Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. BULLETIN No. 703 YS Contribution from the Bureau of Entomology L. O. HOWARD, Chief WASHINGTON, D. C. v November 20, 1918 MISCELLANEOUS TRUCK-CROP INSECTS IN LOUISIANA. I.—INSECTS INJURIOUS TO THE GLOBE ARTICHOKE IN LOUISIANA. By THos. H. Jones, Entomological Assistant, Truck-Crop Insect Investigations. INTRODUCTION. Insect injury to the globe or burr artichoke (Cynara scolymus) apparently has received little attention from American economic entomologists. While the artichoke has not as yet attained the rank of an important food plant in the United States, the demand for the edible heads is increasing in the markets. The crop is grown in Louisiana, and since the fall of 1914, when the writer was assigned for work on truck-crop insects, in cooperation with the Louisiana Experiment Stations, many growers have complained of insect in- jury to the plants. _ The most serious damage to the globe artichoke in Louisiana is caused by two species of plant-lice, or aphids, Myzus braggii Gil- lette and Aphis rwmicis Linnaeus, both usually occurring in the same field and being most numerous during the late winter and in the spring. INJURY CAUSED BY THE ARTICHOKE APHIS, MYZUS BRAGGII. The artichoke aphis is the most common and, generally speaking, the most injurious insect enemy of the globe artichoke in Louisiana. It occurs in great abundance on the under sides of the leaves and its green color harmonizes with that of the leaf. In cases of severe infestation its presence brings about a condition such as that de- scribed in the following letter sent in by a correspondent in Rapides Parish: “ Please let me know what to do for burr artichoke plants attacked by a dark smut which attracts large flies and bees. I had if 58681°—18—Bull. 703——1 2 BULLETIN 703, U. S. DEPARTMENT OF AGRICULTURE. the same disease attack my plants last year about the same time. Most of the plants recovered, but seem to have lost vitality and did _not bear fruit as early or as plentifully as in former years.” The presence of the “dark smut,” the flies, and the bees referred to is accounted for by the “honeydew” from the aphids, and in fields where the Argentine ant (Jridomyrmex humilis Mayr) is present, this obnoxious pest attends the aphids. Besides this complaint from © | Rapides Parish, there are also at hand records of Myzus braggti injuring globe artichcke in East Baton Rouge, Ascension, Iberville, Terrebonne, and Plaquemines Parishes.1 Myzus braggti also infests the yellow thistle (Cirsium horridulum) which is a common weed in Louisiana. (See Pl.I,fig.1.) This plant is closely related, botanically, to the globe artichoke, so that the pres- ence of the same species of insects on the two plants is to be ex- pected. Prof. C. P. Gillette, who described Myzus braggit? from Colorado in 1908, and who has determined material sent to him from Louisiana, states that at Fort Collins, Colo., it is found on Canada thistle (Cirsium arvense) during the latter part of the summer and early fall, and that “the winter hosts are the Russian olive, Hip- pohaes rhamnoides, and Shepherdia arvensis.” * ENEMIES OF THE ARTICHOKE APHIS. While no internal parasite has been found attacking this aphis, a number of predacious insect enemies have been observed. ‘These in- clude the larve of the syrphid flies Allograpta obliqua Say and Syr- phus americanus Weidemann, the larve and adults of the coccinellid or ladybird beetles Scymnus puncticollis LeConte, Scymnus termi- natus Say, Hippodamia convergens Guérin, and Cycloneda sanguinea Linnaeus, as well as the larvee of a chrysopid and a hemerobiid, both undetermined. The coccinellid beetle Alegilla maculata DeGeer and the predacious bug 7riphleps insidiosus Say have been taken on globe artichoke infested with Myzus braggiz and probably feed upon this aphis. The aphid is attacked by a fungus, which Dr. A. T. Speare, Bureau of Entomology, has determined as Entomophthora fresenti Nowakowski. At Baton Rouge Scymnus puncticollis ap- pears to be its most efficient enemy. INJURY CAUSED BY THE BEAN APHIS, APHIS RUMICIS. While not as common on globe artichoke in Louisiana as Myzus braggti, this aphis is more difficult to control by spraying than is the latter species, largely because of the fact that infested leaves 1Dr. F. H. Chittenden states that he has collected the species on globe artichoke at Washington, D. C. 2GILLETTE, C. P. New SPECIES OF COLORADO APHIDIDAE, WITH NOTES UPON THEIR Lire Hasits. In Can. Ent., v. 40, no. 1, p. i—20) ple ale 908: 8 GILLETT, C. P. CONFUSION OF RHOPALOSIPHUM HIPPOHAES Kocu, AND Myzus BRAGGII GILLETTE. In Jour. Econ. Ent., v. 8, no. 3, p. 875-379, pll1T, as. TLS: INSECTS INJURIOUS TO GLOBE ARTICHOKE. 3 become distorted in such a manner that the aphids can be reached only with difficulty with a contact insecticide. (See Pl. I, figs. 1 and 2.) CONTROL OF THE APHIDS ATTACKING ARTICHOKE. During 1917 Myzus braggii and Aphis rumicis were controlled sat- isfactorily at Baton Rouge by spraying with 1 part, by weight, of nicotine solution (containing 40 per cent of nicotine as sulphate) to 1,000 parts of water, with laundry soap (standard, noncaustic type) added at the rate of 1 pound to 25 gallons of water. (See Pl. I, fig. 2, and P]. III.) Because the plants in some rows in the field where the experiments were conducted were never sprayed, these plants served as a constant source of infestation for the sprayed plants, especially those near the untreated plants. The Argentine ant apparently was responsible in part for the spread of the aphids. More frequent sprayings were necessary, therefore, than would have been the