be found only where this plant is known to grow. '^ * Life-liisfory. — Many of the moths emerge from the pupae in the fall and hibernate over winter, while others do not transform till spring, passing the winter in the pupal stage, in a small cell in the ground near the roots of the plant which the larvae have infested. The moths appear during May, and the females deposit their globular, * "Some Insects Affecting the Hop-plant," L. O. Howard, Bull No. 7, n. s., Div. Ent., U. S. Dept. Agr., p. 41. 270 INSECTS INJURIOUS TO STAPLE CROPa yellowish-green eggs upon the tips of the hop-vines just as they begin to climb. '^ The egg hatches in a few days and produces a minute slender greenish larva, spotted with black, which immediately burrows into the vine just below the tip, and spends a part of its life in the vine at this point. The vine soon shows the effects of the insects^ Fig. 154.— Hop-plant Borer {Hydrceda immanis Grt.). a, enlarged segment of larva; b, larva; c, pupa; d, adult, natural size. (After Howard, U. S. Dept. Agr.) work; instead of pointing upward, embracing the pole readily and growing rapidly, the tip points downward, will not climb, and almost entirely ceases growing. This appearance is called by growers a 'Muffle-head.^ When the insect attains a length of about half an inch, or slightly less, it leaves the tip, drops to the ground, and entering the stem at the surface of the vine, feeds upward, interrupting the growth of the vine and lessening its vitality; the larva now changes color, and becomes a dirty- white, with a strong, deep reddish tint, with numerous black spots. The larva, now about an inch in length, and INSECTS INJURIOUS TO THE HOP-PLANT. 271 still slender, burrows downward to the base of the vine at its juncture with the old stock, and eating its way out, completes its growth as a subterranean worker; it is in this state that it is best and most widely known as the hop ' grub,'' and the ravages caused by it are most noted/' * The larvae have mostly left the stems by the last of June and henceforth are mainly sap-feeders. Eating into the stem just below the surface of the ground and just above the old root, they rapidly grow fat upon the juices of the plant. These openings are gradually enlarged so that very often the stem is entirely severed from the root or is so slightly attached that the plant is badly stunted and yields few, if any, hops. The larvfB become full-grown from the middle to the l^Oth of July and are then ^' about two inches in length, fleshy, unwieldy, and very slow in their movements; they are of a dirty white color, speckled with fine, brownish elevated tubercles, each furnished with a single stout hair; the head is brownish and corneous, as is also the top of the first segment." (I.e.) The larva3 now transform to pupa3 in rough cells, close to the roots which they have infested, and the adult moths emerge during August or Se]3tember, or the following spring. The adult moths are found to be most beautifully marked upon close examination, though not of a striking appearance at first sight. '^The general color is a rosy brown, paler at the extremity of the w^ngs. The darker central portion is shaded with dark velvety bronze and marked with two dull-yellow spots. The fore wings are divided into three areas by narrow oblique transverse lines, * ''Hop-insects," Dr. J. B. Smith, Bull. No. 4, o. s., Div. Ent. U. S. Dept. Agr. 272 INSECTS INJURIOUS TO STAPLE CROPS. edged outwardly with pink. The hind wings are jiaier in color, crossed in the middle by a slightly darker line." (Howard, I.e.) Remedies. — Two points in the life-history of the insect afford opportunity for its control. The first of these is when the young larv^ are still in the tips and can easily be crushed by the fingers when tying the vines. ^' Muffle- heads" should always be picked off and destroyed. Early in June when the larvse have left the inside of the vines it is well to remove all the soil from the base of the vine, down to the junction with the old root. The larvas, which will not feed above ground, will go to the old roots, to which they will do but little injury. The roots should be left thus exposed for about a week. A handful of mixture of