608 B M5 py 1 .OSSES TO COTTON What to Look For and Where to Find It Being one of a series of articles in relation to crops, their common diseases, and insect pests to which thev are subject Published by HAIL DKPARTMENT Western Adjustment &. Inspection Co. CHICAGO LOSSES TO COTTON LOSSES TO COTTON What to Look For and Where to Find It Being one of a series of articles in relation to crops, their common diseases and insect pests to which they are subject Pul)lislied by HAIL DEPARTMENT Western Adjustment & Inspection Co. CHICAGO o ^^ \IVO Copyright, 1919, W. E. Mariner ©CI.A5l5aH Stroniberft, Allen & Co., Chicago. Printers 1 I lL ^ -J ' 1 COTTON The raw material of our most im- portant maniifacturino- enterprises and export trade, the nature and special characteristics of its growth. 'Knowledge directeth practice and practice increaseth knowledge." INTRODUCTORY Cotton furnishes the raw material for one of our most important manufacturing industries, and from one-fourth to one-tliird of our total exports. Its economic importance is far beyond numerical ex- pression, for, while the total crop of the world is ap- proximately ascertainable, the effect of cotton upon the commercial and social relations of mankind is too far- reaching for estimation. Of the four great staples that provide man with clothing — cotton, silk, wool and flax — cot- ton, by reason of its cheapness and its many excellencies is rapidly superseding its several rivals. Fifty years ago, only about 2,500,000 bales of cotton, or less than the present production of Texas, were annually couA'erted into clothing. Cotton stands pre-eminent among farm crops in the ease and cheapness of its production as compared with the variety and value of its products. It is less subject to the ravages of insects than any other of the staple crops, and no crop makes so slight a drain u]ion the fertility of the soil. Modern enterprise has found more uses for the several parts of the cotton plant than have been discovered in any other farm crop. The cotton plant produces, in fact, a double crop: (1) a most beautiful fiber and (2) seed — yield- ing both oil and feed — which, although neglected for a long- time, is now valued at one-fourth as much as the raw cotton. In addition to this, the stems are made to yield a liber, which waits only for a machine to work it, and the roots yield a drug. PART I INSECTS There are many insects wliicli derive their food from the cotton plant, Tliis list as a whole comprises about 4G5 species. But a small i)ortion of these, however, can be con- sidered as injurious to cotton, and still fewer numbers have attracted the attention of cotton-planters by their injuries to the cro]). Many of them are enemies of, and prey upon, species which damage the i)lant, while many others are accidental visitors to tlie cotton fields and might have been found as readily in the fields of corn or in other crops in the same general localitv. ?:>" The Cutworm The first insect to attack the young cotton plant in tlie spring is the cutworm. Soon after the young i)lants come up and often after they are fairly well grown, they are likelv to be cut off at tlie surface of the ground bv one of THE COTTON CUTW0R:\I Adult and larva. Natural size. these cateri)inars, all of which liave tlie habit of hiding be- neath the surface of the ground during the day and coming out to work at night. The granulated cutworm is probably the most connnon of the species and is known as the cotton cutworm. A number of other species of cutworms are un- doubtedly concerned in the damage, however. The Boll Weevil The adult boll weevil is about one-quarter of an inch in length, varying from one-eighth to one-third of an inch, with a breadth of aliout one-third of the lenu'th. This THE COTTON BOLL WEEVIL (fl) adult beetle; (h) pupa; {c) larva. Enlarged. measurement includes the snout, which is about one-half the length of the body. The color (grayish or brownish) de- pends upon the time that may have elapsed after trans- COTTON BOLL WEEVIL Late fall boll, showing how beetles hide between boll and inclosure. formation to the adult stage. The recently emerged in- dividuals are light yellowish in color, but pass to a gray or nearlv black shade in a few weeks' time. In the field tlie most conspienons indication of the presence of the boll weevil is the flaring and falling of great numbers of squares. However, unfavorable climatic con- ditions and careless cultivation fre(]uently cause much shedding. If excessive shedding be noticed and the squares upon being cut open show a white, curved grub that has fed upon the contents, there is little doubt that the l)oll weevil is the insect causing the damage. The boll weevil passes the winter in the adult stage. In the spring and throughout the fruiting season of cotton the eggs are deposited by the female weevils in the cavities formed by eating into the fruit of the plant. The squares are greatly i)referred as food and as places for depositing eggs. As long as a large supply of s(juares is present the bolls are not damaged to any serious