case had all the plants in the field been sprayed. The plants were sprayed seven times, January 31, March 2, March 14, March 29, April 19, April 26, and May 26, respectively. The material was applied with a compressed-air sprayer holding about 3 gallons. The first picking of edible heads from the sprayed and unsprayed rows was made on May 11 and at frequent intervals thereafter until June 29. From 65 plants in the sprayed rows 310 heads or burrs were obtained and from 39 plants in the unsprayed rows 39 heads, an average of nearly 5 heads from each sprayed plant and an average of 1 from each un- sprayed plant. The difference in growth made by the sprayed and unsprayed plants was very noticeable and if the weather had not been dry there is little doubt that the increase in the crop from the _ sprayed plants would have been still greater than that from the un- sprayed plants. Jt is especially advisable to begin spraying globe artichokes when the aphids first appear on the plants, which is usually when they are small. One reason for this is that after Aphis rumicis has be- come abundant the leaves are so badly distorted as a result of feeding that it is very difficult to reach them with the spray. Another reason for timely spraying is that if delayed until the aphids have reached their maximum abundance, much of the injury for which they are responsible already has been done, and as the period of maximum abundance under such conditions often comes when the plants have developed a heavy growth of leaves, a larger amount of spray mate- rial and more time for its application are required than when the spraying is done early. Some growers who spray for the control of the aphids, but who do not begin until the plants are large and heavily infested, find it advisable first to cut off and destroy the older and badly distorted leaves. = BULLETIN 703, U. S. DEPARTMENT OF AGRICULTURE. It is interesting to note that a company which grows each year from 10 to 15 acres of globe artichokes in Plaquemines Parish, Louisiana, has found that the aphids. can be killed successfully = a nicormelc tants spray. Mr. E. P. Barrios, county agent of the parish, at whose suggestion the spraying was begun, has furnished the writer with the following information regarding the methods followed. The spray mixture, which is applied with knapsack spray- ers equipped with angled nozzles, is made up as follows: Tobacco extract containing saa) per cent nicotine as sulphate_ouneces__ 8 BYSH-OT! isoap 20 J er poet prea wee fbr ole nel) Worn ne pounds.__ 8 Wiater texte (nn ft. Tnee eect ee ee lee hs Ree gallons__ 50 This mixture contains 1 part of nicotine sulphate to 800 parts of water. As an additional aid in controlling the aphids, the method of planting followed makes it possible to utilize the same ground for artichokes during successive years. The young shoots are trans-— planted each fall in rows between the rows of old plants. Since the old rows are placed 8 feet apart there is ample space between rows to make this practical. When the young sets have taken root the old plants are plowed under and, as they are well covered with dirt, the aphids present on them are killed. The aphids on the young plants now may be more readily controlled by spraying, because of the smaller amount of foliage they present. Tt is possible that aphids on globe artichokes could be economi- cally killed by fumigation, ee peeealigy when only a few are grown, and for this purpose nicotine paper might be utilized, a cover to confine the fumes being placed over each plant as it is fumigated. OTHER INSECTS ATTACKING THE GLOBE ARTICHOKE IN LOUISIANA. The banded leaf-footed plant-bug, Leptoglossus phyllopus Lin- - naeus, feeds on the globe artichoke. Its normal food plant, as has been noted by Chittenden, is the yellow thistle, Carduwus spinosissi- mus (=Cirsium horridulum). The adults and nymphs are often numerous upon both plants, the adults being especially common on the thistle during late winter and early spring. Larve of the corn earworm (CAloridea obsoleta Fabricius) have been found boring into the edible heads, and a plant-bug, Thyreo- coris pulicarius Germar, has been observed clustered upon them. Nymphs of Nezara viridula Linneaus have been found on the heads, and a scarabaeid beetle, Kuphoria sepulchralis Fabricius, has been captured under conditions indicating that it was injuring them. 1 CHITTENDEN, F. H. SOME INSECTS INJURIOUS TO GARDEN AND ORCHARD Crops. U. S. Dept. Agr. Bur. Ent. Bul. 19, n. s., 1899. See p. 47. Bul. 703, U. S. Dept. of Agriculture. PLATE I.’ Fia. 1.—YELLOW THISTLE (CIRSIUM HORRIDULUM), A COMMON WEED IN UNCULTIVATED FIELDS IN LOUISIANA. It is closely related to the globe artichoke, and some of the aphids which attack the latter feed on the thistle. Fic. 2.—GLOBE ARTICHOKES ON WHICH APHIDS, MYZUS BRAGGII, HAVE BEEN CON- TROLLED BY SPRAYING. WILD AND CULTIVATED FOOD PLANTS OF MYZUS BRAGGII. Bul. 703, U. S. Dept. of Agriculture. PLATE Il. FiG. 1.—YOUNG PLANT INJURED BY THE BEAN APHIS (APHIS RUMICIS). FiG. 2.—HEALTHY YOUNG PLANT, SHOWING BENEFITS OF SPRAYING. THE GLOBE ARTICHOKE AND APHIDS. Bul. 703, U. S. Dept. of Agriculture. | PLATE Ill. SPRAYED AND UNSPRAYED ROWS OF GLOBE ARTICHOKE. The aphids Myzus braggit and Aphis rumicis have been controlled in the row at left by spraying With nicotine sulphate, The plants in the row at right have not been sprayed. INSECTS INJURIOUS TO GLOBE ARTICHOKE, 5 Cutworms, the predominating species apparently being Feltia annexa Treitschke and Agrotis ypsilon Rottemburg, cause some in- jury, especially during the cooler months of the year when only the smaller developing leaves are present on the plants. Larve of two agromyzid flies, Agromyza platyptera Thomson var. jucunda Van der Wulp, and Agromyza sp.,' have been found min- ing in the leaves and the membracid E’'ntylia sinuata Fabricius breeds on them. The leaves are also fed upon to some extent by various other insects, among them the larva of the cabbage looper (Autographa brassicae Riley) and the adult of the southern corn -rootworm (Dabrotica duodecimpunctata Olivier). 