coal and wood ashes or ammoniated phosphate should then be applied to each and the plants hilled high. The plant will now send out new rootlets from the main root, and is able to secure necessary nour- ishment through them. INJURING THE LEAVES. The Hop-louse {Pliorodon humuli Schr.). Like many another aphid the Hop-louse has a most interesting life-history, which has been fully ascertained in but recent years. During the winter the small oval black eggs may be found in the crevices aad around the buds of the terminal twigs of plum-trees near infested hop- fields. From these hatch a generation of females, known as ^^stem-mothers," during the following spring. The lice of this generation differ in being stouter, with shorter legs and honey-tubes than those of any otlier geiu^ration. Three generations feed upon the plum, the third becoming INSECTS INJUKIOUS TO THE HOP-PLANT. 273 winged and at once flying to its favorite food in the hop- field. Throughout the summer the lice are j^roduced partheno- genetically, as are almost all plant-lice (see page 136). They " multiply with astonishing rapidity for from five to twelve generations, carrying us in point of time to the hop-picking season.'' '^Each parthenogenetic female is capable of producing on an average one hundred young Fig. 155.— Winter Eggs of the Hop Plant-louse, and shriv- eled skin of the sexual female which laid them — enlarged. (After Riley, U. S. Dept. Agr. ) Fig. 156.— The Hop Plant-louse, stem -mother, with enlarged an- t'mmie above. (After Riley, U. S. Dept. Agr.) (the stem-mother probably being more prolific), at the rate of one to six, or an average of three ^qv day^ under favor- able conditions. Each generation begins to breed about the eighth day after birth, so that the issue from a single individual easily runs up, in the Nectaraphora aveucT, 115 pisi, 182, 183 Noctua clandestiua, 150 Noctuiche, 150 Nysius angustatus, 263 Ophion, 41 macrurum, 42 Orthoptera, 10 Oscinis variabilis, 114 Pachynematus extensicornis, 119 Pachyonerus calcitrator, 98 Pachyrrhinis sp., 90 Palpus, 13 Panicum glabrum, 135 Paragreue, 287 Parajulus impressus, 239 Parasites, 89 Paris green, 285 Parthenogenesis, 136 Pea-louse, 182 Pemphigus betse, 255 Peridromia saucia, 257 Phorodon humuli, 272 Phragmites communis, 143 Phyltotreta vittata, 264 Phytononus punctatus, 177 Pimpla conquisitor, 190 Inquisitor, maggots, 41 Pipiza radicans, 35 Planting, Time of, 28 Plant-louse, mouth-parts, lo Plodia interpunctella, 160, 161 Plowing, Deep fall, 24 Poa pratensis, 111 Poisons, 285 Polygonia comma, 282 interrogationis, 279 Polygonum persicaria, 135 Portulaca solacea, 135 Potato-beetle, Colorado, 243 Potatoes, Injury to, 4 Potato insects, 239 Scab, 239 Stalk-borer, 2, 24, 241 Poultry, 26 Predaceous insects, 30 Proctotrypid*, 43 Protoparce Carolina, 231 celeus, 231 Pyralidte, 260 Pyralis costalis, 186 farinalis, 160, 161 Pyrethrum, 18, 289 Kesin-lime mixture, 288 Respiratory system, 17 Rice-weevil, 26, 155 Root-lf)use, Corn, 134 Grass, 134 Syrphus-tly, 35 Rotation of crops, 28 San Jose Scale, 21 Sarcopliaga carnaria, 65 Sawflies, Wheat, 19 Schizoneura panicola, 134 Schistocerca americana, 12, G7. 71, 196 Sciara sp. ?, 239 Scirpus tiuviatilis, 143 Semicolon butterfly, 279 Sesame grass, 149 Setaria viridis. 111 Sharpshooters, 198 Silkworm, Internal anatomy, 18 Silvanus surinamensis, 156, 157 Sitotroga cerealella, 162 Solanum carolinense, 228 datura, 245 South African fungus, 77 Sphenophorus ochreus, 143 obscurus, 141 parvulus, 141 pertinax, 144 placid us, 144 robustus, 142 scoparius, 144 sculptilis, 144 Spiracles, 15, 16 Sporotrichum globuliferum, 56 Squash-bug. 24 Structure of an insect, 6 Suck fly, Tobacco, 224 Sugar-beet insects, 252 Web worm, 260 INDEX. 295 Sugar-cane borer, 21 Sulphur, 290 Syrphidse, 34 Syrphus americana, 35 -flies, 34 ribesii, 35 Systena hudsonias, 264 tseniata, 264 Systoechus oreas, 63 Tachina-flies, 63 Tarnished plant- bug, 263 Tenebriodes mauritanicus, 158, 159 Tetranychidse, 179 Three-lined leaf -beetle, 252 Thyridopteryx ephemeraeformis, 196 Tipula bicornis, 90 costalis, 90 hebes, 91 Tipulida?, 90 Trachea, 16, 18 Trap-crops, 26 Trichobaris trinotata, 24 Trichograrama pretiosa, 192 Tripsacum dactyloides, 149 Trombidium locustarum, 63, 64 Tobacco bud -worms, 220 -bug, Spined, 219 Tobacco dust, 18 Flea-beetle, 229 Injury to, 4 Insecticide, 289 Insects, 214 Leaf-miner, 227 Stalk- worm, 217 -worm, 231 Web worms, Beet, 259 Corn-root, 130 Weeds, 23 Weevil, Grain, 155 Western Corn root-w^orm, 29 125 Whale-oil soap, 18, 289 Wheat insects, 90 Isosoma, 29 Joint-worm, 22, 24, 93 -louse, 115 Plant-louse, 29 -maggots, 111 ■midge, 122 Saw-tiies, 119 Saw-fly borer, 97 Stem- maggot. 