Slides sickens . ee rer Secean vers CUT TRY $6444440 ¥rvrry OV a ey LOL OODLE EOE OL UO Evy eres ve vrrryrvrre yrry VE NYy VT ey CUE EY COREY YY h - WEEE PEP EW wry F < Sey re errr ee nth ial eh | SOC CU yee” vee Wi inne ne) i =) UYuY peeviceiee y | | Sewn — - Woe dag UPSETS ec ooo ceeelccce uuseeeeteeeraaneete” YET PUUU tia ei vy Veep” -veerr ey Ww eh “Su Y - - ; ] : } A "| al | | 4 7 > / S a} eed Ste Neert og etd ¥ i. : fe ) U.S. DEPARTMENT OF AGRICULTURE, ”” ee. BUREAU OF ENTOMOLOGY—BULLETIN No. 113.) 14) 2-\< fs L. O. HOWARD, Entomologist and Chief of Bureau. THE PRINCIPAL CACTUS INSECTS OF THE UNITED STATES. BY W. D. HUNTER, In Charge of Southern Field Crop Insect Investigations, F. C. PRATT, Late Assistant Entomologist, AND J. D. MITCHELL, Agent and Expert. IssueD DECEMBER 19, 1912. Vi iA Imodts ™\ qnsenian Institue << e C5 JAN. 4 19 AA0OTOA NS fiens| Muse WASHINGTON: GOVERNMENT PRINTING OFFIOE. 1912. 2 bart ea ate hatte eee Sa ae Eh at ON : $5 ‘ vi ae i a ase GF 4 Begs a We bien Ney Pte eae ee ra ee ty 'P Ma) he Hie) yeh ta Aine n LAS er aN eee U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— BULLETIN No. 113. L. O. HOWARD, Entomologist and Chief of Bureau. THE PRINCIPAL CACTUS INSECTS OF THE UNITED STATES. BY W. D. HUNTER, In Charge of Southern Field Crop Insect Investigations, F. C. PRATT, Late Assistant Entomologist, AND J. D. MITCHELL, Agent and Expert. Issuep DrcemBer 19, 1912. WASHINGTON: GOVERNMENT PRINTING OFFIOE. 1912, BUREAU OF ENTOMOLOGY. L. O. Howarp, Entomologist and Chief of Bureau. C. L. Martart, Entomologist and Acting Chief in Absence of Chief. R. S. Cuirron, Executive Assistant. W. F. Tastet, Chief Clerk. F. H. Currrenven, in charge of truck crop and stored product insect investigations. A. D. Hopkins, in charge of forest insect investigations, W. D. Hunter, in charge of southern field crop insect investigations. F. M. Werster, in charge of cereal and forage insect investigations. A. L. QUAINTANCE, in charge of deciduous fruit insect investigations. E. F. Puiuies, in charge of bee culture. D. M. Rocers, in charge of preventing spread of moths, field work. Roitia P. Currin, in charge of editorial work. Maser Coxucorn, in charge of library. SouTHERN FIELD Crop INSECT INVESTIGATIONS. W. D. HuntTer, in charge. W. D. Pierce, J. D. MitcHett, G. D. SmitH, E. A. McGrecor, Harry PINKUS, B. R. Coav, G. N. Wotcort, W. A. THomMAsS, R. W. MorELanp, C. E. HESTER, engaged in cotton-boll weevil investigations. A. C. Morcan, G. A. Runner, S. E. Crump, D. C. PARMAN, engaged in tobacco insect investigations. F. C. Bisuorp, A. H. Jennines, H. P. Woop, W. V. Kina, engaged in tick inves- tigations. T. E. Hottoway, E: R. BARBER, engaged in sugar cane insect investigations. J. L. WEBB, engaged in rice insect investigations. R. A. Cootry, D. L. VAN DINE, A. F. Conrapi, C. C. KRUMBHAAR, collaborators. 2 pay aes les COPIES of this publication may be procured from the SUPERINTEND- ENT OF DOCUMENTS, Government Printing Office, Washihgton, D. C., at 15 cents per copy LETTER OF TRANSMITTAL. Untrep Srares DEPARTMENT OF AGRICULTURE, Bureau or Entromoroey, Washington, D. C., May 3, 1912. Str: I have the honor to transmit herewith a manuscript entitled “The Principal Cactus Insects of the United States,” prepared by Messrs. W. D. Hunter and J. D. Mitchell, of this bureau, and the late F. C. Pratt, who for many years was in the employ of the bureau. In the work of the Bureau of Plant Industry on the utilization of. the prickly pear as a farm crop it became evident that insect injury in plantings was of considerable importance. This observation was made by Mr. David Griffiths. In 1907 he brought the matter to the attention of the Bureau of Entomology and the investigation upon which the present manuscript is based was begun. During the work the bureau has profited by the close cooperation of Mr. Griffiths, and many of his observations are included in this report. I recommend that this manuscript be published as Bulletin No. 113 of the Bureau of Entomology. Respectfully, L. O. Howarp, Chief of Bureau. Hon. James WILson, Secretary of Agriculture. CONTENTS. PIERO Oli gee aeeiveis tas eat st Ao co aie Sah als, wand bebe bvatle MERE EE Historical statement regarding cactus insects.................2.0222--eeeeeeee Numberand ‘classification-of cactus insects........-..0<2..-++.sseeSensebe se The principal insects injurious to Opuntia, in order of their importance........ Peepein sHermne thie Koos or BtCMmBL 1.2.5. |. 8622. . a, Jeanie te sic cs cae species.on the: genus Moneilemia: 22): 2255... 912 Sseeke Mes Severe Description of the larva of Moneilema crassum...........-.-..------- SEES TT SE ee RS ci ad ad) By iene Oe eee LN Re A Qi eeoe PI ORGEEEE Rls ato a2 hae aden ON Ske soem esd I es pecies attacking the joints externally...... 2.2... 2. codec eek bes a slb oe ee Cuaanucnmmrpersp Uber sco. PS eke ols. BL Lo) ae ee PTRRUPEEGIORUINGRY SS ect. = cacti. 5 ee eee eck oe ASs : EUR. Suen ee Bina cL OTE crs Steet? ae eee ee Pa aoe ok os aye aE OS UTENU(r TTeT ak SSRs UM gS Ag ECE See Et ee ee ee OED ALN PET Mole Huge Hal near s. COMd de ESL hs Dacca bi' de Sole pl Mmiveghartaiee cee ete ed et eee ae ae emt tae se nde ew eee hae SONS See a SR I Re ras Rees Oleg Oe Cte tye 5 G3 oie oo Si dames get) pies The control of Chelinidea vittigera and allied species...............--.---- UMUN GRIND IMORLAPENULIS (TOUR. 22.22. s ccc cn. ook cen Hee OR bee SESE ae Be ION Sas Es ts led dod Wa wie wea ele eeleis DTS Bias OR arbennig AC 5 A ape EE ROE AP Se Minor species attacking the joints externally...........,.....22--2222---- Species attacking the joints imternally..2 2-2-0... 2 oe. fo ed ce oe ene owe clean nena Lantern cd EAI a, es 2 Se os we Piverenty Ol dinner cee ee eo oe ae A eee DekcripLion Gb imnmatura niapOd see - 32k dee octets ss sees tee Uae ats eee eee cent Siete Salas Gee ears... 6 PRINCIPAL CACTUS INSECTS OF UNITED STATES. Species attacking the joints internally—Continued. Melitara: dentaia Grote. 0-322. =e 2 eee eee eee eee eee oe Melitora prodeniains Walker. ..2t2e. Sagsnee ee ce ce ee eee ee eee Metitara fernalidialis Huualst <2 7 ee ee oe ee ee ee Cee Gersteckeria porosa Le Conte....-.------- ah Ae Se See ee. ats Gerstxckeria nobilis Le ‘Conte. zoe. asec ae 2 eas eee ae Shee = eaeete Gerstxckeria clathrata* Le. Contets.e cee eee." 2 ane os) = fee 2-2 2 ee Marmara opuntiella Busclee. eemeceis eee tees ert es ee eee ee Spevies injuring the bloomic: ect teee re Ome eer rs Wapedia ok eee ee Species injuring jhe irises. oe oe sla ae ele te oils eee Narnia palhdiconnits Stal a i2s23322-,. Se OSES fet ee ee Deseripiivee.tssoso ce. 52. emit os eee eee Asphondyluie pumntin Welt. 2st is). 0). AeA Os oS SSA eee ee eras Cornifronselautatts Grote... 24.33... 515. 2 see ee ee Alloriina mutabilis Gory snn00 =5 242.2420 uo eee ae ee oe eee Suteonorus luiteiceps Reuters. to.2 23822 22 oe See eee eee ene POUISTES TSI a < = ania. G2 in Se aaltepet omen ao Trotropis contaminatus Uhilers: 214.22 242 2 aa ae eee Dyotopasta yumaella Kearfott. 222. <2... eae aeee eee 26 eee Ozamia lucidalis Walker: \ 2.2322 ig as sac oe eee eee ee eee Plonjnota rostrang Walkers): >. 2.22-5o¢ oe tee te ee eee RCRVONOCTS. a.c's oso ed sete decisis seca sis a =p eee ee ia riein mia Oe ere Copestylum marginatum Say os) ss Bee een fetes So eee FICPIMNCLG SPP ~ = = «2 sj5 0 Se's.2.5 515 So REE Oe Oa ee eae eee SHeromiyia longicornis Big0bs.s2cc-.068 yee ee oe eee Eee eee oer List of the principal cactus insects of the United States...................---- Species which injure,the plant-2- 2222. 225: 3220.5 ae eee Parasites or enemies of the injurious species............--.---.----------- SCBVENGETS esis i's a 5's 52 bisis se re terepere ere ere als Sapo pay Re Ne ihre ay a a Species which merely frequent the flowers................--------------- Species incidentally associated with the plant.....................-.---- bibliography of cactus. insectss...2 eer - ooo sleet ee ee Puate I. Fia. onan & DR LEUST RATION S: PLATES. Longicorn beetle, Moneilema crassum, an important enemy of the AU Malate ete tice es eNe mccrets cats a So te etn eave een: hens ete . Work of the longicorn beetle, Moneilema crassum, on the cactus, SER TOUCRCO SUES «Sake Ne SC Lee See SIG SN te Miele ac . Work of the moth, Mimorista flavidissimalis, on joint of Opuntia... -.- . Larve of the flea-beetle, Disonycha varicornis, on Opuntia leptocaulis. . Two important scale insects of the prickly pear: The cottony cochi- neal insect (Dactylopius confusus) and Diaspis echinocacti cacti... . . Joint of prickly pear showing work of Marmara opuntiella............ . Studies of cactus insects. Fig. 1.—Eggs of Melitara junctolineella on spines of Opuntia. Fig. 2.—Egegs of Chelinidea vittigera on spine of Opuntia. Fig. 3.—Eggs of Copestylum marginatum on Opuntia spines, . Big.4.— Narnia pallidicornis..:- 2-4-0022. s0n22++00sse = TEXT FIGURES. SAA CROAT CAG Eis COG 1 Ne rr on ee ae Oe . Chelonus laticinctus, parasite of Melitara dentata.............---------- GC SELERENOL NOD Wis AUN eect oes ee She ee So Sos ee vs . Marmara opuntiella: Adult, larva, eggs, and pupal case ...........----- . Opuntia fruit with puparia of Asphondylia opuntix............------- b COMER IU WANRNOATUMN MOUND a. so. 2 o5 6 os a tn sei he, See aie aie BRER EP IIETO CRT USO DUES DMM eae tis a2 oS a,c 'c.cAns olka aid de ee oe » Nuctomyia longicornis: Profile, head, and ‘wing.......2..<222225... 4... 32 16 28 30 31 o4 37 38 39 ie i if Ww ra i om ii ) Pid 4 \0) a Seay Tat iV LO CANE iy ye aes THE PRINCIPAL CACTUS INSECTS OF THE UNITED STATES. INTRODUCTION. The cactus plants of the genus Opuntia are among the most strik- ing objects to be seen in semiarid and arid regions. ‘Tuese plants, which are extremely picturesque, are accorded a prominent place in the illustrations and literature of early surveys, undertaken by the War Department,’ and, from a scientific standpoint, are of great interest because they have been found to have adapted themselves to existence in regions of small rainfall in many remarkable ways. The numerous insects associated with cactus plants are naturally of great interest. These insects have adjusted themselves to the general condi- tions in the regions in which the plants grow and have vlso adapted themselves to the structure and habits of the plants themselves. Moreover, cactus insects have always held special interest on account of the cochineal insect. The cultivation of this species, which is indigenous to America, caused the prickly pear to be transported to remote parts of the globe, where it has been planted for the purpose of furnishing food for the dye-producing insect. The industry of rearing the cochineal insect was for years a very important one. It furnished valuable dyes which are still utilized for special] purposes. In the Canary Islands alone, in 1876, the exportation cf cochineal amounted to over 5,000,000 pounds. It has been determined that the bodies of about 70,000 cochineal insects are required to make a pound of the dried product. This gives an indication of the extent of the industry in the Canary Islands, which did not, however, produce nearly all of the supply which entered into commerce. Except for the cochineal insect, the species feeding upon Opuntia have been until recently rather of scientific than of practical im- portance. In the early days, siice it was necessary to cultivate the Opuntia plant as food for the cochineal insect, any species which injured the plant were of economic importance. In fact, the treatises on the cultivation of the cochineal contain directions about the control of various species which damaged the plant. With the decadence of the cochineal industry, the cactus plants became nuisances, except 1 Pacific Railways Report, vol. 4, p. 37, 1856; U. S. and Mexican Boundary Survey, vol. 2, p. 35, 1859. 9 10 PRINCIPAL CACTUS INSECTS OF UNITED STATES. where the tunas were utilized as food.t. They occupied land that could be used to advantage for valuable crops. In this way, in a few years, the plant was changed in character from a valuable one to a weed. Incident to this change the insects feeding upon Opuntia assumed an entirely different character. Instead of being considered pests, they came to be looked upon as beneficial on account of their destruction of the weed. In fact, in South Africa and Australia the encourage- ment of the insect enemies of prickly pear has been proposed as a feasible means of reducing the number of plants. Within very recent years, at least in so far as the United States is concerned, there has been another revolution in regard to prickly pear. It has been recognized for many years in the southwestern por- tion of the United States that the plant furnished a supply of food for cattle during drought that frequently prevented the starvation of large herds. It was considered, however, that this was a rather poor return for the loss of large grazing areas on which the plants grew and which in normal seasons without the prickly pear would have furnished large amounts of forage. Some years ago Mr. David Griffiths, then of the Arizona Agricultural Experiment Station, began an investigation of the feeding value of prickly pear. It was soon found that the plant has a surprisingly high feeding value.? The greatest practical difficulty in the use of the plant for forage was the spines, but it was found to be possible to eliminate this diffi- culty by singeing the plants or by running them through machines which chopped them into small pieces. It was also discovered by Mr. Griffiths,? whose more recent work has been done as an agent of the Bureau of Plant Industry of this department, that when prickly pear is planted it responds readily to cultivation. In fact it was found that artificial plantings of the pear with only meager cultiva- tion furnished a growth in three years that was fully as great as the growth under natural conditions in double that period. At this point, however, it became evident that the insects affecting the prickly pear would need to be taken into consideration. In fact it appeared in the experimental plantings of the Bureau of Plant Industry that the insect injury was one of the most important obstacles to the culti- vation of the prickly pear asa farm crop. In this way there has been 1In this discussion we consider the prickly pear as a crop planted on a large scale but do not overlook the fact that its fruit has been utilized as food for man from very ancient times and is still an important human food in large areas. There has been no revolution as regards the tuna as food for man. It has always been important. How- ever, the tunas are obtained from wild plants, or from those cultivated on a compara- tively small scale about houses, and thus represent a system of growth quite different from the extensive field culture of the early days. 2The Prickly Pear and other Cacti as Food for Stock, by David Griffiths. (Bul. 74, Bur. Plant Ind., U. S. Dept. Agr., March 8, 1905.) Feeding Prickly Pear to Stock in Texas, by David Griffiths. (Bul. 91, Bur. Plant Ind., U. S. Dept. Agr., 1906.) 8 Prickly Pear as a Farm Crop, by David Griffiths. (Bul. 124, Bur. Plant Ind., U. 8. Dept. Agr., February 19, 1908.) The Tuna as Food for Man, by David Griffiths and R. F. Hare. (Bul. 116, Bur. Plant Ind., U. S. Dept. Agr., December 2, 1907.) HISTORICAL STATEMENT. lal a complete revolution in so far as the importance of cactus insects is concerned. HISTORICAL STATEMENT REGARDING CACTUS INSECTS. It has been stated in a preceding paragraph that the insect enemies of Opuntia attracted some attention in former years on account of their injury to the host plant of the cochineal insect. Several of the treatises on the cultivation of the cochineal contain brief suggestions about the destruction of the enemies of the plant, as well as about the enemies of the cochineal itself. In all these considerations, how- ever, only the merest incidental attention was paid to species other than the cochineal. The first systematic work on cactus insects that was undertaken was that done in 1895 by Mr. H. G. Hubbard, who lived in Florida. “He discovered a lepidopterous larva, Melitara prodenialis Walk., which feeds upon the prickly pear, traced out its life history and transformations, and published a most interesting account of his observations.t A few years later Mr. Hubbard sojourned for some months in Arizona. In that territory he made studies of the insect fauna of the giant cactus (Cereus giganteus). Although plants of the genus Cereus will probably never be of importance as forage,? Mr. FHubbard’s studies have a bearing upon insects infesting Opuntia, since the faunas of Cereus and Opuntia are largely the same. After his death, the results of Mr. Hubbard’s investigations were published under the editorship of Mr. E. A. Schwarz.* From 1896 to 1898, on various trips to the region then infested by the boll weevil, Mr. E. A. Schwarz made a number of observations on insects infesting Opuntia. In fact, he discovered a number of the species which have now been found to be of importance in the area in which the prickly pear is undergoing cultivation. Dr. L. O. Howard and Mr. C. L. Marlatt also made observations on cactus insects at about this time. The results of these incidental observa- tions were published in notes in the Proceedings of the Entomological Society of Washington. By 1905 Mr. David Griffiths had begun the cultivation of the prickly pear in the vicinity of San Antonio, Tex., and elsewhere. It was on his experimental plantings that the observation was made that the concentration of the plants under cultivation seemed to increase the amount of insect injury. Recognizing the importance of this matter, Mr. Griffiths immediately began the collection of specimens which, with full notes, were transmitted to the Bureau 1Proc. Ent. Soe. Washington, vol. 3, pp. 129-132, two figs., 1895. 2The Cereus plants are, of course, utilized in many ways by the inhabitants of the region in which they occur, but not as forage. 3 Psyche, May, 1899, Supplement, pp. 1-14. 12 PRINCIPAL CACTUS INSECTS OF UNITED STATES. of Entomology at Washington. This material was placed in the hands of Mr. E. S. G. Titus and Mr. F. D. Couden. In spite of the difficulties of rearing the specimens, due to the transportation to Washington and the utterly different climatic conditions, these ento- mologists succeeded in rearing a large number of specimens. This material, with the rearing notes and the field notes supplied by Mr. Griffiths, has been used in the preparation of this bulletin. In 1907 Mr. Griffiths’ field observations mere than verified his previous impressions regarding the importance of cactus insects. By this time it had also become evident that the rearing work could be carried on to much better advantage in the regions where the Opuntia was grown and that field experiments in control were neces- sary. For these reasons, in 1907 the investigation was turned over to the branch of Southern Field Crop Insect Investigations. In con- nection with other work Mr. F. C. Pratt and Mr. J. D. Mitchell were detailed to institute an investigation of cactus insects in Texas. Mr. Pratt’s work was continued with serious interruptions, due to his ill health, from late in 1907 until the fall of 1910. During this time he and Mr. Mitchell accumulated a very large amount of information about the insects associated with the Opuntia plant and regarding feasible means of control of the more injurious species. The origi- nal intention was that a publication on this subject should be pre- pared by Mr. Pratt. His ill health, which became acute about the time that sufficient material had been gathered to form the basis of a bulletin, and his death soon afterwards, prevented placing the matter in form for publication. This part of the work has been done by the senior author, who has also made some field observations, although the great majority of such observations were made personally by Mr. Pratt and Mr. Mitchell. NUMBER AND CLASSIFICATION OF CACTUS INSECTS. As the result of the work we have done and that of the previous investigators who have been mentioned, 324 species of insects are known to be associated with the cactus plant. These divide them- selves naturally into five categories, as follows: Species injuring the plant, 92; parasites of injurious species, 28; scavengers, 73; flower visitors, 40; species only incidentally associated with the plant, 91. The injurious species affect different parts of the plant. In fact, no important part of the plant is immune from injury. Twelve species are known to attack the roots or stem. ‘Twenty-seven species attack the joints, of which 11 species feed inside of the joints while 16 destroy the outer portion. A considerable number are found in the blooms; a few of these are injurious, but others undoubt- edly assist in the fertilization of the plant. The fruit is injured by 13 species. Bul. 113, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE I. ————— LONGICORN BEETLE, MONEILEMA CRASSUM, AN IMPORTANT ENEMY OF PRICKLY PEAR. Adults feed on exterior of joints of the cactus, while the larve destroy the interior of both joints and stems. Enlarged. (Original.) Bul. 113, Bureau of Entomology, U. S. Dept. of Agriculture. PRATER WoRK OF LONGICORN BEETLE, MONEILEMA CRASSUM, ON THE CACTUS, ECHINOCEREUS SP. (ORIGINAL.) INSECTS AFFECTING THE ROOTS OR STEMS. 13 The foregoing arrangement of five categories will be followed in the body of this bulletin. Within these categories the species will be treated in the order of their importance. In this place, however, we shall include a list of the principal species arranged as they rank in importance regardless of the parts of the plant affected. THE PRINCIPAL INSECTS INJURIOUS TO OPUNTIA IN ORDER OF THEIR IMPORTANCE. 1. Chelinidea, 3 species. Feeding upon the joints externally. 2. Mimorista flavidissimalis Grote. Attacking joints externally at first but later invading inner portion. 3. Narnia, 4 species. Feeding on joints externally. 4. Melitara, 4 species. Feeding within the joints. 5. Moneilema, 8 species. Feeding within joints and stems. 6. Dactylopius confusus Cockerell and PD. tomentosus Lamarck. Feeding on surface of joints. 7. Marmara opuntiella Busck. Forming mines beneath surface of joints. . 8. Asphondylia, 3 species. Feeding on interior of fruit. 9. Stylopidea picta Uhler. Feeding on surface of joints. 10. Diaspis echinocacti cacti Comstock. Feeding on surface of joints. 11. Ozamia lucidalis Walker. Infesting the fruit. 12. Platynota rostrana Walker. Feeding within the fruit. 13. Polistes, 3 species. Feeding on the fruit. INSECTS AFFECTING THE ROOTS OR STEMS. Species of the Genus Moneilema. Among the insects which affect the roots or stems the most impor- tant forms are eight species of the cerambycid genus Moneilema, to which the common name “Opuntia longicorns” may be applied. These are wingless, robust, shining black. beetles from about 15 to 25 mm. in length. (See Pl. I.) They are to be found upon the Opuntia plants as adults throughout the season. In the adult stage they do considerable injury by gnawing the edges of the newly formed joints. This injury, however, is insignificant in comparison with that done to the stems and roots by the larve. The most important species of Moneilema in Texas are J/. crassum Le Conte and M. ulket Horn. These are widely distributed in the State. Other species are included in the list at the end of this bul- letin. It is interesting to note that the work of the adult beetle sometimes results in the dissemination of the plant. Frequently the beetles cut 1 One species, ulkei, is opaque, its surface mottled with whitish. 14 PRINCIPAL CACTUS INSECTS OF UNITED STATES. at the base of a newly-formed joint, so that it is soon broken from the plant. In some cases the joints thus separated from the plants take root upon falling to the ground. As a matter of fact this acci- dental planting by the Moneilema beetles is one important cause for the growth of the prickly pear in very dense clusters around the old plant. DESCRIPTION OF THE LARVA OF MONEILEMA CRASSUM.! About 12 mm. long when full grown. Body white, with a dark-brown chitin- ous head and with a pale-yellow semichitinous prothoracic area. Head trans- verse, rounded oblong, with the labrum, sometimes the labium, and the maxilleze light yellow in contrast to the dark-brown mandibles and occiput. Eyes ob- scured. Antenne single jointed, very small, placed immediately behind the mandibles. Labrum and clypeus transverse; mandibles large, apically emargi- nate, distant; maxillary and labial palpi small. Body sparsely covered with brown sete. Prothorax tumid, twice as large as either mesothorax or meta- thorax. Mesothoracic spiracles plain. Abdomen 10-segmented, the Jast 2 modi- fied, forming the anal region; first 8 segments provided with large, round spiracles; first 6 dorsally prominently bituberculate; first 7 ventrally trans- versely grooved. These larvee infest the main stem and older joints of the prickly pear. The gallery is wide and soon becomes blackened. The frass frequently becomes infested with dipterous larvee of various species. The larve are capable of considerable movement and have been found frequently to travel from one part of the plant to another in order to obtain a better supply of food. After attack the plant appears sickly and shows copious exudations of black sap which becomes so bard that it can be cut with a knife with great difficulty. The ap- pearance of this black exudation is shown in an accompanying illus- tration (PI. IT). The larva makes an imperfect cocoon, in which transformation to the pupa takes places. These cocoons consist of an inner layer of fiber of the cactus plant covered with sand. The texture is very firm. They measure 25 by 835 mm. They are generally found just beneath the prostrate joints on the ground. The duration of the immature stages was not determined, but it is evident that there is only one generation during the season. Adults appear most commonly in April and May and in September. As the Moneilema beetles are among the more important insects of the prickly pear, it may be necessary to combat them in plantings. Three means of attack are in evidence from the account that has just been given, namely, burning, hand picking, and poisoning. The larve and cocoons can be destroyed by burning the prostrate portions of the plants. The injury can always be located by reason of the large number of joints and stems that have fallen to the ground. A 1Prepared by Mr. W. D. Pierce. SPECIES ATTACKING JOINTS EXTERNALLY. 