1 Determined by F. R. Cole. In 1914 Mr. I. J. Condit found larve of Phytomyza (Napo- myza) lateralis Fallén working as leaf miners on globe artichokes at Berkeley, Cal. The reared adults were determined by Mr. Frederick Knab, Bureau of Entomology. i Sis in add seid vet a apenas ol x ge a F toad. svtathrinley, Pecans 7 in ak " “aiod danot: waad evad "ce meyeoong faesg ie nae rort ats she ithe hisdadivsas ode am Td jriatee. smoe, OF mnogu’ hal ge ale tea vs? eal ; ago" Ll geddan add to erat ces ered Be bt 6) eetod. rryoctinee sit. de Hohe ods baw Cyst: Reta ur . - ; Fe : : ; es wiTHO s nasvogarniais host nienint | un . Prion ac eens i a aman te tein commer ab = cman Fe ph ee eg } ‘ es enh. KAGE AY walt) Sn ee hatial tlbae> A as we: ee rei ak y i ae noe Liat sy vine th weetedsiss eo ae erty ae taal ah yolaxow, noe. | vil. dant dghatenr’s, aoe. Galtsensa96 moet oe: oh es i .RSQhargeiaa to sae . alee -) Fy a aa &: + 4! : a ° 5 aa x se * ‘ d : 2 ¥. x. ~— ‘ ~ re . <7 S 3 eT ok ’ ; =e, % ae ee - 4 4 a ’ < a ® 4 ‘ : ? ‘ - - h s NS ‘ 4 : ' c £ : 2 s J > te a * os ] , A tp = at “ ; Ax i r A a 4 A . , ’ x Fr y * " ‘ ‘ 4 Be. : / Ma eg = re ; hie oe & CTA A Se ¥ ; i>, i. i ae) : > A> 1 A, ot . A es iB, + Been. hae = re i Sy 4 aii a as) : ee io Il.—THE GRANULATED CUTWORM,' AN IMPORTANT ENEMY OF VEGETABLE CROPS IN LOUISIANA. By TuHos. H. JONEs, Entomological Assistant, Truck-Crop Insect Investigations. INTRODUCTION. Cutworms periodically cause serious damage to vegetable crops in Louisiana and adjacent territory and it is seldom that they do not occur, at least in small numbers, in land planted to such crops. Complaints of injury are often made by people who have small gardens as well as by those who make the growing of truck crops their livelihood. Observations made in the State from 1914 to 1917, inclusive, indicate that the granulated cutworm (/el- tia annewa Treitschke) (fig. 1) is the principal species attacking vegetables.? Of 1,431 cutworms, rep- resenting collections made from about injured plants at Baton Rouge during the months of April, June, July, August, October, November, and December, of 1915, 1916, and 1917, 1,345, practically 94 per cent, were identified as Feltia annexa. ‘The proportion of this species, in one collection, was as low as 76 per cent, but at other times it exceeded 90 per cent. The remainder of-the collections noted was composed of 47 larve of Agrotis ypsilon Rottemburg (3.2 per cent), 35 larve of Feltia male- jida Guenée (2.5 per cent), and 4 larve of undetermined species. Fig. 1.— The granulated cutworm: Moth above, larva below, Somewhat enlarged. (Chittenden.) 1 Feltia anneza Treitschke. : ?Messrs. C. E Smith, J. L. E. Lauderdale, and M. R. Smith, who were stationed at Baton Rouge, La., for the Bureau of Entomology during this period, rendered vaiuable assistance in the investigations upon which this paper is based. ; ré 8 BULLETIN 703, U. S. DEPARTMENT OF AGRICULTURE. NATURE OF DAMAGE. As is true with other cutworms, the most serious damage done by the granulated cutworm is due to its habit of cutting off small plants near the surface of the ground. Two other types of injury have been noted. Where the plant is too large to be severed near the sur- face the larva ascends the plant and feeds on the foliage. (See Pl. IV, A, B.) Since feeding is done at night the cause of the damage often is not known to the grower. Irish potatoes, beets, and Brussels sprouts have been observed that were defoliated in this way, exami- nation revealing numerous larve secreted in the soil beneath. The other type of injury is to the fruit of certain plants, princi- pally when it rests on the ground. The fruit of tomato and egg- plant, if so located, is sometimes bored into and made unsalable. (PL. IV, C.) DESCRIPTION OF STAGES. THE MOTH. The moth (fig. 1) is one of the somber-colored species of the fam- ily Noctuidae. The fore-wings are covered above with brown, gray, and black scales, among which a few white ones are often present. These scales are so arranged that portions of the wings are brown or gray, or a mixture of the two colors, with black markings. The fore- wings of certain individuals may in general be darker or lighter than those of others of the same sex, but those of the female usually are darker than those of the male. The hind wings are white, more or less dusky along the margins and veins. The antenne of the male are pectinate, those of the female not pectinate. Ten mounted males averaged 37 mm. in width from tip to tip of the fore-wings, the width ranging from 31 to 40 mm. Ten females averaged 40.4 mm., the widths ranging from 37 to 43 mm. The following is the descrip- tion by Hampson: ? 