extent. COTTON BOLL WEEVIL Mature boll cut open at left, showing full-grown larva; the one at the right not cut, and showing feeding punctures and oviposition marks. The bolls, therefore, have a fair chance to develop as long as squares are being formed. Whenever frost or other un- favorable weather causes the plants to cease putting on squares, the weevils attack the bolls. The cotton boll weevil, so far as known at present, has no food plant other than cotton. In the fall when frosts occur, immature stages of de- velopment of the boll weevil may be found in the scjuares or bolls. Provided food supply is sufficient, many of these immature stages continue their development at a very slow rate and adults finally emerge. Thus there may be a some- what continuous ])roduction of adults during the winter. 10 Ordinarily, however, this is not conspicuously the case, since the frosts that destroy the cotton generally kill practically all of the immature stages of the weevil. The Cotton Boll Worm, or Com Ear Worm The boll worm is the common greenish or brownish worm that eats into the bolls of cotton and the ears of both field and sweet corn. Its eggs are usually laid in the top of TRANSFORMATION OF COTTON BOLL WORM (1) Egg on underside of cotton leaf; (2) larva one-third grown boring into square; (3) entrance hole of young larva in square, with excremental pellets at edge of hole; (4) nearly full-grown larva just issued from boll; (5) full-grown larva on leaf stem; (6) pupa shown in center of underground earthen cell; cell shown in longitudinal section; (7) adult moth, light variety; (8) adult moth with light fore-wings; (9) adult moth in resting position, wings slightly elevated, hind border of hind wings slightly showing. the boll, and the young larva soon begins to feed, eating into the cotton at the tip of the boll. As it grows it tunnels down into the boll, burrowing only a part of the lock, yet injuring the whole fiber. 1] The boll worm spends the winter in the pupa state in the ground. Sometimes in late spring, in May or June, the adnlt moths emerge and deposit their eggs on the cotton and corn. Mature larva measure about one and one-half inches in length. The moth, a rather stout insect, measures three- fourths of an inch in length. The larvae vary in color from light green to lu'own, being more or less striped in appear- ance, with alternating light and dark lines. The Cotton Leaf Worm, the Cotton Army Worm or Cotton Caterpillar The cotton caterpillar, the cotton army worm or cot- ton leaf worm, a slender, bluish-green caterpillar with small, black spots and often with black stripes down its back, which loops when it crawls and feeds voraciously on both upper and under surfaces of the cotton leaf, is to be found in cotton fields in the Gulf states all through the summer. It is generally unnoticed in the early part of the season on account of the insignificance of its number. Later, through the ragging of the leaves, it becomes notice- able, and in seasons of abundance the cotton plant is en- tirely defoliated. Farther north the insect makes its ap- pearance later in the season, and there the caterpillars are not the otfspring of the hibernating moths, but of the moths of the first or second generations, which have developed in cotton fields farther south and have flown north with the prevailing southern winds. There is no absolute evi- dence of these insects having any other food plants than cotton, although many entomologists have suspected that the species have a northern host plant. The egg is bluish-green in color and of a different shade from that of the leaf, so that it can be readily dis- tinguished. It is flattened, convex in shape, with many parallel, longitudinal ridges converging at the center above. It is found usually on the under side of the leaves and, as a general thing, toward the top of the plant. As many as five hundred eggs are laid by each female, sometimes several upon one leaf, but never in clusters. The eggs are laid at night, since the moth is a night flyer. In mid-sum- mer the larva hatches in from three to four days after the egg is laid, but in spring and autumn this period is very 12 considerably lengthened. After hatching from the egg, the young larva feeds at tirst npon the nnder side of the leaf, devouring simply the lower part and not i^assing through to the upper side until after the first molt. At first the larva is pale yellow in color, but soon becomes greenish. Before reaching full growth, the caterpillar sheds its skin fi^'e times, the duration of the caterpillar stage being from one to three weeks Early in the season the green THE SMARTWEED CATERPILLAR (a) larva; (b) cocoon; (c) adult. Natural size. color apjjears to |)redominate, while toward fall the black- ish cateri)illars are more abundant, although at any time during the season green and dark worms are seen together. Although the normal food of the caterpillar is the leaves, it will frequently gnaw the tender twigs, but will very rarely damage the bolls by eating into them, and then only in spots. This