15 little work in raking togetner and burning the fallen portions of the plant where they are numerous would serve to hold the insect in check. If this practice has not been followed, it will still be possible to check injury with some satisfaction either by poisoning the adults or by collecting them by hand. On account of their large size and sluggish movements and the fact that they are without wings, hand collecting is not difficult and will be very effective. This process would generally be preferred to that of poisoning on account of its cheapness. When poisoning is practiced, arsenate of lead should be used. It should be applied, in powdered form only, to the young and tender joints, as the adults feed upon no other parts of the plant. The poisoning of these young joints will also serve to control at least one other important enemy of Opuntia, as will be described later. A Cutworm. On several occasions a cutworm, Chorizagrotis soror Smith, has been found to do considerable injury to Opuntia plants. The damage is greatest in the case of young plantings. The pulp that is exposed in cutting the joints into suitable pieces for planting seems to attract these worms. In one of the plantings at San Antonio, Tex., they ate canals through the underground portions of the plants. They are partial to the varieties of more tender structure. Whenever this in- sect is abundant it will be easy to protect the plants by soaking the portions used for seed for a few minutes in a solution of arsenate of lead, or, if more convenient, the sections to be planted could be dusted with the powdered arsenate of lead at the time of planting. Coccidse The only other insects which have been found attacking the roots of Opuntia plants are three species of Coccide, or scale insects. None of these species has been found to be abundant or to have any marked effect upon the vigor of the plant in the localities in which they occur. It is consequently unnecessary to give them further attention. SPECIES ATTACKING THE JOINTS EXTERNALLY. Chelinidea:vittigera Uhler.’ The coreid bug, Chelinidea vittigera Uhler, may be readily recog- nized from the following brief summary of its appearance and habits: It is a yellowish bug resembling the common squash bug (Anasa tristis De Geer) in general appearance (fig. 1), about 15 mm. long, 1 Order Hemiptera, Family Coreide. 16 PRINCIPAL CACTUS INSECTS OF UNITED STATES. feeding generally gregariously on the joints of Opuntia and allied genera. It is chiefly nocturnal in its habits. The first indications of feeding are the occurrence of lighter circular spots on the joints. The whitish excrement of the insect, which covers the surface of the joint, is also conspicuous. During the winter the insects are to be found in large numbers in a somewhat dormant condition under pros- trate joints. This species and its congeners are restricted to cactus plants and are by far the most important Opuntia insects occurring in the United States. On account of the wide distribution and prolific breeding of C. vittigera it is conspicuous in all localities where it occurs. Within its range I/imorista flavidissimalis Grote is proba bly more destructive to the plants, but that species is restricted to a comparatively small portion of the area occupied by Opuntia. NATURE OF INJURY. The small circular discolora- tions on the joints resulting from the work of this insect do not appear until feeding has _ pro- gressed for some time. As soon as they do make their appear- ance, however, they are extremely conspicuous. They may be found upon only a few joints of a plant, g or where the bugs are more abun- Fic. 1.—A cactus insect, Chelinidea vit- dant all the joints may be affected. tigera: Adult. Enlarged. (Original.) is As the injury proceeds, the spots become larger and coalesce, so that the whole area of the epidermis assumes a deadened, yellowish, and pitted appearance. The whitish excrement is discharged more profusely when the bugs are approached and may possibly have some protective effect. As a result of attack the plant is weakened so that it soon falls over. Where the bugs are numerous the fallen plants give somewhat the same appearance as they would if battered down by heavy hail. In some cases, where the attack is not strong, portions of the fallen joints take root and give rise to new plants. More frequently, how- ever, the joints are unable to recuperate and either dry up completely or become the breeding places for the many species of scavenger insects found associated with the cactus plant. As soon as the bugs, whether in the nymphal or adult stages, have weakened a plant they migrate to other plants and continue the work of destruction. SPECIES ATTACKING JOINTS EXTERNALLY. 17 Tt has been observed by Mr. J. D. Mitchell that the joints upon which the bugs have fed, and which may not have shown any special damage during the season, are the ones first injured by frosts during the following winter. This indirect injury sometimes results in set- ting the plants back by as much as the growth of two years. Another form of injury which is suspected but not proven in the case of this bug is the dissemination of the fungous disease Perisporium sp. This disease causes large black spots on the joints. The infected area fre- quently drops out, leaving a more or less circular opening through the joint. The feeding habits of the bug are such as to render it very likely to plant the spores of the fungus when it travels from one joint to another. This species was first called to attention as an enemy of Opuntia by Mr. F. W. Thurow, who, in March, 1893, reported to the Depart- ment of Agriculture that three species of Opuntia growing in Harris County, Tex., were greatly damaged.* DISTRIBUTION. This species is not confined to the prickly-pear region” proper, although there is no doubt that it greatly prefers that plant and that it is much more abundant where the Opuntia occurs in large numbers. Its western limit in Texas, so far as ascertained, is Brews- ter County. In the east it occurs along the Gulf and inland as far as Trinity County, Tex. It has been taken in Dallas and Parker Counties, Tex., wherever Opuntia occurs. It has also been observed in California, Utah, and Colorado, and in fact is generally distrib- uted throughout the Western and Southern States. In the East it is found in Louisiana, Alabama, and North Carolina and has been recorded from Virginia. VARIATIONS. The following notes on variations in Chelinidea vittigera have been furnished by Mr. O. Heidemann, who examined all of the hemipterous insects taken on cactus: © The species is exceedingly variable in structure of the body and in color. The relative length of the head, described by Prof. Uhler as being two-thirds the length of the thorax, can hardly be considered as a constant character. There are specimens which have the head and thorax subequal in length or equal. The peculiar prism-shaped antennal joints are more or less dilated, in some examples very conspicuously. This variation in the dilatation of the antennal joints is noticeable even in those specimens marked as reared from Opuntia. The color of the antenne, elytra, and legs varies considerably, chang- ing from reddish-brown into black. The darkest, most developed forms occur in Colorado and Utah. 1 Insect Life, vol. 5, p. 345. 50975°—Bull. 118—12——2 18 PRINCIPAL CACTUS INSECTS OF UNITED STATES. LIFE HISTORY, AND DESCRIPTION OF STAGES. The vreeding of this insect in the cactus area begins early in the season. At San Diego, Tex., in March, Mr. J. D. Mitchell observed that the first brood had appeared. In April the first young were noticed in Victoria County. The bugs breed continuously throughout the summer and fall. Owing to the fact that certain individuals are retarded in their development no definite number of broods is deter- minable. It has frequently been observed that some specimens reach the adult stage before others from the same mass of eggs have passed the third nymphal stage. This explains the observation of many per- sons that the bugs can be found in all stages on the plants at all times except during cold weather. The eggs are deposited generally on the spines, although in confine- ment the females deposit on the sides of rearing cages and in some instances eggs have been observed on the sides of dead as well as of living joints. The spines, however, are undoubtedly the normal place for deposition of the eggs. (See Pl. VI, fig.2.) During the summer season 5 adults produced 198 eggs in 15 days, averaging practically 40 tothe individual. These females were not reared, so that it is more than likely that the capacity for egg laying is much larger than the figures would indicate. The method of oviposition was observed by Mr. C. E. Hood. He noted that the female begins by rubbing the spines or surface on which the eggs are to be laid with the tip of the abdomen, probably discharging a sticky substance. After the egg is about halfway protruded a circular motion of the abdomen is ob- served. The female then appears to rub the egg over the spine before finally discharging it. In this manner 4 eggs were deposited in 6 minutes. It was observed in the breeding cages, and frequently in the field, that the eggs are not securely fastened to the spines. The attachment is so weak that they fall as the result of even a slight disturbance. THE Hee. Length, 1.25 mm.; width, 0.75 mm. Dark brown, opaque, very finely and uniformly punctured, mottled with a whitish exudation. Hlliptical; lid sub- dorsal, large elliptical. Placed with great regularity about 0.5 mm. apart on spines, with longitudinal axis parallel to spine, each string of eggs from 6 to 25 mm. in length. Duration of egg period, from 12 to 20 days. THe NYMPHAL STAGES. First instar.—Length, 2 mm. Brownish black, except abdomen, which is pea- green in some individuals and a dark crimson in others. The former variety shows a slightly red callosity and margins. Antennie 4-jointed; club short; first joint slightly flabellate; second joint scarcely one-third longer than the third; first and second joints with apical tips terminating in short spine. Head produced, bifureate. Length of stage, 7 days. SPECIES ATTACKING JOINTS EXTERNALLY. 19 Second instar.—Length, 4 mm. Very little change from first instar except that the femora and prothorax have a slightly lighter color. Second joint of antenna with almost straight sides. Spines on first and second joints more pro- nounced. Length of stage, 4 days. nt Third instar.—Length, 5.5 mm. Spines on first and second antennal joints slightly more pronounced, as is the raised callosity on the abdomen. The two transverse brown slits very conspicuous. Prothorax changing to greenish. Antenne more distinctly flabellate; otherwise there is little change. Length of stage, 4 days. Fourth instar—Length, 6.5 mm. Greenish color on abdomen decidedly darker; legs, antennz, head, and thoracic spines olivaceous black. No change in spines. Length of stage, 12 days. Fifth instar.—Length, 7.5 mm. The abbreviated wing-pads appear and ex- tend over the two anterior abdominal segments. General color dull olivaceous black, except tips of antenne, which are orange. Prothorax considerably wider, thus altering the appearance greatly, as the previous stages have a very narrow prothorax in comparison to the abdomen. Length of stage, 14 days. The duration of the fourth and fifth instars was determined during October; that of the earlier stages in July and August. Un- doubtedly the duration of the last stages in summer does not greatly exceed that of the earlier ones. DIMORPHISM. In the examination of several thousand of these bugs which have been under observation: in the field and in rearing cages it was noticed that there was a great variation in the color of the adults from different localities. This variation is much more noticeable in the nymphal stages. The color of the abdomen is either pea-green or dark crimson. Repeatedly experiments in breeding these color va- riations resulted in rearing adults which could not be distinguished. HIBERNATION. At a temperature from 45° to 50° F. these bugs appear to be rest- less, congregating at times, and at other times dispersing in order to find suitable quarters for hibernation. Throughout the winter they are to be found in numbers under fallen cactus joints, in the trash that accumulates at the base of the plants, under grass roots, and in fact wherever they can obtain shelter in the immediate vicinity of the Opuntia. They do not seem to travel any consider- able distances from the plant upon which they were produced. Chelinidea tabulata Westwood The species Chelinidea tabulata Westwood has often been observed in company with Chelinidea vittigera. It is not common, but if it were it would easily rank as a pest of prime importance on Opuntia. It is a Mexican species hitherto not known to occur in the United States. In our collections it has been taken at many localities from Austin, Tex., southward and westward. 20 PRINCIPAL CACTUS INSECTS OF UNITED STATES. Chelinidea sp. A third species of the genus Chelinidea was taken in May at Tuscon, Ariz., on Opuntia arbuscula, O. versicolor, and O. fulgida. This species is somewhat smaller than the preceding. Rearing ex- periments were unsuccessful on account of the shipment of the species into a region of different climate. The Control of Chelinidea vittigera and Allied Species. Two features of the life history of these bugs reveal feasible means of control. These are the clustering of the adults during winter and the gregarious habits of the young. The best control practice to follow is undoubtedly to collect and burn the trash on which the insects are found during the winter. At that time they are almost completely dormant and can be raked into piles along with the débris and burned. The gregarious habit, which is especially well marked in the earlier immature stages, makes it easy to check the _ development in a different way. The use of the gasoline torch, which is found upon all plantations where the cactus is used for forage, gives an economical and effective method of destroying these stages. Whenever the appearance of the small circular spot and of the white excrement shows that the insects are beginning to injure the plants seriously, the torch can be brought into play to excellent advantage. Mimorista flavidissimalis Grote.’ The cactus insect MWimorista flavidissimalis Grote may be rec- ognized easily from the following description: From one to seven yellowish larve feeding invariably on upper edge of young joints of Opuntia under a silken web, sometimes pene- trating the interior. (PI. III.) After the Chelinidea bugs, this insect is the most important enemy of Opuntia in the United States. Unlike the Chelinideas, however, it is restricted in its range. In Texas it is found from Hallettsville and San Antonio southward. West of San Antonio it is rare, but was taken at Tucson, Ariz., in May by Mr. Pratt. In the area where it is common it is by far the most injurious cactus insect. The species was described by Grote in 1877 from specimens re- ceived from Texas. Since then it has not been recorded outside of Texas. It was not until 1905, when the present work was under- taken, that anything was known about the early stages. The first rearings were made at Washington, D. C., from material collected at San Antonio, Tex., by Mr. David Griffiths. 1 Order Lepidoptera, family Pyralide. Bul. 113, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE III. WoRK OF MOTH, MIMORISTA FLAVIDISSIMALIS, ON JOINT OF OPUNTIA. (ORIGINAL.) Bul. 113, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IV. LARVA OF BEETLE, DISONYCHA VARICORNIS, ON OPUNTIA LEPTOCAULIS. (ORIGINAL. ) SPECIES ATTACKING JOINTS EXTERNALLY. 21 THE ADULT. The adult is a moth which expands about 1 inch. It is bright straw colored, with inconspicuous brownish markings arranged in four irregular transverse bands. THE LARVA. Length, 11 mm.; shining; general color yellowish white; legs concolorous; head and cervical shield somewhat darker yellow. Sides parallel, except for slightly raised spiracular callosities; faintly impressed median line. Two minute spots on cervical shield and spiracles black. Hairs long, sparse; most numerous on first six segments; white in color; arranged in subdorsal, marginal, and sub- marginal series; none on median line. THE PUPA. Inclosed in a whitish cocoon of thin, dense, paper-like construction; length, 9 mm.; width, 38 mm.; shining, light brown; head black. On thoracic segment one median and eight lateral fine longitudinal dark lines; the ones on either side of the median line are double for a short distance near their anterior third. SEASONAL HISTORY. A generation of this species is produced in about 30 days. The earliest record of the rearing was made by Mr. J. D. Mitchell on May 29 at Victoria, Tex. In that locality the second generation of the year had developed by June 26. The fifth generation matured by September 15. In all probability there is one additional brood during the season in southern Texas. DAMAGE. The injury by this species is confined to the young joints. Mr. Mitchell has repeatedly seen from 50 to 75 per cent of the new growth destroyed over considerable areas. The moth deposits from one to seven eggs, always on the upper edge of the joint. The first indi- cations of injury are strings of sap exuding from the joints. If this discharge is removed a small hole becomes visible. As the larve develop the discharge of sap from the plants becomes mixed with silk, trash, and excrement discharged by the insects. (Pl. III.) In rare cases, when only a few eggs have been deposited, the joint recovers, although it is always deformed. In most instances, how- ever, decay begins, and the joint turns black and finally drops to the ground. The two features of the attack of this insect which cause it to be of great importance in connection with the cultivation of cactus are, first, the large number of broods occurring throughout the season, and, second, the attack against the new growth. Where the species is at all abundant this attack effectually prevents any additional 22 PRINCIPAL CACTUS INSECTS OF UNITED STATES. growth of the plants. At the end of the season there are no more joints than there were the year before. A hymenopterous parasite of this species, Hiphosoma texana Cres- son, has been reared. It does not appear, however, to be sufficiently abundant to exert much control over the species. CONTROL. Mr. J. D. Mitchell has found by experiments performed at Vic- toria, Tex., that it is not difficult to control the species by the early application of powdered arsenate of lead. As soon as damage be- comes evident in the spring the new growth should be dusted care- fully with this arsenical. In this way the majority of the first brood will be destroyed. Some of the joints infested at that time will recover and there will be little injury from the following broods. The early application of the arsenical is very important on account of the formation of the protective web soon after the larve have begun work. If the first brood should not be reached in time every effort should be made toward applying the eon in ample time for the second brood. In the case of small experimental nian the use of the gasoline torch will furnish an economical means of control. In fags cases the cutting off and burning of the early infested joints will answer the same purpose. Disonycha varicornis Horn.* Disonycha varicornis Horn is a flea-beetle about 7 mm. in length. It is of conspicuous appearance on account of the brilliant polished blue of the elytra. The head and thorax are yellow; the under parts dark brown. So far as known this insect is restricted to Opuntia leptocaulis and Opuntia arborescens. It has never been found on the broad-leafed species of the genus Opuntia. It is observed frequently on its host plants in the adult and immature stages. The larve feed on the surface of the plants without any protective covering what- ever. (PI. IV.) Frequently they occur in such numbers as to cause the death of the plants. As it happens that the cacti attacked by this insect are not of any special economic importance, it is unnecessary to give further attention to the species. Stylopidea picta Uhler.’ Stylopidea picta Uhler is a slender hemipterous insect about 6.5 mm. long. The head and thorax are bright crimson and the wing covers slate color but with narrow yellowish borders. The eyes are 1 Order Coleoptera, Family Chrysomelide, Subfamily Halticine. 2 Order Hemiptera, Family Capside. SPECIES ATTACKING JOINTS EXTERNALLY. 23 placed at the end of the stalk-like prolongations of the head. The under parts are dark brownish. The species has been collected on Opuntia from San Antonio, Tex., to the coast and southward to Brownsville, Tex. It seems to be more abundant in the vicinity of Corpus Christi, Tex., than elsewhere. The injury is not conspicuous. It causes the plants to assume a spotted appearance, but, except where the bugs are unusually abun- dant, the joints recover. It is not a true cactus insect, but has been found upon a variety of other plants. On account of its gregarious habits it could be easily controlled by means of the gasoline torch when it becomes unusually abundant. The Cottony Cochineal Insect.* (Dactylopius confusus Cockerell.) The cottony cochineal insect (Dactylopius confusus Cockerell) is easily recognized by the large flocculent masses of pure white wax which covers the bodies. (Pl. V, upper figure.) When crushed the bright crimson color of the body fluid runs out and contrasts strongly with the white envelope. These scale insects are found on the joints of Opuntia, frequently in large masses. This species is closely allied to the true cochineal insect, Dactylo- pius coccus Costa, which does not appear to occur in the United States.2 The true cochineal has only a light powdery covering, while the form in the United States is provided with the heavy covering of cottony wax which has been described. The true cochineal insect has had a most interesting history. Car- ried to many parts of the world and cultivated with extreme care, for many years the dried bodies of the females yielded a dye product of great importance in the commercial world. It was also supposed to be an important therapeutic agent. — In A. von Humboldt’s Political History of the Kingdom of New Spain, published in 1811, there is a most interesting account of the cochineal industry in southern Mexico. The author relates that there was every indication that the cultivation of the insect had been prac- ticed for many centuries, undoubtedly, even antedating the invasion of the Toltec tribes. During the reign of the Aztec kings the in- dustry was apparently much more important than at the time of Humboldt’s observations. As early as 1592 laws were passed to pre- vent the adulteration of the product. In 1802 the exports through the port of Vera Cruz amounted to 3,868,557 pounds. The greatest development of the cochineal industry occurred about 1876. The decline began at that time on account of the discovery 1Order Hemiptera, Family Coccide. 2 The records from Florida and California in the Fernald Catalogue are probably due to importations. 24 PRINCIPAL CACTUS INSECTS OF UNITED STATES. of aniline dyes. For several years the commercial cochineal crop of the world amounted to more than 7,000,000 pounds. Although the amount produced now is very much smaller, it seems to be more or less constant. In 1909, the last year for which statistics are available, the United States imported 102,000 pounds of a value of $33,875. Prac- tically all of this supply is obtained, either directly or indirectly, from the Canary Islands.. The average annual importation into the United States for seven years ending with 1909 was 130,000 pounds. Cochineal is now used as a coloring matter for fine fabrics, certain kinds of ink, and confectionery. It is also used as a coloring medium for solutions and emulsions, being found practically in every drug store in the country. For many years it was used more or less regu- larly as an anodyne, but this use has been largely discontinued. The cottony cochineal insect occurs practically throughout the cactus region in the United States. It has been found to be abundant as far north as Young County, Tex. It is attacked by a large num- ber of predaceous insects. These tend greatly to hold the cochineal insect in check. Otherwise it would be a pest of prime importance on Opuntia plantations. As it is, it not infrequently becomes so abundant as to destroy portions of the plants and, on occasions, even as far north as central Texas, it has been found that entire plants have been destroyed. ENEMIES. The insect enemies of the cottony cochineal insect, so far as known, consist of eight species of Coleoptera and three of Lepidoptera, as follows: COLEOPTERA. Exochomus latiusculus Casey ; Exochomus marginipennis Le Conte ; Cycloneda munda Say; Chilocorus cacti Linneus; Hyperaspis trifur- cata Schaeffer; Zyperaspis cruenta Le Conte; Scymnus loewii Mul- sant; Scymnus hornii Gorham. LEPIDOPTERA, Letilia coccidivora Comstock; Zophodia dilatifasciella Ragonot; Saluria ardiferella Hulst. CONTROL. Attention has been called to the fact that in the United States the insect enemies of the cottony cochineal insect prevent its reaching great numbers until the middle of summer. In artificial plantings at times it may be necessary to resort to remedial work. In such cases the best plan to follow will be to remove the masses on the joints by means of a very stiff brush or to burn them with a torch. In some cases spraying with kerosene emulsion or the lime-sulphur mixture might be followed, but the extensive secretion of the insect will interfere greatly with the application of any insecticides. Bul. 113, Bureau of Entomology, U.S. Dept. of Agriculture. PLATE V. TWO IMPORTANT SCALE INSECTS OF PRICKLY PEAR. Upper figure, the cottony cochineal insect, Dactylopius confusus; lower figure, Diaspis echinocacti cacti. Lower figure enlarged. (Original.) SPECIES ATTACKING JOINTS INTERNALLY. 25 In hothouses the use of a solution of whale-oil soap or of tobacco stems is recommended for this and other scale insects of cacti. Any preparation that may be used should be applied with considerable force by means of a spray pump in order to reach the insects in the crevices of the plants. Minor Species Attacking the Joints Externally. In addition to the species described in the preceding pages a con- siderable number of forms have been found which occasionally feed upon the joints. None of the other forms is at present known to be of any great economic importance, although they are likely to become abundant and injure the plants under local conditions at any time. The species more likely to do so are mentioned in the following paragraph. Diaspis echinocacti cacti Comstock is a grayish scale insect, the females circular and the males oblong. It sometimes becomes so numerous as to cover entirely the surface of the joint. This con- dition is shown in an accompanying illustration. (PI. V, lower figure.) In artificial plantings and in hothouses this species is of some importance. Under field conditions it rarely reaches excessive numbers. Dactylopius tomentosus Lamarck, which resembles the cottony cochineal insect but differs from that species by the fact that the separate individuals, instead of masses of several individuals, are covered by the cottony secretion, may be destroyed by the means recommended for the cottony cochineal insect. The white ant Termes flavipes Kollar feeds upon a great variety of cactus plants and has been observed to injure the joints thrown on the ground for growing a new crop. It sometimes constructs nests in the damaged joints. The scale insect Hriococcus coccineus Cockerell has been recorded from California. Aphis medicaginis Koch, a plant louse, apparently passes the winter on Opuntia in Texas. During the remainder of the year it is seldom found on Opuntia plants, and on the whole causes only very slight injury. SPECIES ATTACKING THE JOINTS INTERNALLY. Melitara junctolineella Hulst.