ftmoi ocist, l:V J. C. NEAL, Pii. I)., M. I). 23495— Bull. 20 1 WASH IN GTO X: GOVERNMBN1 PRINTING "1 KICK. *9- Digitized by the Internet Archive in 2013 http://archive.org/details/rootkOOusde LETTER OK TRANSMITTAL U. 8. Department of Agriculture, Division of Entomology, Washington, May 10, 188J). Sub : I have the honor to transmit for publication Bullctiu No. 20 of this Division, beiug a report of studies and experiments made upon the Anguillala, which is the cause of the root-knot disease of i lie Peach and Orange in Florida, l.y .!.('. Nral, Ph. 1)., M. D., of Lake City, Pla. Respectfully, C. V. UlLEY, Entomologist. lion. J. M. KrsK. Secretary of Agricultun INTRODUCTORY NOTE. I'm several J ears past com plain I has In 'en made to the I )i\ isiOD of En- tomologj concerning the damage done by various species of Anguillu- inl.e. which affecl the roots of differenl plant.- in differenl sections of the country, and I have frequently been urged, as Entomologist, to in- vestigate the matter. I have always lieeii puzzled to know what repl\ to make in such cases, as no American iuvestigator has undertaken a a systematic study of these Nematodes, ami tbej do not, in a zoological Reuse, strictly belong to the Division work. I have contented myself therefore with recording the various tacts of injury to differenl plants that have come to me in the past twenty years, and sonic microscopic notes in reference to the specimens. One species seems to do consid erable damage to certain plants in greenhouses in the North, while another is equally destructive to the roots of trees and plants in the South, particularly in Florida. Towards the close of the year L887 the complaints of the damage done by the Florida root-inhabiting species were so numerous that, at the request Of the Commissioner Of A-ricul lure, I decided to conduct some investigations as a pari of the Division work. The demands upon the resources of the Division arising from its more legitimate investigations have been such that hut little time and small funds could be spent in this direction. Dr. J. C. Neal, then of Archer, Fla., but now Entomologist and Botanist of the Florida A.g ricultural Experiment station at Lake City, a diligent observer, and associated with me in previous investigations both under the U. s. En- tomological ( 'om mission and under this Division, was commissioned foi live months ami instructed to make as careful studies and experiments concerning this pest as it would be possible to make during the short time of his employment. His work was done between February l and September 1, 18S8, and while I do not claim for'Dr. Neal, any more than he wotdd himself claim, special or technical knowledge in this branch of Zoology, bis work is not without scientific interest. The in- vestigations have been, however, from a practical standpoint, and the results more than justify the slight expenditure. The Bulletin makes no pretense to he a scientific treatise on the life history of these worm-. but is in the main an effort to ascertain a suitable remedy. The genera] literature on the subject has not been at Dr. Neal's command, and my time is so fully occupied otherwise that I can do little or nothing at present in the way of identification of species or of comparing Dr. Neal's results with those of European investigators, which, as a matter of fact, are of little practical importance. The study of the full life history of any one of the species is attended with much difficulty, and will re- quire much time in field and laboratory; while the technical and clas- sificatory treatment of the subject should be undertaken by some com- petent helminthologist. O. V. E. i LETTER (>!•' SUBMITTAL A i;< iir.K. I'i. \.. December 2, 1888 Sir: I have the honor to anbmit the following roporl upon the root- knot disease ami its cause, tin- Anejiilliila. These investigations, conducted under yonr direction, began in Feb rnary, 1888, ami have been continncd to this date. While not conclusive in all respects, they are at leasl contributions to the histor\ of this microscopic post, that mav eventually lend ti> its subjection or to the mitigation of its ravages. In conclusion, allow me to express i<> yon mj thanks for your aid and guidance during the preparation of the report. Respectfully submitted. .1. C. Neal, M I).. Sjll , in I .1 Ijl ,lt . Prof. C X. RlLKY, Entomolofju 7 THE ROOT-KNOT: DEI INITIOS An abnormal .mil irregular growth of the subcortical layer ol roots and Bubterranoan sterna, characterized bj low vitality, the resull <>i an invasion of the tissues l>.\ n Nematode worm. (Note 1.) HI8TOR1 . Since 'the earliest settlement < » t the South Atlantic and (lull state-. In white people tins diseased condition of the roots of trees and plants lias been recognized. Note A very slight inspection has shown the decaying enlargements of roots, imt the cause has usually been attributed to a lacfc in the soil of some important fertilizing ingredient, or cureless cultivation, rather than some potent exterior influence. I have carefully examined all sources ol informational mj command) and can find mi mention of the root-knot in ;m,\ agricultural paper 01 hook prior to the year 1857. That year Hon. 1'. .1. Berckmans established a nursery at Augusta, l trees and plants, and in 1881 Prof. C. V. Riley being at Augusta was shown the effeel of the disease by Mr. Berckmans. In I860 Mr. Gilbert Underdouk, of Nursery. Tex.., noted the disease in his flg, grape, ami peach stocks, especially in damp, undiaiued loca- tions. In 1876 I found the root-knot prevalent over Florida, and learned from old residents that as far bach as L805 it had been known, and from time immemorial had been dreaded as a foe to gardens and groves. About 1874 this disease, however, sprang into prominence, owing to the influx ofimmigrantS, the development of early-market gardens and the sudden rage for orchards of peaches, figs, and oranges. Since thai time the agricultural papers have contained numeronsrci erences to this disease. My own attention was called to this pest by repeated failures to grow certain plants in a rich, damp spot on my farm. This led me to investigate; and sending a specimen of the knotty roots to the Agricultural Department at Washington, elicited theinfoi mation th it a microscopic worm was the cause of the trouble, but that little was known of Mi • Nomatoid family to winch it belonged. 