6 [Male]. Head and thorax red-brown slightly mixed with fuscous; tegulae with slight black medial line; legs black and brown; abdomen pale red-brown, the ventral surface whitish. Fore wing pale red-brown, with some fuscous suffusion below base of cell and on costal area before apex ; an indistinct double, waved, black subbasal iine from costa to vein 1; the antemedial line double, very strongly dentate outwards below costa, in cell and above inner margin, and angled outwards in submedian fold; the claviform defined by black, narrow and elongate; the orbicular and reniform small, defined by black, the former oblique elliptical, open above, and with a black streak in the cell between it and the reniform ; the postmedial line indistinct, strongly dentate, bent outwards below costa, and oblique below vein 4; the subterminal line represented by a series of pale and fuscous dentate marks; the veins of terminal area streaked with black, and with a terminal series of black points. Hind wing semihyaline white, the costa and cilia at apex slightly: tinged with brown. 2 [Female]. Fore wing suffused with fuscous, leaving the costal area to end of cell and the terminal area brown. 1 HAMPSON, GEORGE F. CATALOGUE OF THE NOCTUIDAE IN THE COLLECTION OF THE BRITISH MusEuM. Jn Catalogue of the Lepidoptera Phalaenae in the British Museum, v. 4, p. 354-355. London, 1903. THE GRANULATED CUTWORM. 9 THE EGG. The egg approaches a hemisphere in shape, the smooth lower sur- face being at most only slightly convex. About 38 small ridges or _ ribs originate at the base and converge toward the apex, to which not all of them persist. Crossing between these ribs are numerous smaller ones. A minute “button” is present at the apex. The egg when first laid is yellowish white, becoming darker before hatching. The diameters of 15 eggs gave an average of 0.64 mm., ranging from 0.60 to 0.69 mm. THE LARVA. The following description of the larva, by Dr. H. G. Dyar, is taken from Hampson :* Head 3.5 millim., pale brown, pale reticulate, vertical band dark brown, strongly angled at top of clypeus, which is brown filled. Cervical shield well cornified, shining brown, cut by a pale dorsal line and traces of a subdorsal one. Dorsal space broadly pale, faintly brown, clouded on the centres of the segments, heaviest next the obscure, pale, dorsal line. Skin rather thin, smooth. Lateral space brown with faint pale subdorsal and lateral lines. Substigmatal band broad, distinctly but not brightly or very uniformly white-pigmented, the sub- vertical area becoming translucent. Tubercles dark brown, rather large and distinctly cornified ; anal plate brown. THE PUPA. Riley has already given a very good description of the pupa and the following is taken in part from his notes:? General color brown ochre, the surface smooth and glistening, except for im- pressions. In specimens from which the adult is about to issue the color be- comes of a darker brown, the eyes black. Head small, with front slightly pro- longed. Posterior iateral angle of prothorax with a dark brown transverse _ Swelling, which closes the first spiracle. Abdomen with dorsal surface of seg- ments 47 anteriorly with a transverse, rounded, darker brown ridge, marked with quite a number of very coarse and deep impressions. On segments 5-7 these ridges encircle the segments, though on the ventral surface they are not dark brown and the impressions are not aS prominent. Stigmata black. Tip of last segment dark brown, ending in two stout teeth, each terminating in a very fine spine, which is curved downward. Each side, just before the tip, is a small blackish tubercle, and, dorsally, a little in front of this is a short spine. Ten pupe averaged 18.6 mm. in length and 5.9 mm. in lateral width across the third abdominal segment, ranging in length from 17 to 20.5 mm., and in width from 5 to 6 mm. FOOD PLANTS. The larve are very general feeders and probably attack practically all vegetable crops. We have found them injuring bean, beet, On! cit ape oD: 2RILEY, C. V. THE GRANULATED CUTWORM (LARVA OF AGROTIS ANNEXA TREITSCHKE). In Report of the Entomologist, Ann. Rpt. U. 8S. Commr. Agr. f. 1884, p. 291, 292, Pl. II, fig. 1. 1885. 58681°—18—Bull. 703——2 10 BULLETIN 703, U. S. DEPARTMENT OF AGRICULTURE. Brussels sprouts, cabbage, cauliflower, eggplant, Irish potato, pepper, tomato, and turnip. LIFE HISTORY AND HABITS. HABITS OF THE MOTH. In the insectary the moths remain inactive during the day. In the field their activities probably take place at night, the moths secreting themselves during the day in places that are at most only poorly lighted. Specimens either have been collected in the field or have issued in a well-ventilated insectary during all months of the year except, April and June. OVIPOSITION. No eggs have been collected in the field. In the insectary they were deposited at night singly over objects to which the moths had access, with the flattened side of the egg adhering to the surface ~ upon which it rested. Riley has stated that moths which he had under observation scattered their eggs irregularly and singly on grass, though he considered this here 205 and probably abnormal, as a result of confinement. NUMBER OF EGGS DEPOSITED. During 1917 females were confined in the insectary and records kept of the number of eggs deposited by each. They were fed sweetened water and, once egg-laying had begun, eggs usually were deposited every night during the period of oviposition. The num- ber of eggs deposited by different moths, the number of well-de- veloped eggs in the ovaries at death, and the number of eggs de- posited daily by a single moth, ane greatly. The highest number deposited during a single night was 307. During December eggs were deposited on a night when the thermograph registered as low as 19° F. The confinement of males with females apparently had no bearing on the number of eggs deposited. Males kept alone and with females lived as long as did the females. Table I gives data concerning the female moths. TABLE I.