contingency, however, generally occurs only when the worms are present in excei)tional numbers and the supply of leaves becomes exhausted. It is somewhat of a cannibal and, when other food fails, or even rarely when, leaves are abundant, it will feed ui)on smaller and weaker individuals of its own kind. In spite of its com- paratively small size and slender form, this larva is un- usually greedy and when occurring in numbers, completely ruins the cotton crop. 13 It spins a light silken web, forming an imperfect cocoon, nsually within a folded leaf. It is freqnently seen hanging quite naked u])on the plant, bnt in such cases the THE ZEBRA CATERPILLAR (a) larva; (b) adult. Natural size. leaf in which it was originally spun has been eaten away by other caterpillars. Leaf -Feeding Caterpillars There are many species of larva which feed upon the leaves of the cotton plant. Few of these, however, are strictly confined to this plant for food. One of the most LEAF ROLLER 1 Caterpillar; 2 moth; 3 pupa. 14 commonly noted is known, from its work, as the leaf roller, a title under wliieli another species may also be included. Both species are general feeders and are fonnd in various parts of the country, the former upon apple, peachy cherry, clover, honeysuckle, beans, strawberries, and other plants, and the latter ui)on clover and grass. The larva of the former, in addition to the folding of the leaves of cotton and feeding within the roll, sometimes bore into the young- bolls, although this method of damage is rare. The royal horn caterpillar, sometimes known as the hickory horn devil, a very large, green caterpillar with long recurved red horns, the large green, somewhat hairy larva of the imperial moth and the large spiny larva, also feeds upon cotton. The results of the work of these differ- ent species are identical. Two bag worms are also occa- sionally found feeding upon cotton leaves, constructing their cases from fragments of the leaves sewed together with silk. These are the common bag worm of the north. Insects Injuring the Boll Numerous species of insects are found in damaged liolls which are the results rather than the cause of the THE RED BUG OR COTTON STAINER (a) pupa; (6) adult. Enlarged. 15 damage. There is a class of damage to the bolls which is known to i»lantei's as sharp-shooter work, which is mainly caused by the ininctnres of a leaf hopper. This insect is most abnndant from the first of Jnne on through the season. Prior to the first of June it seems to prefer the young growth and foliage of i)0]3lars and other trees which may grow in the immediate vicinity. Still another insect which at times does considerable damage to cotton bolls, particularly those which are far advanced or have oi)ened, is the red bug or cotton stainer. This insect is not known to be jn-evalent except in Florida and Georgia and neighboring portions of South Carolina and Alabama, The insect does its damage by ])uncturing the bolls and sucking the sap, causing them to become diminutive or to remain immature. Later, however, the insect may enter open bolls, puncturing the seed and dam- aging the fiber by its yellowish excretions. Grasshoppers Grasshoppers are considered one of the most common class of insects which do injury to the foliage of the cotton plant. Several s])ecies of grassho]i])ers have this habit, and THE SMALLER MEADOW GRASSHOPPER the list of cotton insects contains the names of fourteen grasshoppers which are found upon the plants. The dam- age which the grasshopper causes to the foliage of cotton is similar to that of the bag woVm and the hickory horn devil. The Cotton Stalk-Borer Puncturing of the terminal portion of the stalk by l^lant bulk occasionally occurs, but is com])aratively rare. There is but one borer of the stalks of cotton, and that is the long-horned beetle known as the cotton stalk-borer. It is occasionally mistaken for a direct enemy of the plant, 16 but investigation has shown that it lays its eggs upon, and its larva bore into, only such stalks as have been damaged by some other cause, such as rust. It follows injury to the plant, therefore, rather than causes it. There is only one brood of these insects a year, and they commonly reach maturity in the middle of August. THE COTTON STALK BORER (a) larva from above; (6) larva from side; (c) tunneled cotton stalk, showing exit hole; (f/) adult beetle. All enlarged except c. They frequently pui)ate in the stalk, especially in the case of large, hollow stalks, but sometimes burrow a short dis- tance into the ground for pupation. The adult is a moth of a wood-brown color sprinkled with yellowish dots. It is one of the night flyers. The eggs are laid in the early si)ring on the stalks attacked. This insect frequently be- <'omes abundant enough to do serious damage to plants. White Grubs The young of the May beetles or June bugs are capable of devastating and frequently destroying large portions of farm crops by eating the roots. The crops commonly dam- aged include two of our most important staples, namely, corn and potatoes, but the beetles also attack