* Melitara junctolineella Wulst and the other species of the genus are true cactus insects. They may be recognized from the following brief description: Large’ indigo-blue (young) or conspicuously banded (last stage) larve living within the joints of Opuntia, cause large excavations and tumor-like swellings of the infested joints. The adult is a grayish moth of an expanse of 14 inches. The eggs of this species are very similar to those of Melitara pro- denialis Walk. which are described on another page. They are deposited in exactly the same manner. The remarkable arrangement 1Order Lepidoptera, family Pyralide. 26 PRINCIPAL CACTUS INSECTS OF UNITED STATES. is shown in one of the accompanying photographs. (Pl. VII, fig. 1.) The individual egg masses may contain as many as 30 eggs. There seems to be only one brood each year. As soon as the larvee hatch in the spring they begin feeding upon the surface of the joint. Within a few days they make their way to the inside and never appear upon the surface. The experience of all observers is that only one or two larve are ever found within a joint. This is remarkable in view of the fact that the eggs are deposited in such numbers. Apparently it is not a case of the young larve traveling from one joint to another, since frequently only one or two joints on a plant are found to be infested. Undoubtedly the larve are cannibalistic in habits, and this accounts partly for the fact that these isolated indi- viduals are found; but there is also another factor to be considered. The work of the larve immediately causes a strong reaction on the part of the plant. A copious secretion of proliferous tissue is formed and larve have been frequently found completely engulfed in this formation. Undoubtedly the pressure frequently results in the destruction of the larve. Although this species is an internal feeder, the indications of its work are more or less conspicuous. The joint soon takes on a yel- lowish appearance and the large swellings on both sides of the joints are common sights in the cactus country. The entire interior is destroyed and the proliferous growth causes the swellings which frequently result in the increase in the thickness of a joint by three or four fold. Strangely such swollen joints are sometimes found to contain no larve. The evidence of their work is always present. Pressure from the proliferous growth may have caused the death of the larvee in such cases. The effect upon the plant is generally to cause the death of the joint or joints which are infested. The injury is made greater by a number of scavengers, principally dipterous. As the larve fre- quently make their way through the stem from one joint to another, it is not uncommon for several joints to be killed outright. Of course the portion of the plant above the infested joints dies from lack of nutrition. After a time the wind causes the diseased branch to fall to the ground. In case the larve are killed by pressure the swelling subsides. The sides, however, do: not unite and the joint remains deformed. Mr. J. D. Mitchell, who has made many careful observa- tions on this species, believes that the partial healing of the injury follows when the exit is at the lowest part of the stem, and that the joint falls invariably when the exit is near the top and the softened excrement and proliferous tissue can not escape. Although this insect is not extremely abundant in any locality where observations have been made, it is to be found throughout the cactus area. In some localities at least one plant in every clump has SPECIES ATTACKING JOINTS INTERNALLY. 27 some portion infested. The total damage done is consequently con- siderable. DIVERSITY OF HABITS. All of the Melitaras reared from cactus during the course of this investigation have been identified by Dr. H. G. Dyar as Jelitara junctolineella Hulst. However, certain peculiarities in habits have been observed which lead to the suspicion that more than one form may occur. In the region south and east of San Antonio, Tex., the only form occurring makes no opening through the surface of the joint, but packs its excrement in the cavity made in the process of feeding. This form spins a cocoon on the joint or on the ground in case the joint has fallen, but this cocoon is not intermixed with sand or dirt. In the region from Kerrville, Tex., westward, a form occurs which invariably provides an orifice in the joint of the Opuntia through which the excrement is dropped to the ground. This gives a characteristic appearance of the joint which is easily recognized at a considerable distance. This form seems invariably to enter the soil for pupation, and a considerable amount of sand is intermixed with the cocoon spun for the protection of the pupa. DESCRIPTION OF IMMATURE STAGES. THe LARVA." Early stages whitish; subsequent stages up to the last deep indigo-blue; last stage, 30 to 50 mni. long, conspicuously banded. These bands are dark brown and occupy the posterior quarter of each segment. Head 2.5 mm. wide, dark brown; clypeus rather deeply emarginate, with light colored band at base. Anal plate almost semicircular in outline, yellow; feet yellow, crochets in ellipses; skin plainly wrinkled on dark annulations, less wrinkled on lighter portions; spiracles elliptical, one and one-half times as long as broad, deep black; thoracic legs light brown; hair very sparse, light yellowish, con- fined to head, sides, and underside. THE PUPA. Incased in loose silken cocoon, sometimes intermixed with sand, 25 mm. long by 9 mm. wide, uniform mahogany brown, spiracles darker; head and thorax transversely rugose; anterior portion of abdominal segments very finely punc- tured; posterior portions more sparsely punctured and slightly wrinkled. PARASITE. A tachinid parasite of this species, Phorocera comstocki Williston, is common. It has been reared from material collected throughout the cactus area. CONTROL, The process of singeing the spines of prickly pear preparatory to feeding undoubtedly destroys many of the eggs of this species. In 1The larya described by Dr. Dyar as probably that of M. junctolineella (Proc. U. 8. Nat. Mus., vol. 25, p. 396) evidently belongs to some other species. 28 PRINCIPAL CACTUS INSECTS OF UNITED’ STATES. experimental plantings the use of the gasoline torch in the spring- and the burning of the joints that appear injured will keep the species in check. Melitara dentata Grote. Melitara dentata was described by Grote in 1876 from Colorado. Tn 1892 Prof. V. L. Kellogg published an account? of the transforma- {ions of the species in the leaves of Opuntia missouriensis taken in eastern Colorado. All stages were described and illustrated. The occurrence of blue and white larvae, which we have observed fre- quently in the case of Melitara junctolineella, was noted by Prof. Kellogg. The same species was collected by Mr. David Griffiths in Trinidad, ponheeal Colo., in June, 1906. Hino this material a large number of parasites, Chelonus laticinctus Cresson (fig. 2), were reared. ao =x, = os & Melitara prodenialis Walker. The species J/eli- tara prodenialis of Walker was de- scribed in 1863. In 1877 Miss Mary Treat sent cocoons from Opuntia poly- Fic. 2.—Ohelonus laticinetus, a parasite of a cactus insect, antha collected at Melitara dentata: Adult. Enlarged. (Original.) Green Cove Springs, Fla., to the Bureau of Entomology. In 1895 Mr. H. G. Hubbard published an interesting account of the oviposition of the species on Opuntia vulgaris at Crescent City, Fla., and also included an account of the habits of the larve. Previously Dr. J. B. Smith? had de- scribed briefly the method of placing the eggs on the plant. These few records constitute all that has ever been published concerning the species. The notes on oviposition of this species and the habits of the larvee, made by Mr. H. G. Hubbard, are as follows: The eggs are laid at night, and the operation of depositing them has not been observed. It must, however, be a wonderfully interesting performance. The egge-stick * * * is 80 mm. long. The separate eggs are cylindrical and 1Kans. Univ. Quarterly, vol. 1, pp. 39-41. 2 Entomological News, vol. 3, p. 208, 1892. SPECIES ATTACKING JOINTS INTERNALLY. 29 measure 2 mm. in length by 7 mm. in width. The surface is beautifully reticulated with wavy raised lines anastomosing obliquely. The eggs are cemented together with a brownish glue which, under the pressure exerted upon the mass, is squeezed out at the sutures between each two eggs in the stick and hardens there, forming a ring or colar which always adheres to the egg beneath when two eggs in the stick are separated. It sometimes has the appear- ance of a circle of spinules, owing to the corrugations of the surface upon which it is moulded. The young larvee of Melitara prodenialis, on hatching from the eggs, feed for a time externally upon the bud-like leaves of Opuntia. When they become larger and stronger they cut through the silicious skin of the pads. The wounds made by them in the plant exude a gummy liquid, and a scab-like crust is formed. Under this the larve live in companies, large or small, according to the size of the plant, until they are about one-third grown. After this they burrow deeply into the substance of the succulent stems. The larvie, as long as they live upon or near the exterior of the plant, are light brown in color, but after they burrow into the pulp and approach their full size, they attain a most beautiful dark-blue color. In pupating they form a loose cocoon of yellow silk, which is concealed somewhere about the Opuntia clump, usually under a prostrate pad. There appear to be two broods produced during the year, since moths were found issuing in Florida in June and again in October. Melitara fernaldialis Hulst.* This species, which occurs in Arizona and New Mexico, has not been found breeding in Opuntia, but was found by Mr. Hubbard to infest the giant cactus, Cereus giganteus. In all probability it will be found io attack Opuntias in the region in which it occurs. In fact, in May Mr. F. C. Pratt discovered a larva which may have been of this species in Opuntia engelmanni at Tucson, Ariz. This larva discharged its excrement through an opening in the surface of the leaves exactly as does the form which occurs in the western portion of Texas. Apparently the same form was observed by Mr. Pratt at Albuquerque, N. Mex., in June. At Sante Fe, N. Mex., during the same month, about 30 per cent of the plants of Opuntia arborescens were more or less injured. Unfortunately, it was impossible to rear any of these larva. Our supposition that they were of the species fernaldialis is based upon the known range of that form and the fact that they appeared to be different from the Melitara larva ob- served in Texas. | Gersteckeria porosa Le Conte.’ The presence of the weevil Gerstackeria porosa Le Conte is readily shown by the occurrence of flat discolored areas about three-fourths inch in diameter on the surface of the joints. In the early stages of attack these areas are yellowish, but later become whitish. They cover the cavities excavated by the larvie. 1Order Lepidoptera, Family Pyralide. 2 Order Coleoptera, Family Curculionide. 30 PRINCIPAL CACTUS INSECTS OF UNITED STATES. This species is distributed throughout the cactus region. It has been taken as far north as Denver, Colo., and as far south as San Diego, Tex. Its range extends into Arizona. . The winter is passed in the pupal state within the cells in the Opuntia joints. The adults issue from April to June. There ap- pears to be only one brood during the season. The species is re- sponsible for a large amount of disfiguration of the cactus joints, but as the cells are largely superficial the growth of the plant is not seriously affected. In fact, in no cases observed have the joints been found to be destroyed primarily by the insects. In some cases, how- ever, the cells attract scavengers of various species, which increase the diseased area and may cause the destruction of the joints. The adults appear to feed by scraping the epidermis from the sides of the joint. Gersteckeria nobilis Le Conte. The work of Gers- teckeria nobilis Le Conte (fig. 8) is pre- cisely like that of the preceding species ex- cept that the cells con- taining the immature stages are located on dé the margins of the Fic. 3.—A cactus weevil, Gersteckeria nobilis: Adult. joints. In these locali- Enlarged. (Original.) : ties a hard black ex- udation frequently forms, and this interferes with the development of new growth. For this reason it is more important than the pre- ceding species, although it is of less extensive distribution. Our records include many localities in Texas from Dallas to Corpus Christi. It does not appear, however, to extend far to the west, Hondo being the westernmost locality in our records. Gersteckeria clathrata Le Conte. Gersteckeria clathrata Le Conte works exclusively on Opuntia leptocaulis, so far as known, although it may rarely infest allied species. Its work in the plants is similar to that of the other species. It is partial to the new growth, which is often killed. Although thus more destructive than the preceding forms, it is of less economic importance on account of the uselessness of its host. It is recorded from Colorado to Brownsville, Tex., and westward to Arizona. A fourth species, @. hubbardi Le Conte, was reared from Opuntia vulgaris in Florida by Mr. H. G. Hubbard. It appeared to follow the work of Melitara prodenialis Walker. SPECIES ATTACKING JOINTS INTERNALLY. 31 The four species described are true cactus insects, being dependent upon the plant for food and places for breeding. Although only four species have been discovered breeding in cactus, it is likely that upon investigation other species of the genus will be found to injure it. The genus contains 22 species, of which 11 are found in the United States and the remainder in Mexico. It is doubtful whether it will ever be necessary to resort to control measures in the case of any of the species of Gersteckeria. If con- trol should become necessary, it would be extremely difficult on ac- count of the fact that the immature stages are passed beneath the surface of the joint. No remedy except the removal of the infested joints can be suggested. Marmara opuntiella Busck.* The tineid moth, J/armara opuntiella Busck (fig. 4), deposits its eggs just beneath the epidermis of the leaves of Opuntia. The first Fic. 4.—A cactus insect, Marmara opuntiella: a, Adult; b, larva; c, eggs and pupal case. Enlarged. (Original.) indication of injury is a slight elevation of the epidermis above the gallery which the larve have begun to excavate. The first attack (Pl. VI) is generally near the base of the joint. Later the epidermis above the galleries becomes white and the galleries may cover the entire surface of the joint. This is certain to be the case where sev- eral eggs are deposited in one joint. A gummy exudation appears and the whole surface of the joint becomes covered with a yellowish secretion that conceals the mines. The larve work immediately beneath the epidermis and never penetrate the interior of the joint. On this account they have little effect upon the growth of the plant. Only on rare occasions when the attack has been directed against the new growth does the joint fall to the ground. The species is widely distributed in Texas, having been taken from New Braunfels south- ward to Brownsville. 1 Order Lepidoptera, Family Tineide. 32 PRINCIPAL CACTUS INSECTS OF UNITED STATES. The only cases in which it will be necessary to combat this insect will be those in which the new growth of the plants is affected. The only course to follow is to remove these joints and burn them. SPECIES INJURING THE BLOOMS. In the category of species injuring the blooms there is only one that is of importance. This is 7richochrous (Pristoscelis) texanus Le Conte. It is a slender beetle, 8 mm. in length, uniformly oliva- ceous above, highly polished, with reddish legs, the upper surface of the body covered with rather dense growth of short whitish hairs. It has been collected at southwestern Texas and in New Mexico. At Albuquerque, in the latter State, on June 16, Mr. F. C. Pratt found it in such abundance that no blooms without indications of injury were noticed. The great majority of the plants had been fed upon to such an extent that fruiting had ceased. As many as 153 beetles were found in a single bloom. No larve could be found in the vicinity. It is possible that this species is not at all peculiar to cactus. but is to be found in blooms of various kinds. There was a remarkable absence of flowers on all plants except the Opuntias growing at Albuquerque at the time to which reference has been made. This may account for the concentration of the insects in the blooms of the Opuntias and for the damage accomplished. No simi- lar cases had been observed_in the numerous observations that had been made in Texas. Euphoria kernti Haldeman* is a very common beetle in cactus blooms in Texas. It is a robust species of very variable color. Some specimens are pure black and all gradations between this form and in- dividuals in which the ground color is yellow, but covered with nar- row black stripes, are to be found. The species seems to feed upon the columns and anthers more than upon the petals. Even where it is so abundant that several individuals are to be found in every bloom no special injury to the plants has been detected. On this account the species is included in the list at the end of this bulletin as one which has no other association with the cactus plant than that it frequents the bloom. SPECIES INJURING THE FRUIT. Narnia pallidicornis Stal. Of the species that injure the fruit, by far the most important are the bugs of the genus Narnia, the most common being WV. pallidicornis Stal.2 The species can be recognized readily. (Pl. VII, fig. 4.) It is of a brownish-yellow color, about 15 mm. in length. The posterior femora are lengthened, very robust, and covered with heavy black 1Order Coleoptera, Family Scarabeide. ?Order Hemiptera, Family Coreide. Bul. 113, Bureau of Entomology, U.S. Dept. of Agriculture. PLATE VI. JOINT OF PRICKLY PEAR, SHOWING WoRK OF MARMARA OPUNTIELLA. (ORIGINAL. ) Bul. 113, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VII. STUDIES OF CACTUS INSECTS. Fig. 1.—Eggs of Melitara junctolineella on spines of Opuntia. Fig. 2.—Eggs of Chelinidea vittigera on spine of Opuntia, Fig. 3.—Eggs of Copestylum marginatum on Opuntia spines. Fig. 4.— Narnia pallidicornis. (Original.) SPECIES INJURING THE FRUIT. ae spines. The posterior tibizw are expanded just beyond the middle into fanlike dilations. This insect is essentially an enemy of the fruit of the Opuntias. Although it has been observed very commonly in Texas, it has never been found to injure the joints. Like the bugs of the genus Che- linidea, it and its immediate relatives are gregarious in their habits. The range extends from Mineral Wells, Tex., southward to Browns- ville and westward to El Paso. DESCRIPTIVE. THE Hea. Eog.—Length, 1.5 mm.; width, 1 mm. Dark brown in color, cylindrical, sharply truneate at both ends, surface very finely roughened. Toward the upper end the lid appears as a raised spot with a light ring. Placed with ends contiguous on cactus spines, from 12 to 25 on a spine, sometimes several strings alongside of each other on the same spine. Length of egg stage, about 27 days. THE NYMPHAL STAGES. First instar—When first hatched, the bugs are slightly less than 4 mm. in length, orange in color, but soon change to a reddish hue. Antenne brown, 4-jointed, club and first joint equal, second joint slightly longer, basal joint barely one-half the length cf the others; all joints covered with hairs, those on the club shorter. Legs reddish, hairy; tarsi dark brown, having shorter hairs. Head reddish; eyes brown; pronotum reddish and armed with a pair of erect spines; abdomen reddish, with four pairs of red spines located on the first, second, fourth, and fifth segments. Margins of abdomen with a row of six erect spines, those at base being longest. Each spine terminates in a short, black, motile bristle. The third and fourth pairs of spines are located on a raised callosity. Length of this stage, 7 days. Second instar.—Length, 5 mm. Antenne lighter in color than in previous stage, except club, which is dark brown; front and middle pairs of legs yellow, posterior pair darker, dilations on tibie now appearing; terminal tarsal joints bearing claw, which is dark brown; head, thorax, and pronotum dark brown: front of head yellow, abdomen reddish. Spines as in first stage, the pronotal spine being twice the length of the others. Length of this stage, T days. Third instar.—Length, 6 mm. General color of body brown; antennie, except club, and front and middle pairs of legs yellow; club of antenne and posterior legs brown, except joints and tarsi, which are yellow; callosities on pronotum and margins of abdomen whitish, those on abdomen black. An additional pair of spines appears on thorax. Length of this stage, 13 days. Fourth instar—Length, 9 mm. Antenne as in third stage. General color dull velvety black and speckled as if dusted with white powder; sparsely covered with shiny, white hairs, those on posterior Jegs longer and more dense; abdomen reddish beneath. Length of this stage, five days. Fifth instar—Length, 15 mm. Same coloration as preceding stage, hairs apparently more dense, pronotal spines yellow at base. Thorax well defined. Wing-pads have now appeared, extending over pronotum, yellow. Abdomen yellow, beneath black. Length of this stage, 7 days, 50975°—Bull. 113—12——3 34 PRINCIPAL CACTUS INSECTS GF UNITED STATES. As has been stated, this is an important enemy of the Opuntia plant where the fruits are desired for food. In cactus plantations, however, where the plants are reproduced by cuttings, it is of com- paratively little importance. On account of its gregarious habits and its location on the parts of the plant easily reached by a gasoline torch, its control is not a difficult matter. There are three other species of Narnia which feed upon the fruit of Opuntia and related plants. After pallidicornis, the most com- mon species is femorata, which is as widely distributed in Texas as that species and extends its range as far westward as Los Angeles, Cal. It has also been taken in Mexico at Aguascalientes, Victoria, and Durango. In general appear- ance it resembles pallidicornis very closely, but is somewhat larger. J. pallidicornis has the dilation of the hind tibia narrower, lanceolate shaped, and the inner part of the dilation broadest behind the middle. The remaining species of the genus which we have observed on cactus are ¢nornata and snow. The former has been taken in California and Mexico only, while we have only a single record of the latter species, at Albuquerque, N. Mex., in April. Asphondylia opuntiz Felt.’ Asphondylia opuntie Felt ranks next in importance to the Narnia ; bugs so far as injury to the fruits Fic. 5.—Opuntia fruit with puparia of of Opuntia is concerned. It is not Zephondyla! opunite’ — Hulerged. " Testrictpd, . hOweverin0 etoe.egulia ay but sometimes infests the margins of the joints. Its presence is first detected by a yellowish coloration of the fruit or joint and later by the protruding puparia in close groups of sometimes as many as 10 individuals (fig. 5). This species has a wide range. Specimens have been taken at many points in Texas and southward to San Luis Potosi, Mex., and west- ward to Los Angeles, Cal. There are evidently several generations in the season, the first adults appearing in southern Texas in March. Especially in California this species is extremely abundant. On this account it is fortunate that its injury primarily affects the fruit and does not interfere seriously with the growth of the plant. It 1Order Diptera, Family Cecidomyiide. SPECIES JNJURING THE FRUIT. 35 can not interfere seriously with the production of forage. It is of greatest importance in Mexico, where the fruit of the Opuntia plant is a very common article of diet for the natives. Instances of curious deformations of the plant result from the work of this fly. The infested fruit, instead of developing as such, is transformed into a very short joint, which gives rise to a larger or nearly normal joint. The remarkable change in the appearance of the plant caused in this way is sometimes very conspicuous. The result of the work of the same or a similar species was described as an abnormal fruit of Opuntia ficus-indica from Caracas by A. Ernst.* Three additional species of Cecidomyiide have been reared from Opuntia. They are included in the list at the end of this bulletin, but need not be considered in this connection on account of their very rare appearance. Cornifrons elautalis Grote.’ Cornifrons elautalis Grote is a small grayish moth infesting the green fruits of Opuntia. It was first collected by Mr. J. D. Mitchell in May, 1908, at Hondo, Tex. Later it was taken at Tucson, Ariz., but on the whole seems to be of rare occurrence. The larvee bore into the fruit to a depth of 1 inch and eject a reddish-colored excrement on the crown of the fruit, causing its death. At Tucson, Ariz., in May, Mr. F. C. Pratt noticed that many fruits were injured by these larvee. On some plants practically all of the fruits were injured, and it was found that the larve traveled from one fruit to another. In that vicinity fully 10 per cent of the fruits were injured. The larve are generally to be found just beneath the corolla, which remains on the crown longer than when the fruit is uninjured. When the corolla falls the larvee web over the orifice made in the fruit, and the protection is augmented by the addition of the reddish excrement. They also occur in the blooms, but leave them as soon as the flower parts become dry. It is evident that eggs are generally deposited in the blooms, although this is not by any means invariable. Many fruits were observed in which entry had been gained from the side. The larvee are blackish, with a shining black head and narrow, lateral crimson bands. Allorhina mutabilis Gory.’ Mr. E. A. Schwarz informs us that Allorhina mutabilis Gory is a common enemy of the fruit of Cereus in Arizona. It is well known for its damage to fruits of various kinds. 1 Nature, November 25, 1882, p. 77. 2 Order Lepidoptera, Family Pyralide. % Order Coleoptera, Family Scarabeide. 36 PRINCIPAL CACTUS INSECTS OF UNITED STATES. Sixeonotus luteiceps Reuter.* The adults of Sixeonotus luteiceps Reuter are 3 mm. long, with dark steel-blue wing covers and red head and thorax. The nymphs are bright scarlet. The range of the species is in southwestern Texas. It is not a true cactus insect, although frequently found upon the plant. It seems to prefer yuccas. On these plants it has frequently been observed in great numbers, while Opuntia growing in the immediate vicinity remained uninjured. When cactus plants are attacked the preference seems to be for the ornamental forms of the “pitallo” group. When in large numbers it disfigures these plants considerably, and sometimes causes their death. The first indication of injury is a yellowish discoloration, while the surface is covered by numerous black specks of excrement. Polistes spp.” Two species of wasps of the genius Polistes, namely, rubiginosus and texanus, have been taken commonly in Texas, and one, flavus, was taken on Cereus in Arizona by Mr. H. G. Hubbard. The adults of these species are found everywhere on the fruit of Opuntia and other cacti. They cut open the partially ripened fruit with their mandibles and feed upon the juices that exude. They are of very little importance from the standpoint of the cultivation of the plant. Liotropis contaminatus Uhler.’ . The species Liotropis contaminatus Uhler, recorded by Prof. H. Osborn‘ on fruit of Opuntia fulgida near Tucson, Ariz., occurs also at El Paso, Tex., and in the Inyo Mountains, Cal., at the latter locality at an elevation of 7,000 to 9,000 feet. Dytopasta yumaella Kearfott. Reared from Opuntia fruit collected at Hondo, Tex., by Mr. J. D. Mitchell in June. Also taken in Arizona. Ozamia lucidalis Walker. Observed at Victoria, Austin, San Antonio, and Hondo, Tex. Larva moves from fruit to fruit, thus destroying sometimes as many as five. Cocoon whitish, silky, unmixed with foreign mstter, placed on side of fruit. Evidently widespread, but never abundant. Platynota rostrana Walker. Reared from Opuntia fruit collected at Brownsville, Tex., in May by Mr. J. D. Mitchell. This is the only record we have obtained. 1 Order Hemiptera, Family Capside. 3 Order Hemiptera, Family Pentatomide. 2 Order Hymenoptera, Family Vespide. 4 Wnt. News, vol. 20, p. 177, 1906. PRINCIPAL CACTUS INSECTS OF UNITED STATES. oT SCAVENGERS. In the list of insects found associated with the cactus plant at the end of this bulletin we have included 73 species in the category of scavengers. Many of these species feed only upon the joints when these have been killed by other insects or when they are blown to the ground. A an Aled Aa iM ‘ INDEX. Page Acailes clathratus, bibliographic reference... ..2.-...-2-...........20 cece lense 56 ADR EEREN EA COMMUTE et ests! SU oR 56 mobiles, pip uopranhie fererence. is Ye ee eee 55, 56 PT REECE TORUS © 2.54mi secd seer tte ote en 56 fusnpane. pibloapraphic #eierence: s. bel ei a oak 55, 56 = ERT E MONTE MUR DIA My sot Nao M remy Foe ern ee MOLE Shi UN) Sens 55, 56 Micanthococcus sp, bibliographic reference. <~.2 224.2522 22s es 55 Acmxodera pulchella frequenting flowers of cactus..........---.-.22-..-------- 49 quadrivittata frequenting flowers of cactus. -..................-... £ tubulus frequenting flowers of cactus....--.--..........-..--+.-.- 49 pitas emo, HCA Venger Il CACtUs.yo.26- 2. Sees e ey ee OY oe oe 48 Agapostemon texanus frequenting flowers of cactus.............-.......------- 50 Agrypnus sallei incidentally associated with cactus.................2.-.--..-- 51 Ber nanannis ScHvenore tm Caehig oi oo NT) ee ele eee oeee 47 Aleocharine, genus unknown, scavenger in cactus...........--.-..-..-.-...-- 47 peiacul ieven peavenger Inicaetise. 2.222 See ese eee ccc ewe 48 Allorhina mutabilis, an injurious cactus insect............----.-..-.0...2200- 35, 43 Anasa tristis incidentally associated in cactus. ..........-........2225..2200- 51 Anthicus inferens incidentally associated with cactus. -..........-...----..-- 52 Ant, white. (See Termes flavipes.) Apanteles (Pseudapanteles) sp., possible parasite of cactus insect (Melitara). - .- 46 sp., possible parasite of cactus insect (Melitara)................... 46 Apaniesis arge in list of injurious cactus insects.............-...-----....-..- 44 Apheloglossa rufipennis, scavenger in cactus................----.---.....---- 47 Aphis medicaginis, hibemating on Opuntia, = -..2.-2 222.2 .22202s-5-.----- 25 in eiiOb myurioUs: cactus Insects. . 2! 5245.00.02 2 222. ce sp. on Echinocereus, attended by Formica subpolita.................. 53 Opuntia versicolor and Opuntia fulgida, attended by Cremastogaster No cavcoge ba aBeendod osShosoetec ceo Gas 52 Opuntia engelmanni, and Opuntia fulgida, at- tended by Iridomyrmex analis..........-..-- 53 Apotrepus densicollis incidentally associated with cactus. ..................-- 52 Wreenatacn lead arainst ‘Cherizagrotimsorors. tess. 2.22 asl. c ee a kes 15 Monettenin araasint Hak BeOS IE Rt 2 Sad 15 powdered, against Mimorista flavidissimalis...........-.-.-- 22 Ashmeadiella cactorum frequenting flowers of cactus.............-..--.------- 50 echinoceret frequenting flowers of cactus. ...............-.------ 50 opuntiz frequenting flowers of cactus...................---..--- 50 Asphondylia, three species injurious to cactus. ............----.---...--2---- 13 Asphondylia arizonensis, bibliographic reference..............-------------++ 57 in list of injurious cactus insects..............-..--.- 45 bethels, bibliographic sererence see. 2. SSS ee cee 56, 57 an. list of injurious’ cactus msécis:.! 224.2252... 2-2... 45 Opuntia, an IMjurioud caciieaancech.- 2 .}s2.. 202). ok cee 34, 45 Pibloepraniic rereweneGs fee. foe! cs sis os ee ee tee 57 Ataxia crypta included in list of injurious cactus insects...........----------- 51 . 59 60 PRINCIPAL CACTUS INSECTS OF UNITED STATES. Eh Page Atomosia puella included in list of injurious cactus insects. .......----------- 53 Atiagenus hornii, scavenger. Cactus. een.csetes ae eee eee eee es ee ee 47 piceus, scavenger in cactus.........-.-..- BA ABR Ne thle Meee tee 47 Augochlora neglectula frequenting flowers of cactus. .....-....--------------- 50 Banana, Calandra remota in etemssl esses eee ee een eee eee ae 52 Belonuchus ephippiaius, scavenger in Caeiis... 25+ ocecec-oa-25-5-5--2 esses - 47 zanthometas, Scavenger an cae hiphr oe 22 26-50 aaa nese soe eee see 47 Blapstinus pratensis incidentally associated with cactus..........--...----.--- 51 Bothrideres cactophagi, enemy of cactus insect (Cactophagus v Wee Sen tte 46 denticollis incidentally associated with cactus. - say tek SVE 51 Brachytarsus sp:, SCAVENGER IN CacChise, 5. 22 .a.cu.25en cer. Sas a eee ee 48 Brochymena obscura incidentally associated with cactus. ....-.....----------- 51 Bruchus sp. irequenting flowers of cactus... ..-2: 2835 heaseee ee ee 49 Burning against. Chelimdea wrvthigera......\. seed eee eee eee 20 cottony cochineal insecty.c5: 2b see fo eee eee eee 24 Mehitarajunctolinzellas i oaceate Se eee eens Jae eee eee eee 28 Monetlema erassum: 3-2 as wir oan ae eee Ait Wien ieee ote 14-15 Cacitophagus spinole, bibliographic reference...) 5.22 23-2: te5255-=< eee 54 in list of injurious cactussnsects 144.14 -42)-caenee See 44 striatoforatus in list of injurious cactus insects.......------------- 44 validus, bibliographic reference: ....\).-. 2ej3dec)- a2 Ses eee eee 54 prey of Bothnderes cactophagts,...=- 22s. 25h-Geeee- eee 46 synonym of Cactophagus spinolz......-<-2e. 26209 -4..5: SS es aS aifeln thas ae oe 55 conjusum,; bibliograplie reference: ._-2 28 {acai 25 ee eee 55 Gochineal, early history’ of industry 22-52 es ale oe se a Se 23, 24 former extent ‘of Industry. >. .< soacuWed- a eee aie ee eee 9 insect (see also Dactylopius coccus). exports from Canary Islands:2.- e542 3 ene een eee 9 not a native onthe United Statesiwsitetaasccdsc ak ee ae 23 cottony. (See Dactylopius confusus.) Cenopeus palmeri, bibliographic reference........----2-2-502s2--22e--2-40000 54 Colaspoides macrocephalus frequenting flowers of cactus........-..-.---.-------- 49 Coleocerus marmoratus incidentally associated with cactus......--.....----..- 52 Compsomeris 4-notata incidentally associated with cactus...........--.----.-- 53 Compsus auricephalus incidentally associated with cactus.......---...-------- 52 Copestylum marginatum, an injurious cactus insect............-.2---.-------- Bi biblicsmphic references, (258s... 8 eee 54, 55 Maseochara valida reared from puparium..........-. 47 scavenger in cactus..........-- Jcusdeee yee. 48 Cornifrons elautalis, an injurious cactus insect......-.--.---- Sh. Me een ete 8 35, 44 Corythuca decens in list, of iajurious cactus insects’ ':\. ty. 32 Sindy. St set eee 41 Cossonus hubbardi incidentally associated with cactus. .............----....- 52 Cremastogaster linecolata incidentally associated with cactus................... ne sp., attendant on aphis on Opuntia versicolor and Opuntia fulgida. 52 incidentally associated with cactus............-.-.....-. 52 Cutworm. (See Chorizagrotis soror.) Cycloneda munda, enemy of cactus insect (Dactylopius confusus)............. 24,46 Cynzxus angustus incidentally associated with cactus.............-........--- 52 Cyphomyia schaefferi, scavenger Im.cactus).! 22 .\soiceut <.seeedh. ce ak eke 48 Dactylopius (Coccus), near confusus, in list of injurious cactus insects. ........ 42 spp. in list of injurious cactus insects...........-.---. 42 coccus (see also Cochineal insect). in list of injurious cactus insects. ..2.2.4sela.y-. gs. 5 bebe 42 confusus,an injurious cactisimeects. 0228 #0. ates a ee 13, 23-25, 42 control: 2 1'2 fee a ee eae a Oe eS nae eT 2 24-25 BHCIMIIOS, |... - Pie ee teeerG e acme Be aE uc. oe 24 prey ot Chilosorus tachis: Weasel es freee. et 46. Cycloneda miupidiimie. Gl ae sere Loe ee 46 Drosophila avipelophila... rien). ocd. kts! 47 PHANCO. 54 TNE CO COLOMINIRG a5 od Cato a lacy davai bhe oR a= ath o'sea age 54 Dasymutilla orcus incidentally associated with cactus...... a shh dos Bees nee 53 Dendrocoris contaminatus in list of injurious cactus insects........-.....-.-.-- 41 Diabrotica 12-punctata frequenting flowers of cactus. ......-.-.......-------.- 49 Diadasia australis frequenting flowers of cactus. ...........-.-.-.-.-...-.---- 50 opuntiz, bibliographic reference. ...:........05.5..0+.---- 56 frequenting flowers of cactus. ........-.......-.-- 50 rinconis frequenting flowers of cactus. ...................-- 50 bituberculata frequenting flowers of cactus. ..............---2-.-2-. 50 piercer frequenting flowers of cactus. .).).)22 12). so ss8/ 22 oe deni eoea nes 50 Spp-; Dine MEA NIG RETEKONCe - 6 ats itind ah Sootindecis. ase ede ois 56 unicornis, bibliographic reference. yay hte 27k Ze eee Veoh taRe 56 opuntix, bibliographic palemencs. sieht hee hits en 56 Dialictus occidentalis frequenting flowers of cactus. ................-.-...-.-. 50 Draspis cacti.in list of injurious.cactusjusects. .....\1s202 1.20. ceegseee soe 42 opunticola in list of injurious cactus insects. .................--. 42 echinocacti in list of injurious cactus insects.....................-... 42 each; an: injurious, cattus insect, ) .jviseesste leds ~ +++) 18, 25,42 opuntix in list of injurious cactus insects................. 42° Diczxlus costatus incidentally associated with cactus....................----- 51 Dichopetala brevihastata incidentally associated with cactus...............-..- 50 emarginata incidentally associated with cactus.................-. 50 sp. incidentally associated with cactus......2............--....- 50 ' Dichromorpha viridis incidentally associated with cactus................----- 50 Dictyobia permutata in list of injurious cactus insects.................22..2.2-- 41 Dicymolomia julianalis, enemy of Thyridopteryx onbemiarseforiitis: pet BS Das da Se 44 in list of injurious cactus insects...-.............-... 44 opuntialis, bibliographic reference......................2...2--- 57 in list of injurious cactus insects. ...............-.-- d4 Py nlodus lusius, enemy of cactus Insects.<.:. 0 0es woe O Lak Subee J. So 45 Diplotaxis truncatula incidentally associated with cactus...................-- 51 Discoderus impotens incidentally associated with cactus................-..---- 51 Disonycha varicornis, an injurious cactus insect..................-.------++- 22,43 Ditoma gracilis incidentally associated with cactus........ ESE ee EAE: felt ee sulcata incidentally associated with cactus.................-.-------- 51 Dorymyrmex pyramicus var. flavus incidentally associated with cactus.......-. f 52 64 PRINCIPAL CACTUS INSECTS OF UNITED STATES. - Page. Drosophila ampelophila, enemy of cactus insect (Dactylopius confusus)......-- AT punctulata, enemy of cactus insect (Dactylopius confusus).........- 46 quinoria;. bibliographic teterem@ee.. sateen ree ae ee ae oe 54 Dyotopasta yumaella, an injurious cactus insect............---.-.---.-------- 36, 45 Echinocereus, flowers frequented by Dialictus occidentalis..................-- 50 food plant’ of aphisrc ct 7 (ae eRe eeemarn oR) ene 53 Echinocereus sp., flowers frequented by Ashmeadiella echinocerei.............-- 50 spp., food plants of Sixeonotus luteiceps..........---.---...--++-- 41 Echinocactus ottonis, food plant of Diaspis echinocactt.............--..-------- 42 setipennis, food plant of Gersteckeria bifasciata.........--...----- 43 sp., food plant of Diaspis echinocacti cacti......-.....------------ 42 tenuispinus, food plant of Diaspis echinocacti..............------ 42 wislizent, flowers frequented by Augochlora neglectula...........- 50 Lithurgus echinocacti..........-:- 50 Eiiphosoma texana, parasite of cactus insect (Mimorista flavidissimalis).....-.--. 22, 46 Eleodes armata incidentally associated with cactus...........----..----------- 2 carbonaria incidentally associated with cactus..........-..--..-.------ 52 var. soror incidentally associated with cactus.............-. 52 texana incidentally associated with cactus. ..............--.-----:---. 51 tricostata incidentally associated with cactus.........-...........----- 51 ventricosa incidentally associated with cactus. ......-....-- yu rae Se 52 Emmenastus texanus incidentally associated with cactus.....-............-.-. 51 Hphisten.us cactophilus, seavenger in cactus: vases 2208 5 pee eee 47 Epicauta trichrus frequenting flowers of cactus...........--..---------------- 49 Epiplatea scutellata incidentally associated with cactus.............---------- 53 Epricromyia floridensis incidentally associated with cactus............-.------ 53 irchonvus converus, scavenger Mucactiss 1 2 ee is ee. SUSIE Se 47 punchipennis, scavenger in cactus.gee2 22s 5. 2/205 eee 47 Eriococcus coccineus, an injurious cactus insect. .....-. BNL A ee 25, 41 Euczla sp. incidentally associated with cactus...............--.------------- 53 Eucera unicornis. (See Diadasia unicornis. ) Euglossa surinamensis incidentally associated with cactus...................- 53 Tuynicrus lucanus, scavenger in waetuss-22 = 335.2) 95. 02a eee ee ne 47 Euphoria kernii frequenting flowers of cactus......-----.....-.------...--- .. 32,49 Eupogonius vestitus frequenting flowers of cactus.................--..---.--- 49 Eurymetopon muricatulum incidentally associated with cactus...............-- 51 Burytoma.sp., parasite of cactus Imsects.c2.6 iste ee. Ve ee 46 Exochomus latiusculus, enemy of cactus insect (Dactylopius confusus).......-- 24, 45 marginipennis, enemy of cactus insect (Dactylopius confusus)..... 24, 45 Wintagria sp., scavenger in.cactus. 1254.01 26.4) OL ye Sa ee 47 “Fly, droop-winged.’’ (See Stictomyia longicornis.) Forelius maccooki incidentally associated with cactus...................---- 53 Formica subpolita attending aphis on Echinocereus...................------- 53 incidentally associated with cactus................-----.--- 53 Fungous disease. (See Perisporium sp.) : Gamaside taken from pulp of Cereus giganteus.............2--.22-22222----- 53 Gasoline torch against Chelinidea vittigera..... 2.25. 22-.50.0220e. ete 20 Melhitare ‘junctolineellai ese oc VRE EG FA. 5 28 Mimoriata flavidissumalis 2s 3205 B25 UPI ATR fo 22 Narnia pallidicorniss : 20k. SORE: a, ESTAS, Be 34 STYLODUeN Miche ats SE eC Oe) Od Be ee 23 Gersteckeria, systematic treatment of genus, bibliographic reference......... 57 Gerstzxckeria alternata, bibliographic reference. ......--......--.----+-+-2+---- 57 basalis in list of injurious cactus insects, .-...-..-eeeeeeeeeeeeece 43 INDEX. 65 Page. Gerstxckeria bifasciata in list of injurious cactus insects...............22..---- 43 cactophaga, bibliographic reference......-..........2-.......22-- ag in list of injurious cactus insects...........-..--2..2.2- 44 clathrata,-an injurious cactus msect (=. 222.2222 ek 30, 44 bibliographic melerence 22222020022. A See 57 hubbardi in list of injurious cactus insects. ..-.................-- 43 cms Charatan nlaamis. hae eh ts PUNE SEIS 30 nonhs, an invarious cactus-insects./J6205.. 20.9 A Pee 30, 43 opuntie, bibliographic reference=)).--. 22.2). 02220 57 ins list of njurious cactusinsects./f2. 02429. et 44 poross; ‘an anjurous cactus inset! Lo) [522 ee PT 29-30, 43 tessellata, bibliographic reference’. {5.3.2.0 ) 2) 2222. oe ee 57 turbida in list of injurious cactus insects..........--...2..--..-2--- 44 Gnaphalium, food plant of Platynota rostrana..............-.-.-..--2--2---- 45 Hadronema robusta in list of injurious cactus insects..................22..--- 40 Moketus:ap.irequenting flowers of cactus): 05.22 ell) OA Ae: 49 Hand picking against: Monetlema crassum. - 2.0022... 25 0 0 oe Pe 14 Helicobia quadrisetosa, scavenger in cactus. ..........-.2--.....2 22222 eee eee 49 Helops farctus incidentally associated with cactus................2....---.-+-- 52 Heriades gracilior frequenting flowers of cactus. .............--2.2-------+--- 50 Hermetia chrysopila, an injurious cactus insect..........--....-..------------ 38-39 BEACH Pern CRCKIN erm: MIE Dmstaih ie OL el lee 48 hunter, an. injurious cactus inseet!.2. 021 fou. Sfivyeiry. 2. as soles 38-39 Piblorraphie retereucenwes) seivo. eehye ria es, ya kee m2: 57 SGAV ENP EE Ei CACIIS. 5 sce US EMs age ET oc 48 Buoreiin decens, seavenper inreachus.: 222-20 eio. 2) see ewe sees Zeke 49 ITippodamia convergens, enemy of cactus insects (aphides)...............-.-- 45 nigialepin each), Seca veneer 1 Cachis.) 2. 2.42 j. et) be eer 42 Dagsony Chi WOriCOR AsO Ao oth eee ale eee 22 UGE TUS: SUCEUT CEILS > eee a ee ee 40 Myrmecocystus melliger taken thereon ...7..-......-------- 53 probable food plant of Melitara fernaldialis...........---- 29 erbuscula, food. plant of Cheliindes sp. as eee See i een eee 20 banburjana, food plant of Cecidomyia opuntix...........-.-.-2-+------ 45 bernardina, /oibliograp bie rererencenen eee y=. een eee ee 54 food plant.ot (Conoapeus palmert\ campo set. secs sae 43 eycloides, food plant, of Pseudocoeens sp. 24 o) seas ot a ie 42 elongata, food plant of Diaspis echinocacti opuntiv......--.--...----- 42 engelmanni, bibliographic references...............-------------- 54, 55, 56 flowers frequented by Diadasia australis rinconis.....----- 50 Megachile:sidalcere 2a. nee eee 50 ROOU. plant OF atunis. ot. c55 kk eee ne nee einen ee 53 Copestylum marqginatum.......-.---++------ 47 DOLE DUS CHOI cela 2 Use ss aaNet ar 42 PORATIBDOUCIY OMG Ue i 22 are et Sn 42 GersteChenvugiQUilign oe es aa eee 43 Hyporhagus tevanus found theréin................-.--.-- 48 probable food plant of Melitara fernaldialis. .........---- 29 INDEX. 69 Opuntia ficus-indica, food plant of Diaspis echinocacti.........-----++---+-+--+ 42 result of work of insect therein described as abnormal sce oN eT ADEE pel EY YEE EY ay ae See or ee meee 35 fulgida, bibliographic reference.....-- ..------+.-24=$ 4-2-4+--+-0+- 5% 56 Ba ENE ON Ree ia seen scialss bee Sa pd elt ree 4 Ns 52, 53 CMU SS een 2 2.2 Lio te oe ia ae cae Eee 20, 40 Dianiglo nis tomentose. -.-, = 2555 sm le) = noi- a ynin Bea 42 TOA YCR GRINS 2 es os og thao ny) ate = ee 42 CON OLOL COO e eh, tue, sci ee 42 Tnotropis contaminatus......:-.---.-----2+-+-+- 36, 40 ORY ChODAIIS TY BTCD =e 25) =o 2 2 = as Ao tm Aad shee 44 Volucella avida a scavenger therein...........-.--.-.---.------ 48 leptocaulis, bibliographic reference. ........-/.------------+-------+- 56 flowers frequented by Diadasia australis rinconis......--- 50 food plant of Diaspis echinocacti cacti........---..-------- 42 DSORY CRE POTICOERIS. = = os og oe son oa in = = Sy GRenSTee CRETUG: COUNT OUD. e-Peiets = winie Seto eae 30. 44 Onychobaris mystica. .......-.2+++--+-+++++- 44 lindheimeri, Apanteles (Pseudapanteles) sp. taken thereat. .--.--.----- 46 Buglossa surimamensis thereon.......----.--------+-+-+5-- 53 flowers frequented by Diadasia australis rinconis.. ...-.-- 50 food plant of Diadasia echinocacti cacti..........-..-.----- 42 Puiorare. piniormaplit TeICFENCe 8. = - egw ale ew = 2 an ma = renin 56 flowers frequented by Diadasia australis opuntix...........- 50 “‘longicorns,’’ common name for species of Moneilema..-...........--- 13 missouriensis, food plant of Melitara dentata...........-..----------- 28 polyantha, food plant of Dactylopius (Coceus) sp...------------------ 42 MCP IODCHIGUS se olsen ea eng =e tae 28 Rr DIDUIGATRIMLU TOICEENCE sto S08 oa es had yey ns pele oe SSPE 55 Qype Wohe ane cligr sy) DAC RET 7) aR a a ee Roe ee 52, 53 GEOL EST aR ORE i A Ae 20 vulgaris, food plant of Gerstackeria hubbardi..........-.--.----------- 30, 43 MERE, VOMENLIS. ont ie oe eee inet 28 Opuntiaspis philococcus. (See Lepidosaphes [O puntiaspis] philococcus. ) Oscinis coxendix incidentally associated with cactus................--22.:.---- 53 Othnius senecionis incidentally associated with cactus... ........-.-...------ 52 Germ tecidahs, an injurious cactus insect-.../-..-..-.-.-s-0------2-4.-- 13, 36, 44 Pachycondyla harpax incidentally associated with cactus..............-----.-- 52 Paratiphia sp. incidentally associated with cactus............---...----.------ 53 PETG CONSOTS -ECAVEDPEF IN CACUUS <0 02. 3 5.2 - seme pense atemeee ee ue 48 eR Mitts V CNV AT ERC TMIR oe oo once os ola oo aim ae pedi fes wale Te ae 48 CRPIRETaTIrE ECE ITC ATA GIES oye os cw ge icin Spall =n x ue 48 Eph See PG EE WTCRCLMAEE: Cote os onan. = xk eee see = «me snide yes bas 48 Pasimachus californicus incidentally associated with cactus... .......-------- 51 depressus incidentally associated with cactus .........-.---.------ 51 iP MLOsOIRG CLPULOSUTN, BCAVCNPEE IN CACLUS.. 25... 2... ~~~ ~~. nee gece reece ay ee 47 Perdita megacephala frequenting flowers of cactus. ...........-.--- apie et ieee 1 50 Perisporium sp., fungous disease of cactus, probable dissemination by Chelinidea TATE hi Ua Lee ga SE Ra a aa sede all 1 ala aati iy aed gee 17 Pheidole sp. incidentally associated with cactus. ...............------------- 52 Phileurus cribrosus incidentally associated with cactus............--.--------- 51 Panna prariGens BCR VEDPCY 1 CACEUD..- >.’ 22 sac o2+. 2 2-----------24-222 62" 49 Phorocera comstocki, parasite of cactus insect (Melitara)..............---.---. 46 Melitara yunctolineeiia: .. 2.222 2 ee 27 70 PRINCIPAL CACTUS INSECTS OF UNITED STATES. 2 Page Phyllotreta pusilla frequenting flowers of cactus...............2-.--.--2-22--- 49 Physetoporus grossulus, scavenger im Cactus.! .7.27 27.22 oan sks) oe. 4. ee 47 Platymetopius fuseifrons in list of injurious cactus insects... ......-..-..--..- 41 Platynota rostvana, an injurious 'cactusimsects: -y540- eases eee eee 13, 36, 45 Platypedia putnami in list of injurious cactus insects... ........-.----------- 41 Polistes; three species injurious to Camtus=e: 222. 9e Sees. SoU tee eine 13 Polistes flavus, an injurious wactus misecte see eee s-s 22e 4. Bo eee 36, 45 rubiginosus, an injurious cactus Imseet ls + 2) 262.2 Sas ee - 36, 45 LecanNUs, BN INjUOUs Caius ANBeehes a o-2- < aay on su tec ee a 36, 45 Pontia protodice incidentally associated with cactus................-----....- 52 Prenolepis viridula subsp. melanderi incidentally associated with cactus........ 53 Prickly pear. (See Cactus and Opuntia.) Pristocelis texanus. (See Trichochrous texanus.) Proarno valiata im list of injurious cactis insécts-..5- 22.6. ...- 5 eee ee 41 Pseudococcus longispinus in list of injurious cactus Insects. ................... 42 obseurus, bibliographic relerence: 2 - {2.4.42 2a. eee 57 in‘ list'of injurious cactus incsects®: 8. Jo eee 42 ep. in list oF injurious cactus insects. .-..<: so AT) eee 42 wirgatus in list of injurious cactus Insects............6.....-.-4.. 42 Pseudomyrma brunnea incidentally associated with cactus... ..........-.---- « ‘eg Pseudoparlatoria parlatorioides in list of injurious cactus insects .......-..---.-- 42 Pseudoscorpionid taken from pulp of Cereus giganteus.........-...----.---- 53 Pycnomutilla texana incidentally associated with cactus............-...-.---- 53 Randia, food planter Platynotamnosirand..:2 02° 2 aed. Seine ee. eae 2 45 Rehnia spinosa incidentally associated with cactus... ................-...--. 51 °hagodera n. sp. incidentally associated with cactus.............-....------- 51 Repersia spin List, of injurious cactus insects: 225...070 22. - 2. 20.0 =. eee 42 Ravethe Sp. ScaVenper im CAChUR IE Sook 20k Seo e eek. 8 a er 49 Biryinia, toad plant of Plaiynota rosirand....0- 20.5. -=~s- <»=.5 5 aaa ee 45 Saluria ardiferella, enemy of cactus insect (Dactylopius confusus).......------ 24, 46 Saprinus pennsylvanicus, SCAVENGER In’ CACTUS 4. 2. :)2'4)-)4 41: 1 21 4 ee 48 Sapromyza vulgaris, scavencer im cactus. 225000 oto Se one ae 49 Scale insects. (See Coccide.) Sentopse sp., scavenger Im Cachis se.) tt oye Ses ee eek Sek ee 48 Scymnus hornii, enemy of cactus insect (Dactylopius confusus).......-.------- 24, 46 loewii, enemy of cactus insect (Dactylopius confusus).......-..----- 24,46 Sinea raptoria, enemy of cactiis Insecta 225.7: con) Se eee ee See 45 Saveonotus luteiceps, an injurious cactus insect... ....---)- .2.-5-5-=-4--o-e2ee 36, 41 mmerips hypocoproidés, scavencver Ih CkCtUS. 525.5255 4 ae ee ee 48 Smicronyx spretus incidentally associated with cactus.............-.-..------- 52 Solanaceee, Lineodes integra reared thereon............---.--+----.---.--+--- 52 Sowbugs, injury to Mammillaria phellosperma..........-----------+--+--+--+--- 53 Sphenophorus spinole. (See Cactophagus spinolz.) Spongophora apicidentata incidentally associated with cactus.............---.- 50 brunneipennis incidentally associated with cactus.........---.-- 50 Stictomyia longicornis, an injurious cactus insect.............------+--+------ 39 SCAVENGER IMYGAGHUIA 24-2 5a es oe eee eae eee ee ee 49 Stipator grandis incidentally associated with cactus..............----------.- 51 haldemanni incidentally associated with cactus........-.--.--------- ol mitchelli incidentally associated with cactus... ...............------ 51 nigromarginata incidentally associated with cactus.........-.......-- 51 pratt incidentally associated with cactus..............--.-+-----+-- 51 Stomatocera rubra incidentally associated with cactus..............--...-.-+--- 52 va INDEX. Tk , Page. Stylopidea picta, an injurious cactus insect.......-... Nee ee Lee, ye 13, 22-23, 41 MAdnneacriEa Grands, Scavenger M CACtUS..;.. 2.2.04. .225-f22-5.0202-22-00205 47 Tempyra biguttula incidentally associated with cactus. .............--------- 51 Terps ENIAC, A TAYTMeOCOPRNe |. oa = 52s se ee ee De sites eb ee ee 48 HEA RCNSCE AN CHOUEE ei Lb oe Aa tte oben oo ate ake to 48 meaiien faves an Wwijurious cactus msect.....'.-..2----.22--.12228.2--+--.+ 25,40 Tetranychus opuntiz, bibliographic reference.............--.-..----+--2-+++-+- 57 RHE ON CACHIESUAOCIA 22 Loe bak ss on ee dG 40 Thyrido pteryx ephemerxformis, prey of Dicymolomia julianalis.......-------- 44 Tobacco extract in control of cottony cochineal insect................-..-...-- 25 Trichochrous (Pristocelis) texanus injuring blooms of cactus. ..............-.-- 32,42 Trichodes bibalteatus, enemy of Melitara and other cactus insects........-..---. 46 Pomegieyn sp, seavenger iit CAchUs..... 2-2. -< 22+ ce. - de eso cee. eens eee 47 Triorophus nodiceps incidentally associated with cactus..........-..