—Hgg-laying records of Feltia annexa, Baton Rouge, La., 1917. Number of, il alive diab Moth |7Totalnum-|“escsin | _ Total Female moth issued. . . ber eggs : number laid. laid. died. ovaries at laid. death: of eggs. DEVE FETT as ICTs Gen En LL 1917 1917 1917 1917 Seni al0S sie 20 0s ee ee Sept. 12 | Sept. 20 | Sept. 20 812 0 812 Bp eb el a Nov. 22} Dec. 91] Dec. 11 878 385 1, 263 INDY O2 sk) ohio sR ee | vente eRe a Nov. 29| Dee. 6] Dec. 1 392 MOV SE? . tS ee ee ee Nov. 20} Dec. 8] Dec. 15 1,106 268 1,374 Novi A cele s Re ee Nov. 18] Dec. 8] Dec. 17 4 781 1D (ct Sie a re ae een eet et elon mom eeeee Dec. 18 311 311 INOVES0 Sones once ee Ae eee Dec. 2] Dec. 8] Dec. 19 5 433 438 a AU fe A Se Dec. 4] Dec. 26] Dec. 27 883 0 883 INV «292 Meets o'r ks oe he Ry Dec. 3] Dec. 26} Dec. 30 1,060 79 1,139 INOW a0 8 sc BR Seok: 2 ei ee Dec. 22} Dec. 29} Dec. 30 360 1 Confined with male. THE GRANULATED CUTWORM. 11 HABITS OF THE LARVA. The larve feed at night, and during the day usually are found in the soil near the plants upon which they have fed the previous night. At Baton Rouge larve have been taken in the field during all months except March, May, and September, and it is believed that they may be found throughout the year. There are apparently five and possibly six generations a year in this locality, and these so overlap that, at certain times, all stages are present in the field simultaneously. There has been considerable variation in the number of times larve have molted in confinement. Some were observed to have 5, some 6, and others 7 larval instars. Larvee from the same lot of eggs varied in this respect, though usually there was a variation of only one instar. Generally the individuals that spent the longest time in the larva stage underwent the least number of molts. LENGTH OF EGG, LARVA, AND PUPA STAGES. The length of time spent in the egg, larva, and pupa stages is governed apparently by the temperatures to which these stages are exposed. Table II, collated from notes, gives data on eggs, larvae, and pupe under observation at different seasons of the year in the insectary at Baton Rouge. The minimum period for the egg, larva, and pupa stages combined was as low as 88 days during July and August, while a period of 54 days was spent in the egg stage alone during December, 1917, and January, 1918. At this time tempera- tures below 30° F. were several times recorded on a near-by thermo- graph and during this period 8° F. and 11° F. were registered. These low temperatures prevailed during a period of weather un- usually cool for Baton Rouge and were apparently the cause of the failure of many of the eggs to hatch. Some larvee that issued on January 6 also were killed, apparently by these temperatures, although others survived. TABLE I1.—Lengths of egg, larva, and pupa stages of Feltia annexa, Baton FOUge: EGS 197: WnDeS Number Eggs de- Eggs hatched.| daysin, Larve issued. Larve pupated. larvee posited. under obser- ene stage. vation. July 14,1917 | July 18,1917 ANlemahy WS 1Ol7. 2 sea 2 Aug. 10-14, 19171......-- 12 Aug. 25,1916 | Aug. 31,1916 Gp Aue. SI OIG. 2: Sept. 24-Oct. 6, 1916..... 19 Oct. 22,1916 | Nov. 3,1916 D2 NOV LOR IONS ae ers Fan t3—29 sO Gs. eee il Dec. 6,1917| Jan. 29,1918 54 |e Mar 1s; 190g. = Apr /25-30; 4917. te 19 Number Number Number Sunbes Larve pupated. Adults emerged. es Heder ae stage. vation. stage. FHA Nas v10-14) TOTO) ILRI INE 0) Sart AY A Mi ce Bal 12 11-14 24-36 | Sept. 24-Oct. 6, 1916...........-- OCEIZE26 51916 ee oe ae yt 19 18-20 64-80 | Jan. 13-29, 1916................-- NMariG—2O ev OGe - eet Sst cine il 45-53 SoS ives DES Ohi es ee May 2220) 917 ao Po oe 19 19-21 1 Larve stopped feeding and entered soil Aug. 8-12 and it is assumed that they pupated two days later. 12 BULLETIN 703, U. S. DEPARTMENT OF AGRICULTURE. ENEMIES. A tachina fly, Linnaemyia comta Fall., identified by W. R. Walton, and an ichneumon fly, Enicospilus purgatus Say, identified by A. B. Gahan, have been reared from larve collected at Baton Rouge. A sarcophagid fly, determined by J. M. Aldrich-as Sarcophaga heli- cis Townsend, issued from a rearing jar containing larve of Feltia annexa and may have been parasitic on them. Dead larvee, invested with fungus, have been found also in rearing cages. The fungus has been identified by Dr. A. T. Speare as Entomophthora virescens Thaxter. METHODS OF CONTROL. Experiments indicate that, of the four methods of control follow- ing, only the use of poisoned baits and the treatment of attacked plants with arsenicals will prove satisfactory. The latter method is especially applicable when large plants are being injured and in certain instances, especially where severe injury to foliage is being done, both methods might be used simultaneously to advantage. HAND PICKING. One contro] measure is suggested by the fact that larve are found during the day in soil about plants on which they have fed during the previous night. This method is sometimes followed in Louisiana. Vegetable fields, usually fields where transplanting has been recently done, are examined and when cutworm injury is noted, search for the larva is made in the soil about the base of the damaged plant. _If the larva is discovered it is killed. This work can be done best in the early morning. Later in the day wilting of the severed part of the plant makes it more difficult to locate the injury, and the larva may move from the injured plant or bury itself deeper in the soil as the day advances. This method of control, even if practiced for several days and care- fully done, is expensive and by no means satisfactory. It is impossi- ble to discover all the larve in a field by following such a method and - the plan furthermore rests on the unsatisfactory basis that some in- jury must be done before the larva is killed. If larve are