111 Straw-w^orm, 96 White grubs, 28, 44:, 252 Winthemia 4-pustulata, 83 AVireworms, 24, 28, 29, 48, 252 SHORT-TITLE CATALOGUE OF THE PUBLICATIONS OF JOHN WILEY & SONS,. 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Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe 12mo, morocco, 1 50 Furman's Manual of Practical Assaying Svo, 3 00 Miller's Manual of Assaying 12mo, 1 00 O'DriscoU's Notes on the Treatment of Gold Ores Svo, 2 00 Ricketts and Miller's Notes on Assaying. Svo, 3 00 Wilson's Cyanide Processes 12mo, 1 50 " Chlorination Process -. 12mo, 1 50 ASTRONOMY. Craig's Azimuth 4to, 3 50 Doolittle's Treatise on Practical Astronomy Svo, 4 00 Oore's Elements of Geodesy Svo, 2 50 Hayford's Text-book of Geodetic Astronomy Svo, 3 00 Merriman's Elements of Precise Surveying and Geodesy Svo, 2 50 * Michie and Harlow's Practical Astronomy Svo, 3 00 * White's Elements of Theoretical and Descriptive Astronomy. 12mo, 2 00 BOTANY. 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Boiler's Practical Treatise on the Construction of Iron Highway Bridges Svo, 2 00 * Boiler's Thames River Bridge 4to, paper, 6 OO Burr's Course on the Stresses in Bridges and Roof Trusses, Arched Ribs, and Suspension Bridges Svo, 3 50 Du Bois's Stresses in Framed Structures Small 4to, 10 00 Foster's Treatise on Wooden Trestle Bridges 4to, 5 OO Fowler's Coffer-dam Process for Piers Svo, 2 50 Greene's Roof Trusses 8vo, 1 25 " Bridge Trusses 8vo, 2 50 " Arches in Wood, Iron, and Stone Svo, 2 50 Howe's Treatise on Arches 8vo, 4 00 6 Johnson, Bryan and Turneaure's Theory and Practice in the Designing of Modern Framed Structures Small 4to, 10 00 Meniman and Jaeoby's Text-book on Roofs and Bridges: Part I.— Stresses in Simple Trusses 8vo, 2 50 Part II.— Graphic Statics 8vo, 2 00 Part III.— Bridge Design. 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Public Water-supplies Svo, Wegmann's Design and Construction of Dams 4to, " Water-supply of the City of New York from 165S to 1895 4to, Weisbach's Hydraulics and Hydraulic Motors. (Du Bois.) . .Svo, Wilson's Manual of Irrigation Engineering Small Svo, Wolff's Windmill as a Prime Mover Svo, Wood's Turbines Svo, " Elements of Analytical Mechanics Svo, MATERIALS OF ENGINEERING. Baker's Treatise on Masonry Construction Svo, Black's United States Public Works Oblong 4to, Bovey's Strength of Materials and Theory of Structures. . . .Svo, 7 " 2 00 5 00 6 00 2 50 3 00 4 00 5 00 1 50 2 50 4 OO 3 00 2 50 2 00 5 00 4 00 4 00 5 00 5 00 5 00 10 OO 5 OO 4 00 3 OO 2 60 3 OO 5 OO 5 OO 7 50 Burr's Elasticity and Eesistance of the Materials of Engineer- ing ,..8va, 5 00 Byrne's Highway Construction 8vo, 5 00 " Inspection of the Materials and Workmanship Eim- ployed in Construction 16mo, 3 00 Church's Mechanics of Engineering 8vo, 6 00 Du Bois's Mechanics of Engineering. Vol. I Small 4to, 10 00 Johnson's Materials of Construction Large Svo, 6 00 Keep's Cast Iron. {In preparation.) Lanza's Applied Mechanics Svo, 7 50 Martens's Handbook on Testing Materials. (Henning.) 2 vols., Svo, 7 50 Merrill's Stones for Building and Decoration *. . Svo, 6 00 Merriman's Text-book on the Mechanics of Materials Svo, 4 00 Merriman's Strength of Materials 12mo, 1 00 Metealfs Steel. A Manual for Steel-users 12mo, 2 00 Patton's Practical Treatise on Foundations Svo, 5 00 Rockwell's Roads and Pavements in France 12mo, 1 25 Smith's Wire: Its Use and Manufacture Small 4to, 3 00 Spalding's Hydraulic Cement 12mo, 2 00 " Text-book on Roads and Pavements 12mo, 2 00 Thurston's Materials of Engineering 3 Parts, Svo, 8 00 Part I. — Non-metallic Materials of Engineering and Metal- lurgy Svo, 2 00 Part II.