10 Beyond doubt, the disease is peculiar to the South Atlantic and Gulf coast within a limit of 150 miles from tide-water. (Note 3.) Mr. I'. J. Berckmans remarks on this score — and I know no better au- thority — " that it is indigenous to a large portion of the South seems un- deniable, as I have seen it in places in Georgia and Alabama where neither trees nor plants had ever been introduced from other sections." Mr. Onderdonk also states a similar opinion. Other correspondents at Mobile, Ala , and in Texas confirm these statements. PLANTS INVADED. -Uncultivated : a. Slightly affected: Capselln buraa-paatoria (Shep- herd's J'nrse). Rubus villoana . Badly affected : Portalacit oleracea (Purslane). Sosuvium pen land ruin (Sand Purslane). Verbeaina aiegesbeckia et ainu- ata. Artemisia caudata (Wormwood). Cbenopodrnm botrya (Jerusalem Oak). Amarantna spinoana (Careless Heed). The above list, no doubt, will in time, and with a careful investiga- tion, be greatly extended; most of these are the commonest of weeds in old iields and badly cultivated grounds, and the Ghenopodium alone would be an ample shelter and breeding- place for the Anguillnla, inde- pendent of other wild or cultivated plants. The Enpatorium and Chenopodiuin are perennials, spread rapidly, and have great vitality, and for years it has been noted that where these weeds abound the root-knot exists in the greatest degree. The Sesuvium and Portulaca, both with fleshy roots, are very com- mon, and are an easy prey to the worms, but my experience indicates the Amarantus spinosus as the most dreaded and destructive agent in the spread of the root-knot, its roots being apparently the favorite of the Anguillnla. in Georgia, my correspondents deem the Verbesina and Artemisia the weeds most diseased, but in Texas, Mississippi, and Alabama, the list is about the same as I have given for Florida. (Note 4.) It will be seen that it will be impossible to determine certainly Un- original food-plant of this pest, as it seems to attack the roots of so many; and the inference that any tender growth not impregnated with a decided toxic principle may be invaded is a doubtful conclusion to my mind. II II. <„/',., Useful, a Sliffbtl) offei let! -> i • I ■■(■■ hoi bacon in el barbo dense I ' 'otton ). Solannm tuberosum el oscnlon 1 1 1 in t l'ni,ii,< nnd Egg I'lmi j Capsionm annunm ' Bplnaoin olei v on I Spinai J >. i opba raanihol I Zen mais ( ( '01 » | /.. Bftdlj affected. The Qenns Brassii i • dbbagt , Kale,* '■ R Ipll.llllli nil l\ II- i RoWi Hibiaons eaonlenl na Plsum sal i \ inn | / • Araohia hj pogroa | Pea »»' I. I toliohos cat iang ' '■>»" I'' a Pbaseolna rnlgaria | Bean). Phaseolna Innatua el nanna i Beau). All of tin- Qenns Cucurbits (8qHO*h< -. • '■ All ..f the Gonna Citmllns - Mel mi ). All ct" the Genna Cucumie eumbi r). Lyoopersicum escnlontum | /•■ mnti) l. Beta vulgaris, varieties i /■'■ d. Ornamental. .1. Blightlj affecte* Bibisens syriaons et coccinncna, .Mrsi'iiiliivaMllii'iiiiiiii.vai ion oies i /'•< -plant). Mik.un.i seandons I Parlor Try). Pharbitis pnrpnrca e( al. Bp. i Morning Glory I. Nolana, ap. Potnnia, ap. » Petun Bonsainganltia basselloidea. II, ( 'nil ii nil I < 'on I limed. /. I : • . 1 1 n .hi. . i. .1. Konign Mini itiin.i. [beris unibi I I i I. i^i ii. ii 1. 1 \ ulgai i- i Qourd |. Begonia, ip. /■'• /■■ I lahlin \ ai iabilia Flollanthna an n una i Sunfloici i | ( lolena, \ 1 1 p A i li> rani he i, i a ip A 1 1 1 : 1 1 . 1 1 1 1 1 1 ■ \ :ir. ip. Shrnbt and 1 1 • ■ I Bofnl, a. Slightly affooted. ( 'iii m \ nlgai i- I Bill* > nvet ' Oi - ang Citrus aurantinm, \.u Bp . 1 1 mon, etc.). Viim. \ ar. Bp {Oi apt I Pi anna mj robolanua I 1'hnn |, Bronsaonettia papyri fora {Paper Mnlhi i , Morns, \ or. sp. I Vulberrg). Jnglana cinoren i 'I aTnnt). Caryaolii Dfonnis (Pecan) h. Badly affected. Prnnns domestics I Plu Prnnns arineniaca if icot). Prnnns vulgaris I /'<"■ Prnnns commnnis I Union 1 1 Fiona caries I Fig). Jnglana i tglish ll'nlniiti. Sal i x . var. sp. ( Willows). d. Ornamental. Spires Borbi folia, var. Bp. Spirea). Prnnns nana el lam lata I Flow- i ring llmond I. Bnddloia, var. ap. Gardenia florida I Capt ■> mine). This lone: list embraces tlio greater part of our most valnable food- plants, frnit-trees, and many of the choicest Bowers, and it folly justi- fies the inquiry now made as to the history and means to prevent the spread of the disease induced !>y the Aniruillula. I think it useless to endeavor to account for the apparent vagaries oi the A.ngnillnla, as, for instance, to ascertain why the mots of the Prnnns vulgaris arc so badly nffected, while Prnnns cerasns are unhurt ; or why the Logmninosffi are susceptible and the Cmbcllifene are not. It is reasonably Biiro that rapidly growing, soft tissued roots are better sub- jects for invasion, expansion, and decay than those of slow growth and 12 denser structure, and the self-evident corollary is that methods and fer- tilizers promoting a rapid succulent growth should l>e avoided in all locations infected with the root-knot. EFFECTS OF THE INVASION OF TIIE ANGIILLI'LA. 1 have found mature worms, males and non-pregnant females, in root- lets hut a few days old, and under circumstances which involved the necessity of invasion from without the root. See Experiment Xo. 22. These Anguilluhe were small enough to enter the " stomata" of epi- dermal tissues, active and strong enough to even penetrate cell-walls, or to separate cells in loosely connected tissues. Once within, they could easily pass through the Cienchymatous system of the Parenchyma to any portion of the root, and 1 think it not unreasonable to infer that in this manner they obtain entrance in young rootlets. Their presence causes a rapid proliferation of cells, resulting in a soft, unnatural, irregular growth of the root, with low vitality, and a varied effect upon the plant or tree. The Chenopodium, Eupatorium, Artemisia, Amarantus. Gossypium, Solanum, and Petunia have the enlargements usually on the sides of the main stem, near the surface. The " tap-root," descending deeply is rarely affected, and the plants seem slightly affected till the sub-corti- cal layer is fdled with worms in all stages of growth. This checks growth, either by their absorption of the nutrition gathered by the root- lets, or obstruction of the Cienchymatous ducts, the food supply is cut off before decay is visible, the leaves wither, the steins shrivel, the plant dies. (Plate VIII, la, 4 6.) The roots of the Okra, Radish, Turnip, Cabbage, Cucumber, Melon, Cow-pea, Peanut, Tomato, and Egg Plant enlarge enormously, soon be- coming little else than masses of decaying tissues. The plant stops growth, the fruit either becomes distorted or drops prematurely, the leaves change color and fall off, and the plants die so rapidly as to justify the usual expression '• struck by lightning," applied to the fields of Melons, Cucumbers, Tomatoes, and Cow-peas so often badly affected by the root-knot. (Plates I, II, III, IV, and VIII.) In nurseries of young fruit-trees the greatest mischief occurs. The soil is usually carefully prepared by heavy fertilizing and culture, and the seeds of the Peach, Orange, and English Walnut are sown for stocks. When the tender shoots first appear many wither and die at once, others grow vigorously till the end of the first season, when they are usually budded with known and valuable varieties of fruit. The next spring these buds put out tardily and make a weak growth, the leaves become spotted or yellow, then drop, the bud dies, feeble strag- gling shoots sprout around the stem, which maintain a sickly vitality till the first drought, when the tree dies, and an examination dis- closes the cause in the knotty, decaying roots, without rootlets or tibiilhe. 