abun- dant, a large number of young plants are often cut off during the first night after they have been set out. BARRIERS AROUND PLANTS. Experiments made in cages and in the field indicate that in setting out plants injury may be reduced, to a certain degree, by wrapping the stems with newspaper or oiled paper, or placing cylinders of wrapping paper or metal about them. Such practices do not entirely PLATE IV Bul. 703, U. S. Dept. of Agriculture. ‘ware Aq Arnfut ZuruoAoid ur sued ur} Jo onTea Surmoys syuryd ose qqeqa—q ‘ware, Aq pormfurt qm OVwUIOL—'O ‘“PPYoyy ur wader Aq o#erpoy yoo 07 Ainfuy—"q “pley oy} ur wArey Aq pornfur synords spossnag, Jo yuRTT—"V "NYHOMLND GALVINNVYS SHL PLATE V Iture, icu of Agr Dept. s U Bul. 703 ‘sued poseadsuy— y ‘aojet skep ez toye? o10M Sydeis0joyd oy, “Wore Ul pouyuod o1eM wArvy Jo stoquinu jenbo ‘SAIL OY} SUT[[O1}MOD UT SuTAvAds Jo on[vA sULMOTS *sjurjd pokerdg— eUIT} 04 98 XOq Youo UT 010M SyurTd osvqqvo Jo JoquInu oeUrLVS OUT, "NYOMLND GALVIANNVYS SHL THE GRANULATED CUTWORM. 13 prevent injury and besides the expense of placing these barriers around the plants, their presence may retard the growth of the plants. In the experiments larvae sometimes ascended the barriers, either when the stems were wrapped with the material or when the barrier was at some little distance from the stem. If food plants, unpro- tected by barriers, are present there is less damage to the protected plants than is the case when only protected plants can be reached. This is shown in Plate IV, A, B, D. The plants protected by the cans, containers such as canned goods are sold in, with the tops and bottoms removed, show no injury, while the unprotected plants have _ been seriously fed upon. POISONED BAITS. Satisfactory results have been obtained in destroying the larvee in cages and in the field with poisoned bran mash. A mixture made up in the following proportions has given good results: BS Res1 01 Ga ee a a OS FCI De AN oA Eo Fh pounds__ 10 VIO AIS SCS patie eae Na AE all tb eR yl Wn at Bhat Cue ey lt J SVEN): (225 ELS ot a at LANGE aR SEA a RP Dec pound__ 4 NYY CY BOCA ea a A on RS eA EN A NA quarts_. 7 Juice and finely chopped rind and pulp of 2 oranges. In cages where young cabbage plants were growing larve were observed to feed upon this poisoned mash after it had been scattered thinly over the soil. No damage to the plants was noted and larve were dead on the following day. Of 202 larve collected from the soil 88 per cent were dead within three days after the mixture had been scattered over a field of Brussels sprouts that were being in- jured. A portion of the remainder apparently were not killed be- cause they had completed their growth and stopped feeding before the poisoned mash was put out. A mixture of 20 pounds of bran, 2 pounds of powdered arsenate of lead, 4+ gallon of molasses, and about 14 quarts of water has also given good results in killing larvee in the field. When the larve are found to occur in abundance in a field at plow- ing time and this field is to be immediately planted, it would seem advisable to apply poisoned baits before the field is planted rather than to wait until the crop shows injury. TREATING PLANTS WITH ARSENICALS. When the larve are feeding upon the leaves of plants it is pos- sible to reduce their numbers by applying arsenicals to the foliage. This method is especially applicable in the case of plants that have reached a considerable size, and under certain conditions the ar- senical may at the same time prevent injury by other leaf-eating insects. Plate V shows two boxes of cabbage plants. The plants in 14 BULLETIN 703, U. S. DEPARTMENT OF AGRICULTURE. one box were sprayed with powdered arsenate of lead at the rate of 2 pounds to 50 gallons of water, with 2 pounds of yellow laundry soap added. The plants in the other box were left untreated. Larve were then confined in both boxes. The appearance of the sprayed plants 23 days later is shown in Plate V, A, and that of the unsprayed plants in Plate V, B. The larve in the box containing the foliage to which poison was applied fed but little before being killed, while those in the other box continued to feed until their larval growth was completed. nee sir ei saci. pe IIJ.—EXPERIMENTS IN CONTROLLING THE TOMATO FRUITWORM WITH ARSENICALS. By TuHos. H. JONES, Entomological Assistant, Truck-Crop Insect Investigations. Spraying and dusting experiments for the control of the tomato fruitworm (Chloridea obsoleta Fabricius) were conducted during 1916 and 1917 at the Louisiana Experiment Station, Baton Rouge, La. This work was carried on in cooperation with Dr. C. W. Edger- ton, plant pathologist of the station, who was especially interested in the fungicidal value of some of the materials used. In 1916 a spring and a fall crop of tomatoes were used in the ex- periments. In the case of the fall crop a heavy frost occurred be- fore much fruit had matured. The next day all fruit was gathered and weighings and counts made. In 1917 only a spring crop was used in the experiments. The sprays were applied by means of small compressed-air spray- ers of about 24 gailons capacity. The materials were carefully ap- plied. On the spring crop of 1916 about 10 gallons of spray were used on an average in spraying eight times a row of 54 plants, set 2 feet apart in the row. On the fall crop of 1916 approximately 43 gallons were used in spraying the same number of plants seven times. For spraying the same number of plants five times in the spring of 1917 about 7 gallons were used. The dusting was done with a dust gun. In dusting the spring crop of 1916 approximately 17 ounces of undiluted powdered ar- senate of lead were used in making eight applications to an aver- age row of 54 plants, set 2 feet apart in the rows. In dusting the same number of plants of the spring crop of 1917 five times, ap- ‘proximately 124 ounces were used. For the dusting a specially prepared, light, finely powdered arsenate of lead was used, as was also used in spraying the spring crop of 1916. In Tables I-III “wormy” refers to fruit that was apparently injured by the larva of Chloridea obsoleta. Without doubt the in- | jury to a small percentage of this fruit was due to other causes, | principally the hornworms, Phlegethontius spp. and larve of the granulated cutworm: Feltia annexa Treitschke. 