cotton and are often extremely destructive. These insects require three years to complete their life cvcle, and usually only one l)rood is destructively active in 17 a given locality. An abundance of May beetles one year forecasts a large growth of grnbs the following season. It should be remembered that injury from white grubs, as well as from many other pests, may be forestalled by WHITE GRUBS Showing the 3-Year ] eriod of their cycle life. ' the correcting of farm practices ; but after cotton or any field croj) has become infested it is imjiossible to prevent further injury to that particular crop for the current season. The Garden Web Worm This widely distributed and common insect is espe- cially notable because of its occasional outbreak. Its ordi- nary food plants are a number of common weeds, especially pigweed and purslane, but when these are used up because VARIOUS STAGES OF THE WEB WORM. of exceptional abundance of the larva, the latter readily devour cultivated crops, including cotton. Web worms are especially fond of the finer and softer grasses in the south, such as butTalo grass and Johnson grass. The mature larva, about five-eighths of an inch long, are whitish or dusky or even greenish, with black dots. They spin a loose but evidently individual web, rarely more than one worm occupying the same web. This web incloses more or less of the foliage of an infected plant. The larva are very active, feigning- death when dis- turbed or spinning a thread and dropping to the ground, slipping out of sight in crevices or loose earth. Most of the feeding is done at night, the larva usually resting in the web by day until the last stage, when they are active during the daytime. Plant Lice While the cotton i)lant is yet young and tender, the damage which plant lice do by gathering upon the young shoots and tender leaves, and curling and distorting them, may be very considerable. Eecent investiuations have shown that these insects COTTON LOUSE Cluster of lice on cotton leaf (greatly enlarged) . are identical with the species which occurs commonly through the south and the north upon melons and cucum- bers and which derives its food from a great variety of plants besides cotton. As the cotton plant grows larger and stronger, the work of the cotton ai)hi8 becomes of no imi)ortance, partly because of the hardier condition of the plant, but prin- cipally because the many natural enemies of the lice in- crease to such numbers as nearly to annihilate them. The insects are small greenish, bluish, or brownish lice, almost unnoticeable except when they congregate in clusters on the ])lants, and they are too easily identified and too well known to need further description here. 19 PART II DISEASES "To know tlie disease is the coiinnem-t'ineiit of tlie cure." Cotton diseases may be classed in three general divi- sions according- to their methods of attack: First, diseases affecting the leaves only, such as mo- saic, or yellow leaf blight, red leaf blight, and angular leaf blight. Second, diseases which may attack any part of the plant ; these include f renching, sore shin, damping off or seedling rot, authracnose, root rot, cotton leaf blight, areo- late mildew, cotton boll rot, and ripe decay of bolls. Third, diseases which injure the roots only, such as root galls, knots, etc. Soil and Seed-Sick Conditions In common with other field crops cotton is subject to a number of fungous and bacterial infections which live in the soil and seed and which are manifest in various de- formations, blights, leaf and stem deterioration, root decay, and general sai)ping of plant vitality and inmiaturity or dis- ease infection of bolls. Such infections are manifested by the rotting of root systems and a tendency to re-root above the infected parts, by spots and holes on the leaves, by discoloration and de- cay of the veins and stems, and by the rotting of bolls and locks. The infections have been given various local names, most of them derived from some characteristic of the in- jury inflicted. xVs they will be conunonly encountered under such designations, they are here described under those titles, all of which might be generally termed soil-sick or cotton-sick conditions. Cotton Wilt, or Frenching The cotton wilt, now widely distributed and yearly l^re-em]jting more territory, is caused by a fungus that plugs the water ducts in the veins of the stem and cuts off the water supply to the parts above, always reducing the vii>or of the ])lant and usually causing s])eedy death. Soil 20 21 COTTON WILT A row of wilt-i'esistant cotton. Note non-resistant varieties of adjoining rows are entirely gone. «MW^ . -«;. p • 'V -'•• , >%. . ft .iT^ 1. ^Ji.i -Sf - ♦ . *^ .t.tt^>' 'i* ■ .T ^■' rfur- COTTON WILT Cottonfield destroyed by wilt. Note few plants still svn-viving, but these will eventually become infected. wliicli ])i'odn('es a sick cro]) one year is so infected witL the casual fungus as to insure a rea})pearance of the dis- ease in more extensive areas in subsequent cro])i)in,i>s. Tlie destruction of this disease, which not only