13 With older trees taken from healths Locatiousuud sel iu iufoctuil soil the program varies. Tin- Poach aud Fig ofteu grov vigorously oue 01 two years, aud bear Eruil thai is verj proue to drop immaturely, tbou tin- tree takes "ii an irregular gro« tb of stunted limbs aud small lea> es. The tips of these limba die back gradually to the bodj of the tree. If the soil is clayey the tree will put oul feeble sprouts ofteu foi several years. With tlic Pecan, English Walnut, and Willow, older trees remain sta tionui > a year or bo aud die \\ it Ii the occasion of a severe drought. In iii;iu\ cases, especially In old fields, the seeds of trees and plants I >. i rely germinate, or cuttings hardlj form rootlets till thej are invaded and destroy f<\. In all of these cases the effect is to deprive the stems and leaves of fowl and moisture j the knots grow, the branches do not. The annual destruction of nursery stock is enormous, especially the Peach, Fig, Willow, Spiraea, Buddleia, Colons, etc. In the sketches taken from nature, attached to this report, are show u typical specimens as far as possible. The Grape, Fig, Mulberrj , and Orange are prone to circular kuob like knots on the sides of the larger roots, and an occasional enlargement it the junction of small roots. (Plates IV and VII. The Peaoh, Plum, Walnut, and Spiraea grow irregulai masses, involv- ing the whole root seemingly, (Plate \ Che N\ illou , < >kra, etc, enlarge, and the decaj is usually \ isible tirsl at the extreme tip of growth from the central stem. (Plates VI, I, aud II.) TERRITORY OCCUPIED BY THIS DISEASE. Barly in the beginning of my studies of the Anguillula, I addressed letters of inquiry to most of the leading nurserymen and horticulturists in the United States, especially those in the southern section, asking an examination <>t" diseased trees, and inclosing samples of the rool knot for comparison. The replies I received are conclusive that the disease is unknown be- yond any point in the interior 150 miles from the coast. It does not exist except in locations lice from extreme cold, and (lie northern boundary is not far from the January isotherm of .In . as shown in the No. J. Isothermal Lines of the I'. S. Signal Service, 1881. Letters from the Teaeh districts of Michigan, Maryland, ami New Jersey complain of the " Yellows," but investigators do not report tind- ing the diseased roots indicative of the Anguillula. It is not found at Denison, Tex. (Munson), onlj along the coast in that State, and then only in sandy, wet locations. (Onderdonk.) The usual dry air of New Mexico, California, and regions west ot the Mississippi River, with the summer parched soil ot' these sections, forms apparently a barrier to the growth aud spread of the disease, but coming 14 eastward it is progressively worse, till it reaches a climax in Florida, which seems to possess the requisite soil, humidity, aud warmth for the proper environment of tttii Anguillula, and consequently its complete development for mischief in gardens and groves. Add to this the cultivation of special food plants extremely suscept- ible to invasion by the worm, and there can be no wonder at its prodig- ious increase. TEMPERATURE. The question of temperature is no doubt one of great importance in determining the boundaries of this disease, perhaps more so than food- plants or soils. The soil that is annually frozen from to 10 inches is nearly disin- fected from the worms, especially those existing in a free state in the soil, or inhabiting the soft l'oots of annual plants, and this may explain why southern Michigan, northeastern Ohio, and New Jersey, with as sandy a soil as Florida or south Georgia, still escape the plague in the Peach orchards. The Ghenopodium, Artemisia, etc., abound in these States, aud no doubt are the habitat of Anguillula?, but the continued cold reduces their number to the minimum each year, and the hbrous-rooted trees are unharmed. Again, in some cold localities the trees kept in hot-houses arc af- fected; those without in open ground escape. Places favored with hot, dry summers and cold, wet winters will not likely ever suffer from the ravages of the root knot. My experiments are conclusive that below 50° in fluid, and above that, dry, the worms are inactive, paralyzed by cold, and shriveled by dryness and heat, aud the inference is plain that parties wishing best results must either choose unsusceptible stocks, for grafting or budding trees liable to infection by the Anguillula, remove to favored loca- tions, or find some means of destroying the worms. The arid regions of the "West fill one indication, the others are still subjudiee, but in a fair way for determination. SOILS. It can not be questioned but that a light, sandy soil oilers least re- sistance to the progress of the Anguillula alter its liberation from de- caying roots either encysted or free. Experiments with air-dry soil show that water penetrates sand in half the time that it will penetrate clay, and over huge areas of cultivated land the proportion would still be greater in favor of the sand. Loose soils, mixed with decaying vegetation and humus, offer still better facilities for irrigation, and this explains the fact that locations highly fertilized with composts, stable manure, or leaf-mold show the root-knot (pucker in plants than compact or virgin soils, and the worst 15 results ure (band in gardens planted in long cultivated, fully fertilized, : l 1 1 * 1 thoroughly pulverized areas. Moisture is an essential to the vigorous growth of the Auguillula, though it withstands an enormous amouut of drying. The cysts shrivel, pregnaul females become irregulai in outline, ins line worms si ill en ami remain imle I'm itch \\ illi 8U8peuded vitality, but resume action with the application of suffloieul moisture. (Note 5.) A friable soil, with compact day near the Burface insuring needed dampness, presents then the typical envirpnmenl foi the Auguillula, and this, alas, also is regarded in this section as the must advantageous location for a garden or _;n>\ c. Another vorj favorable locatiou for these worms is the boggj bank of a lake or river, where there is r mass of wet, decaying vegetation. EXPBRIMEN is. A series of experiments, under the direction of the Bntomologisl of the United States Agricultural Department, was begun in February, 1888, to determine the migration and life history of the Auguillula, as well as to investigate the effect of various insecticides. Thai these are not complete ami conclusive, is owing to the extreme difficult} of trac- ing any individual worm by reason of its size and its surroundings. A quantity of both ordinary Bandy soil and clay was heated several hours to a temperature of t n '> F. A number of 6 inch earthen pots were also subjected to the same heat. The earth and the pots were tested for living AuguilluliE and found sterile. Font sterile pole with ' cubic fool of sterile >.mI in oacb pot. (•_' B Mo. l, nsing aterile clay instead ofsnrface Boil. La No I, nsing yellow anbsoil from infected locations. \^ No. :i, using day snbsoil from infected locations. - No. 1. nsing infected sui face soil from infected locations In each pot were planted tour seeds of the ( Jow-pea | I lolicbos), selected because of its ease iii germinating and great susceptibility to the An- guillnla. All came up within the week and grew fairly well ; at the end of each week one plant was removed and the roots examined. In Nos. 1 and 1' UO knots were visible at an\ Btage of growth ami the last plant grew to maturity. Iii Nos. 3 and 1 the plants were but slightly affected, and at the end of the fourth week each remaining plant had made a fair growth, de- spite the terminal roots weie becomiug enlarged. In No. 6 half the plants died before the appearance of the third leaf. and the remainder made a sickly, feeble growth. The roots were badly knotted, deca\ in every case appearing at the terminal ends of the root lets, which turned brown and dropped oil' at the slightest touch. I repeated this series of experiments, using small seedling peach trees in place of the cow-peas. The results were similar — the trees in Nos. l 1G ami i' growiug vigorously, with fully developed roots and leaves; in No. ■>, at I lie cud of tour mouths the trees were living, but feebly, and tin- roots showed signs of decay. In No. 1 the trees