15 16 BULLETIN 703, U. S. DEPARTMENT OF AGRICULTURE. TaspLeE I.—Tomatoes set out in field Apr. 11, 1916. Applications of sprays and dusts made Apr. 25, May 5, May 15, May 24, June 2, June 12, June 22, July. 8, and July 18. No. 3 not sprayed after May 24. No. 4 not sprayed after June 12. Nos. 5, 6, and 7 not sprayed, and No. 9 not dusted, after July 3. Harvesting began June 14, ended Aug. 3. EARLIANA VARIETY. Num- Total Per Total ber of Num-| Per No. Material used. appli- ae aw ele cent!) stumber ber cent ca- y. | Weight | toma- | ormy.| wormy ious toes wormy toes Pounds.,| Pounds. ei) ACHE CK Wye) ea eee ee PE een - 266.7 73.1 27.4 1,413 436 30.8 2 | Bordeaux mixture, 44-50.......-- 9 297.5 61.0 20.5 1,718 357 20.7 3 | Commercial powdered arsenate of lead, 14 pounds to 50 gallons 44— 50 Bordeaux mixture..........- 4 216.9 49.8 22.9 1,441 368 25.5 AG SAMeAasuNO sean pre eae 6 359. 4 63.4 17.6 1, 862 344 17.9 SURES Fae Pe eee! ay est 8 262.5 29.2 eat 1,415 177 12.5 6 | Commercial Bordeaux and arse- nate of lead mixture, 1 pound tol6 gallons «water... -°..----..-- 8 229.1 24.8 10.8 1,392 157 11.2 7 | Commercial powdered arsenate of lead, 14 pounds to 50 gallons WaLOLE RS a5 eal sine eee 8 238. 2 23.2 9.7 1,385 145 10.4 8-| Dusted with 9 parts powdered sul- j ee and 1 part commercial pow- ered arsenate of lead, by weight . 9 303. 1 30.2 9.9 1,786 170 9.5 9 | Dusted with commercial powdered : arsenate of lead, undiluted...... 8 348. 4 20 6.0 1,468 105 fil GLOBE VARIETY. TUS CGAY Y eS Ia a rey eee a ae een 203. 8 36.8 18.1 1,180 211 17.8 2 | Bordeaux mixture, 44-50........- 9 236. 8 23.8 10.0 1,252 126 10.0 3 | Commercial powdered arsenate of lead, 14 pounds to 50 gallons 4— 4-50 Bordeaux mixture........- 4 190.6 13.0 6.8 1,120 86 (ets Syl Sain OFas INO ss ase ee cee Beh ees 8 221.4 11.6 5.2 1,073 51 4.7 6 | Commereial Bordeaux and arse- nate of lead mixture, 1 pound § tol6izallons water) ---see eee 8 317.5 19.2 6.0 1, 468 92 6.2 7 | Commercial powdered arsenate of lead, 14 pounds to 50 gallons wa- t Chere. weer ee peas cha tee. ay 8 254.2 16.8 6.6 1,318 74 5.6 8 | Dusted with 9 parts powdered sul- phur and 1 part commercial pow- dered arsenate of lead, by weight 9 24522 16.8 6.1 Hesse 75 5.6 9 | Dusted with commercial powdered arsenate of lead, undiluted...-.. 8 249.6 10.9 4,3 1,474 46 3.1 VaBLE II1.—Tomatoes set out in field Aug. 14 and 15, 1916. Applications of sprays made Sept. 2, Sept. 12, Sept. 22, Oct. 2, Oct. 12, Oct. 23, and Nov. 2. Harvesting began Oct. 24, ended Nov. 15. EARLIANA VARIETY. Num- Per Total ae Total | Num-| Per No. Material used. aber ok | weight Weight Coa number |_ ber cent PPACa-|t omatoes. y- SAU |tomatoes. |wormy. |wormy. tions. wormy. Pounds. | Pounds. 1901 @ bY 1c) Geer nee eee nS 8 FTN ee | Senin ee 41.2 9.3 2. 588 113 19.2 2 | Bordeaux mixture, 4-4-50........- 7 100.1 27.8 Diet 849 241 28.3 3 | Commercial powdered arsenate of ; lead, 3 pounds to 50 gallons 4-4— 50 Bordeaux mixture.........--. eet 109.5 16.9 15.4 1,012 144 14.2 4 | Commercial powdered arsenite of zinc, 3 pounds to 50 gallons water. 7 113.9 19.3 16.9 1,122 188 16.7 5 | Commercial Bordeaux and arse- nate of lead mixture, 1 pound tooleallonsiwaters--.—--5 ee seeee 7 108. 7 P5e5a M14ss 1,147 139 Zea: 6 | Commercial powdered arsenate of lead, 3 poundsto 50 gallons water. 7 80.5 113 14.0 880 112 12.7 CONTROLLING THE TOMATO FRUITWORM. 17 TasLeE II.—Tomatoes set out in field Aug. 14 and 15, 1916—Continued. HYBRID VARIETY.1 Thy st] 4G) (STO) ice th #8 ase heer leS events ip 5 acy Naima S| ee eee a 69. 2 9.3 13.4 694 93 13.4 2 | Bordeaux mixture, 4-4-50........- 7 66.9 13.3 19.8 546 94 17.2 3 | Commercial powdered arsenate of ; lead, 3 pounds to 50 gallons 44— 50 Bordeaux mixture........... 7 82.3 itilaul 13.4 724 73 10.0 4 | Commercial powdered arsenite of zinc, 3 pounds to 50 gallons water - 7 107.3 12.7 11.8 852 88 10.3 5 | Commercial Bordeaux and arse- nate of lead mixture, 1 pound toogallons waters peeas sees 7 95.9 1} aS 7 856 78 9.1 6 | Commercial powdered arsenate of lead, 3 pounds to 50 gallons water. 7 57.7 3.8 6.5 597 33 §.5 1 Hybrid selected by Dr. Edgerton, the parents being the Earliana and a wilt-resistant hybrid. TABLE III.—Tomatoes set out in field Apr. 4 and 6, 1917. Applications of sprays ' and dust made May 3, May 12, May 22, June 1, and June 12. Harvesting began June 11, ended Aug. 11. EARLIANA VARIETY. Num- Per Total F Total Num-| Per No. Material used. ber of | veignt | Weight | cent | number | “ye, | cent appli- tomatoes,| WOrmy- weight] toma- Sams Gra cations. ; wormy| toes. mmy. y Pounds. | Pounds. iL [MO aYevel te Trae ie ee coe tek a he el Ad 247.1 47.9 19.3 1,747 398 225 2 | Bordeaux mixture, 4-4-50........- 5 216.7 41.5 19.1 1,682 370 21.9 3 | Commercial powdered arsenate of ie lead, 3 pounds to 50 gallons water 5 303.1 37.4 12.3 2,102 362 2, 4 | Commercial Bordeaux and arse- nate of lead mixture, 1 pound to6gallonsiiwaterits. 