takes the crop 22 but impairs the usefulness of the soil as well, cannot be estimated. Its injnries can be realized only by those who have experienced its effects. Wilt lias long been known by cotton planters and is now prevalent in many sections throughont the whole cotton belt. The first appearance of the wilt is a yellowing of the lower leaves at the edges or between the main roots, which portions may become almost white. Later they turn brown and die. A single leaf often presents the three conditions — green (healthy), yellow (sick), and brown (dead) — side by side in bands parallel to the main ribs and radiating from the leaf's stem. The dead parts may break away, leaving the leaf ragged. The upper leaves may rapidly pass through the same process as the lower ones and soon become af- fected over all the plant, leaving only a bare stalk. In mild cases, wdiere the disease runs its course more slowly, the intervals between the different stages are more prolonged. In light sand the disease may progress very rapidly and consist of only two stages — the sudden wilted condition, then speedy death. The final characteristic of the disease, however, as of many other wilts, is the darkening of the affected veins, which change from the normal white to light brown or black. Cotton Anthracnose and Boll Rot Anthracnose is a mold-like fungus infection which in- vades bolls, stems, seed, and seedlings of cotton. When a boll becomes infected, the spores spread rapidly through the lint and seed, becoming manifest at first as small round spots, dull reddish or grayish black, which gradually enlarge until often one-half of the boll is affected. Sometimes two or three spots become apparent on a single boll, and, as they spread, finally join together in one large diseased area, affecting virtually all of the boll. When these are cut open, the entire inside is found to be discolored or rotten. When very young bolls are attacked they are some- times" killed outright, while at other times they are dwarfed or affected on one side only. Bolls which are not badly diseased or those invaded late in their development may open an a])parently normal head, but the seed in these dis- eased locks is either destroyed completely or so inoculated 23 EFFECTS OF ANTHRACNOSE ON THE BOLL Cotton bolls infected with anthracnose. EFFECT OF ANTHRACNOSE ON THE BOLL Cotton boll, showinji only a small spot on the outside, yet the entire lock is decayed by anthracnose. with the spores as to make them a source of infection in tlie succeeding' crop, slionld tliey l)e used for phmting. 24 The young i)lants from this kmd of seed are often at- tacked and killed by these spores even before tliey reacli the surface of the ground. Unfavorable weather causes a damping off of the young plants at the ground line. This action of tlie infection may be recognized by the dark- colored and diseased condition of the stem below the EFFECT OF ANTHRACNOSE ON THE BOLL A boll of cotton badly diseased with anthracnose and covered with a mass of pink spores. ground. Cold, dam]) weather in the spring is especially likely to cause this, and under such climatic conditions the spores of anthracnose are usually |)revalent and destructive. Owing to their i)eculiar property of dissolving in water, the spores of fungi often become suspended in rain drops and are thus carried from infected to uninfected fields by rain and wind, and by insects and animals on whose bodies they have lodged, having been deposited by drops of rain. As the fungi cling to the stalks and live in the ground and seed and thus infect fields from year to year, recurrence of 25 EFFECT OF ANTHRACNOSE ON THE SEED Diseased seedlings caused by anthracnose. the disease condition will be noted from season to season to the final total failnre of cotton on that particnlar field nnless seed selection and crop rotation — to clear the seed and soil from the infection — are practiced. Angular Leaf Spot Angular leaf spot is named from the dark angular spots which appear in the. leaves. It is very widespread, but rarely appears to such an extent as to attract attention. Carefnl observation would x^robably reveal it in every cot- ton field during the growing season from May to July and frequently later. The disease is first manifested l)y a watery appearance in definite spots which are bounded liy the veins of the leaves. The spots are sometimes very nu- merous and frequently unite into one large area of infec- tion. Often the disease follows one or more of tlie nuiin 26 ribs of the leaf, being bounded on either side by an ir- regular zigzag line. In time the spots become blackish and then brown, and are frequently bordered by a blackish color where the disease has spread outward from a centrally infected spot. The dead s])ots in the leaf sometimes break out, leav- ing many perforations with ragged edges, somewhat as often results in cotton leaf blight ; the disease hastens the falling of the leaves. In the very earliest appearance of the spots, when the watery condition is coming on, these spots swarm with bac- teria; these