---------- 51 RMR TMAI NIN oe he 5 8S ee we ges s vie Se wos de yee ti de'eed sey 10 Pen clongnris, ScAVeUper I CACtUS.... 2 2'5 220-52 s222-25- 5-22 tee ann eee 47 Ulosonia marginata incidentally associated with cactus. ...-.........-------- 52 . Volucelia avida, an injurious cactus insect. ......-..-...-.-.-2--2 2222s e eee 38 mn CGEM! 25255 sc bites Mare a sae Ro Sue vac: eee 48 Prene, a0 snirious eachus Insect. <- 4.225. , kee eds ese be 38 LoL EE ia oth ae ae oe ee ede eS gs EO 48 WIAeia aA OMOUs CACLUS ANSCCL.. 2.2 22... - - ae 22s oes eee ence 38 Diora te Fererenices. x42. 2a 8)... teh ees he be we dee ee 54 ae ameattemEa TEL COLNE oS en Se SOU eee oe Sue on sg aS 48 pis ae aurIOs CACtis IseCEs fo. 622-5 25g oe od is Lee eo 38 BEY TOMER IRE ats oe ee Sides Velveeta eas 48 Whale-oil soap in control of cottony cochineal insect .................-...--- 25 eLantholinus dimidatus, scavenger in cactus... ...........---../2+--.-20----- 47 Xanthopygus cacti, scavenger in cactus... -......-..-- Daleits iat: Nes Ap eee Ae ote 47 = necas, 100d planta ot Sizeonotus huferceps......).-..----- 2. a2 ene en ens t 36, 41 Zophodia dilatifasciella, enemy of cactus insect (Dactylopius confusus)......-. 24, 46 O ve ait » ea! 1 ila A Ae Pea aie t ee Wieniy % Higa Dees } ma ' hi i XICAN nae BOLL WEEVIL. | » Rupon' se wi oe : a ©): *. MESSAGE FROM THE | PRESIDENT OF THE UNITED STATES | ; eager TRANSMITTING 4 COMMUNICATION FROM THE pe _ SECRETARY OF AGRICULTURE _ SUBMITTING A REPORT ON THE MEXICAN COTTON- -BOLL WEEVIL Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE I. @ o y/ a l Yj l LK ANY Y), i> \ S Py @ , MIN tS = rt A 4 eal LZ Wie g/ ” FA Ni), | oil il) l vil ! Tel ~ 4, Yee ’ y bi Gh y Y fi) " WM \\ af ; f We NG Tay AER i Hh bal N\ i ORS bn COTTON PLANT ATTACKED BY BOLL WEEVIL. a, Hanging dry square infested by weevil larva; b, flared square, with weevil punctures; ec, cotton boll, sectioned, showing attacking weeyil and weevil larva in its cell. (Original. ) 62D CONGRESS : { DocuMENT 2d Session t SENATE t No. 305 MEXICAN COTTON-BOLL WEEVIL MESSAGE FROM THE PRESIDENT OF THE UNITED STATES TRANSMITTING A COMMUNICATION FROM THE SECRETARY OF AGRICULTURE SUBMITTING A REPORT ON THE MEXICAN COTTON-BOLL WEEVIL WASHINGTON 1912 LEITER OF TRANSMITTAL. To the Senate and House of Representatives: I transmit herewith for the information of the Congress a commu- nication from the Secretary of Agriculture, accompanying the manu- script of a report on the Mexican Cotton-boll Weevil: A Summary of the Results of the Investigation of this Insect up to December 31, 1911. (Bulletin No. 114, Bureau of Entomology.) The report contains valuable information of great public interest to cotton planters of this country and those depending upon the cotton-plant industry, and I cordially indorse the recommendation of the Secretary that the report be printed for distribution by Congress as well as by the department. Wo. H. Tarr. Tue Wuite House, February 12, 1912. 3 LETTERS OF SUBMITTAL. DEPARTMENT OF AGRICULTURE, OFFICE OF THE SECRETARY, Washington, February 8, 1912. To the PRESIDENT OF THE UNITED STATES. Mr. Preswwent: I have the honor to submit herewith, for your information and that of the Congress of the United States, a bulletin entitled “‘The Mexican Cotton-boll Weevil: A Summary of the Results of the Investigation of this Insect up to December 31, 1911,” by Messrs. W. D. Hunter and W. D. Pierce of this department. This is an elaboration of a bulletin published in 1905 and of which a special edition was ordered by Congress. Since that date the weevil has spread throughout the State of Louisiana and has entered the States of Arkansas, Mississippi, and Alabama, and threatens to spread throughout the entire cotton-growing area east of the arid regions. In the course of this eastward and northward spread, new conditions have been encountered; the habits and life history of the weevil have undergone some change, and it has met with new parasites and natural enemies. There is a great demand among the cotton planters of this country and among those dependent upon the cotton-planting industry for the information contained in this bulletin, and, in view of this fact, I respectfully recommend that this report be transmitted to Congress, together with the maps, illustrations and diagrams accompanying it, to be printed by order of Congress; and I further recommend that not less than 10,000 copies be printed for the use of this department, in addition to such number as Congress may order for the use of its Members. I have the honor to remain, Mr. President, Very respectfully, : JAMES WILSON, Secretary. DEPARTMENT OF AGRICULTURE. Bureau or EntTomovoey, Washington, D. C., January, 1912. Sm: I have the honor to transmit herewith and to recommend for publication a manuscript entitled ‘‘The Mexican Cotton-boll Weevil: A Summary of the Results of the Investigation of this Insect up to December 31, 1911,” prepared by Messrs. W. D. Hun- ter and W. D. Pierce, of this bureau. This manuscript contains in the briefest possible space an account of the exhaustive investigations of the Mexican cotton-boll weevil which have been conducted by this bureau for some years past. The last comprehensive bulletin on this subject was issued in 1905 and is now far out of date. There is urgent demand for information on this important pest, and this demand will undoubtedly continue as the insect invades new regions. Respectfully, L. O. Howarp, Entomologist and Chief of Bureau. Hon. JAMEs WILson, Secretary of Agriculture. at rR eet "pep ‘oe ay 4 a), hs : ir r i ee a Raft a ao aa a wal eh AE e. dos a0 — fz i an is ‘. i rudy cy" OiOR | } uf id. ft. ot etl Pgh ACE. Early in 1905 the Bureau of Entomology published as Bulletin 51 an account of the information concerning the Mexican cotton-boll weevil which was available at that time. Since 1905 the work on the investigation of this important insect has been continued by the Bureau of Entomology and by various other agencies. As the result of this recent work certain features of the life history of the pest have received full treatment in publications of the bureau. This is the case with hibernation,! natural control,? parasites,’ proliferation,* and repression.’ Important contributions Have been made by State agencies. The result has been that the original bulletin has been out of date for some time. On many topics the amount of informa- tion now available is more than double that at hand at the time the previous publication was issued. Moreover, it seems advisable that the history of the pest in the United States and an account of the losses occasioned by it should be brought up to date. For these reasons the present publication has been prepared to include all of the more important available information concerning the boll weevil. It is based upon Bulletin 51, from which many extracts have been used, and will supersede that publication. In the nature of the case it is impossible to include all of the data which have been published with reference to certain phases of the life history of the boll weevil, such as hibernation and parasite con- trol. In all such cases, however, the main essentials regarding these ae topics have been incorporated. Persons who desire more etailed information may consult the various special publications, which are still available. As might be supposed the accumulation of many additional data has necessarily changed some of the conclusions drawn in the earlier publication. It is to be noted, however, that these changes are generally of little consequence. The investigation of the boll weevil was begun by the then Division of Entomology in 1895 and has been continued, more or less con- stantly, to the present date. The vast amount of information which has thus been accumulated is to be credited to a large number of entomologists, many of whom are now doing work in other fields, The earlier investigations of the weevil were conducted by Dr. L. O. Howard and Messrs. C. L. Marlatt, C. H. T. Townsend, E. A. Schwarz. and Frederick Mally. The State officers who have assisted mate- rially in this work have been the entomologists of Texas, Messrs. E. D. Sanderson, A. F. Conradi, C. E. Sanborn, and Wilmon Newell; of Louisiana, Messrs. H. A. Morgan, Wilmon Newell, J. B. Garrett, 1 Bull. 77, Bur. Ent., U.S. Dept. Agr., 1909. 4 Bull. 59, Bur. Ent., U. S. Dept. Agr., 1906. 2 Bull. 74, Bur. Ent., U.S. Dept. Agr., 1907. 5 Farmers’ Bull. 344, U. S. Dept. Agr., 1909. ’ Bull. 100, Bur. Ent., U. S. Dept. Agr., 1912. / 8 PREFACE. T. C. Barber, H. Dean, M. S. Dougherty, A. H. Rosenfeld, and G. A. Runner; of Oklahoma, Messrs. C. E. Sanborn and A. L. Lovett; of Arkansas, Dr. George F. Adams; of Mississippi, Messrs. Glenn W. Herrick, R. W. Harned, S. F. Blumenfeld, an R N. Lobdell; and of Alabama, Dr. W. E. Hinds and Messrs. W. F. Turner and I. W. Car- penter. The work has been facilitated by the commissioners of agriculture of the various States, including Col. Charles Shuler, for- mer commissioner of agriculture of Louisiana, Mr. H. E. Blakeslee, commissioner of agriculture of Mississippi, and Mr. F. W. Gist, former commissioner of agriculture of Oklahoma. The agents of the Bureau of Entomology who have contributed to this bulletin are: Messrs. F. C. Bishopp, J. C. Crawford, R. A. Cush- man, F. L. Elliott, A. F. Felt, C. W: Flynn, J. B. Garrett, W. H. Gilson, S. Goes, G. H. Harris, W. E. Hinds, W. H. Hoffman, T. E. Holloway, C. E. Hood, W. A. Hooker, R. C. Howell, C. R. Jones, B. T. Jordan, O. M. Lander, Thomas Lucas, E. A. McGregor, J. D. Mitchell, A. C. Morgan, A. W. Morrill, D. C. Parman, T. C. Paulsen, H. Pinkus, F. C. Pratt, V. I. Safro, E. A. Schwarz, J. S. Slack, G. D. Smith, H.S. Smith, C. S. Spooner, E. 8. Tucker, G. N. Wolcott, and W. W. Yothers. Of these agents Dr. W. E. Hinds, who for several years was the principal assistant in the cotton boll weevil investigations of this bureau, was the most extensive contributor. To him we owe a large share of the accurate data on the life history and habits of the boll weevil. He also did a large amount of work in the prepara- tion of Bulletin 51, upon which this publication is based. e have attempted throughout the bulletin to credit the various agents with © the work for which they have been directly responsible, but in this place it must be stated that the results obtained are due to the faithful and efficient service of the whole corps of entomologists who have been associated with the writers. The work has also been greatly facilitated by the constant interest and encouragement of the chief of the bureau. Special credit is due to Mr. E. S. Tucker for skillful preparation of the plates. THE AUTHORS. CONTENTS. ET) 2 ne de SePipiMslMne AP. asian 355i sebeedeeecses sc ccacesiesssersesei ee Pe... Moca due tp ane: bollimeeval ns 22 ie Beh SEG os 2S 25 bees oss seereerts ke. Indirect losses caused by the boll weevil. ..................0.2...---------- Compensation for losses caused by the boll weevil...............-...--2.----- 2 TVS Se Aad 2 ec Sool, hee EGE oreo Ee Sane cia a Ser Insects often mistaken for the boll weevil. ....................222..-------- Peon peutnelMeybOll weewll»=2o2-252222c22......-.-.---..- -).----Jee4--.2--- Hileets\or Hooding) upon the weevil: .22.......... 2.22 22s. LE LUN CTATC OTE 26 cP a lien A Sa eae Eee SBM SN Sg ye hal Ps Ss (hilerpnnses OF plang Controls: -f-.2-2.5 22. ook eae ee cee meee oe Ree eee tee es ee ge eee Oe oe eee oo Ente St A MOL Se Parasitic and. predatory: insect, CHeémies:-... 2.25. 5.2 2.2866: foe eae A brief summary of the insect species attacking the boll weevil... .. _ D5 TOE ISR) wah ti a Rll Baa uae es Ne Fa, AEA f one moe od ae ke Rae ECORI a er ae eek Ie Str eee iE ey Le 5 Rs tos os A i co Ritect or hurial-or synares'and weevils. .- 0.2.2.2... 2.2 Ce Papariuory experinienis mm burial: 2.5.0 22 soe. 20 2h oe Sees Burial of adult weevils at time of hibernation...................-..- Comelcuons irom burial experiments... 82202222222 See ee - CLEP BEVIN Sis, Leggs Ee a ge ala Bi trae” a umaered aincnate OL le8O < t fas wcs Abe soe ee oto ce See eects LT TL NET 2 hI Rpts A hel i ale lak pA 1 ee ee SiN rMPaERIIMET ere eee ee noe renee tee, 2 Al he i 2 LTE ILIA’ ANT as pe Eee ia a ae aaa RAL nt) Ree ae Futile methods which have been suggested. ........-.-.---------------- Mineral paint and cottonseed oil. .........-..--. i ees Ae 4 SUSTSE TOTES Peat ee yeas Ei ia i rere ie a gt eee SPLIT NEE, atngs eben hy at thei ena een Sele anlage Iie a ee LAS [Ere TG ee ete 7 ew A ee Re aR eee ee Trapping at light.. Ap si epee kes ek eke ats Oe Other proposed remedies. . =i S|! ae Requirements of a satisfactory method of boll-weevil control............. ais ior FHORUE OF SOPTOMOE sce 25a. Soin ons monte ene ns oe eeee ies Parsee Summary of means of repression of the boll weevil. ..........-.----------- Destroying the boll weevil in cotton seed . .........-...-.-------------- Legal restrictions regarding the boll weevil .............-.---------+---- UNO San eit Shc Ui 2 ea a a a be ah kee Quarantines of the ewer State. foo TS ike ee = LET op cog Eh ek 2a ae Nig RY <7 a: 5 al mil eae ee OPA A ee 2-1) Ihave Lene ey A es oad A? Soe Seca A ih g Bis aie Re AO ae Pe ie Ds le Puate I. i Lik LNG VI. VEL. VIII. IVLUSTRATIONS. PLATES. . Page. Cotton plant attacked by boll weevil. a, Hanging dry square infested by weevil larva; b, flared square with weevil punctures; c, cotton boll, sectioned, showing attacking weevil and weevil Jatva, Ti tts Celle edi eee se ae ote ba ee a ee eee Frontispiece. The boll weevil and insects often mistaken for it. a, The cotton boll weevil, Anthonomus grandis; b, the mallow weevil, Anthono- mus fulvus; c, the southern pine weevil, Pissodes nemorensis; d, the cottonwood flower weevil, Dorytomus mucidus; e, Conotrachelus erinaceus; f, the pecan gall weevil, Conotrachelus elegans........ 28 Anatomical structure of the boll weevil. a, Dorsal view of anal segments of larva; 6, front view of head and anterior segments of larva; c, ventral view of anal segments of larva; d, lateral view of adult; e, lateral view of larva; f, ventral view of adult; g, dorsal view of adult with wings spread; h, ventral view of pupa; 7, ventral view of anal segments of pupa; j, ventral view of anterior portion SY OU! SEV > aoe ee Re Se a aie ees Seek aoe ade 32 The adult boll weevil and emergence holes. a, Squares of Peruvian cotton showing emergence holes of the Peruvian cotton square weevil; b, square of upland cotton. showing emergence hole of the cotton boll weevil; c, adult boll weevil on cotton square; d, adult boll weevil puncturing cotton square; e, adult boll weevil emerg- ing from cotton boll; /, small dry bolls showing emergence holes; g, hull of boll. with weevils found hibernating......................- 36 . Effects of boll weevil attack on leaf and squares. a, Cotton leaf much fed upon by adults; b, square with two egg punctures; c, flared square with many feeding punctures; d, square prevented from blooming by puncture; e, bloom injured by feeding punctures; f, poor blooms caused by feeding punctures. ...................... 40 Injury by boll weevil to squares. a, Bloom checked by attacks of larva; b, square opened, showing grown larva; c, square opened, showing pupa; d, dwarfed boll opened, showing oun tees and two pup; e, weevil escaping from square; f, emergence hole of adult I SQUANC soci So come RS > Bah Here ae a ceeeeiae Siete See ee 44 Injury by boll weevil to bolls. a, Three larve in boll; 6, emergence hole in dry, unopened boll; c, two larve in boll; d, weevils punctur- ing boll; e, opened boll with two locks injured by weevil; f, large bolls: severely punctured 25. ot aoc ee ge en ee eee 44 Field conditions in territory occupied by the boll weevil. Fig. a.— Newly planted cotton field, with sprouts from overwintered cotton roots. fig. b.—Fallen infested squares .........-.-.-.-.-.--.--- 76 . Relation of boll weevil cells to seed. a, Boll weevil pupa found in cotton seed; b, boll weevil pupa in cell of lint from boll; c, weevil cell in dwarfed cotton boll containing live pupa taken among seed; d,;weevalicells:inibolls-e. cotton: seeds=--). ase eee nee eee eee 92 . Fig. a.—Boll weevil remains after passing through fan from gin. Fig. b.—Ten-sectioned hibernation cage...........-------------- 96 . Hibernation conditions for the boll weevil. Fig. a.—Cotton field adjacent to timber covered with Spanish moss. Fig. 6.—Proxim- ity of moss-laden trees, conducing to high infestation by weevil. - 96 . Hibernation conditions for the boll weevil. Fg. a.—Standing dead timber and forest environment favorable for hibernation of weevils. Fig. b.—Litter in forest, suitable for hibernation of weevils....... 100 . Hibernation conditions for the boll weevil. Fig. a.—Spanish moss on trees, very favorable for hibernation of weevils. Fig. b.— Density of Spanish moss as a protection to weevils in hibernation.. 100 ILLUSTRATIONS, Piate XIV. Natural control of the boll weevil. a, Pilose and nonpilose stems co oo ~I ao He OO Nr Se aS * cotton; 6, larva of boll weevil crushed by proliferation; c, aof Catolaccus incertus on pupa of cotton-boll weevil; d, larva icrobracon mellitor attacking boll weevil larva; e, a holes ot Mer by Solenopsis geminata: in effecting entrance into in- eTpe SUE Vee ey ee eS eS es ee Oreo eae ee XV. The difference between hanging and fallen squares. Fig. a.— Cotton squares with short ‘absciss layer, permitting infested squares to fall. Fig. b.—Cotton squares with long absciss layer, retaining infested forms to hang and dry.........-----.------- XVI. Boll weevil ants. a, Eciton commutatus; 7H Cremastogaster lineo- lata; c, Dorymyrmex pyramicus; d, Monomorium pharaonis; e, Solenopsis molesta; f, Iridomyrmex analis ..........-.-+++---- XVII. Boll weevil parasites. a, Eurytoma tylodermatis, male; b, Eury- toma tylodermatis, female: c, Microdontomer us anthonomi, female; c’, antenna of same; d, Habrocytus piercer, female; d’, antenna of same; e, Catolaccus ‘hunteri, female; e’, antenna of same; f’, antenna of Catolaccus incertus........+-.2+220000eeeeeeeee lee XVIII. Boll weevil parasites. a, Lariophagus texanus, female; b, emer- gence hole of Tetrastichus hunteri from weevil larva; c, Tetra- stichus hunteri, female; ce’, antenna of same; d, puparium of Ennyomma globosa in weevil larva; é, Ennyomma globosa; f, Cerambycobius cyaniceps, female; /”, ‘natural position of same. . XIX. Effect of Paris green on cotton. Fig. a.—Cotton before treat- ment with Paris green. fig. b.—Cotton one week after treat- POSTGAME ALIS, PTOI): 62 ojo ens leieraee'sjs Gowen we we oon eas XX. Cultural control of the boll weevil. Fig. a.—Early fall destruc- tion of stalks, the fundamental method for controlling the boll weevil. W indrowing stalks for burning. Fig. b.—Chain cul- tivator passing through cotton rows ......-----.------------- XXI. Use of chain cultivator. Fig. a.—Space between cotton rows before passage of cultivator. Fig. b.—Effect after passage of UR at ne acer ceca crete maa en A ¥ciw mc wweigecingasinde = XXII. Results of early and late planting of cotton. Fig. a.—Late- planted cotton under boll-weevil conditions, given same cul- ture asearly planting. Fig.b.—Early- planted cotton Pens the late planting under same conditions..........-..-.-.-- . TEXT FIGURES. . Map showing the distribution of the cotton-boll weevil on January 1, 1912. . Map of portion of Texas, showing movement of the center of cotton produc- ELON WESU WANG beste es ee SEO Meee Sey SS aceite Seis Oe Se sie Some oe k . Secondary sexual characters of Anthonomus QTONGIS eee cee ae a eee A . Cotton-boll weevil: Head showing rostrum, with antennz near middle and Mimgiplerat end. Tiandibbes > oo. le dos deen dese e cee o- Bone Diagram showing average activity of five female boll weevils............ . Diagram to illustrate influence of temperature on average rate of oviposition 2 boll sri I as Se ES ee A ae engi A ead See . Diagram illustrating Soom = temperature to the egg period of the boll weevil and showing variations due to humidity.........-- . Diagram illustrating relationship of temperature to larval period of the boll weevil and showing tinemdue to Bumidityie 3... 35 -- e ee pn ate nisin e's . Diagram illustrating relationship between temperature and the pupal period of the boll ‘weevil and showing variations due to humidity....-... . Diagram illustrating effect of time of falling of infested squares upon period 12. of development of boll weevil at Victoria, Tex., August, 1904......... Diagram illustrating temperature control of developmental period of the boll weevil. . Diagram illustrating normal developmental period of boll weevil in celts by months, at Victoria, Tex., Ardmore, Okla., and Vicksburg, Miss. - . Diagram illustrating seasonal history of the boll weevil at Victoria, Tex. . Status of the boll weevil in Texas in August, 1906; percentage of infestation 00) ILS TOTES cage NES Se Se ee A ee. 120 136 140 140 144 148 160 20 95 25 ol 39 59 60 ILLUSTRATIONS. . Status of the boll weevil in Texas in August, 1908; percentage of infestation ofall forms. 2 22), 22.2222 2 See ee ee, See _ Status of the boll weevil in Texas in August, 1909; percentage of infestation of all forms. |: 2-222 5 S28. 2 ee ee ee eee ec oe _ Status of the boll weevil in Texas in August, 1910; percentage of infestation of all forms--; i: :<2 25242 nesses oe eee eae ae ee ee eats. a _ Status of the boll weevil in Texas in August, 1911; percentage of infestation Of all-torms = 2... oe 282 Ses a ie ee Pe ee Pee oe _ Curves of numerical strength of the boll weevil and its parasifies!.......- . The spread of the cotton-boll weevil from 1892 to 1911.................-. 22. Diagram illustrating average length of hibernation period of the boll weevil as related to date of entering hibernation.......-. . Diagram illustrating relations ‘of effective temperature and precipitation to date of beginning emergence of the boll weevil...............-.-.-.-.-- . Diagram illustrating average rate of emergence of the boll weevil from hiber- nation in Texas and Louisiana. Pr CONE 3e S RS SLA Ree ee . Diagram illustrating average longevity of boll weevils after emerging on a olven' date... si Se A ee eer eee $3. 90 Otisiatneee eee were: see weet me nee, She hs See deh l Lise, vue Tcpisg ta) EEE: Beek 260 Go 2518 bee LES D6 ae eS ee ete eee Ores 5. 20 Olslahom ayes fy 28 prey bpr oer. tether oe te hag centage sels 11.05 Tee 77 aa RE pee eae: «eee ea ee meee Se 1.95 Messrs. Norden & Co., of New York, have made a conservative estimate of the average annual loss in the various States, as follows: Per cent. Mexasrnhoubre -sereriserseiieyrey. S82 3 te eepee. eat ys jes SS heehee 15 RRO gta eee OR 6 PR or eee ed 15 FAUT KSRTE SASS ee ace an RE tra os cig ie ke er 15 oii isle dempep ieee «seh len, Sele val ek Wey ee ta aoe og Sete 21 The Bureau of Statistics of this department estimated the losses to the cotton crop in 1909 from various causes as shown below: ! TaBLE III.—Amount of injury to cotton crop of 1909 due to various causes. Loss in seed cotton per acre from— State. F P . en Ball Boll- Other Ane eae Total ES weevil. worm. insects. iseases. ; 2 ‘ tions. causes. | Pounds. | Pounds. | Pounds. | Pounds. | Pounds. | Pounds. | Pounds. ATKANSAS foo <<. cee 2 cass Sais n cist = 112.2 21.5 2-5 0.7 14.4 0.7 152.0 TL isih¥ 0 ee ee ae ee ee 5 38.8 148.8 8.5 83} 11.0 1.4 209.8 IMISSISSID Dl os oe sac te emcee 103.3 14.1 8.0 0.7 18.8 3.1 148.0 Oktanama. 2. See se ee ere 147.3 11.0 oa 0.4 2.2 3.4 168.0 ANTS oS 2S Ro Se ee eee 100. 4 37.6 8.7 0.0 aod 0.6 155.0 Average of infested region - 100. 4 46.6 6.2 0.6 10.8 1.8 166.4 According to this estimate, the boll weevil was responsible for 28 per cent of the loss in the five infested States and 14.9 per cent of the loss in the United States. This loss was estimated as 1,267,000 bales of 500 pounds, which, at the current price of cotton in 1909, would be worth $88,056,500. Although the estimate of the Bureau of Statistics may be high, it was based upon the reports of numerous trained observers throughout the infested territory. Frequently misconceptions arise regarding the manner in which the weevil has affected cotton production in Texas. This is due to the fact that the total crop of the State has been maintained more or less regularly since the advent of the pest. In order to obtain exact information on this point we must examine the statistics of produc- tion in different parts of the State.’ It is necessary to divide the State into three areas. These are eastern, central, and western Texas. The divisions are made in accordance with variations in normal annual precipitation and other factors. Eastern Texas as used in this bulletin is bounded on the west by a line running practically north and south from the western 1Crop Reporter, vol. 12, No. 12, p. 94, December, 1910. : 2 The following four paragraphs and table are extracted, with afew modifications, from Circular No. 122, Bureau of Entomology, pp. 5-8. 94 THE MEXICAN COTTON-BOLL WEEVIL. line of Lamar County to the western line of Brazoria County. In this region the rainfall is 45 inches per year or more. It comprises the counties listed below. Practically the whole area is covered with forests. It covers 40,180 square miles. Central Texas com- prises a broad belt from the Gulf to the Red River, beginning on the west with the limit of the belt of 32 inches normal annual rainfall, and extends eastward to the line just described as defining the western boundary of the eastern Texas area. Central Texas consists of 45 counties? and comprises 38,868 square miles. It is for the most part prairie country, although there are wooded valleys and occasional strips of timbered uplands. Western Texas comprises the remainder of Texas, beginning with the line marking the western limit of the area of 32 inches normal annual precipita- tion. It is largely a prairie region, though wooded valleys are numerous. Another factor in differentiating western Texas from central Texas is the increased elevation. A careful study has been made of the manner in which the weevil has affected the production of cotton in the three regions mentioned. Use has been made of the Census records of production from 1899 to 1910, a period of 12 years, as shown in Table IV: TaBLeE 1V.—Eastern, central, and western Texas cotton production compared, 1899-1910 from United States Census. [500-pound bales.] Eastern. Central. Western. ? Years. oe Per Propor- tion o tion o tion of Bales. meses Bales. Ticseas Bales. iene crop. crop. crop. Per cent. Per cent. Per cent. Lo aca mas eg RR ETE a ey ETRE AETE ASE 637,872 22.44 | 1,633,618 62. 61 337, 528 12. 94 T9012 ee neces eR Le ut EA 2 811,413 23.59 | 1,892,669 55. 04 734, 304 21. 36 iS UL See es a ee oe et 8 633, 620 25.32 | 1,448,872 57.90 419, 674 16.77 OO 2S eae en sees Sis tes Sek a es Fa 736, 660 29.48 | 1,332, 487 53. 34 428, 866 ily aly TOOSH Ys eee EF fh Ee Ss hE cs oe 545, 288 22.06 | 1,242,654 50. 28 683, 139 27. 64 Average, 1899-1903.............- 672,970 24.88 | 1,510,060 55. 85 520, 702 19. 26 1M pc Sees Seton as Soeee Res: 52 720, 671 22.91 | 1,700,224 54.15 724,475 23. 07 TODS es S524. et ae ee eek e 329, 523 12.96 | 1,414,115 55. 63 798, 294 31.40 NGO G iets ere ac SR ea yas SSE 672, 497 16.11} 2,213,863 53.03 | 1,287,846 30. 