had grown somewhat better and had a brighter color, but the roots were knotty. No. 5 showed poorly, leaves smaller, roots quite knotty, and one tree dead. The same results followed using the Weeping Willow as the test plant. The inferences are : That the Anguillula is destroyed by a heat of 212°; that healthy trees set in infected soil soon are invaded by the Tree Anguillula in the soil ; that soil taken from the depth of 2 or more feet below the surface is comparatively free from the worms, and that clay subsoil is less infected than the sand. Another series of experiments testing the effect of various chemicals, fertilizers, and insecticides was tried, using four sterilized pots in each test, the pots each containing n',, cubic foot of infected sandy soil, and the chemical, at the rate of , „'„,, of the weight of the soil d' t grains), thor- oughly mixed or dissolved. In each pot was planted a seedling peach and four cow-poas. No. G. Tobacco dust. 7. Tobacco duel with 24 grains sulphate potash 8. Tobacco dust with •>! grains sulphide potash. '.). Tobacco dust with "24 grains sulphite potash. to. Tobacco dust with 24 grains muriate potash. 11. Tobacco dust with 24 grains hyposulphite soda. 12. Tobacco dust with ','1 grains sulphate iron. 115. Tobacco dust with 24 grains caustic lime. I I. Tobacco dust with 24 grains uuleachcd ashes. 15. Tobacco dust with 24 grains sulphur. 16. Bisulphide carbon. 17. Sulphate potash. 18. Muriate potash. III. Unleached ashes. 20. Caustic lime. These experiments were also repeated in the nursery and open field on small peach trees, using (102 grains to each tree, equivalent to lu \ )0 part by weight of the soil. (Note 6.) In the pots the results in Nos. grew nearly as well as Nos. G and 7 ; No. 20 made a tine growth, with very few enlarged roots. The peach trees died soon in Nos. 8, 9,11, 12. 15, and Hi. made a lair growth in Nos. (>, 7, 10, 13, and 1 1. were killed at once in No. lti, and grew the best in Nos. 17, IS, 19, and 20. " In the tield Nos. 11, KJ. and' 8 appeared to at once kill the trees. Nos. :i ami i) ii i.i n>> effect visible, Nos. 0, 7, 10, uud 11 made a bcttui growth ili.iu N.i>. 17 50, Itoot-kuol was preseul on all bal Nos. 13, I I, .in.l 20. Oil Mill In <;rl II..-. .l|.|illr.l ;'l I he I .lie of 27 pounds |o I he I Iit. \i, .. 0, l.;, l i, 17, 18, 19, iiihI U gave good results, especially U and 1 7, <; .1 n. 1 is, (i ami 19. riieae mixtures seemed to promote n vig s growth of health \ roots, ami Nos. u ami 20, rich 27 pounds i'» the tree, well mixed witb the Burface soil, appears to !»• as neat a preventive ol the ■• kuol " a- a'i> thiug I ha\ e 11 ied. I tried the bisulphide of carbon without any effect other than the deatb of the trees, some fifty or more, and the kerosene emulsiou to saturation of the surface soil produced a similar result, uud in view of the expense II nd labor iu vol ved [ did not repeat the experiment (Note 7.) A number of the prepared artificial fertilizers were tried : those con- taining ammonia, guano, bono, aud fish produced a rapid growth, soft ami easily attacked by the Auguillulfe. Ina Qeld near raj place, beavilj fertilized with a bone and potasli compound, the roots of the pea nut became masses of kuotty roots, the worst cases of the disease 1 evei saw, and peach-trees growiug iu that Held an- ruined. 1 have found nothing of value when applied to old bearing frail trees, if badly affected, as any insecticide capable of absorption i>\ the roots invariably has killed the trees when used to the amount of ,,',,, the weight of the surface soil, l foot in depth and the area of the circle tilled by the roots. Alkaline mi Mures, l'ii to 10 pounds to each tree, or r tustic lime, kainite, muriate and sulphate potash or wood ashes, naed several years in succession, have come nearest a enre, destroying no doubt many fret- worms, and inducing a vigorous, tough growth of roots. more difficult of penetration, and possibly rendering the sap ill some way obnoxious. (Note 8 The addition of tobacco dust iu large quantities supplies nitrogen, and makes a very vigorous growth of roots aud limbs. Lt also seems to have considerable preventive effect on the worms. Experiments con- ducted by one of our market gardeners has convinced him that the mixture of tobacco dust and muriate of potash in old Holds iu great measure prevents the ravages of the Anguillula in < >kra, Cabbage, ami ISgg plant, ami he has adopted this as a .standard fertilizer for all his products. I have seen his use of this, and am neaih prepared to sus- tain his views. Kainite is no doubt fully as good, but further export menting is necessary. Another series of experiments was made upon plants to determine the time and degree of infection. No. 21. Sterilized pots with , ,; ., cubic foot of atei ile soil, iu which four cow- peas were planted at various depths, one half inch, three fourths inch, and 1 inch, were covered 1 inch with infected earth and kepi wa- tered. The results showed infection of the roots in about the same ra- 23495— Bull. 20 2 18 tioas the (list a nee from the surface. Reversing the process, putting the infected soil below, showed the roots affected soonest in the peas planted deepest, indicating but little action in the worms outside of that pro- duced by the percolation of water, No. 22. Another series of pots were watered with muddy water from infected earth, and though the pots contained sterilized sod the loots of the peas were badly affected. Microscopic investigation of the per- colate showed both free and encysted Anguilluhe. (Note 9.) No. 23. Tots with sterile soil had one transplanted infected peach seedling in each, and four cow-peas. The trees soon died, and very shortly afterward the peas showed the infection, those nearest the dead peach roots the most markedly. In a spot of new and non-infected ground several trees, Peach and Pig, were planted. The central tree was knotty-rooted and died in a few months: the next year the loots of the nearest trees. \r> feet away, became knotty nearest the dead tree, and now, after the lapse of tour years, the disease extends to the tips of the roots of all the Fig and Peach trees in a circle 120 feet distant each way from the original infected tree. In another case, in a nursery on high pine land, clay subsoil and free from disease, a number of peach roots, badly knotted, were brought from a distance and heeled in for a week. The disease spread in all di rections from this nucleus. Again, in another peach nursery was a spot of low, damp, black soil. There was no root-knot the first year it was planted in peaches; the seedlings grew well. The second year, a few trees Mere found in this spot with enlarged roots and destroyed. The third year, hardly a tree escaped, the disease extending along the thickly set rows of seedlings upward and in all directions on to the higher land from the hollow spot first infected. In another case, clean fibrous-rooted trees were heeled in a day or so and planted in non-infected ground. The next year proved the most of them diseased. These cases prove conclusively that in areas not infected the disease can be easily introduced (1) by planting infected trees; (2) by the use of composts of muck and weeds from infected soils; (3) by the distribu- tive action of water and air, the water carrying particles of soil and worms downward from an infected elevation, or by dry soil, frag- ments of dry roots, desiccated free or encysted worms carried in the air during sand storms, whirlwinds, or the heavy currents of air preceding storms that often blow " bare " acres of plowed land and overwhelm ad- jacent fields with the soil thus borne on the wind; (4) soil containing these worms I have no doubt has been carried on the feet of men and animals and deposited in healthy fields, forming the nucleus of a de- structive agency, months afterward made visible by its effects. Instances are not wanting that can not be explained except by some such theory of contagion and manner of travel. I'J REMEDIES. 