also often occur on the plant bolls which pre- sent spots of watery a])])earance, and these finally terminate in rot and death. In this case the general weakness of the l)lant naturally extends to the boll also. Mosaic, Yellow Leaf Blight, or Black Rust The first signs of mosaic are yellowish spots which give the leaf a checkered ai)pearance. These discolorations oc- cur first in small areas, which are roughly rectangular MOSAIC DISEASE, OR YELLOW LEAF BLIGHT 27 owing to the limitation cansed by the veins and are situated at points most remote from the main feeding veins. In later stages these weakened areas may be over- grown by various fungi. Usually the centers of these spots soon turn brown, and the brown parts enlarge and show a series of concentric markings. If very dark-colored fungi grow upon these spots, they soon become black-coated, and from this fact take the popular name black rust, which, however, bears no similarity to, or relation with, the rust of the cereals. The attack of the fungus causes the pre- mature falling of the leaf, thus preventing the proper ma- turity of the i^lant. Losses may vary from 5 to 50 per cent, and, being widely distributed, such losses are often very heavy. It may be safely asserted that this disease cannot attack a cotton plant that is in full vigorous growth, but a sudden checking of growth and lowering of vitality from any cause . will render it liable to serious injury if the weather conditions favor the growth of this fungi. Frosty Mildew The leaf spot caused by frosty mildew is limited sharply by the smaller veins, and bears upon the lower surface numerous colorless spores upon a colorless coat- ing, thus lending a frosted appearance. MILDEW OF COTTON Showing the spots of mildew on the leaves. • 28 As seen from above the spots are light yellow or of a paler green than the normal leaf tissue. Widespread, though not especially destructive, frosty mildew does not usually attract the attention of the planter, with the re- sult that the damage done by this disease is most generally said to be due to the attack of some insect, or some other disease. Red Leaf Blight The foliage of cotton frequently presents a red colora- tion which is not unlike the red or brown of autumn leaves. It is of exceedingly common occurrence toward the matur- ity of the cotton, even where the growth is quite healthy and rank, but is of rarer occurrence in rich soils than on poor land. It is es])ecially common on the drier ui)lands where the soil is worn and poor. Here it occurs (|uite early in the season, and cotton sometimes makes but little prog- ress before the leaves become red. Sore Shin, Damping Off, and Seedling Rot Sore shin, damping off and seedling rot are names ap- plied to a very common disease which causes young i)lants to rot off partially or entirely at or near the surface of the ground. There seem to be several phases of the disease. Sometimes the tissues undergo a soft rot which progresses very rapidly, the early stages not being marked by any striking color characteristic. Primarily the disease is manifested by an ulcerous wound upon the stem near the ground, accompanied by red- dening or browning of the leaves. If the ulcer enters deep into the stem so as to interfere with the stalk, it may cause death. This is of unusual occurrence, however, since a healing of the wound generally occurs before the disease has progressed too far. Infection often results from the mechanical injuries caused by tools, the bacteria gaining a foothold in these bruised spots, Texas Root Rot Texas root rot lias been known to attack cotton in very destructive forms in Texas, Oklahoma, New Mexico, and Arizona, though it has not yet been found east of Texas. In the state of Texas in one season alone the damage caused 25) |.\ III! , lIlNOM'^r \\n-. 0:,| III1.iI.mI hI j|i.'l,( >(>(»,( 1(10 r^^^\\\^' I'l.MllIrl ITfitll «l It MM M WOl'hiM'IKMII) lIlMII IIk' '"'H \\rr\il 111 I III'. (lisoMMt* M \\'\\ ol' I ln» phllll . 111,1 \ Will iliul ill \ II I' III n »la\ Till' II ii.ilh orciii'. ill or Itrlitrr MnrKcmii!.', ov rUNioiuillv upon I'l.iiil . oiih m Irw iik-Iuvm lii^li. Lnlot' iiuinN |>l\ lli>' iMfcnci' ol iinnu'i \\\\^ ItOinlini",, (lonti |'l;inl . I'lio I'l.inl . willioi mo'l i;i|Mill\ Slu>\\u\^ iKo t\vv>( i\>( v»l »'vvU\\\\ on \\kA vIh\s, TolUvwrnK vmw, U\\\ \uA so rMpi^lly \\\ oonruuuHl ilrv wonlluM' l''s|H>oiull\ al'lor i\ rnin livinn plauls. sur roiuuloil l\\ vlocul oju*s» uu\y show syn>ptou\s oT tl\<> (Hsonst* \\\ llio I\mmu ol" wartliko l^uiit^s upv>n tho hiprool. All mI' fooloil pUuUs lm\o vlisoastnl ro^>|s markovl by i\\\ iujuroil miuI sln'UuktM\ («prool» tuvoiupaiiuHl Uy dopit^ssoil spv>ls whirh ^rv.Mt Urst, luMHlortnl U\ m ro»i\lish vlisvolorMliou, Tho oasuni ruuHU!^ i*^ a^^^* nppnroni l\oro. at l\rs( as a wlulo uu>lo, whioh UUtM' turns l>ro\vu v>r yollow nml tiually \iovolo|>s « wartlike luMiHloulu\i\ Mularj^oniouls Tiom wliivli now rv»ol^ sHO nil' pill I'o/tli <)\'\('ii o'-'-iir »)(',•!)