— Iron and Steel Svo, 3 50 Part III. — A Treatise on Brasses, Bronzes and Other Alloys and Their Constituents Svo, 2 50 Thurston's Text-book of the Materials of Construction Svo, 5 00 Tillson's Street Pavements and Paving Materials Svo, 4 00 Waddell's De Pontibus. (A Pocket-book for Bridge Engineers.) 16mo, morocco, 3 00 " Specifications for Steel Bridges 12mo, 1 25 Wood's Treatise on the Resistance of Materials, and an Ap- pendix on the Preservation of Timber Svo, 2 00 " Elements of Analytical Mechanics Svo, 3 00 RAILWAY ENGINEERING. Berg's Buildings and Structures of American Railroads. .4to, 5 00 Brooks's Handbook of Street Railroad Location.. 16mo, morocco, 1 50 Butts's Civil Engineer's Field-book 16mo, morocco, 2 50 Crandall's Transition Curve 16mo, morocco, 1 50 " Railway and Other Earthwork Tables Svo, 1 50 Dawson's Electric Railways and Tramways. Small 4to, half mor., 12 50 " " Engineering " and Electric Traction Pocket-book. 16mo, morocco, 4 00 Dredge's History of the Pennsylvania Railroad: (1879.) .Paper, 5 00 • Drinker's Tunneling, Explosive Compounds, and Rock Drills. 4to, half morocco, 25 00 Fisher's Table of Cubic Yards Cardboard, 25 Oodwin's Railroad Engineers' Field-book and Explorers' Guide. 16mo, morocco, 2 50 Howard's Transition Curve Field-book 16mo, morocco, 1 50 Hudson's Tables for Calculating the Cubic Contents of Exca- vations and Embankments Svo, 1 00 Nagle's Field Manual for Railroad Engineers 16mo, morocco, 3 00 Philbrick's Field Manual for Engineers 16mo, morocco, 3 00 Pratt and Alden's Street-railway Road-bed Svo, 2 00 Searles's Field Engineering 16mo, morocco, 3 00 " Railroad Spiral 16mo, morocco, 1 50 Taylor's Prismoidal Formulae and Earthwork 8vo, 1 50 * Trautwine's Method of Calculating the Cubic Contents of Ex- cavations and Embankments by the Aid of Dia- grams 8vo, 2 00 * " The Field Practice of Laying Out Circular Curves for Railroads 12mo, morocco, 2 50 * " Cross-section Sheet Paper, 25 Webb's Railroad Construction 8vo, 4 00 Wellington's Economic Theory of the Location of Railways. . Small Svo, 5 00 DRAWING. Barr's Kinematics of Machinery Svo, 2 50 * Bartlett's Mechanical Drawing Svo, 3 00 Durley's Elementary Text-book of the Kinematics of Machines . {In preparation.) Hill's Text-book on Shades and Shadows, and Perspective. . Svo, 2 00 Jonee's Machine Design: Part I. — Kinematics of Machinery Svo, 1 50 Part II. — Form, Strength and Proportions of Parts Svo, 3 00 MacCord's Elements of Descriptive Geometry Svo, 3 00 " Kinematics; or. Practical Mechanism Svo, 5 00 " Mechanical Drawing 4to, 4 00 " Velocity Diagrams Svo, 1 50 * Mahan's Descriptive Geometry and Stone-cutting Svo, 1 50 Mahan's Industrial Drawing. (Thompson.) Svo, 3 60 Reed's Topographical Drawing and Sketching 4to, 6 00 Reid's Course in Mechanical Drawing Svo, 2 00 " Text-book of Mechanical Drawing and Elementary Ma- chine Design Svo, 3 00 Robinson's Principles of Mechanism Svo, 3 00 Smith's Manual of Topographical Drawing. (McMillan.) .Svo, 2 50 Warren's Elements of Plane and Solid Free-hand Geometrical Drawing 12mo, 1 00 " Drafting Instruments and Operations 12mo, I 25 " Manual of Elementary Projection Drawing. .. .12mo, 1 50 " Manual of Elementary Problems in the Linear Per- spective of Form and Shadow 12mo, 1 00 " Plane Problems in Elementary Geometry 12mo, 1 25 " Primary Geometry 12mo, 75 " Elements of Descriptive Geometry, Shadows, and Per- spective Svo, 3 50 " General Problems of Shades and Shadows Svo, 3 00 " Elements of Machine Construction and Drawing. .Svo, 7 50 " Problems, Theorems, and Examples in Descriptive Geometry Svo, 2 50 Weisbach's Kinematics and the Power of Transmission. (Herr- mann and Klein.) Svo, 5 00 Whelpley's Practical Instruction in the Art of Letter En- graving 12mo, 2 00 Wilson's Topographic Surveying Svo, 3 50 Wilson's Free-hand Perspective Svo, 2 5d Woolf's Elementary Course in Descriptive Geometry. .Large Svo, 3 00 ELECTRICITY AND PHYSICS. ' Anthony and Brackett's Text-book of Physics. (Magie.) Small 8vo, 3 00 Anthony's Lecture-notes on the Theory of Electrical Measur- ments 12mo, 1 00 Benjamin's History of Electricity 8vo, 3 00 Benjamin's Voltaic Cell 8vo, 3 00 Classen's Qantitative Chemical Analysis by Electrolysis. Her- rick and Boltwood.) 