85 LOOVER A ntsc eee cee Oe Pin FREER Ete ec eee ee 222) | secs see ACwerape zs cis. Sie! ral de Sa) Sa ee es Le. Bee ee ee ee eee 192 COLOR OF WEEVIL. Color is very often a variable character in insects, and the boll weevil presents considerable range in this respect. Normally, the general color becomes darker with age. Consequently, hibernated weevils are the darkest found, but another factor must be considered. As has been noted, whatever influences the size of the larva affects directly the size of the adult, and it is noticeable that weevils of the same size are also, as a rule, similar in color. In general, the smaller the size of the weevil, the darker brown is its color; the largest weevils are light yellowish brown. Between these two extremes are the majority of average-sized weevils, which are either of a gray-brown or dark yellow-brown color. In the opinion of Dr. W. E. Hinds the principal reason for the variation in color les in the degree of development of the minute, hair-like scales, which are much more prominently developed in the large than in the small specimens, although the color of old specimens is often changed by the abrasion of the scales. These scales are yellow in color, while the ground color of the chitin bearing them is a dark brown or reddish brown. The development of the scales appears to take place mostly after the adult weevils have become quite dark in color, but before the chitin becomes fully hardened. They seem, therefore, to be, to a certain extent, an aftergrowth which depends upon the surplus food supply remaining after the development of the essential parts of the weevil structure. Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IV. THE ADULT BOLL WEEVIL AND EMERGENCE HOLES. a, Squares of Peruvian cotton, showing emergence holes of the Peruvian cotton-square weevil; b, square of upland cotton, showing emergence hole of the cotton-boll weevil: ¢, adult boll weevil on cotton square; d, adult boll weevil puncturing cotton square; ¢, adult boll weevil emerging from cotton boll; f, small dry bolls, showing emergence holes; g, hull of boll, with weevils found hibernating. (Original.) DESCRIPTION. ab SECONDARY SEXUAL CHARACTERS. * We are indebted to Dr. A. D. Hopkins, of the Bureau of Entomology for indicating the most strongly marked points of difference in the sec- ondary sexual characters of ‘he boll weevil. (See fig. 3.) The dis- tinctive characters are found upon the snout and upon the last two abdominal segments. The differences are subject to some variation, but are still sufficiently constant to enable a close observer with the aid of a hand lens positively to differentiate males from females. Female.—The snout of the female is slightly longer and more slender than that of the male. When viewed from above it usually appears to taper slightly from each end toward the middle. The antenne are inserted slightly farther from the tip than is the case in the male. The insertion is at about two-fifths of the distance from the tip of the snout to the eyes. As arule the surface of the snout is more smooth and shining than in the male. A slight depression, 3 g oy length, O58 min. Vip ro msertion, O12 iin: ea) \ : Q 77 OFZ 7 77D eed OSE 7 ROP YGIDIUM —— GLY” \pyG/DIUM———" & Fia. 3.—Secondary sexual characters of Anthonomus grandis. (rom Hinds and Yothers, after Hopkins.) rather elongated and much larger than any of the other punctures upon the snout, occurs between the bases of the antenne. When the wing covers and wings are unfolded the abdomen shows seven distinct dorsal segments. The last segment visible in the female, called the propygidium, can be seen only from the sides. jt a the male the snout is slightly shorter, thicker, and more coarsely punctured than in the female. ‘The depression mentioned in the fatale is lacking. The antenne are inserted at practically one- third of the distance from the tip of the snout to the eyes. The sides of the snout are very nearly parallel. In the abdomen the male shows eight distinct dorsal segments, the terminal segment (pygidium) not being covered by the propygidium as is the case in the female. In general practice an examination of the beak is sufficient to deter- mine the sex of each weevil. 1 This discussion ig modified from Bull. 77, Bureau of Entomology, pp. 91, 92. 88 THE MEXICAN COTTON-BOLL WEEVIL. SEASONAL HISTORY. THE ADULT WEEVIL. EMERGENCE.? (Pl. IV, 6, e; Pl. VI, e, f.) The adult boll weevil’s normal method of escape from squares and small bolls is by cutting with its mandibles a hole just the size of its body. In large bolls the escape of the weevil is greatly facilitated by the natural opening of the boll. Often the pupal cell is broken open by the spreading of the carpels, and when this is the case the pupa, if it has not already transformed, becomes exposed to the attack of enemies or, what is probably a more serious menace, to the danger of drying so as seriously to interfere with a successful transformation. If the cell remains unbroken the weevil always escapes by the path of least resistance, cutting its way through as in the case of a square. CHANGES AFTER EMERGENCE.’ At the time of emergence the weevils are comparatively soft, and they do not attain their final degree of hardness for some time after they have begun to feed. The chitin is of an orange tinge at the time the weevils leave the squares or bolls, but after exposure for some time it turns to a dark chocolate brown. PROTECTIVE HABITS. Not only is the boll weevil protected from its enemies by its color, which resembles both the dry squares and also the pulverized soil upon which it frequently drops, but it has a protective habit, found more or less commonly among insects. At the first disturbance of the cotton plant, or sometimes even at a movement of a large object in the vicinity of the cotton plant, the boll weevil becomes very alert, raising its antenne and standing almost motionless. If the disturb- ance continues, the weevil falls to the ground with its legs drawn up close to the body and the antenne retracted against the beak, which is brought inward toward the legs. In this position it often remains motionless for some time, but if further disturbed, it will start up quickly, run a short distance and again fall over, feigning death. This habit is popularly known as ‘‘sulling”’ * or “playing possum.” Frequently, in falling, the weevil comes in contact with some part of the plant and immediately relaxes and takes shelter on the plant, or sometimes it spreads its wings and flies away instead of falling to the ground. In July and August the weevils become more alert than at any other season of the year, and flight more frequently follows the dropping from the plants. FOOD HABITS. Before escaping from the square the adult empties its alimentary canal of the white material remaining therein after the transformation. The material removed in making an exit from the cell is not used as 1 Extracted from Bull. 51, Bureau of Entomology, pp. 39, 40. 2 Extracted from Bull. 51, Bureau of Entomology, p. 40. 8 Undoubtedly a corruption of ‘‘sulking.”’ SEASONAL HISTORY. 39 food, but is cast aside. Weevils are ready to begin feeding very soon after they escape from the squares or bolls in which the previous stages have been passed. For several days thereafter both sexes feed almost continuously. They much prefer squares, but in con- finement will feed upon leaves, flowers, or bolls. Under natural conditions any portions of the plants other than the squares and bolls are seldom attacked. The bells are only slightly attacked so long as there is an abundance of uninfested squares. 1The method of feeding is alike in both sexes. The mouth parts are very flexibly attached at the tip of the snout (fig. 4) and are capable of a wide range of movement. The head fits smoothly into the prothorax like the ball into a socket joint and is capable of a con- siderable angle of rotation. The proboscis itself is used as a lever in prying, and helps to enlarge the puncture through the floral envelopes especially. Feeding is accomplished by a combination of movements. The sharply toothed mandibles serve to cut and tear, while the rota- tion of the head gives the cutting parts an auger-like action. The forelegs especially take a very firm hold upon the square and help to bring a strong pressure to bear upon the proboscis during certain portions of the excavating process. The outer layer of the square, the calyx of the flower, is naturally the toughest portion that the weevil has to penetrate, and only enough is here removed to admit the snout. After that is pierced the puncture proceeds quite rapidly, combinations of chiseling, boring, and prying movements being used. While the material removed from the cavity is used for food, the bulk of the feeding is upon the tender, closely compacted, and highly nutri- tious anthers or pollen sacs of the square. When these are reached the cavity is en- larged, and as much is eaten as the weevil Fic. 4—cotton-boll weevil: Head, canreach. The form of the entire puncture ™uchenlarged, showing rostrum, “ Seas: with antennze near middle and becomes finally ike that of a miniature flask. — mandibles at end; mandible, Only after weevils have fed considerably — fnaly °°" 3 MERE COmE: do sexual differences in feeding habits begin to appear; from this time on the females puncture mainly the base and the males the tip of the square. Feeding punctures are much larger and deeper than are those made especially for the reception of the eggs; more material is removed from the inside of the square or boll and the opening to the cavity is ‘never intentionally closed. Feeding punctures are most frequently made through the thinner portion of the corolla not covered by the calyx. The exposed tissue around the cavity quickly dries and turns brown from the starting of decay. As a number of these large cav- ities are often formed in one square (PI. V, c), the injury becomes so great as to cause the square to flare immediately, often before the weevil has ceased to feed upon it. Squares so severely injured fall in a very short time. The injury caused by a single feeding puncture is often overcome by the square, which continues its normal course of development. When feeding punctures are made in squares which are nearly ready to bloom, the injury commonly produces a distorted 1 The following four paragraphs are borrowed from Bulletin 51, Bureau of Entomology, pp. 50, 51. 40 THE MEXICAN COTTON-BOLL WEEVIL. bloom (PI. V, ¢, #), and in very severe cases the boll will drop soon after setting. After the females begin to oviposit their feeding habits become quite different from those of the males. Up to this time both sexes move but little, making a number of punctures in a single square; but from this point we must consider the feeding habits of the sexes separately. Males puncture the tip portion of the square not covered by the calyx more often than do the females. The yellow or orange colored excrement is abundant, and owing to the somewhat sedentary habits of the males it accumulates often in rather large masses, so that it is often possible to tell whether a square in the field has been attacked by a male rather than by a female weevil. Observations made by Dr. Hinds on 70 specimens under both field and laboratory conditions show that for the first few days of their life the males make from six to nine punctures a day, but that during their entire life they average about 1.2 punctures per day and an average of 2.6 punctures per square, injuring only about two squares every three days. Whether in or out of doors, the activity of feeding decreases as the male becomes older. After they begin to oviposit females seem generally to feed less upon one square or in one puncture than they do previous to that time. They obtain quite a considerable portion of their food from the excavations which they make for the deposition of their eggs, and as they show a strong inclination to oviposit only in clean or pre- viously uninfested squares their wandering in search of such squares keeps their punctures scattered so long as plenty of clean squares can be found. When clean squares become scarce, the normal incli- nation can not be followed, and the number of punctures made in each square will be greatly increased. Table VIII is presented to illustrate the feeding activity of both sexes: TaBLeE VIII.—Rate of making egg and feeding punctures by the boll weevil. | | | Total. Average. | Num- | Num- = : | Character of lot. sd eel aa haute Egg hie Fee Punc- | Period of | males. | males. is evi aS pune- 1epeMenTNeS WES SE observa- ays. | punc- | tures. | Per .weev il female tion! tures. di day. day. : 922 eee ert exes | eo. Staal Hibernated weevils in Days. IR DOTETON Yio nS ot ace o> 55 54 | 4,938 | 17,406 | 5,702 +3.5 +2.3 +45.3 Weevils of first genera- tion in laboratory....-- 31 27} 3,258 | 16,487 | 3,565 +5.0 —2.4 —56.2 Hibernated females in HELOICALOSS Sasso see aoe. tote eee + 93 284 489 +3.0 —5.3 —23.3 First-generation females InWeldtedpees.. esc cscs|-sesce a 5 uf 263 435 —3.8 +6.2 14.0 Males in laboratory - -. - -- Goat feces 23492) | vO sGL7 ss ER 28" 225. AFI +38. 3 Males in Held: 4.2.45" Dialteee see 145 Ue Gale eae 115) ee Se EES +29.0 Wr) Ss PE ae 156 | 90 |, 10,996: | 40) 2344/10/08) 5 2c: - aa 5 eee sems- sacle. . snot AW OLELO Sic. cite ane IEP tates oc ce oc cece en oes | 5 os ee | Veer 3.6 2.4 44.7 1 Modified from Bulletin 51, Bureau of Entomology, p. 52. Bul. 114, Bureau of Entomology, U. ept. of Agriculture EFFECTS OF BOLL-WEEVIL ATTACK ON LEAF AND SQUARES. a, Cotton leaf much fed upon by adults; b, square with two egg punctures; ¢, flared square with many feeding punctures; d, square prevented from blooming by puncture; ¢, bloom injured by feeding punctures; f/, poor blooms caused by feeding punctures. (Original.) eh a #: et a : ea y a 7 > Wi ‘ i a ? ee 7 ‘ Bie 5S ea SEASONAL HISTORY. 41 ABILITY TO LOCATE COTTON. When hibernated weevils emerge from their winter quarters in search of food they are frequently long distances from the nearest cotton field. It has been a question of considerable interest whether the weevils are able to locate cotton or whether they find it by chance. Dr. A. W. Morrill conducted a series of experiments in the laboratory to test the attraction of cotton squares for the weevil, but the results were not conclusive. In the eight years of study of the boll weevil, there have been very few records of weevils on any other plants than cotton, notwithstanding the fact that special collections were made in the woods and fields near the cotton fields in search of boll weevils. In the season of 1905 extensive collections were made by means of sweeping nets by several men for weeks during the dispersion season, and yet not a single weevil was found outside of the cotton fields. All of this would indicate that there is some attraction of the weevils to cotton. The concentration of weevils upon the earliest plants in the spring and upon the greenest and most luxuriant portions of the fields in the fall are also evidences of the ability of the weevils to find desirable places for feeding. FEEDING HABITS OF HIBERNATED WEEVILS. Whether there be few or many hibernated weevils makes no differ- ence in their feeding habits. The stage of the cotton at the date of emergence determines largely the nature of the food habits at that time. The first weevils to emerge obtain their food from the tender, rapidly growing, terminal portions of the young plants. ‘They place themselves upon the node where the two cotyledons branch. In fact, this seems to be the point usually attacked in cases of very young cotton plants. In almost all cases the puncture of the weevil at this point results in the death of the plant. Sometimes the attack is made a little above the node on a petiole of the cotyledon, in which case the one cotyledon falls and the other remains, and the plant usually recovers. However, it frequently happens that the same weevil attacks both of the cotyledons. This form of attack is fatal to the seedlings unless they have become very vigorous—sometimes until they have developed two true leaves. Later the central bud, young leaves, or tender stems are attacked, and upon these the weevils easily subsist until the squares are developed. (See PI. V,a.) Incases where the emergence from hibernation is very large the weevils may come out in such numbers upon the newly sprouted cotton as to stunt or even kill the growing plants by their dapradntions upon the terminal portion. Weevils which have fed upon tender tips of plants seem perfectly satisfied with their food supply, and it appears that their first meal upon squares is largely the result of accident. After having begun to feed upon squares, however, it appears that their taste becomes so fixed that they normally seck for squares. In the spring of 1895 Mr. E. A. Schwarz found the first emerged hibernated weevils working upon plants which had sprung from 2-year-old roots. In the spring of 1903 in one field of comparatively early cotton, 2 or 3 acres in extent, the senior author found, between April 24 and May 11, 23 weevils working on the buds and tender leaves of stubble plants before a single weevil was found on the 42 THE MEXICAN COTTON-BOLL WEEVIL. young planted cotton having from four to eight leaves. At Victoria, early in June, 1902, Mr. A. N. Caudell found, in examining 100 stubble plants growing in a planted field, that fully one-half of the squares upon these plants were then infested. The planted cotton was just beginning to form squares and was slightly injured at that time. It appears, therefore, that stubble plants, where such exist, receive a large part of the first attack of the hibernated weevils, not because of any special attraction, but for the reason that they are present long before the planted cotton has come up. The occurrence of volunteer and stubble cotton in the fields in the early spring is of considerable importance in the boll-weevil problem. Throughout the coast regions, especially of southern Texas, stubble cotton is very common in the fields, and there is hardly a region of the South where volunteer cotton can not be found before the normal planting is up. (See Pl. VIII, a.) It is by no means certain that all or even a large proportion of the hibernated weevils may be found upon the early plants, and this renders their use as traps entirely impracticable. A number of observations have shown that weevils frequently occur upon the pened cotton, even when numbers of vigorous stubble plants may e found within a comparatively short distance. In fact, at Victoria, Tex., in 1904, many weevils were found feeding upon the planted cotton for more than six weeks after the stubble plants were producing fruit. DESTRUCTIVE POWER BY FEEDING.! A glance at the figures in Table VIII is sufficient to show the reat destructive power of the Mexican cotton-boll weevil. It may e seen that both in the field and in the laboratory the weevils of the first generation are more active in making punctures than are the hibernated weevils. These generations overlap too far to justify us in attributing this difference to the influence of a higher temper- ature alone, though this factor will account for a large part of it. A comparison of the figures for males alone with those for females alone or with those for males and females together shows that it is very conservative to state that males make less than half as many punctures as do females. By the habit of distributing their punc- tures among a greater number of squares the destructiveness of the females becomes at least five times as great as that of the males. This great capacity for destruction has been one of the most evident points in the history of the spread of the weevil and has deeply impressed the entomologists who first studied the insect in Texas. In 1895 Mr. E. A. Schwarz, in writing of the work of the weevil at Beeville, said: Each individual specimen possesses an enormous destructive power and is able to destroy hundreds of squares, most of them by simply sticking its beak into them for feeding purposes. ATTRACTIVENESS OF VARIOUS SUBSTANCES. Experiments have proved that the report which has sometimes been circulated to the effect that cottonseed meal attracts the weevil is due to mistaking other insects for it. Many tests, both in the laboratory 1 Extracted from Bulletin 51, Bureau of Entomology, p. 61. SEASONAL HISTORY. 43 and in the field, have shown that sugar and molasses, either in solution or otherwise, have no attraction whatever for the weevil. Honey exerts a very weak attraction, but not enough to be of any practical use in control. In fact, it has not been found that any substance exerts a special attraction for the weevil. The experiments have dealt with many chemicals as well as plant decoctions. SENSE OF COLOR. A series of interesting observations on the color sense of the boll weevil was made by Mr. C. R. Jones at Calvert and Victoria, Tex., and Alexandria, La., in 1907. Tubes of different colors were placed in a box, all with an equal amount of sunlight, and the weevils were given food. The observations were made at intervals during the day, and each time the weevils were all shaken back into the box. Table IX shows the total number of weevils found at each color for the series of observations and also the weighted average attractiveness. Fourteen shades were used, but these may be grouped under eight colors. The three most attractive shades were light-blue, dark-green, and light- pink. While it is rather difficult to explain the results, it nevertheless appears that there is some preference for certain colors on the part of the weevil. TaBLE IX.—Relative attractiveness of colors to the boll weevil. Number of | Number Average Color. observa- | of weevils | attractive- tions. attracted. ness. Per cent. FEA Cn os aie le ATES ee lk MR Fae mee arpa 8 64 461 the? (Qign cial. py tyes SE ee eer Eee fi ee ee 43 261 6.0 pital len sc: 2 a ee re ee Se eee a 32 123 3.8 Sa ay eae eR Si a a a es ee 107 411 3.8 WEG ERe hae so Si eee a ee seca ode thls Sad oe 11 24 il LEFT TO) CGE ae ee re ete ee EOI A ne a 32 29 -8 OVEN pes esse es es. Ae Pe Seas Sete 10 5 Sh 15 El oe one a ae een mele a, Sep a Ae SR a nea eee 21 6 Ar? MOVEMENTS ON FOOD PLANT. Various observations have been made to determine the amount of movement of weevils at night. In July, 1904, at a mean temperature of 76.3° F., Mr. A. C. Morgan found, in an aggregate of 134 weevil nights, that eight weevils had moved but 25 times. Each weevil had moved only once every six nights. On cloudy days weevils are much more sluggish than on sunny days. Relative humidity influ- ences the activity, but no definite observations on this point have been made. The effect of temperature on locomotive activity may well be illus- trated by a series of laboratory experiments conducted by Dr. A. W. Morrill. A thermometer was passed through a cork and inclosed in a test tube, which in turn was placed within a hydrometer cylinder of sufficient depth to inclose it. Weevils were inclosed in the test tube with the thermometer, and the temperature of the cylinder was varied either by heating gently or by the use of ice water. Starting with the thermometer at 64° F., the 10 weevils inclosed were found to move slowly, half of them being quiet. As the temperature was gradually 44 THE MEXICAN COTTON-BOLL WEEVIL. raised the activity of the weevils increased up to 105° F. When the temperature reached 95° F. or over the weevils were running up and down the tube. By filling the cylinder with cold water the temperature was lowered to 86° F., at which point the weevils began to cluster at the top on the cork and were crawling slowly. By the addition of ice in the cylinder the temperature was lowered to 59° F., at which point five weevils were struggling on the bottom of the test tube or clinging to one another, four were clustered on the stopper, while one was slowly crawling downward. At 50° F. six weevils at the bottom showed slight signs of life, and one was crawling slowly. At 45.5° F. slight signs of life were still shown, while at 40° F. occasional movements only were noted. When the tempera- ture was raised weevils began crawling as 50° F. was passed, and at 64° all had left the bottom and were crawling upward. Some recov- ered more quickly than did others. The temperature was again lowered, this time by the use of salt with ice. All movement ceased at 37° F. The cooling, however, was continued to 33° F., after which it was slowly raised to 42° F., at which point movements began. EFFECTS UPON SQUARES AND BOLLS OF FEEDING BY THE BOLL WEEVIL. From numerous large, open feeding punctures a square becomes so severely injured that it flares very quickly, often within 24 hours. (See Pl. V, c.) Males usually make the largest punctures, which they always leave open while they remain for a day or more working upon the same square. It has been often found that squares thus injured by a male will flare before the weevil leaves it. The time of flaring depends upon the degree of injury and the size of the square. Thus small squares which receive only a single large feeding puncture in the evening are found widely flared in the morning. On the other hand, large squares which are within a few days of the time of their blooming may receive a number of punctures without showing any noticeable flaring. Frequently a square which has flared widely will be found later to have closed again and to have formed a distorted bloom, and occasionally such squares develop into normal bolls. (See Pl. V, e, f.) In squares of medium size a single feeding punc- ture does not usually destroy the square. The destruction of a square by feeding results either from drying or decay which follows the weevil injury. TasLe X.—Destruction of squares by the feeding of the boll weevil. Number of 1 Average : Total Total Average : squares number of Perio. famaber Of) rie | Sa eee cubisecd feeding eee, ponetiates falling 12 ‘| punctures. ~~" | Der square. ec June Ul yest eres. bess. oltec we. so. dances 751 170 335 1.9 528 ATIPUSt-SPP LEMIRE cat ose sete goon eae 426 183 383 2.0 4.4 October-November.......-.-.----- a Aaa 176 74 216 2.9 15.2 MOta Sas soe eae en mee often seats oro 1,353 427 O84 | Pio A203 3.045 clo 5 eee Weighted /averagesss.! see == see 2k we > 24: aos eon wadaloegee eek eee an cewicle oe 2.0 7.0 Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VI. INJURY BY BOLL WEEVIL TO SQUARES. a, Bloom checked by attacks of larva; b, square opened, showing grown larya; ¢, square opened, showing pupa; d, dwarfed boll opened, showing one larva and two pup; e, weevil escaping from square; f, emergence hole of adult in square. (Original.) Bul. 114, Bureau of Entomology, U. S, Dept. of Agriculture. PLATE VII INJURY BY BOLL WEEVIL TO BOLLS. a, Three larvee in boll; b. emergence hole in dry unopened boll; ec, two larvee in boll: d, weevils puncturing boll, e, opened boll, with two locks injured by weevil; j, large bolls severely punctured. (Original.) SEASONAL HISTORY. 