1. l)i; \iN.\i;r.. > 1 ; 1 1 1 \ gardens .ind orchards are badlj located ou mmIn partly satu- rated w it 1 1 water, oithoi at tho inorgius of rn urs oi lakes oi on rieb de posits of vegetable remains botb \om aud damp. Tbe reasous for this cboice are general!) tbo superior quality of tbe land and tbe rapidity of growth induced by the moisture, bid iu the territory infected i>\ the Anguillula the beat aud rich soil cause precisely the looseness of tissue so favorable to the Bpread of the worms. A. dry soil, with solid root-growth, is on tbe contrary unfavorable; hence iu many Ideations drainage lias eutirelj changed the character of the land, so that peaches and figs grow ulnae thoj would not before. Experiments in Texas con Qrin this fnllj and suggest the utility of thorough drainage of wet locations, or, better yet, the avoidauce of such places for groves and gardeus. In this connection it may be remarked as one of the not expected results of the •• New Agriculture" in maintaining a permanently damp sod by means of water pipes below the Surface, that w hen it is ill VOgUC we will have not only a great increase oi crops bul a greater increase of "root knot" iii the cabbages, beets, radishes, etc., thus grown. What effect the ingestion of Anguillulae will have upon the human economy remains to be seen ; as, so far as I know, no record occurs of experiments having been tried to ascertain. (Note l<».) 2. Peost. In many places north of 29 there is cold enough each year to at times freeze the surface a considerable depth. Where this occurs, b\ plowing the soil at the beginning of winter and at times during thai season, it IS reasonable to suppose ureal destruction of the free Auguil- lula 1 will ensue. 3. FlKK. The value of heat in the destruction of the germs of the root knot lias been often demonstrated in Florida, nsnalK unwittingly, and the lesson taught has been in a measure lost In clearing old fields, badly infected with the worms, as shown by the crops of cotton or peas, it is customary to burn log heaps and stumps ; if, then, peaches and figs have been planted on this burned land tbe result has been freedom from root knot for a series of years. Such trees make a vigorous growth and bear well, while adjacent trees, not on burned ground, wither and die. It would seem practicable in this wooded section to easily build small compact heaps of chips, wood, pine knots, even dry weeds and grass, pver the area of say 2 feel radius from each tree stake prior to pi: 20 ing, burn the heap to ashes, excavate the soil as far as heated, and re. new the fire (ill (lie .subsoil is readied and the depth of al least a fool of soil in all is thoroughly sterilized by heal. In many eases, where wood is plenty, dead standing timber to be removed, and stumps to he burned, the plan would succeed to stake out the held and build a log-heap at each stake; but if not convenient, the annual growth of weeds and grasses, well dried, will furnish fuel enough. 4. Sterile Soils. (Note 11.) Among the early settlers of Florida the practice prevailed, when planting trees, of digging out the soil to the depth of 1' or more feet and tilling in around the tree with clay or yellow subsoil obtained from virgin land and li or more feet below the surface. This plan succeeded, in that it surrounded the tree with sterile soil till it formed firm roots and a hardened epidermis. My investigations show that in infected soils the deep roots are but slightly atl'ected in comparison with those near the surface, and that the greatest destruction prevails in young trees, nursery stock, and plaids having surface roots. If a tree acquires age aud the roots reach deep subsoil, the Anguil- lulse do little damage. Hence the utility of using clay or subsoil, derived from virgin forest, around newly-set trees. This old plan deserves attention and can be recommended; Vail since the war, in their haste to promote the growth of groves and gardens. the later horticulturists reverse this method, imbed the young tree in surface soil, and use nitrogenous fertilizers to encourage rapid develop- ment, this certainly causes increase of the root-knot. 5. Disuse of Land. Keeping land clean, free from all growth for two or more years, has proved of great benefit if done before trees are planted. I believe the worms require living tissues to develop in, and deprived of this they would die, probably within the limit I have given. In many places where the soil has not been cultivated for a long series of years, and the Broom Sedge Grass has exterminated all other weeds, I have failed to find any traces of the Anguiilula, and I regard this as confirmatory proof that disuse of laud prevents the root-knot. 6. Disuse of Easily Infected Crops. In most of our Southern States, where the (Movers and Buckwheat will not prosper, it has been the almost universal custom to substitute the Cow-pea as a soil-renovator. Drilled or broadcast it is the great crop for "laving by" corn, and as a second or third crop after rice, oats, or market garden. Very few groves or orchards but have annu- ally from one to three crops of pea-vines plowed in for fertilizing. 21 Again, as n " flrsl crop," after ulenring ofl the timber, il is in general use For new land. Few plants ar» litivc to the attacks of the \ n -ii 1 1 in l.i. ; ii ill few have roots so badlj infected with these worms, and this common oastom of planting the Com pea is mentioned onlj to lie condemned, as, if continued, in time all groves and gardens in these sainh soils will be failures. The Lespedeza stri;it;i (Japan Olover), Desmodium molle (Bi Weed), and Riehardsonia Bcabra (Mexican Clover), will prove Que sub- stitutes for the Cow pen as forage and fertilizer If the Tow pea mnsl he grown, keep it away from garden and orchard, and ;it planting time use large quantities of Bome strong alkaline fertilizer on the soil. The economical babil of plauting market gardens in orchards should be dis couraged. It is c;is\ to see the reason and the danger from the nso of ammo- niacal fertilizers so necessary to induce rapid growth of vegetables, and the spread of the Angnillulte from the roots of tin' .Melons, < Incumbers, etc. to the trees. Manv instances of this sort can be seen over the South, and should serve as warning to <>nr horticulturists in the future. I believe that in badly infected grounds some relief could bo given by drilling tlic Cow-pea, and, when in bloom, cutting <>iv the stems for forage; then to plow ami carefully rake np the roots in piles for burn- ing when dry enough. This method of destroying the infected roots of Okra, Melons, etc., and the roots of the Chcuopodium, etc., would no ilonbl bo of great value in small areas, and even in larger fields, by the aid of improved machinery for gathering the roots. It needs only the mention that plauting ol trees from infected local- ities should be avoided ; even those not liable to the disease themselves ina\ carry soil containing A.ugnillui(B among the roots. 