8vo, 3 00 Crehore and Squier's Polarizing Photo-chronograph 8vo, 3 00 Dawson's Electric Railways and Tramways.. Small 4to, half mor., 12 50 Dawson's " Engineering " and Electric Traction Pocket-book. 16mo, morocco, 4 00 Flather's Dynamometers, and the Measurement of Power. . 12mo, 3 00 Gilbert's De Magnete. (Mottelay.) 8vo, 2 60 Holman's Precision of Measurements 8vo, 2 OO " Telescopic Mirror-scale Method, Adjustments, and Tests Large 8vo, 75 Landauer's Spectrum Analysis. (Tingle.) 8vo, 3 00 Le Chatelier's High- temperature Measurements. (Boudouard — Burgess.) 12mo, 3 00 LOb's Electrolysis and Electrosynthesis of Organic Compounds. (Lorenz.) 12mo, 1 00 Lyons's Treatise on Electromagnetic Phenomena 8vo, 6 00 * Michie. Elements of Wave Motion Relating to Sound and Light 8vo, 4 00 Niaudet's Elementary Treatise on Electric Batteries (Fish- back.) 12mo, 2 50 • Parshall and Hobart's Electric Generators..Small 4to, half mor., 10 00 Thurston's Stationary Steam-engines 8vo, 2 50 * Tillman. Elementary Lessons in Heat 8vo, 1 50 Tory and Pitcher. Manual of Laboratory Physics . . Small 8vo, 2 00 LAW. • Davis. Elements of Law 8vo, 2 60 * " Treatise on the Military Law of United States. .8vo, 7 Od ♦ Sheep, 7 50 Manual for Courts-martial 16mo, morocco, 1 50 Wait's Engineering and Architectural Jurisprudence 8vo, 6 00 Sheep, 6 50 " Law of Operations Preliminary to Construction in En- gineering and Architecture 8vo, 5 00 Sheep, 5 50 " Law of Contracts 8vo, 3 00 Winthrop's Abridgment of Military Law 12mo, 2 50 MANUFACTURES. Beaumont's Woollen and Worsted Cloth Manufacture. . . . 12mo, 1 50 Bernadou's Smokeless Powder — Nitro-cellulose and Theory of the Cellulose Molecule i2mo, 2 50 Bolland's Iron Founder 12mo, cloth, 2 50 " The Iron Founder " Supplement 12mo, 2 50 " Encyclopedia of Founding and Dictionary of Foundry Terms Used in the Practice of Moulding. . . .12mo, 3 00 Eissler's Modem High Explosives 8vo, 4 00 Eflfront's Enzymes and their Applications. (Prescott.) {In preparation,} Fitzgerald's Boston Machinist 18mo, 1 OO 10 Ford's Boiler Making for Boiler Makers 18mo, 1 OO Hopkins's Oil-chemists' Handbook 8vo, 3 OO Keep's Cast Iron. (In preparation.) Metealf 8 Steel. A Manual for Steel-users 12mo, 2 OO Metcalfs Cost of Manufactures — ^And the Administration of Workshops, Public and Private 8vo, 5 00 Meyer's Modem Locomotive Construction 4to, 10 00 * Reisig's Guide to Piece-dyeing Svo, 25 OO Smith's Press-working of Metals Svo, 3 00 " Wire : Its Use and Manufacture Small 4to, 3 00 Spalding's Hydraulic Cement 12mo, 2 OO Spencer's Handbook for Chemists of Beet-sugar Houses. 16mo, morocco, 3 OO " Handbook for Sugar Manufacturers and their Chem- ists 16mo, morocco, 2 OO Thurston's Manual of Steam-boilers, their Designs, Construc- tion and Operation Svo, 5 OO Walke's Lectures on Explosives Svo, 4 00 West's American Foundry Practice 12mo, 2 60 " Moulder's Text-book 12mo, 2 50 Wiechmann's Sugar Analysis Small Svo, 2 50 Wolff's Windmill as a Prime Mover Svo, 3 00 Woodbury's Fire Protection of Mills Svo, 2 50 MATHEMATICS. Baker's Elliptic Functions Svo, 1 50 * Bass's Elements of Differential Calculus 12mo, 4 00 Briggs's Elements of Plane Analytic Geometry 12mo, 1 00 Chapman's Elementary Course in Theory of Equations. . .12mo, 1 50 Compton's Manual of Logarithmic Computations 12mo, 1 50 Davis's Introduction to the Logic of Algebra Svo, 1 50 Halsted's Elements of Geometry Svo, 1 75 " Elementary Synthetic Geometry Svo, 1 60 Johnson's Three- place Logarithmic Tables : Vest-pocket size, pap., 15- 100 copies for 5 00 Mounted on heavy cardboard, S X 10 inches, 25- 10 copies for 2 OO " Elementary Treatise on the Integral Calculus. Small Svo, 1 50 " Curve Tracing in Cartesian Co-ordinates 12mo, 1 OO " Treatise on Ordinary and Partial Differential Equations Small Svo, 3 50 " Theory of Errors and the Method of Least Squares 12mo, * " Theoretical Mechanics 12mo, •Ludlow and Bass. Elements of Trigonometry and Logarith- mic and Other Tables Svo, « Trigonometry. Tables published separately. .Each, Merriman and Woodward. Higher Mathematics Svo, Merriman's Method of Least Squares Svo, Rice and Johnson's Elementary Treatise on the Differential Calculus Small Svo, " Differential and Integral Calculus. 