42454-4465 5 261.8 31.8 12.1 1,850 317 17.1 5 | Commercial powdered arsenate of lead, 3 pounds to 50 gallons 4—4— 50 Bordeaux mixture...........- 5 297.0 38.8 13.0 1,929 313 16.2 6 | Commercial powdered arsenite of zinc, 3 pounds to 50 gallons water. 5 265. 5 27.8 10. 4 1, 856 270 14.5 7 | Commercial powdered arsenate of calcium, 3 pounds to 50 gallons Wie GOB yaretate oc oeicyarcrarrercterate oreretaloane 5 298. 2 31.8 10.6 1, 936 270 13.9 GLOBE VARIETY. 2 | Commercial powdered arsenate of calcium, 3 pounds to 50 gallons Water e Waeeas sos coe oeen 5 248.5 28.0 3 | Bordeaux mixture, 4-4-50....-.-.- 5 194.8 22.5 11.5 1,240 175 14.1 4 | Commercial powdered arsenite of zinc, 3 pounds to 50 gallons water. 5 227.5 22.1 9.7 1,597 200 12.5 5 | Commercial powdered arsenate of ABI CMOCCK tan eat eemaern watts eI ee ee 2157 24.2 11.4 1,473 207 14.0 lead, 3 pounds to 50 gallons 4-4— } | 50 Bordeaux mixture..........- 5 186.6 21.0 11.2 1,219 150 12.3 6 | Commercial powdered arsenate of lead, 3 pounds to 50 gallons water. 5 247. 4 20.7 8.3 1,701 180 10.5 7 | Commercial Bordeaux and arse- nate of lead mixture, 1 pound toi6 gallons:‘water-2..-...--...-- 5 205.1 19.5 9.5 1,570 159 10.1 THIRTEEN VARIETIES. Uae C kateb ei Si aa ee aa clas eet se etews 228. 0 43.2 18.9 1, 438 335 23.2 2 | Dusted with commercial powdered arsenate oflead, undiluted...-..- 5 159.3 11.9 7.4 1,199 124 10.3 The results of the two years’ work show considerable variation. None of the treatments can be considered to have reduced the injury profitably. Arsenate of lead, applied undiluted as a dust, gave the 18 BULLETIN 1703, U. S. DEPARTMENT OF AGRICULTURE. best results. It was to be expected that the sprays and dusts used on the spring crop of 1916 would show better results than those used on the spring crop of 1917, as in 1916 their application was con- tinued longer after harvesting began. On the fall crop of 1916, however, where harvesting was completed 13 days after the last spraying, the spraying apparently had little or no effect in some in- stances in reducing injury. In this connection it should be stated, however, that the plants used as checks produced but a small amount of fruit, partly because they were badly injured by Phlegethontius larve when small. Comparisons of results from sprayed and check plants may, therefore, not be indicative of the true value of the sprays. It is to be noted that the Earliana variety of tomato showed a higher percentage of injured fruit than did either the Globe or the hybrid. | The diagrams (figs. 2-5) show the number of tomatoes produced © each week by Earliana and Globe plants set out in the springs of 1916 and 1917, part of these being sprayed with arsenate of lead and the others serving as a check. The percentage of the number of fruit showing injury is also given. The diagrams show that the Earliana produced the greater portion of its crop sooner than did the Globe and that in 1916 both varieties produced their crops within a shorter period of time than in 1917, there being a pronounced “second crop” during 1917. 500 or 100% Fic. 2.—Diagram, prepared from weekly totals during harvesting season, showing number of tomatoes of the Earliana variety and percentage apparently injured by the tomato fruitworm in 1916. Spaces between horizontal lines represent 100 in case of total number of tomatoes, and 20 in case of percentage wormy. Vertical lines represent , weeks. The solid line represents the total number of tomatoes from the unsprayed check; the dotted line, the percentage of check wormy; the line of dashes, the total number of tomatoes from plants sprayed with arsenate of lead; the line of dots and dashes, the percentage of sprayed tomatoes wormy. CONTROLLING THE TOMATO FRUITWORM. 19 Fig. 3.—Diagram, prepared from weekly totals during harvesting season, showing number of tomatoes of the Harliana variety and percentage apparently injured by the tomato fruitworm in 1917. Spaces between horizontal lines represent 100 in case of total number of tomatoes, and 20 in case of percentage wormy. Vertical lines represent weeks. The solid line represents the total number of tomatoes from the unsprayed check; the dotted line, the percentage of check wormy; the line of dashes, the total number of tomatoes from plants sprayed with arsenate of lead; the line of dots and dashes, the percentage of sprayed tomatoes wormy. Wie. 4.—Diagram, prepared from weekly totals during harvesting season, showing number of tomatoes of the Globe variety and percentage apparently injured by the tomato fruitworm in 1916. Spaces between horizontal lines represent 100 in case of total number of tomatoes, and 20 in case of percentage wormy. Vertical lines represent weeks. The solid line represents the total number of tomatoes from the unsprayed check 3 the dotted line, the percentage of check wormy ; the line of dashes, the total number of tomatoes from plants sprayed with arsenate of lead; the line of dots and dashes, the percentage of sprayed tomatoes wormy. 400 2 oo 80x 3 Cee 5 aa 300_or 60% Fic. 5.—Diagram, prepared from weekly totals during harvesting season, showing number of tomatoes of the Globe variety and percentage apparently injured by the tomato fruitworm in 1917. Spaces between horizontal lines represent 100 in case of total number of tomatoes, and 20 in case of percentage wormy. Vertical lines represent weeks. The solid line represents the total number of tomatoes from the unsprayed check; the dotted line, the percentage of check wormy; the line of dashes, the total number of tomatoes from plants sprayed with arsenate of lead; the line of dots and dashes, the percentage of sprayed tomatoes wormy. 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