1 have noted that Hie Peach and Pig obtained from Northern nur- series Beem extremely easy to take the disease, far more bo than the native stocks. 1 only moution the fact, but have not ascertained the reason. 7. ixsr.ri Enemies. I have found but one, the small blackish brown ant that inhabits rot ton wood and decaying roots — very common in this section — the Sole- nopsis xyloui. This, when the roots of the Okra, Pea, etc. begin to decay, burrows into the tissues and drags OUt the pregnant AnguillulflD for destruction. I was puzzled at first to limit he dead roots of the Okra, Melon. Peach, and Pig free from cysts or pregnant worms, thongh in partially rotting enlargements I found plenty of Anguillula. Closer and extended examination showed this ant in the act of de vouring the enlarged worms, and its service to the orchardist is be- yond value in this respect Inasmuch as a dry soil is favorable to ant life, it will be readily seen how drainage is useful in aiding the propagation of this tiny destroyer. 22 Upon crashing a mature, pregnant worm various forms of micrococci arc visible by the microscope as existing within the Anguillula, evi- dently not hurtful, and when seen exterior to the worm seem not preju- dicial to its life; but more study is needed on this point. 8. Use of Vermicide Fertilizers. Experiments looking to the adoption of some mixtures capable of de- stroying the worms while in the root tissues have not proved a success. The use of smaller quantities per acre than one-tenth of 1 percent, of the surface soil for 1 foot in depth and 10 feet radius to each tree — about a ton to the acre — produced no perceptible effect on the disease, and a greater amount injured the trees. The use of bisulphide carbon, kerosene emulsion, and various arsen- ical solutions destroyed so great a percentage of the trees that on that account, and the expense of application, it was abandoned. Alkaline mixtures have done better, and will bear repetition, espe- cially the sulphites and muriates. For nursery stock, it no doubt will pay to thoroughly incorporate some of these chemicals with the soil some weeks before planting seeds, cions, or young trees, using it at the rate of at least one-tenth of 1 per cent, of the surface soil cultivated. Alkaline fertilizers, as hard-wood ashes, muriate and sulphate of pot- ash, kainite, or ash element produce a hard growth but little, if any, affected by the root-knot. Usually the fertilizer is applied in too small a quantity. Not less than 3,000 pounds to the acre should be used to produce the required effect, one-half in December, the remainder in May. A fertilizer containing a small percentage of carbolie acid, carbolates, tbymol-cresol, or an easily decomposed sulphite would no doubt be valu- able in this infected section. 9. Non-infected Stocks. After all, I believe the use of trees that are not susceptible to the root-knot, for stocks on which to graft or bud the susceptible varieties is the proper solution of the root-knot problem. The matter of location, soil, fertilizer, and prevention then need not worry the intending or- chardist. Find the disease- proof tree and the thing is done, and most of my experiments have been directed to secure in some measure this result. It is, perhaps, too soon to say that complete success has been realized, but the gain is perceptible. For the Orange I can recommend the hardy bitter-sweet or sour species as nearly disease-proof and a vigorous grower. The Citrus trifoliata and the Japanese " Unshiu," or Satsuma, both seem resistant, but the time of trial lias been too short. This last is a slow grower, with dense roots, and promises to be the best of any of tin 4 Citrus family. Its hardiness, freedom from thorns, and vigoi recom. mend it. Grapes of the Viuifera type as well as those of the Estivalis group arc Bnbject to the root-knot, if growu on their owu roots, 1ml grafted into stocks of the Oordifolia or Vulpina races have made superb growths free of the disease. I have ton im I no stock for Fig "i Mnlberrj that baa stood the test. For the Peach famibj either the seedlings ol the Wild Goose Plain, the Man.imia. or the recently introduced Japauese Plums, Kolsey, Sal smiia, or Ogru, arc valuable. Three j ears' test of the Marianna prove that for that time, at least, the roots resisted the Anguillula and were free from knots. When the peach died the Myrobolan was infected slightly, and eveu the native plums suffered with the disease. It is too soon to give an unqualified appiw al of this as a stock, but so far it is thi> very best, growing from cuttings and very rapidly, making a tree that is nearly borer- proof as well as free from the Anguillula?. Some seedlings of our American lMuins are destined to replace the Teach as a stock, nuless the Japanese varieties prove superior. I have found nothing of value for the English Walnut a- a Mock, nor for the Weeping Willow. 1 have indicated tin- probable Hue of act ion to mitigate or prevent the disease in gardens — the use of alkaline fertilizers, the exposure to frost, the gathering of diseased roots to hum, the removal of certain weeds, and the disuse of land and cow peas. KXI1M OF DESTRUCTIVE BFFECTS OP THE DISEASE. Within the district infected by the Anguillula it would be well nigh an impossibility to give even an approximate idea of the losses sus- tained each year by the farmer, the gardener, and the horticulturist from the ravages of this worm. All over the southern section of the United States hundreds of market gardens have been planted at an immense outlay of time ami money, only to have the fields of vegetables blighted from this mysterious trouble, as if scorched by tire or frost. Thousands of trees have been planted only to dwindle away and die; and, as the defect has been usually ascribed to the fertilizer or the climate, the injury has been enormous, while the real cause has not been suspected, and, as far as I know, no effort made to ascertain a remedy. The Orange is slightly affected now, lint in the future, when the soil will he filled with cysts and worms. Grange trees will he as uncertain. I fear, as the Peach or Pig at the present time. From the best testimony I can get, in the early days of the white im- migration, except in damp locations, peaches grew without an\ disease . save the •• Borer." Now, in many places, the trees that do well are the exception, and in these locations it is idle waste of time labor, trees, and fertilizers to attempt the culture of an orchard. In such infected spots the usual program is to apply some costly 24 ammoniaeal manure to the land, cultivate early vegetables between the trees; then, after that crop is removed, sow the land in cow-peas. The result is bewildering. Next year the unfortunate planter is discouraged to liml many of the trees dying back, the vegetable crop with knotty roots and irregular fruit. Another heavy fertilizing, another crop of peas, and that spot is done for. The disgusted farmer tries another vocation, and gives over the place to weeds and desolation. With young, closely-sel rows of trees the disease causes greatest dam- age, spreading rapidly from tree to tree. In market gardens, especially the Tomato, Cucumber, Melon, and Squash, the Anguillula often either destroys the plants before fruiting or reduces the size of the fruit till it fails to pay expenses. A number of disastrous failures with gardens, that have come to my notice, no doubt resulted from this cause. LIFE HISTORY OF THE ANGUILLULA. The