■ \\\c tsoi) (^iii'fui('«, Kv<'n tli<' lint of l)j<' >. Ttjy root knot, i*xf'ii]ft by an nxanilnHthm of tfjtt rootn, in inii/'l< n o.sihit i>i wilt, |>jw^aw>l pjuntji ar<^ difetir^/dly )stur*ttf>/i, hut not ii\f\n'i*i\H\Ay dafonn^lf nh In wilt, an^l Imv** Q Q Q O o - ?'2 ^ I ii o '-4^..: .V ?* 32 33 a peculiar sickly yellowish-green color on both leaves and stem. In times of drought affected plants are the first to show the lack of water and may wilt slightly in the middle of the day. If snch a plant is pulled carefully or, better, dug up with a shovel, the roots will be found to be covered with swellings, or galls, from the size of a pinhead to half- inch or more in diameter. If one of these knots is broken open, numerous pearly white rounded bodies about half the size of a small pinhead can often be seen with the naked eye. "When root knot occurs with wilt, which is often tlie case, the symptoms of both diseases are present. The plants usually all die or are so badly dwarfed that little or no cotton is produced. Root knot is essentially a disease of light soils. Al- though the disease may occur on heavier soils than wilt, yet it is not as a rule serious on soils containing a large portion of clay. The jilaces of greatest damage are usually light sandy spots or ridges in infected fields. 34 PART III CONTRIBUTING CAUSES "A field requires three things, fine weather, good seed, and a good husbandman." A grower is often unable to explain why his crop is not as hardy or as flourishing as that of his neighbor. The answer may be his failure to follow some one or all of the simple yet necessary practices of good farming operations. His loss may be due to poor cultural methods, failure to select seed carefully, too frequent cropping of the land to the same thing, improper cultivation, or carelessness in some other fundamental. An investigation of methods often offers a clear explanation of otherwise inexplainable failures. Shedding of Bolls or Squares The shedding of bolls or squares, or their drying up while still attached to the plant, is very frequently encoim- tered. This is almost always claimed as hail damage and may often be confused with the work of the boll worm or with punctures made by some other insect. Sometimes part of the shedding is due to the work of the boll worm, but the dropping off referred to here is a purely climatic trouble or a natural stage of the i)lant's development. It occurs most frequently in extremes of either dry or wet weather or during the change from one extreme to an- other. It may occur to some extent under normal climatic conditions, especially if the cotton plants are too thick or the variety of cotton is one which develops a very large number of bolls in Y)roportion to the leaf surface. During a normal period of growth the plants put out as many boll forms as would quickly mature should favor- able conditions continue. If a very dry period follows this, interfering with the supply of nutriment and moisture, a partial withholding of tissue-forming material results at a very critical period in the life of the boll, thus forcing the tissues into an unnaturally matured condition. A long rainy season may also cause the young bolls to fall, the soil being so saturated with water as to interfere with the roots' absorption and to disturb the assimilative activity of the leaves. The falling away of the dead im- 35 SHOWING RESULTS OF PROPER FARMING Thirfty plants grown from selected seed in a well-prepared seed bed and in soil of good fertility. 36 '\<'^% :-. -5.r- mM tf § Ph 37 mature bolls and forms when it does occur is a useful pro- vision of nature, since the plant is left in better condition for the gathering of the crop which does mature. "Wlien the cotton is putting on squares or blooming, the claimant often contends that hail knocked the squares off, when it is a matter of common knowledge that cotton will ordinarily throw off two or three times as many squares as it will put on bolls. It is as natural for cotton to shed its squares as it is for the cherry and apple tree to shed their blossoms. The more or less complete separation of the squares at the line of division between the healthy and dying por- tion depends upon the point of attachment of the bloom to the stem, and f6r this reason they sometimes remain at- tached to the plant though withered and lifeless. Climatic Conditions During all stages of its growth the cotton jilant is sub- ject to destruction by various climatic conditions, each of which resembles hail damage very closely. Unless an ad- juster is familiar with these and prepared to ascertain the true cause of the damage, a dishonest claimant will use every effort to convince the adjuster that these are losses for which he should be paid under his hail contract. Sand Storms When the tender plants have pushed their way out of the ground and before they have become hardy enough to withstand such damage, the action of the wind sifting sand across the land will completely cut off young plants and often cause total losses to entire fields. On close examina- tion the shifting of the sand and the conseciuent damage caused can be plainly pointed out to the