2 vols. in one Small Svo, Wood's Elements of Co-ordinate Geometry Svo, " Trigometry: Analytical, Plane, and Spherical 12mo, 1 OO 11 1 50 3 OO 3 00 2 00 5 00 2 0© 3 OO 2 50 2 OO MECHANICAL ENGINEERING. MATERIALS OF ENGINEERING, STEAM ENGINES AND BOILERS. Baldwin's Steam Heating for Buildings 12 mo, Barr's Kinematics of Machinery 8vo, * Bartlett's Mechanical Drawing 8ve, Benjamin's Wrinkles and Recipes 12mo, Carpenter's Experimental Engineering 8vo, " Heating and Ventilating Buildings Svo, Clerk's Gas and Oil Engine Small Svo, Cromwell's Treatise on Toothed Gearing 12mo, " Treatise on Belts and Pulleys 12mo, Durley's Elementary Text-book of the Kinematics of Machines. {In preparation.) Flather's Dynamometers, and the Measurement of Power . . 12mo, " Rope Driving 12mo, Cill's Gas an Fuel Analysis for Engineers 12mo, Hall's Car Lubrication 12mo, Jones's Machine Design: Part I. — Kinematics of Machinery Svo, Part II. — Form, Strength and Proportions of Parts Svo, Kent's Mechanical Eiigineers' Pocket-book 16mo, morocco, Kerr's Power and Power Transmission. {In preparation.) MacCord's Kinematics; or. Practical Mechanism Svo, '* Mechanical Drawing 4to, " Velocity Diagrams Svo, Mahan's Industrial Drawing. (Thompson.) Svo, Poole's Calorific Power of Fuels Svo, Reid's Course in Mechanical Drawing Svo, " Text-book of Mechanical Drawing and Elementary Machine Design Svo, Richards's Compressed Air 12mo, Robinson's Principles of Mechanism Svo, Smith's Press-working of Metals Svo, Thurston's Treatise on Friction and Lost Work in Machin- ery and Mill Work Svo, " Animal as a Machine and Prime Motor and the Laws of Energetics 12mo, Warren's Elements of Machine Construction and Drawing. .Svo, "Weisbach's Kinematics and the Power of Transmission. (Herr- mann—Klein.) Svo, " Machinery of Transmission and Governors. (Herr- mann—Klein.) Svo, " Hydraulics and Hydraulic Motors. (Du Bois.) .Svo, "Wolff's Windmill as a Prime Mover Svo, Wood's Turbines Svo, MATERIALS OF ENGINEERING. Bovey's Strength of Materials and Theory of Structures. .Svo, 7 50 Burr's Elasticity and Resistance of the Materials of Engineer- ing Svo, 5 00 'Church's Mechanics of Engineering Svo, 6 00 -Johnson's Materials of Construction Large Svo, 6 00 Keep's Cast Iron. {In preparation.) Ivanza's Applied Mechanics Svo, 7 50 IMartens's Handbook on Testing Materials. (Henning.) Svo, 7 50 -Merriman'9 Text-book on the Mechanics of Materials .... Svo, 4 00 Strength of Materials 12mo, 1 00 13 2 50 2 50 3 00 2 00 6 00 3 00 4 00 1 50 I 50 3 00 2 00 1 25 I 00 1 50 3 00 5 00 5 00 4 00 1 50 3 50 3 00 2 00 3 00 1 50 3 00 3 00 3 00 1 00 7 50 5 00 5 00 5 00 3 00 2 50 Metcalf s Steel. A Manual for Steel-users 12mo, 2 OO Smith's Wire: Its Use and Manufacture Small 4to, 3 00; Thurston's Materials of Engineering 3 vols., 8vo, 8 OO Part n.— Iron and Steel Svo, 3 5a Part III. — A Treatise on Brasses, Bronzes and Other Alloys and their Constituents Svo, 2 5a Thurston's Text-book of the Materials of Construction. . . .8vo, 5 oa Wood's Treatise on the Resistance of Materials and an Ap- pendix on the Preservation of Timber Svo, 2 00 " Elements of Analytical Mechanics Svo, 3 OO STEAM ENGINES AND BOILERS. Carnot's Reflections on the Motive Power of Heat. (Thurston.) 12mo, 1 5a Dawson's "Engineering" and Electric Traction Pocket-book. 16mo, morocco, 4 Oa Ford's Boiler Making for Boiler Makers 18mo, 1 Oa Hemenway's Indicator Practice and Steam-engine Economy. 12ma, 2 Oa Button's Mechanical Engineering of Power Plants Svo, 5 Oa " Heat and Heat-engines Svo, 5 Oa Kent's Steam-boiler Economy Svo, 4 00 Kneass's Practice and Theory of the Injector Svo, 1 50 MacCord's Slide-valves Svo, 2 Oa Meyer's Modern Locomotive Construction 4to, 10 00 Peabody's Manual of the Steam-engine Indicator 12mo, I 5a '' Tables of the Properties of Saturated Steam and Other Vapors Svo, 1 00 " Thermodynamics of the Steam-engine and Other Heat-engines Svo, 5 00 " Valve-gears for Steam-engines Svo, 2 50 Peabody and Miller. Steam-boilers Svo, 4 00 Pray's Twenty Years with the Indicator Large Svo, 2 50 Pupin's Thermodynamics of Reversible Cycles in Gases and Saturated Vapors. (Osterberg.) 12mo, 1 25 Reagan's Locomotive Mechanism and Engineering 12mo, 2 00 Rontgen's Principles of Thermodynamics. (Du Bois.) . . . .Svo, 5 00 Sinclair's Locomotive Engine Running and Management. .12mo, 2 00 Smart's Handbook of Engineering Laboratory Practice . . 