study of this microscopic worm has been exceedingly difficult, and many points in its history are not yet fully ascertained. The limit of its existence, periods of growth, sexual characteristics, generation, variation of form, and the precise action occasioning the abnormal growth in roots, are all undetermined questions which will take a long continued series of observations to solve. (Note 12.) As first observed, a mass of cells appears within the uterine corn u a, cells averaging .,,, 7,,,,, inch in diameter, arranged in bands from T , to roooo ' ncn i" width, reaching across to the walls of the uterus. (Plate XX, A, B.) These bands appear at the smaller end of the uterus, beginning from 10 2 ° 00 to ,,,-,"0,1 inch from the free extremities, extend jng downward , :i ,"„ n to , ,;„"„„ inch. Lower down, these cells show a ten- dency to aggregate into irregular masses (Plate XX, 15, U), then into ovate forms, eventually becoming ovals ,,,;;,,,, by ,,,",,',,,, inch. At first these cysts have no epidermis, but a thin coating appears and thickens as they approach the normal size of l, 1 ,,',,,, inch in length and ,„',;;,„ inch in width. (Plate XX, D, 2.) During the life of the female the cysts form rapidly, until the whole uterus becomes enormously enlarged, and contains cysts in every stage, from the primary agglomeration of cells to free Anguilluhe. (Plates XIX and XVIII.) The decay of the environing root exposes the pregnant female to changes in weather, and with a slight increase in heat the contraction of the exterior expels the contents of the uterus and disperses them. This in most cases appears to be through the upper segment, though often it occurs through the fissure in the head. (Plate XIX.) The cyst at first is a solid mass of granular cells. (Plates IX, 1, and X. 1.) It divides centrally at the shorter axis (Plates IX, 2, 3; X, 2, 20,4): each half repeats tin's process till four or live segments are visible- A longitudinal fissure then appears, causing eight segments (Plates 25 I \ , . 10, 18) j the \\ alls "t the segments are absorbed each side the central long fissure l'l rte IX, 8, 10, 15, 10, I ■'. 18), w bicli extends to the margin of the oysl in ouo direction, and upon separation ai thai end motion begins, and the Anguillulu awakes to life and ac t ton. (Plates IX, 17, is; nnd XI, I.) The growth within the cyst continues till the worm attains n length of ,,',,;:,, inch or more, nnd a central diameter of , . im-h ; the cysl raptures, the worm is free (Plate XI, 2, 3, 7), leaving the emptj shell Bbrnnlcen and lorn. (Plato \ I. I. I". I'p to tli is | it ii nt I have failed to discriminate the sexes. Both appeal blunt at one end, which is marked with a fissure ,,,,',,,,, inch to inch iii length, often with a circular binge-like termination (Plate \ 1 1, So, la, . A.I'.; 1, .""», A, P>, 0, and 0; XV, 2, 3), then by the time the worm leaches the age represented in Plate XVI, 11, 12; PlateXVI, 3,4, become changed into a bicornate ovarium or aterns, which at lull term attains the length ol , inch in many coils, and contains one hundred and fifty or one hundred and sixty full-sized cysts. The shapes and si/.-s of these pregnant females vary greatly, and I believe are the result ol' the environment. In suit tissues of the Cow pea. Radish, and the like rapidly -growing plants they attain a transt erse diameter of inch, and a length of ; ;,;;:;„ inch. The tail is reduced to a short spine ( Plates \ I V, .; ; and XV. _'. 3), which disappears later on, as the worm approaches the transverse diameter of inch. (Plate XVII, 3, I. I'll.' thickness of the exterior wall varies from ,„,;,.„ inch at the lower part of the bodj to inch at the vertex, and is exceedingly tongh and resistant. In color it appears yellowish by transmitted light, but a brilliant white by reflected light When fully developed, il is partly transparent, showing the coils of the uterus with its cysts. The exterior is granular or corrugated, especially near tl head" Plates XIV, 0, and XIX . and with an apparently radiate arrangement of cells from a center near the tail, or perhaps marking the disappoaram f that appendage. Plate X X I 26 The head varies from a form like Plates XVII, 3, 4, 7, 9, and XVI, 9, L2, 13, 11, to dial shown by Plates XVI, 10, 11, 15; XVII, 2, 5, 8, and XVIII, the neck from a mere contraction of the body, Plates XVII, G, and XVI, 15, to a long tube, as in Plates XVI, L4, and XVII, 9. The body varies from almost a globe (Plate XVI. 9, 13j to an oval (Plate XVI, 1 1 ; XVII, 9), or nearly a cylinder. (Plate XVI, 15.) The worms found in woody tissue are usually of the forms of Plates XVI, 10, 11, ami XVII, 5, 8; in soft tissues like Plates XVI, 14, and XVII, 7, 9, but I am unable to understand the reason of this variation. In roots, as a rule, the bodies radiate from the central axis of the root witli the " heads" to the axis. When once enlargement of the, body begins, the worm becomes a fix- ture, and remains incapable of progression in any direction; the en- largement is gradual and the cells of the root tissues become smaller by the pressure, forming a rigid wall on every side of the worm. How long the worm exists is an unsolved problem which I hope to solve in time. Apart from vegetable tissues, I have noted signs of life in the An- guillula after being kept air- dry six months, but have no record of any reliable experiments with the worms in the roots ; but the vitality is very great. When motion is first perceived in the cyst, the worm is an average of r oouo ' nca ™ length and 10 JUo extreme thickness; soon after it be- comes free it enlarges and lengthens till it casts its skin, which it does as shown in Plate XI, 5, leaving the old skin shrunken as at (!, same plate; a fragmentary cast is seen on Plate XII, 1, but 1 have not de- termined the number of times in its life it sheds the, skin, as it is rare to find a perfect cast for measurement. Among the- thousands of Anguilluhe I have examined, therearea great many variations and arrangements of cells that are not easily explainable. Plates XV, XIII, and XII, 5, 8, 7, fi, exemplify some of the, most marked, riate XIII, 2, 3, is very singular; a cyst-like form, with segments. Also at 3, a peculiar arrangement of cells, large and small ; in fact. I have never found two worms exactly similar in the grouping of cells; the resemblance is general, but with wide variation of details. The ex- amples given in the plates justify this conclusion, sketched as they were from living specimens. The arrangement of the cysts in the uterus is generally as shown by Plates XVIII, XIX, and XX, though that often becomes changed, as indicated in Plate XXI. (Note 13.) In mature and apparently aged worms. I have found as many as a dozen free worms within the uterus, having attained motion and liber- ation there. In plates showing the changes in vegetable tissues, "A'' refers to the enlargements and nests of Anguilluhe. " B" to spots of decay. 27 NOTES v> " 1 1' i Owing to a look .>i literature on the subject,] hav< pro vis allj named this worm iii'iiiilliihi arenaria, but il maj belong to li an Angnil lnla.il isverj in n Hio A. ItroviapinoBua, bnl as (ho spine disappears In mature forma, I havo called tin- \ irenai in. Won '.' rbis information rnmo from one of tin il of il from ilw Spanish reeldente in I- " Won I Letters received from corrcapondenta at nenrlj over] important town gave ill.' data Woni i Mi mra Berokmana, Ondordonk, Munaon, and Stello arc rel I to. Won G [kept fall j dovoloped pregnant fomaloa in a watch glass drj foi six months, and when wot, thoj expanded, and the grown worms within the cyata in the ut< roan mod mot ion. Won 6. The average weight ofaenbie foot ofordinarj sandy surface soil ia(5,( grains, equal to B6 08 ponnda avoirdnpoia; tin- at the ti mperatnre ol 70 . tho -..il being air-drj . Ni>i ! 