claimant contend- ing for an unfair allowance. Action of Rain Hard, beating rains, accompanied by high winds, will also cut off the tender plants, and a claimed hail loss is the inevitable result. Unusual care must necessarily be exercised in the adjustment of such losses to separate this loss properly from that actually caused by hail. Another 38 effect of beating rains is to pack the sandy soil too firmly aronnd the yoimg cotton plant, "choking" it off and re- tarding or totally stopping the growth of the stalk. In either event a sickly stalk or a dead one results. When the plant is more mature and the bolls open, a hard rain will cause the cotton to shred out and hang in strings from tlie plant. Such injury often resembles and has been erroneously claimed as hail damage. The present form of "Open Cotton" clause excluding liability after the bolls have opened was adopted on this account. Seed Selection for Cotton But few crops are as susceptible to material loss from lack of proper seed selection as is cotton. The inevitable results of indifferent methods of seed selection are mani- fest in a sickly stalk, fungous infection, inferior quality, and subnormal yield. Where some system of careful selection is not prac- ticed by the grower, such conditions are almost always evident in the growing crop. A great variation is always noticeable in such fields, one stalk having a large number of bolls, while another, growing by its side, will be almost barren. If a seed-breeding plat is kept by the grower, isolated from the general fields to prevent an intermingling of pol- len and possible fungous infection or insect infestation, and careful elimination is made thereon from year to year, the results are bound to show in the field, and the higher grad- ing of i3lants thereby obtained will eliminate the cause of many illegitimate claims now made for hail damage. The use of adapted seed instead of the imported va- riety results in a stronger, healthier growth of cotton which is less affected by either hail or other climatic or disease conditions. There is one source of infection of cotton seed that is not applicable to any of the other crops, and that is the danger of impurities or fungi becoming mixed with the seed when it is ginned. In many places a special device is in use by the ginner to guard against infection or mixing of seed, but, even with such precaution, carelessness in clean- ing the saws will inoculate the seed cotton with anthracnose or other bacterial disease. The grower who has selected his 39 seed and had it ginned in a presumably clean gin is nnable to believe that the resultant loss is due to any other cause than a hailstorm. Inquiries as to methods of seed selection and ginning are never out of order if the loss appears to be due to a fungus infection or ])oll-rot condition. Crop Rotation To restore the necessary quantity of organic matter to the soil, a system of rotation is essential. Where some proper cropping scheme is not followed, poor yields, total failures, or disease-infected iields are commonly encoun- tered regardless of the fact that cotton is one of the few crops that does not exact a heavy annual toll from the soil. Cotton can be planted more years in succession on the same plot of ground without completely depleting the fertility than can, possibly, any of the other staple crops; yet extended cropping of cotton will in time wear away the best soil or permit it to become fungus-ridden. When any form of fungus infection has gained a footing, rotation is the only means of elimination of this soil-sick condition. The depleted field is the first to show the effects of un- favorable climatic conditions, and deficiencies of moisture are first seen in a field that has long been planted to cotton alone. Losses from Deep Cultivation While normally the cotton plant has a strong, branch- ing taproot penetrating deeply, the root system is subject to much modification, owing to the nature of the soil and the subsoil. In many instances the taproot may be absent, while in other instances a well-developed ta])root has often been traced in sandy soil and subsoil to a depth of two to three feet without coming to its end. In heavy clay loam only one plant out of twenty-one was found which had a well-developed taproot over 9 inches long. In either kind of soil the lateral roots begin about 3 inches below the sur- face of the soil and spread out in all directions, most of them being within 9 inches of the surface. Most of the lateral roots originate at li to 2 inches below the surface of the ground, and their direction is such that deep cultivation would break a large proportion of the roots. Losses caused by too deep cultivation of the cotton 40 plant are often attributed to some other cause of damage. T]ie sickly appearance of a plant whose roots have been broken by a cultivator shovel closely resembles damage caused by insects working on the roots, by cotton-sick soil, or by lack of moisture, and hail is quite frequently blamed for such conditions. 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