45 Table X shows that the number of feeding punctures per square is determined by seasonal influences, as is also the average number of days before falling. A comparison of the average time from the date of the attack to the falling of the square shows that squares which are only fed on, fall, as a rule, somewhat more quickly than do squares which only contain larve and have never been fed upon. Flaring takes place more rapidly as the result of feeding injury by the adult than from oviposition and injury from the developing stage. While only one egg is generally laid in a square, it appears from Table X that two feeding punctures are usually made in a square. Bolls are quite Jargely fed upon after infestation has reached its height. Small and tender bolls are often thoroughly riddled by the numerous punctures and fall within a short time. (See Pl. VIL.) Larger bolls may receive many more punctures but do not fall. In bolls an abnormal woody growth sometimes takes the place of the punctured fiber, and a softening and decay of the seeds often accom- panies this change. One or more locks may be destroyed, while the remainder of the boll develops in perfect condition. SUSCEPTIBILITY OF VARIOUS COTTONS.! During 1903 and 1904 experiments were conducted at Victoria, Tex., to ascertain the relative susceptibility of several varieties of American Upland, Sea Island, Egyptian, and Cuban cottons. The observations at the laboratory were made by carefully examining the plants, looking into each square, and removing every weevil and infested square found. If there were any distasteful or resistant cotton among these it would surely be found in this way, and if any variety were especially attractive to the weevils it would be equally apparent. Since infested squares were removed, the accident of association or proximity would not determine the location of the weevils found, but all might be considered as having come to the cotton with equal opportunities to make their choice of food, and accordingly their location has been considered as indicating such choice. The period of observation extended from June to November, except with the Cuban cotton, which was planted late and began to square during the latter part of August. For the purpose of this comparison both the several varieties and the various plats of the American cotton will be considered together, as no evidence of preference was found among them. In making a comparison of the results three elements must be con- sidered for each variety of cotton: First, the number of plants of each variety; second, the number of days during which each kind was under observation; third, the total number of weevils found on each class of cotton. The elements of numbers of plants and time under observation may be expressed by the product of those two factors forming a term which we may call ‘“‘plant days.’”’ The total number of weevils found upon any class of cotton divided by the number of plant days will give the average number of weevils attracted by each plant for each day, and these numbers furnish a means of direct com- parison and show at a glance the average relative attractiveness of 1 The following discussion is extracted, but modified, from Bul, 51, Bureau of Entomology, pp. 61-64, 46 THE MEXICAN COTTON-BOLL WEEVIL. each class of cotton. The results of this series of experiments are tabulated below: : TaBLE XI.—Relative attractiveness of various cottons to the boll weevil. Total. Average. a ee Ree ; Relative ass of cotton. er oO r 4 Pere nfested | attrac- plants. | Plant w reg f In d ww ens ils squares | tiveness. aGare vils ested | per plant per wee- **’- | found. |squares.| per day. vil 1903. AINONICSTIG. aes cence ster so 5 cee essere 62 | 4,920 287 3,507 | 0.058+ 12.2+ 1.0 Cuban ese 5 iss So asan eee aes 5 120 11 136 .092— 12.4— 1.6+ Seatisland:: --S2ostess-ss2 sh. seen ee 8 552 64 | 1,089 . 116— 17.0+ 2.0 IB Sy Dia eee ern ae eee eee 8 808 207 | 2,013 - 256+ 9.7+ 4.44 Total of 3 non-American cottons. - 21 1,480 282 | 3,238 .191— 11.5— 3.3— : 1904. American 60 | 3,780 O40) seeker O91, |g sea see 1.0 Sea island ms 5 315 HLT ee ee SOUL See ata te 4.0 Egyptian 4 252 10) RE ea 2405— | 2 - 9 47.4 10 52.6 itt es ie Bee Ae See ee ee ee Wallulahyha 2 Ae... -c2kshs 475 54.7 393 45.3 REO cre ca ose een oe a sce wae daetieebeh Societe eee ty A ee a SHdil asaya Wielzi Led averages te a iaimnicicin nln eo sec ee oR aloe ee + deo 7 fal as St 48.3 TaBLeE XVIII.—Sex of autumn boll weevils ready to enter hibernation. } Male. Female. Year. Number.) Per cent. | Number. } Per cent. Oe ane a 3 Eee oe Se ee ee eee eae a ed Rc Some 557 63.7 317 36.3 Bee artes. See. ae aoa A ered. gees: bet 2ckk cps 31 62.0 19 38.0 RNR ey ae Re cet A Er ons hopeyhe wale stalclaiestin endian toraeman cattiogac 63 57.7 127 42.3 US ce a ae Ae SS A ae a oe ae Se Oe SR ee a 173 68.9 78 31.1 HN ee Ser nara ats late cyan eriaia AOR ie ee ee atc a ammeian 173 Ly 127 42.3 TE Pibcinte, Sette See SGC SEE aS Ot cic ele rt a Se he 19 57.6 14 42.4 hae te A Sad AOR AACE SIRE Rise tthe Ia or ae eee 29 52.7 26 47.3 PUOUAI Om Atos oats tte be cetacean oe teeta e ete i OAGn | ace LOS (secsee aoe Nyielgnted tverspet = eee een eee ee koe Pee GOSOW ot os a2 4 40.0 Total and weighted averagefor all seasons. ...................-- 7,017 Svnee| 5, 418 42.8 52 THE MEXICAN COTTON-BOLL WEEVIL. From these determinations it appears that males are somewhat more numerous than females, the percentage based on our observa- tions being 57.2 males to 42.8 females. It is noticeable also that the males are in preponderance throughout the year. Since the males are less active in their movements than are the females, the advantage of the existence of the majority of males becomes apparent. The larger number of males and the more active habits of the females serve to increase the chances for the meeting of the sexes. It has been shown by rearing experiments conducted at low tem- peratures that the retardation of the development, such as is due to cold weather, favors the development of the males. FERTILIZATION. AGE AT BEGINNING OF COPULATION. After the adult weevils have left the squares a certain period of feeding is necessary before they arrive at full sexual maturity. This period varies in length according to the temperature prevailing and appears to bear about the same ratio to the developmental period as does the pupal stage. With weevils fed upon leaves alone the period preceding copulation is about twice the normal length, in the cases observed, of those having squares tofeed upon. Mr.Cushman, in observations at Tallulah, La.,in 1910, found that the period from emer- gence of the female to copulation varied from two to seven days, with an average of 4.4 days. During hot weather it is probable that this eriod averages three or four days, but as the weather becomes coider it increases gradually until the weevils may become adult, feed for a time, and go into hibernation without having mated. It should not be understood, however, that weevils do not usually copulate before hibernation. Mr. C. E. Hood made numerous observations of the exercise of this function in the fall of 1909 at Mansura, La. SEXUAL ATTRACTION AND DURATION OF COPULATION. The distance through which the attraction of the female insect will influence the male varies extremely. In observations made by Dr. Hinds at Victoria, Tex., it was found that the male was unable to recognize the female at a much greater distance than aninch. Obser- vations carried on in the field, as well as in the laboratory, tend to show that the sexes are attracted only when they meet, as they are likely to do either on the stems or upon the squares of the plant. In a considerable number of cases that were timed the average duration of the sexual act was very nearly 30 minutes. The earliest spring records of copulation available are for April 15. DURATION OF FERTILITY. _ Anumber of femaies which were known to have mated were isolated to determine the duration of fertility. Although the limit was not determined exactly, the results proved very striking. Several of the females laid over 225 eggs each, and nearly all of them proved fertile. Selecting three cases in which the facts are positively known, it appears that fertility lasted for an average of something over 66 days SEASONAL HISTORY. 53 and that during this period these females deposited an average of nearly 200 eggs. The maximum limits may possibly be considerably higher. In fact, a single union seems to insure the fertility of as many eggs as the average female will lay, and its potency certainly lasts for a period fully equal to the average duration of life. It 1s probable, however, that there are many cases of repeated fertilization of females. PARTHENOGENESIS. Several series of experiments were conducted at Dallas, Tex., in August, 1906, to determine whether the boll weevil can reproduce arthenogenetically. Mr. R. A. Cushman kept 24 unfertilized Eales in confinement for 259 weevil days, and found that they deposited only 43 eggs, all being placed outside of the squares. No fertile eggs were laid. The rate of oviposition was one egg per female every six days. With a similar purpose Dr. Hinds isolated 40 indi- viduals as soon as they Paliine Each beetle was supplied daily with fresh, clean squares and careful watch was kept for eggs. The first point noticed was that no eggs were found till the weevils were about twice as old as females usually are when they deposit their first eggs. After they began to oviposit it was found that a very small Byepariion of the eggs were deposited in the usual manner within sealed cavities in the squares, but nearly all of them had been left on the surface, usually near the opening of an empty egg puncture. This same habit was shown by a number of females, and so can not be ascribed to the possible physical weakness of the individuals tested. The number of eggs deposited was unusually small, and the few placed in sealed cavities failed to hatch. After somewhat more than a month had been passed in isolation a few pairs were mated to see if any change in the manner of oviposition would result. The very next eggs deposited by these fertilized females were placed in the squares and the cavities sealed up in the usual manner, showing that the infertile condition had been the cause of the abnormal manner of oviposition. OVIPOSITION. AGE AT BEGINNING OF OVIPOSITION. As has been shown, normal oviposition never takes place until after fertilization has been accomplished, but it usually begins soon afterwards. Observations upon the age at which the first eggs are deposited can be made more easily and more positively than those upon the age at which fertilization takes place. In a general way, therefore, the observations here given may be cited as also throwing light upon the time of beginning copulation. Table XIX is intro- duced to summarize the various observations which have been made upon the period preceding oviposition. It will be noticed that the range is from 4 to 14 days during the breeding season. Of course, the weevils which hibernate before ovipositing are not to be consid- ered as of this category. 1 Bulletin 51, Bureau of Entomology, pp. 91, 92. 54 THE MEXICAN COTTON-BOLL WEEVIL. TaBLE XIX.—Age of the boll weevil at beginning of oviposition. Number | Number Date adult. Place. Date first egg. of fe- weevil | Average males. days. age. June 8-14, 1903.....-..--.- Wietoria, Tex :- 22 2.) JUNE G19 rer sae 27 150. 0 5.55 July 8-1 JOO 22-5. s Fe Pallulah, La... 2.s-..<: July di4—19. cet 2252 11 66. 0 6. 00 MUily 293 leet O10 see ees se |e eee Cs Coy eh te? ce] ALU O= 1s aac ae Sila. 7 44. 0 6.29 Aue. 14-225 VOLO: s:2n stone s}ose (0 (0 ee ae ee ree 5 ANI D8 tee ieee et 16 106. 0 6. 66 Sept. 4-9, 1902.........-- WACTONIO eh exer eee SepilGaWie neces eccr- 8 72.5 9. 06 Sept. 10-20, 1910......... Tallulah, iba eee Sept. 18-Oct. 8......-- 9 116.0 12. 89 Oct 2) 1902 ees ee aes Mictorian lex 3.2m. OCT Goa oak ces 4 56. 0 14.00 INOW. G=115 802 Jesse Soleo GOs see tetpenene NOW LG=19 5 poe cue eae 10 73.0 7.30 Jane SsNovedile seca - 2 reeset agsses- tae oe June 16-Nov. 19......- 92 683.5 7.40 EXAMINATION OF SQUARES BEFORE OVIPOSITION. In the course of a great many observatious upon oviposition it was found that females almost invariably examine a square carefully before they begin a puncture for egg deposition. This examination is conducted entirely by means of senses located in the antenne and not at all by sight. In fact, the sense of sight appears to be of com- paratively small use to this weevil. In regard to the actual time spent in the work of examination before beginning a puncture, over sixty observations are recorded. These show that the average time is over two minutes. This examination of squares is made by females only when they intend to oviposit. Males have never been observed acting in this way, nor do females generally do so when their only object is to feed. SELECTION OF UNINFESTED SQUARES FOR OVIPOSITION. The sense by which the weevil examines the squares frequently enables it to detect an infested condition when no external sign 1s visible. Females sometimes refrain from placing eggs in squares, even when they are apparently searching for a place to oviposit and anxious to do so. The acuteness and accuracy of the preliminary examination is well shown by the fact that when aed with more squares than they have eggs to deposit they do not often place more than one egg in a square. Where a totally infested condition is reached, as is frequently the case in the field, no choice between in- fested and uninfested squares could be exercised, and then, unless the female happens to be in a condition to refrain from oviposition, she is forced to ana more than one egg in a square. Table XX illus- trates the distribution of egg and feeding puncture as collated from many records. TABLE X.X.—Selection of squares and relation of feeding to oviposition of the boll weevil. ene F Squares with Squares with Bapan erat both egg and | Squares fed on 1 egg each. feeding punc- oaly. P Total egg each. Place and time of aginanee tures. observation. aeercd : A eR ES ER ee eee ete eee ee er cen er cen er cent er cen Noe of total yas of total ps of total vile hae of total * | squares. ~* | Squares. * | squares. * | squares. In laboratory, 1902... .. 630 477 75.7 19 3.0 24 3.8 110 17.4 In field, 1902........... 151 56 37.0 33 21.8 46 30. 4 16 10.5 Infield: 10035. 3-¢.en:. 560 317 55.9 83 14.8 50 8.9 110 19.6 tela s 1G0bre cee see 1,036 531 51.2 415 40. 0 90 8.6 0 0.0 InifieldS 907-2 - <2 5.225 2,679 413 15. 4 0 0.0 | 1,832 68. 4 434 16.2 MOtala.see sae 5,056 | 1,794 |.......... BOO! | Seeaeeeere Pay | eae eh Ue 670\'|Peseeeeess Average percentage....|.....-...-]--.---- SOs Ad eater OFS | pees A058 ilar 13.2 SEASONAL HISTORY. 55 The observations show that 86.7 per cent of all squares attacked received eggs. It may also be seen that 40.9 per cent of all squares oviposited in received only one egg each. The squares which were only fed upon formed but 13.2 per cent of the total number attacked, and, as has been shown above, those receiving both egg and feeding punctures constituted 40.3 per cent. As the weevil injury overtakes the production of squares the proportion of squares containing both egg and feeding punctures increases rapidly. here several eggs are placed in a square it is rarely the case that more than one larva develops.1_ If two or more hatch in a square one is likely to destroy the others when their feeding brings them together. Should eggs be laced in squares which already contain a partly grown larva, those eothee would probably find the quality of the food so poor that they would soon die without having made much growth. Since one egg will insure the destruction of the square and a number of eggs would do no more, it is plain that the posstble number of offspring of a single female is increased directly in proportion to the number of her eggs that she places one in a square. Favorable food conditions for the larva are likewise best maintained by the avoidance of feeding upon squares in which eggs have been deposited and also by refraining from ovipositing in squares which have been much fed upon. Selection of uninfested squares is, therefore, of the greatest importance in the reproduction of the weevil, since this insures the most favorable con- ditions for the maturity of the largest possible number of offspring. Feeding and oviposition are common in the same boll, but unless the infestation is very heavy it appears that only rarely is more than one egg placed in one lock, though several are often deposited in the same boll. The number deposited depends considerably upon the size of the boll. The smallest, which have just set, receive but one, as do the squares, and these fall and produce the adult weevil at about the same period as in the case of squares. Bolls which are larger when they become infested have often been found to be thickly punc- tured and to contain 6 or 8, and in one case 15, larve. (See PI. VI, d; Pl. VII, c.) DEPENDENCE OF REPRODUCTION UPON FOOD OBTAINED FROM SQUARES.” During the fall of 1902 a series of experiments, lasting for 12 weeks, was made to determine the length of life of weevils fed solely upon leaves. In one lot, consisting of nine males and eight females, the average length of life of the radios was 25 days, while that of the males was 36 days. Though this period far exceeded the normal time usually passed between the emergence of adults and the begin- ning of egg deposition, no eggs were found. Dissection of the females which lived longest showed that their ovaries were still in latent condition, though the weevils were then 81 days old. Few instances of copulation were observed among weevils fed upon leaves alone, and among nearly 70 weevils which were thus tested no eggs were ever deposited. After a period of three weeks upon leaves, 11 weevils were transferred to squares. Females in this lot began to lay in four days, and four of them deposited 323 eggs in an average time 1 In one case four normal pup were found in asinglesquare. This observation was made at Shreveport, La., by Mr. H. Pinkus. ® From Bull. 51, Bureau of Entomology, pp. 112, 113. 56 THE MEXICAN COTTON-BOLL WEEVIL. of 20 days. The conclusion seems plain that so long as leaves alone are fed upon, eggs do not develop, while a diet of squares leads to the development of eggs in about four days. It is worthy of note that the interval between the first feeding upon squares and the depo- sition of the first eggs is almost the same with these weevils taken in middle life as with weevils which have just emerged. An examination of hibernated females taken in the spring of 1903, which had fed for six weeks upon cotton leaves, showed that their ovaries were still latent. Copulation was rarely observed among hibernated weevils until after squares had been given them. In a few days after feeding upon squares, mating and oviposition began. The average period was from three to five days, and, having once begun, oviposition continued regularly. It has been found that food passes the alimentary canal in less than 24 hours. Assimilation therefore must be very rapid. It is evident that while leaves will sustain life certain nutritive elements found only in squares are essential in the production of eggs. These experiments were repeated in 1904 with similar results. Upon dissecting weevils just taken from hibernation, it was found that females contained no developed eggs, but that their ovaries were in an inactive condition, similar to those of females which had fed for months entirely upon leaves during the previous fall. Upon examin- ing females taken from stubble cotton later in the spring, but before squares nad appeared, it was found that they also were in similar condition. ‘This was also true of females kept in the laboratory from the time of emergence from hibernation until squares became abun- dant, with only leaves for food. It seems peculiar that upon a purely leaf diet eggs are not developed, but all observations made indicate that this is the case. It can not be said definitely whether the females examined had been fertilized, but it is certain that they were not ready to deposit eggs. PLACE OF EGG DEPOSITION. The location of egg punctures, while variable, still shows some selection on the part of the weevil. This may be due partly to the form of the squares and partly also to the size of the weevil, but what- ever the explanation, the fact remains that in a majority of cases the egg puncture is made on a line about halfway between the base and the tip of the square. When so placed the egg rests either just inside the base of a petal or among the lowest anthers in the square, accord- ing to the varying thickness of the floral coverings at that point. Punctures are very rarely made below this line, though they are some- times made nearer the tip. Almost invariably the egg puncture is started through the calyx in preference to the more tender portion of the square, where the corolla only would need to be punctured. With bolls no selection of any particular location has been found, but eggs seem to be placed in almost any portion. THE ACT OF OVIPOSITION. While engaged in making egg punctures, the favorite position of the weevil is with its body arallel to the long axis of the square and its head toward the base. e tip of the weevil’s body is thus brought near the apex of a medium-sized square. It may be that the position SEASONAL HISTORY. 57 described is especially favorable for obtaining a firm and even hold and this may have something to do with the regularity with which it is assumed. Having selected her location, the female takes a firm hold_ upon the sides of the square and completes her puncture while in this position. The female begins drilling a hole by removing with the mandibles a little flake of the outer epidermis. Then, with her feet strongly braced by gnawing and pushing with an auger-like motion, she thrusts her beak into the tender portion of the square. At the bottom of the puncture she makes a small cavity by gnawing, at the same time moving about the hole with the beak as a pivot. Withdrawing her beak, she turns about with the center of her body as a pivot. This places the tip of her abdomen directly over the puncture, into which she thrusts hor ovipositor. The ovipositor is protruded to the bot- tom of the cavity in which it appears to be firmly held in position by the two terminal papille and the enlarged terminal portion. Slight contractions of the abdomen occur while this insertion is being made. In a few moments much stronger contractions may be seen, and often a firmer hold is taken with the hind legs as the egg is passed from the body, and its movement may be seen as it is forced dios within the ovipositor and down into the puncture. Only a few seconds are required to complete the deposition after the egg enters the opening to the cavity. Having placed the egg, the ovipositor is SeNaraee and just as the tip of it eaves the cavity a quantity af mucilaginous material, usually mixed with some solid excrement, is forced into the opening and smeared around by means of the tip of the abdomen. This seals the egg puncture, and the act of oviposition becomes complete. Sometimes the weevil fails to locate the puncture imme- diately with her ovipositor. In this event she searches excitedly, moving the tip of the abdomen about feeling carefully over the sur- face of the square. In this search, however, she never moves her front feet, apparently using the position of these as a guide to the distance through which she should search. Failing to locate the puncture in this way she again turns around and searches for it with her beak and antenne. When the cavity has been found again the female invariably enlarges it before turning again to insert the ovi- positor. If the search with the antennz does not prove successful, the female generally makes another puncture in the same manner as at first. The usual habit of the female in puncturing through the calyx enables it to seal the wound more thoroughly because of the healing power possessed by the calyx tissue. Punctures made in the corolla must remain open or are closed only by the slight filling of mucilagi- nous excrement by the weevil. Punctures through the calyx will, in most cases, be healed by the natural outgrowth of the tissue so as completely to fill the wounds in a manner analogous to the healing of wounds in the bark of a tree. The custom of the weevil in sealing up its egg punctures with a mixture of mucous substance and excre- ment is of great advantage and assistance to the plant in the healing process. While undoubtedly applied primarily as a protection to the egg, it serves to keep the punctured tissues from drying and decay, and thus promotes the process of repair. As a result of the growth thus stimulated in the calyx, the wound is healed perfectly in a short 58 THE MEXICAN COTTON-BOLL WEEVIL. time, and a corky outgrowth appears above the general surface plane. This prominence has been termed a ‘‘wart.’”’ The healing is com- pleted even before the hatching of the egg takes place, and thus both egg and larva partake of the benefit of its production. Occasionally warts develop from feeding punctures which were small, but the exact conditions under which this takes place have not been determined. Nevertheless, the presence of warts is the most certain external indi- cation of oviposition in squares. In aseries of observations they were found to follow oviposition in 84 per cent of the cases. TIME REQUIRED TO DEPOSIT AN EGG. Careful observations have been made upon the time of egg deposi- tion. As in all other processes of the life history of this insect, the period of egg deposition is influenced by climatic conditions. It was found at Tallulah, La., in the early part of the summer of 1910, that the time required for making the puncture varied from 1 minute and 20 seconds to 8 minutes and 27 seconds, with an average of 3 minutes and 36 seconds. On the other hand, at Victoria, Tex., in October, the average time was 5} minutes, and the range from 1 to 13 minutes. At Tallulah the period for the deposition of the egg and the sealing of the puncture varied from 2 minutes and 45 seconds to 9 minutes and 30 seconds, with an average of 4 minutes and 41 seconds. At Victoria the period ranged from 3 to 16 minutes and averaged 74 minutes. STIMULATING EFFECT OF ABUNDANCE OF SQUARES UPON EGG DEPOSITION.! Four actively laying females were confined together upon a few squares from September 22 to October 14, 1902. During this period they laid a total of 227 eggs, or an average of 2.37 eggs per weevil per day. For the next 13 days these same weevils were isolated and supplied with an abundance of squares. During this shorter period they laid 236 eggs, or 4.54 eggs per female daily. These figures are the more striking, because the stimulation was plainly shown in spite of the general tendency to lay fewer eggs as the weevils grow older and as the average temperature becomes lower. ACTIVITY OF WEEVILS IN DIFFERENT PARTS OF THE DAY. Two series of observations have been carried on to determine the hourly activity of the weevils. The experiments at Victoria were conducted in the early part of September, when the temperature was ranging from a little under 70° F. to 95° F. during the day. It was found that there was almost a perfect coincidence between the temperature curve and the curve of the average activity of the females in ovipositing. This is shown in the accompanying diagram (fig. 5). it also appeared that the activity of the weevils began and ceased at about 75° F. Perhaps this indicates that the act of oviposition requires a zero of effective temperature different from that of develop- ment. This would be entirely analogous to conditions in flowers, where it is found that the various functions of the plant are governed 1 Modified from Bulletin 51, Bureau of Entomology, pp. 87, 88. SEASONAL HISTORY. 