7.— 'I'lif qnantity required to saturate 1 1 uhic fool « aa 2.3 gallons of tho kero Bono emnlaion. Wont 8. The amount of lime need «a^ .'<• ponnda to tho tree, fort j nine trees to tin acre. Notk 9.— Water ponred upon tho pots percolated through tho soil and out at tin bole in the bottom '>f the i »• -t . Thia was allowed to evaporate considerably and exam- ined with magnifier 350 diameters, eye-piece It. objective one-half inch. Wotk 10. — Radiahea and turnips are very BU8coptiblo to thoAnguillnla. (See Plate III. draw ii from actual Bpeoimen, natural Bize. ) Wont 11. A common practice among tho ' old time Blavea, who toll mo it waa tho mlo made bj the old whites aa fat back as 1805. The reason they gavewas"tho peach lovea olay and yellow Band." Won 12. I . ..ii i,i only approximate the growth and development l>y tho use of audi plants as the Cow-pea and Radish— planting Boed in infected soil, and at certain dates pulling up tho plants and examining the knots, making n carefnl sketch, drawn t.. seal... each limo. All attempts at cultivating in flnids failed. Wotb 13. i:> softening the oxterior with a Bolntion of caustic potash, snipping oil the head and gontlj pressing the body in fluid, « ith a cover glass, tin nterus exuded a-- Bhown in Plate XIX o EXPLANATIONS TO PLATES. PLATE I. i of Con Pea, showing enlargements oansed by Angnillnla: A, enlargement and nests; B, spots of decay. (Origins PLATE II. Roots of Okra, show Lng enlargemi nts oansed by Angnillnla : A, enlargements and : B spots of decay. (Original.) ri.\ l l. ill Roots of Radish, showing enlargements oansed by Angnillnla: A. enlargements and nests; B, spots of decay. (Original.) PLATE IV. Roots "i Grape [ Black Hamburg ], showing enlargements oansed by Angnillu enlargements and nests; B, spots of decay. (Origin i PLATE V. Roots of Peach, showing enlargements oansed by Angnillnla. (Original. | PLATE VI. - of Weeping Willow, showing enlargements oansed by Angnillnla — natural (Origin i PLATE VII. Roots <>f Fig/showing enlargements oansed by Angnillnla — natm l 'nor- mal.) PLATE VIII. kion of root of Okrr», showing enlargements oansed by Angnillnla : '.'. I same; '■'. Grape, sam< — enlarged four times: i, Weeping Willow, same— natural - A, enlargements and nests; B, spots of decay. (Original.) PLATE IX. Reproductive cysts which form in the nterns of the female Angnillnla: 1. fast lid mass of granular cells ; 2, 3, segmentation or division into two parts; 4. 86, .">, 5a, 6, segmentation into four parts: 7, longitudinal tissnn' appearing, which causes segmentation into eight parts; 8,9, 1". 11. 12, L3, 1 1. 15, 16, IT, 1-, walls of mentB absorbing each side of the central longitudinal fissure which extends to the margin of the oyst in one direction, until upon separation at that end motion hegins — greatly enlarged. (Original.) - 30 PLATE X. Reproductive cysts (continued) : 1, la, first stage ; 2, 3, 4, 26, bi-seginentation or di- vision into two parts; 5, 6, 7, 8, 9, segmentation into four parts; 10,11,12,13,14,15, 16, 17, 18, segmentation into eight parts— greatly enlarged. (Original.) PLATE XL Developed or free Anguilluhe within the reproductive cysts: 1, free Auguillula within cyst not yet broken ; 2, 3, 7, cyst broken ; 4,4a, empty shell of cyst from which Auguillula; have emerged ; 5, young worm casting skin ; 6, empty skin cast by young worm— greatly enlarged. (Original.) PLATE XII. Growth of Anguillula* : 1, cast skin of young worm ; 2, 3, 4, 5, 6, 7, 8, worms showing bluntness at one end, with fissure haviug a circular, hinge like termination at A, and granular masses of cells within — greatly enlarged. (Original.) PLATE XIII. Growth of Auguillnlae (continued): 1,2, 3, worms showing masses of fine cells irregu- larly arranged within, and fissure at blunt end with circular, hinge-like termination at A — greatly enlarged. (Original.) PLATE XIV. Growth of Anguillul® and chauges within the female : 1, 2, female worms showing granular masses within; 3, 4, 5,6, chauges in shape in the female, preceded by for- mation in upper and lower thirds of body of dark masses of cells, A, B, C, which eventually unite — greatly enlarged. (Original.) PLATE XV. Changes within female Anguillula? (continued) : 1, 2, 3, enlargements in shape of the female, with formation of masses of cells at A — greatly enlarged. (Original.) PLATE XVI. Changes in form of female Anguilluhe: 1-15, outlines showing chauges in form, from leaving the reproductive cyst until the female is herself filled with cysts, also showing changes in the form of the head aud disappearance of the tail — greatly en- larged. (Original.) PLATE XVII. Changes in form of female Anguilluhe (continued) : 1-9, outliues of changes in form of body and head, with the disappearance of the tail — greatly enlarged. (Original.) PLATE XVIII. Gravid female Auguillula, showing contracted head and neck as in some females, and the arrangement of cysts in the uterus — greatly enlarged. (Original.) PLATE XIX. Arraugement of cysts in uterus of female Auguillula aud expulsion of young worms through fissure in the head — greatly enlarged. (Original.) ;{1 PLATE W An. in^iii t of oyata Id nterns oJ female Angnillnla i continued A B, oyata nr- raii^<-;unls reaching aerom to the walla of the uterna ; B gAtion of oella Into irregular maaeee within the nteraa; C D, aggregationa >>i oella arranged in two rowa in the nteroe; D-E, oyata thai have attained ii"' normal aise eud b< i om ated w ith .1 iliin epidennie— greatly enlai ged. ' Original > PLATE \\1. A changed arrangement of oyata within thenternaof the female Angnillnla which oi'tfu oconia greatly enlarged. (Original. I Bulletin 20, Divmon of Entomology, Dri • PLATE I. } ] ' , v i COW PEA. Bulletin 2d. DlviliOn of Entomology, Oopt. Ag PLATE II. OKRA L Bulletin 20, 0i«iiion gy, Dopt Agncultui*. PLATE III. / i RADISH ^ Bulla' PLATE IV. GRAPE Vitis Vimfera — Black Hamburg r i Builuif, 20, D ■ jmology, Dtpt A< MLATfc V. PEACH Bultoli" 20, 0.. . in o( Entomology, D«pt Agntuiiuro, PLATE VI WEEPING WILLOW Natural size. 1 PLATt VII FIG Natural size. ( "■r *r PLATE VIII. "ir OKRA Sectpon X 4 PEACH Secti. GRAPE Section X 4 * WILLOW Natural sue L Bulletin 20, Olvflion of Entomology D»pt Agocul'uft, PLAT 4a 5a ■^ 10 12 13 14 15 16 17 CYSTS OF ANGUILLULA. 18 B PLATE X V I ; • i d 26 9 ■.■I V V 10 12 Y f 1 ^ 15 16. 17 16 CYSTS OF ANGUILLULA. ■7 /• DEVELOPMENT OF ANGUILLULA. ' II*. PLATE XII. . a , f 8 ' % DEVELOPMENT OF ANGUILLULA. Bulletin 20, Oivition of Entomology, D*pt. Agriculture. PLATE XIII W DEVELOPMENT OF ANGUILLULA. jltuce. PLATE XIV. . S\ V B ft V 'V' V \ I B. GROWTH AND CHANGES IN THE FEMALE ANGUILLULA PL A' CHANGES IN THE FEMALE ANGUILLULA. PLATE XVI 15 I* - ,n J500 CHANGES IN FORM OF THE FEMALE ANGUILLULA. PLATE XVII CHANGES IN FORM OF THE FEMALE ANGUILLULA. .'0, O'K'lion n( EntomelOO .lluro, PLATE • GRAVID FEMALE ANGUILLULA, SHOWING CYSTS IN UTERO. Bulletin 20. Ovmon ol Entomotof) PLATE XIX. FEMALE ANGUILLULA, SHOWING EXPULSION OF YOUNG. I, Oh ilturt. PLATE XX B-C ARRANGEMENT OF CYSTS IN FEMALE ANGUILLULA IN UTERO. Sullvtin 20, I PLATE! : • ••> ■'■■ ARRANGEMENT OF CYSTS IN FEMALE ANGUILLULA IN UTERO. Slip