12mo, 2 50 Snow's Steam-boiler Practice Svo, 3 00 Spangler's Valve-gears Svo, 2 50 " Notes on Thermodynamics 12mo, 1 00 Thurston's Handy Tables Svo, 1 5a " Manual of the Steam-engine 2 vols., Svo, 10 00 Part I.— History, Structure, and Theory Svo, 6 00 Part II. — Design, Construction, and Operation Svo, 6 Oa Thurston's Handbook of Engine and Boiler Trials, and the Use of the Indicator and the Prony Brake Svo, 5 00 " Stationary Steam-engines Svo, 2 50 " Steam-boiler Explosions in Theoiy and in Prac- tice 12mo, 1 50 " Manual of Steam-boilers, Their Designs, Construc- tion, and Operation Svo, 5 00 Weisbach's Heat, Steam, and Steam-engines. (Du Bois.). .Svo, 5 00 Whitham's Steam-engine Design Svo, 5 Oa Wilson's Treatise on Steam-boilers. (Flather.) 16mo, 2 5Q Wood's Thermodynamics, Heat Motors, and Refrigerating Machines Svo, 4 Oa 13 MECHANICS AND MACHINERY. Barr's Kinematics of Machinery 8vo, 2 50 Bovey's Strength of Materials and Theory of Structures. .8vo, 7 50 Chordal. — Extracts from Letters 12mo, 2 00 Church's Mechanics of Engineering 8vo, 6 00 " Note3 and Examples in Mechanics Svo, 2 00 Compton's First Lessons in Metal-working 12mo, 1 50 Compton and De Groodt. The Speed Lathe 12mo, 1 50 "Cromwell's Treatise on Toothed Gearing 12mo, 1 50 " Treatise on Belts and Pulleys 12mo, 1 50 Dana's Text-book of Elementary Mechanics for the Use of Colleges and Schools 12ma, 1 50 Dingey's Machinery Pattern Making 12mo, 2 00 Dredge's Record of the Transportation Exhibits Building of the World's Columbian Exposition of 1893 4to, half mor., 5 00 Du Bois's Elementary Principles of Mechanics: Vol. L— Kinematics Svo, 3 50 Vol. IL— Statics 8vo, 4 00 Vol. III.— Kinetics Svo, 3 50 Du Bois's Mechanics of Engineering. Vol. I Small 4ta, 10 00 Durley's Elementary Text-book of the Kinematics of Machines. (In preparation.) Fitzgerald's Boston Machinist 16ma, 1 00 Flather's Dynamometers, and the Measurement of Power. 12mo, 3 00 Kope Driving 12mo, 2 00 Hall's Car Lubrication 12mo, 1 00 Holly's Art of Saw Filing 18mo, 76 * Johnson's Theoretical Mechanics 12mo, 3 00 Jones's Machine Design: Part I. — Kinematics of Machinery Svo, 1 50 Part II. — Form, Strength and Proportions of Parts. .. .8vo, 3 00 Kerr's Power and Power Transmission. {In preparation.) Lanza's Applied Mechanics Svo, 7 50 MacCord's Kinematics; or. Practical Mechanism Svo, 5 00 " Velocity Diagrams Svo, 1 50 Merriman's Text-book on the Mechanics of Materials Svo, 4 00 * Michie's Elements of Analytical Mechanics Svo, 4 00 Reagan's Locomotive Mechanism and Engineering 12mo, 2 00 Reid's Course in Mechanical Drawing Svo, 2 00 " Text-book of Mechanical Drawing and Elementary Machine Design Svo, 3 00 Richards's Compressed Air 12mo, 1 50 Robinson's Principles of Mechanism Svo, 3 00 Sinclair's Locomotive-engine Running and Management. .12mo, 2 00 Smith's Press-working of Metals Svo, 3 00 Thurston's Treatise on Friction and Lost Work in Machin- ery and Mill Work Svo, 3 00 " Animal as a Machine and Prime Motor, and the Laws of Energetics 12mo, 1 00 Warren's Elements of Machine Construction and Drawing. .Svo, 7 50 Weisbach's Kinematics and the Power of Transmission. (Herrman — Klein.) Svo, 5 00 " Machinery of Transmission and Governors. (Herr- (man— Klein.) Svo, 5 00 Wood's Elements of Analytical Mechanics Svo, 3 00 " Principles of Elementary Mechanics 12mo, 1 25 " Turbines Svo, 2 50 The World's Columbian Exposition of 1893 4to, 1 00 14 METALLURGY. Egleston's Metallurgy of Silver, Gold, and Mercury: Vol. I —Silver 8vo, 7 50 Vol. II.— Gold and Mercury 8vo, 7 50 Keep's Cast Iron. (In preparation.) Kunhardt's Practice of Ore Dressing in Lurope 8vo, 1 50 Le Cha teller's High- temperature Measurements. (Boudouard — Burgess.) 12mo, 3 00 Metcalf's Steel. A Manual for Steel-users 12mo, 2 00 Thurston's Materials of Engineering. In Three Parts Svo, 8 00 Part II.— Iron and Steel 8vo, 3 50 Part III. — ^A Treatise on Brasses, Bronzes and Other Alloys and Their Constituents 8vo, 2 50 MINERALOGY. Barringer's Description of Minerals of Commercial Value. Oblong, morocco, Boyd's Resources of Southwest Virginia Svo, " Map of Southwest Virginia Pocket-book form. Brush's Manual of Determinative Mineralogy. (Penfield.) .8vo, Chester's Catalogue of Minerals 8vo, paper. Cloth, " Dictionary of the Names of Minerals Svo, Dana's System of Mineralogy Large Svo, half leather, " First Appendix to Dana's New " System of Mineralogy." Large Svo, " Text-book of Mineralogy Svo, '* Minerals and How to Study Them 12mo, " Catalogue of American Localities of Minerals . Large Svo, " Manual of Mineralogy and Petrography 12mo, Egleston's Catalogue of Minerals and Synonyms Svo, Hussak's The Determination of Rock-forming Minerals. (Smith.) Small Svo, 2 00 * Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests Svo, paper, 50 Rosenbuseh's Microscopical Physiography of the Rock-making Minerals. (Idding's.) Svo, 5 00 * Tillman's Text-book of Important Minerals and Rocks.. Svo, 2 00 Williams's Manual of Lithology Svo, 3 00 MINING. Beard's Ventilation of Mines 12mo, 2 50 Boyd's Resources of Southwest Virginia Svo, 3 00 " Map of Southwest Virginia Pocket-book form, 2 00 •Drinker's Tunneling, Explosive Compounds, and Rock Drills 4to, half morocco, 25 00 Eissler's Modern High Explosives Svo, 4 00 •Goodyear's Coal-mines of the Western Coast of the United States 12mo, 2 50 Ihlseng's Manual of Mining Svo, 4 00 Kunhardt's Practice of Ore Dressing in Europe Svo, 1 50 O'DriscoU's Notes on the Treatment of Gold Ores Svo, 2 00 Sawyer's Accidents in Mines Svo, 7 00 Walke's Lectures on Explosives Svo, 4 00 Wilson's Cyanide Processes 12mo, 1 50 Wilson's Chlorination Process 12mo, 1 50 15 2 50 3 00 2 00 4 00 1 00 1 25 3 50 12 50 1 ou 4 00 1 50 1 00 2 00 2 50 Wilson's Hydraulic and Placer Mining 12mo, 2 00 Wilson's Treatise on Practical and Theoretical Mine Ventila- tion 12mo, 1 25. SANITARY SCIENCE. Folwell's Sewerage. (Designing, Construction and Maintenance.) 8vo, 3 00 " Water-supply Engineering 8vo, 4 00 Fuertes's Water and Public Health 12mo, 1 50 Water-filtration Works 12mo, 2 50 Gerhard's Guide to Sanitary House-inspection 16mo, 1 00 Goodrich's Economical Disposal of Towns' Refuse . . . Demy 8vo, 3 50 Hazen's Filtration of Public Water-supplies Svo, 3 00 Kiersted's Sewage Disposal 12mo, 1 25 Mason's Water-supply. (Considered Principally from a San- itary Standpoint Svo, 5 00 " Examination of Water. (Chemical and Bacterio- logical.) 12mo, 1 25 Merriman's Elements of Sanitary Engineering Svo, 2 00 Nichols's Water-supply. (Considered Mainly from a Chemical and Sanitary Standpoint.) (1S83.) Svo, 2 50 Ogden's Sewer Design 12mo, 2 00 Richards's Cost of Food. A Study in Dietaries 12mo, 1 00 Richards and Woodman's Air, Water, and Food from a Sani- tary Standpoint Svo, 2 00 Richards's Cost of Living as Modified by Sanitary Science . 12mo, 1 00 Rideal's Sewage and Bacterial Purification of Sewage Svo, 3 50 Turneaure and Russell's Public Water-supplies Svo, 5 00 Whipple's Microscopy t)f Drinking-water Svo, 3 50 Woodhull's Notes on Military Hygiene 16mo, 1 50 MISCELLANEOUS. Barker's Deep-sea Soundings Svo, 2 00 Emmons's Geological Guide-book of the Rocky Mountain Ex- cursion of the International Congress of Geologists. Large Svo, 1 50 Ferrel's Popular Treatise on the Winds Svo, 4 00. Haines's American Railway Management 12mo, 2 50 Mott's Composition, Digestibility, and Nutritive Value of Food. Mounted chart, 1 25 " Fallacy of the Present Theory of Sound 16mo, 1 00 Ricketts's History of Rensselaer Polytechnic Institute, 1824- 1894 Small Svo, 3 00 Rotherham's Emphasised New Testament Large Svo, 2 00 " Critical Emphasised New Testament 12mo, 1 50 Steel's Treatise on the Diseases of the Dog Svo, 3 50 Totten's Important Question in Metrology Svo, 2 50 The World's Columbian Exposition of 1893 4to, 1 00 Worcester and Atkinson. Small Hospitals, Establishment and Maintenance, and Suggestions for Hospital Architecture, with Plans for a Small Hospital 12mo, 1 25 HEBREW AND CHALDEE TEXT-BOOKS. Green's Grammar of the Hebrew Language Svo, 3 00 " Elementary Hebrew Grammar 12mo, 1 26 " Hebrew Chrestomathy Svo, 2 00 Gesenius's Hebrew and Chaldee Lexicon to the Old Testament Scriptures. (Tregelles.) Small 4to, half morocco, 5 00 Lctteris's Hebrew^ Bible Svo, 2 25 16 16 IPOQ JAN 14 1902 ,h. ' ['■.:'■ Hl't', (,■./!/ i"c'- -/'.*. i ■ 'v •:>,&'. :'^a'^-'^'' ^"- ■•■■ -$ '■*' "'i Sr LIBRARY OF CONGRESS ^ III! Ill DDDDflfiflDfi03 y_