59 by independent laws of effective temperature. It appears also that the activity is much less on cloudy days than on clear days. At Tallulah, La., in 1910, observations were made on the periodic division of daily oviposition. The results are shown in Table XXI. TIME Fig. 5.—Diagram showing average activity of flve female boll weevils. (After Hunter and Hinds.) TABLE XXI.—Summary of periodic division of oviposition, based upon nine boll weevils, Tallulah, La., July, 1910.1 Average pee oent Average Period. pont ri 85S ee oviposition pe hour Salat per hour. ff) eS [oh itl a eee ocean 25 5.00 23.15 0. 63 Cis 5 Ti oe UE 125s SE ES 4 as Res oat hae 10 -59 9.26 07 ETA LES eit Soe Sei ae ee ae 21 2.10 19. 44 26 DAA Le pe a fae ee Se AEE Se ee ee 17 2.13 15.74 27 UE E la Sny of i eae ae nen aaeee oases oo eae 35 4.38 32. 41 55 From these records it may be seen that the warmest part of the day is the most active period for the weevils. SEASONAL RATE OF OVIPOSITION. Since the period of reproductive activity of the boll weevil is so long, the rate at which eggs are deposited is a question requiring much time for its determination. The rate of oviposition is at least as strongly influenced by variations in temperature as is the rate of development, and it is very probable that some of the previously unaccountable and abrupt variations in the rate upon succeeding days may be explained by the relative humidity or by the amount of sunshine. The rate is influenced also by the abundance of clean squares which the weevil can find, so that it is greater in the early art of the season as the degree of infestation is approaching its imit than after infestation has reached its maximum. Several series of observations have been made upon the rate of egg deposi- tion. These have been tabulated below in Table XXII. 1 From Cushman, Journ. Econ. Ent., vol. 4, p. 436. 60 THE MEXICAN COTTON-BOLL WEEVIL. TABLE X XII.—Seasonal rate of oviposition of the boll weevil. Aver- Aver- . Aver- Maxi- Num- age age Num- 2 Total age mum Place. Time. ber of dase spent number|num ber sili number females. days. | posi- of eggs. | of eggs per in one tion. daily. | female. Fay: Wictoria ex: so.6.45 2646s. Aug.-Dec., 1902... 31 135 135 255 LS SSa" 25570) oes i De) See See ey a Sept.-Oct., 1902... 40 247 6 1,248 5.05 LeBel ae eee 23 227 2.37 joy gape ee ih Bis WOH hah, - don. ceAteaet 4 { a \ 9 { St Dae aed (Me cha, Me Doves eee eee Oct.-Dec., 1902... 9 352 39 990 2.81 TONG) se es Dole aust dene May-July, 1903....) 251] 2,018 39 | 5,254] 2.60] 103.0 18 ND Yay See, Bees. een epee Nae June-Sept., 1903... 324] 1,395 58 | 3,541 2.53)| Lalo |aoaeeeee DO badass AIS: A Q04S Se Fe 3 21 7 112 5.32 SHBG" Ens onee & Terrelle Pexsts 5. accor Septs; 1904-2 22-2 22 4 12 3 55 4.56 Vey el lee Dallas) Dexeos-sateles: July-Aug., 1905... 2 23 11 81 3. 68 40.5 8 DOE Pee eee Aug.-Sept., 1905. -- 3 108 36 233 2.15 77.6 20 Taliplah Seite 25 ke June-Aug., 1910... 39 310 34} 1,830 5.90 | 203.3 20 Dosa aaa. IS ee Aug.-Oct., 1910... 34 183 45 887 4.85 | 221.7 12 Rotel Posts suse tose ae eee Ee 154 A 840 il As 2 dae J42 949) ck 2 bose eee 20 Averagelee Fe 33. TLE 2 ORS ee els See se Se ee ee Bild |e ae Ba 38 (Ry a Al ee oe = 1 Hibernated weevils. 2 First generation weevils. 3 Observed for entire oviposition period and used in discussion of fecundity. The influence of temperature upon the rate of oviposition may be shown by the following diagram (fig. 6), which expresses in a single line the mean number of eggs laid daily at a There is, of course, more. NUMBER OF £66s Day. CBE TIGR SAG given temperature. or less fluctuation from the mean, and it is due mostly to differences in humidity. The maximum number of eggs deposited by TEMPERATURE, DEGREES Fo Fic. 6.—Diagram to illustrate influence of temperature on average rate of oviposi- tion of boll weevil. (Orig- inal.) any weevil in one day has been recorded by Mr. Cushman as 20 at Tallulah, La. At Vic- toria, Tex., Dr. Morrill recorded two weevils to have laid 108 eggs in three days, or at the rate of 18 eggs per day. Dr. Morrill found that the size of weevils na not affect the rate _ per day, as four very small females laid 761 eggs at the rate of 3.3 eggs per day. It will be noticed that this rate is higher than the average of all the records in Table XXII. The number of eggs produced on the first day of Oviposition varies from one to seven. About 67 per cent of the weevils at Victoria were found to oviposit fewer than three eggs on the first day. IS THE FECUNDITY OF THE WEEVIL DECREASING? In view of the fact that recent observations have shown a decrease in the fecundity of the gipsy moth in Massachusetts,! we have selected from the foregoing table (Table XXII) on the seasonal rate of oviposition the rather meager data bearing on the whether the fecundity of the boll weevil is decreasing. uestion of e find 76 1 Howard and Fiske, Bull. 91, Bur. Ent., U.S. Dept. Agr., pp. 109, 110, 1911. SEASONAL HISTORY. 61 weevils at Victoria, Tex., in 1902 and 1903, laying an average of 119 eggs in an average period of 46 days, and at the rate of 2.6 eggs per day, with a maximum of 18 eggs in one day; while at Tallulah, La., in 1910, 13 weevils laid an average of 209 eggs in an average period of 37. days and at the rate of 5.7 eggs per day, with a maxi- mum of 20 eggs in one day. While these facts appear to indicate that the fecundity of the weevil is not decreasing, they do not, on the other hand, because of the great difference in the places of observations, prove an increase. More detailed data will be obtained on this point in the future. PERIOD OF OVIPOSITION. With the exception of hibernated weevils it appears that ovipo- sition begins with the majority of females in about seven days after they emerge as adults to feed and continues uninterruptedly until shortly before death. In the case of 43 weevils observed at Tallulah, La., in 1910, the average preoviposition period was 7.72 days, the minimum 5, and the maximum 23 days. While females fre- quently deposit their last eggs during the last day of their life, a period of a few days usually intervenes between the cessation of oviposition and death. The known maximum number of eggs laid by a single individual is 304. This was in the case of a weevil which lived for 275 days and deposited eggs at the rate of 7.6 eggs per day for 41 days. The maximum period of oviposition recorded is 135 days. In the case of 52 hibernated weevils at Victoria the period of oviposition averaged about 48 days, the maximum being fully 92 days. In an average rate with 21 females in the first generation the actual period was almost 75 days, the maximum being 113 days. The average period for the females of the first two generations appears to be longer than that for any other. In the third generation the average period for 11 females was 58 days, the maximum being 99 days, and in the fifth generation for 5 females the period averaged 48 days, with the maximum only 62 days. At Tallulah, La., m 1910, the average oviposition period was found to be 34.44 days. The average period for all of the records available is but 31 days. The approach of cold weather cuts short the activity of the weevils which become adult after the middle of August, thereby decreasing the length of their oviposition period. Weevils which pass through the winter usually live longest, but as it requires more or less vitality to pass through the long hibernation period, their activity in the spring is thereby lessened. EFFECTS OF OVIPOSITION UPON SQUARES. As has been explained elsewhere, the attack of the weevil on the square causes it to form an absciss layer, which ultimately causes it to separate entirely from the plant. One of the immediate effects of tthe is the flaring of the square, that is, the spreading of the bracts and their subsequent yellowing and drying. (See Pl. 1.) Flaring may result from many other causes besides boll-weevil injury. When resulting from Geel: injury it does not begin, as a rule, immediately after the injury, but only within from one to three days of the time 62 THE MEXICAN COTTON-BOLL WEEVIL. when the square will be ready to fall. In especially severe cases of feeding injury flaring often results in less than 24 hours. Occasionally the growth of the square overcomes the injury from feeding, and the bracts, after having flared, again close up and the square continues its normal development and forms a perfect boll. When injured by the feeding of a young larva as the direct result of successful oviposi- tion, flarmg was found in 193 cases to take place in an average of 7 days from the deposition of the egg. (See Pls. V, VI.) After an average period of 2.5 days subsequent to flaring the square was found to fall to the ground, although it may sometimes hang by a thread of the bark. The average time from egg deposi- tion to the falling of the square in 539 cases from June to September was found to be about 9.6 days, which is about the middle point of the weevil development. It has been shown in another place (Table XXVIT) that the period before the falling of the square has a direct bearing upon the period of the development of the weevil. PROBABLE ORIGINAL BREEDING HABIT. There is nothing to indicate that the boll weevil has changed its food plant, although it may have done so. It is now confined, as far as we know, to the various species and varieties of the genus Gossy- pium. ‘The boll weevil belongs to a genus of weevils every species of which is confined in its food habits to a single species or genus of food plants. The majority of the species of Anthonomus and perhaps all that belong to the true genus normally breed in buds. It 1s therefore reasonable to assume that the normal habit of the boll weevil is to breed in the cotton buds or “squares,” and that its habit of breeding in the bolls is an adaptation due to the necessity of providing for the great number of weevils which develop in the later part of the season. A study of the length of the development of many species of Antho- nomus leads the authors to believe that the short developmental eriod in squares is perfectly normal and that the longer period in Bells is due merely to environmental conditions, as is explained under the subject of development. THE EGG. DURATION OF EGG STAGE. Concealed as the eggs are beneath several layers of vegetable tissue, it is impossible to examine them to ascertain the exact length of the egg stage without in some degree interfermg with the natural- ness of their surroundings. The beginning of the stage is easily obtained by confining female weevils with uninfested squares. By making a large series of observations about the time that the larve should hatch it is possible to obtain the average length of the egg stage. The extreme range which has been observed in the duration of this stage is from 1 to 17 days, while the average period for the whole number of observations is but 3.7 days. _It is possible that the embryo can undergo an even greater retardation without losing its vitality. The period of embryonic development is lengthened by decreases in the temperature and also by lowered atmospheric humidity. Thus it was found that between 79° F. and 81° F. the SEASONAL HISTORY. 63 egg stage averaged 1.9 days at Alexandria, La., 2.61 days at Tallulah, La., 3.73 days at Victoria, Tex., and 4.1 days at Dallas, these differ- ences corresponding quite regularly to the differences in the humidity of the various places. TEMPERATURE, DEGREES _F SEE TE TAT C6 NOE Ne 2 ‘/ 2; / WU t9 - o HER Table XXIII is presented to show the data Fic. 7.—Diagram illustrating relationship of temperature to the egg period of the boll weevil at Victoria, Tex., in 1902. (Original. ) which have been obtained on this stage, and is ig a by two diagrams (figs. 7 and 8) to illustrate the relationship temperature and the length of the egg period. etween TABLE XXIII.—Duration of the egg stage of the boll weevil. mean Place. Year. Eggs laid. 1902 | Sept. 4-29....... 1902 | Oct. 7-20........ 1902 | INOW ip ccnncoese 1902 | Nov. 24-28...... 1902 | Dec. 2-9........- 1903 | May 27-June 5. . 1907 | Aug. 31-Sept. 5.. 1908 | July 17-20....... E908 Ap 14S 1910 | June 27-July 10. . Eggs hatched. Sept. 7-Oct. 3... Oct. 11-24....... Sept:i2-7-2-..-.- July 20-23. ...-.. Total ae num- | Aver- | Mean anreees of | age |temper- a egg | period.| ature. * | days. Days SLE. 384] 1,434] 3.73 81.0 95 430 4.52 73.0 12 72 Bin Bee Soe 17 214} 12.59 62.0 19 ZA) | Al 9'5 alee ore hy = 25 93 3.75 72.5 229 436 1.9 79.2 35 145 4.1 81.6 11 33 3.0 88.0 44 115 2.61 78.9 S71y | da 236i asy-ezcle ant +. EEE en ote 7 74.6 64 THE MEXICAN COTTON-BOLL WEEVIL. HATCHING. While still within the egg the larva can be seen to work its man- dibles vigorously, and although a larva has never been seen in the act of making the rupture which allows it to escape from the egg, it is believed that the rupture is first started by the mandibles. The larvee do not seem to eat the membranes from which they have escaped, but owing to the extreme delicacy DAYS of the skin it is almost impossible to find any trace of it after the larva has left it & and begun feeding on the square, the mem- x branes having been found in only a few ‘ cases. G50, yp HATCHING OF EGGS LAID OUTSIDE OF COTTON FRUIT. It occasionally happens that a female is unable to force an egg into the puncture prepared to receive it, and the egg is laid on the outside of the square or boll. Eggs so placed usually shrivel and dry up within a nie time. To test the possibility of a Fic.8—Diagramillustratingrelation- larva, making its way into the square from Tiod of the boll weevil and showmg the outside a number were protected from Tarjations due to humidity. (Ong drying. Of the 19 eggs tested, 6 hatched in from two to three days. In no ease, however, was the young larva able to make its way into the square, and it soon perished. The hatching of eggs laid outside, therefore, appears to be of no importance, since the larvee must perish without doing any damage. On August 23, 1906, Mr. R. A. Cushman observed the hatching of ye larve under water from eggs which had been submerged over 24 hours. TEMPER ATO: EATING OF EGGS DEPOSITED OUTSIDE. The number of eggs left outside increases as the female becomes weakened and is especially noticeable shortly before her death. Repeated observations have shown that unfertilized females generally deposit their eggs on the outside, and only occasionally is an infertile egg deposited normally, though the attempt is regularly made to do so. The number of such eggs which may be found is greatly decreased by a peculiar habit observed many times, which will be described. Occasionally it appeared that the puncture which the female had made for the reception of an egg was too narrow to receive it, and after a prolonged attempt to force it down the female. would with- draw her ovipositor, leaving the egg at the surface. She would then turn immediately and devour the egg. In some cases more than one has been devoured after repeated failures to place them properly in the squares. SEASONAL HISTORY. 65 PERCENTAGE OF EGGS THAT HATCH. Definite records have not been kept regarding the percentage of eggs that hatch, but in the many hundreds of eggs followed during these observations very few have failed to hatch. Though some are much slower in embryonic development than areotherslaid at the same time and by the same female, it is probable that less than 1 per cent of the eggs are infertile or fail to hatch. It must be considered, however, that proliferation crushes many eggs. This proliferation is most aggressive against the eggs in the bolls in the late fall. THE LARVA. FOOD HABITS.! It is plainly the instinct of the mother weevil to deposit her egg so that the larva upon hatching will find itself surrounded by an abun- dance of favorable food. In the arp majority of cases this food consists principally of immature pollen. This is the first food of the larva which develops in a square, and it must be both soft and nutritious. Often a larva will eat its way entirely around the inside of a square in its pursuit of this food. In most eases the larva is about half grown before it feeds to any extent upon the other por- tions of the square. It may then take the pistil and the central portion of the ovary, scooping out a smoothly rounded cavity for the accommodation of its rapidly increasing bulk. So rapidly does the larva feed and grow that in rather less than a week it has devoured two or three times the bulk of its own body when fully grown. It sometimes happens that the square is large when the egg is depos- ited therein, and the bloom begins to open before the injury done by the larva becomes sufficient to arrest its development. In many cases of this kind the larva works its way up into the corolla and falls with it when it is shed, leaving the young boll quite untouched. Occasionally the flower opens and fertilization is accomplished before any injury is done the pistil, and in rare cases a perfect boll results from an infested square. Sometimes the larva when small works its way down into the ovary before the bloom falls, and in such cases the small boll falls as would a square. (See Pl. VI, a, 6, d.) In large bolls the larve feed principally upon the seed and to some extent upon the immature aber. A larva will usually destroy only one lock in a boll, though two are sometimes injured. When the infestation is severe a number of weevils, occasionally as many as SIX or even more, may be developed in a single boll, which is completely destroyed by the feeding of the larvee. (See Pl. VII, a, c.) GROWTH. The rate of growth, of course, is dependent upon many external conditions. It has been found that in squares during the hot weather, the length of the body increases quite regularly by about 1 mm. a day. Full grown larvee vary in length from 5 to 10 mm. across the tips of the curve. Larve of normal size in squares average from 6 to 7 mm. The largest larvee are developed in bolls which grow to maturity. 1 From Bulletin 51, Bureau of Entomology, p. 49, 28873°—S. Doc. 305, 62-2——5 66 THE MEXICAN COTTON-BOLL WEEVIL. - MOLTS. To accommodate the rapid growth of the larvee two or three molts occur. The first occurs at about the second day, and the second at about the fourth day. Whether a third molt occurs before pupation can not be positively stated, but having occasionally found larve which had certainly just molted, but which were not larger than the usual size of the second molt, we are led to suspect that three larval molts may sometimes occur, though possibly not always. In bolls where the length of the larval stage is often three or four times as great as that usually passed in squares, it seems almost certain that more than two larval molts occur regularly. According to Dr. Hinds’s obser- vations the skin splits along the back, starting at the neck, and is then pushed downward and back- ward along the venter of the larva. The cast head shield remains at- tached to the rest of the skin. DURATION OF LARVAL STAGE. TEMPERATUAE, DEGREES F- The length of the larval stage, as a Tule, is about equal to the sum of that of the egg and pupal stages. It lengthens as the temperature Fic. 9.—Diagram illustrating relationship of tem- falls and alsoas the amountof mois- Deen tones dudtohumidity. (Ongmal) ture decreases. It is also probably influenced by the nature and con- dition of the food supply. These influences will be discussed more fully under the subject of developmental period, as more data are avauable for the entire period than for any of the stages in this period. The observations which have been made upon the duration of the larval stage are tabulated and charted below (Table XXIV and fig. 9). TABLE XXIV.—Duration of the larval stage of the boll weevil. Total | Aver- | Mean Num- number | age lar-| tem- Place. Year. Hatched. Pupated. He a of larva | val pe-| pera- days. riod. ture. Days. pel Victoria, Tex... 2<<-<.a-- 1902 | Sept.6.--=-a.024 OGHDS ne. -3ae8e 195 | 1,462.5 0.5 78.7 JOO OCeR RED ODODEN ET $902) Sept 2625. ce en POCtarwl nace ce 15 142.5 9.5 73.6 DO Bieceeniae saree a 1902. | Now. TI aoocb oe. 1D PES Se 15 375.0 25.0 62.5 Victoria, Tex. (ice box)..| 1904 | Aug.26-Sept.3..|.-.....--..--.-.1- 88 | 1,100.0 12.5 69.0 Alexandria, La...........| 1907 | Aug. 26-Sept.5..| Aug. 28-Sept. 7. - 149 | 1,096.0 7.3 79.9 Dallas, Tex.c: 0. 2s-242--- 1908 | July 18-29....... Aug 12S eee 50 435.5 8.7 83.7 DOs¢ seeders see 1908 Aug. 3-19......- Aug. 17-31....-- 44 390.0 8.8 84.1 Tallwlab son. fo.e-e awe 1910 | June 27-July 7...| July 7-17......-. 98 618.5 16.3 79.1 Totalsc. 33.2293 hess June 27-Nov. 11.| July 7-Dec. 12.... 654 | 5,620.0 8.5 76.2 1 The extremes were 5,2 and 7.3 days. SEASONAL HISTORY. 67 PUPAL CELLS. As the larva becomes larger it gradually forms about itself a hardened black cell, composed of its cast skins and excrement. This cell is of a very tough leathery nature and seems to hold its moisture for a considerable period. In bolls the cell is even harder, as it becomes more or less mixed with lint and attains a considerable firmness, which often gives the cell the hardness and appearance of a seed. These pupal cells frequently include a portion of the hull of a seed, and it has also been found that the larva sometimes forms its cell within a single cotton seed. In these cells the larva trans- forms to the pupal stage. (See Pl. [X.) PUPATION. The formation of the adult appendages has progressed considerably before the last larval skin is cast. The wing pads appear to be nearly one-half their ultimate size. The formation of the legs is also dis- tinctly marked, and the old head shield ap- pears to be pushed down upon the ventral eg eat es eae side of the digran by the gradual elongation of the developing proboscis. Finally, the tension becomes so great that the tightly stretched skin is ruptured over the vertex of the head, and it is then gradually cast off, revealing the delicate white pupa. The cast skin frequently remains for some time attached to the tip of the abdomen. The actual period of ecdysis is about 45 minutes. DEGREES F % TEMPERATURE, THE PUPA. ACTIVITY. Mey Fic. 10.—Diagram illustrating rela- The pupal stage of the boll weevilismore on eee tthe tolbeeceil or less an active stage. The pupaissocon- and showing variations due to structed, with a forked prong at the posterior = "™™{"Y- (Omisinal) tip and with two strong tubercles on the thorax, as to have an axis upon which it can revolve without injuring its more delicate append- ages. As the cell is almost round, this movement of the pupa is more or less free in all directions and tends to make the salt harder and more durable. A person with acute hearing can detect the presence of a pupa by holding a square close to the ear. (See Pl. VI, ¢, d.) DURATION OF THE PUPAL STAGE. In general, it may be said that the length of the pupal stage is about equal to that of the larval stage minus the length, of the egg stage. This stage varies considerably, as do the two previous stages, the range being from 2 days at high temperature to 14 or more days at low temperature. During the winter it may be as long as several months. Table XXV and figure 10 are presented to illustrate the variations in the pupal period in their relationship to mean tem- perature. It may be stated briefly that the length of the pupal stage increases as the temperature decreases, and that the average humidity also influences the stage in the same manner. 68 THE MEXICAN COTTON-BOLL WEEVIL. TABLE XXV.—Duration of the pupal stage of the boll weevil. Total | Aver- Num- Mean 2 number| age %, Place. Year. Pupated. Emerged. ber of of pupa | pupal temper: pup® | days. | period. es 8 Degrees Victoria, Tex..........- 1902= eal ely! Galsees ane July 10=165esescr 27 97 34a) F. Le Soe # ase cee eels do....| July 12-18......- July 16-22....... 22 84 3.8 82.65 RO: or sees aes ale ne Go==.| Willys —2a sso eee July 23-28....... 86 392 4.5 oe Doothh Ss sa aeesec(eee do...| July 24-25......- July 29-30......- 23 111 4.8 DOL eit ae Sate |= Go<: -.|/ Senin lb s2- 5225-1 Sepb. 204..¢52525 4 20 5 79.05 WO eres ace seas) sos do..-.|) Oct. 2)-28. 7-222 Oct. 27-28. ...-.. 5 24 Cy oe eS 11 1 Ae eee! er do Noy: 2-62 ..-=-.. Nov. 9713. ...... 29 212 (63: 69. 2 DO! can deo nn sees |See do:--3|) Deex2-13-2e2 5 2 Weer Us 20. oa oF 56 14 61. 55 Victoria, Tex., ice box. .}.-.- GRE 4 Paes beach adnande ISSock desees55 ons: 88 660 7.5 69 Dallas) Mex... . <.sctecciss 19072 al) ume Sos cce5- 4), wuTe LO es 1 5 5 80.1 Alexandria, La.........]-.- GOf ee | PAUP Ore eee eee AU pies Socneee 20 43 21 85.7 ee Socospenecaoas siz do:..-| Sept. 10-1327... - Sept. 16-18...... 141 717 5 (2.4 Dallas: Next. 23-54. .-<- 1908222) -Augol=65e8e— 3 Aug d= oe: 10 41 4.1 84.5 Tallnlah, Lat... 25-25: 19103224) Duly f—lWiere esse July 14-21....... 50 167.5 13.3 79.1 MNotalinc ied. 3 520% ha June 13-Dec. 13 | June 19-Dee. 29. 510 | 2,629.5 531 74.3 1910. 1 The extremes were 2.8 and 3.9 days. PERCENTAGE OF WEEVILS DEVELOPED FROM INFESTED SQUARES.! During the season of 1902 part of the many squares gathered in infested fields for the rearing of weevils were followed to learn some- thing of the percentage which produced normal adults. No exam- ination was made for those not yielding a weevil. The decay of the square during the period from its falling to the maximum time that must be allowed for weevils to escape normally so obliterates any small amount of work by a larva that it is difficult, even with exam- ination, to determine accurately the number of dead small larve. TABLE XX VI.—Percentage of boll weevils from infested squares. Number | Number Apis Locality. Approximate date. of of producing squares. | weevils. petal 1902. Wate, VOR .< sss ecco bee July tor APsuUsb: 35.54 2 Jocdgse58= -teeeces 1,125 360 32.0 Guadalupe, Tex 5-.. 122-3 AUBUSUS Pas aes coaaecoeiaeceee see ee ee cee 387 108 28.0 1903. Mictoms, (exe.—. oe oat VUNG: Sere eee art Sob - pancee een aoe tere 334 106 32.0 DOS eS ck oo ee Junetto Ampustt...- 9200.3. eee 873 355 41.0 10 ER See ee eee naar August to September. ....-=--......--=- 368 192 52.0 1904. 10) ee eee eeeeeecce ae June to. Septemiben. «4.0 se tec 3.5 eee ies 951 469 49.3 Tevteal. te 85) ee Sale I. SSS SES) py ae eee he ae NE ce 4, 038 1,590 39.4 It seems safe to conclude that throughout the season fully one-third of the squares which fall after receiving weevil injury may be expected to produce weevils. 1 From Bul. 51, Bureau of Entomology, p. 92. SEASONAL HISTORY. 69 LIFE CYCLE. DURATION OF LIFE CYCLE. We have shown that the average duration of the egg stage under different conditions is 3.7 days, of the larva 8.5 days, of the pupa 5.1 days, of the preoviposition period 7.7 days, and of the oviposition period 31 days. Consequently, the average time from the deposition of the egg to the completion of oviposition by the resulting adult is 56 days. The average required for the combined egg, larval, and pupal stages is 17.3 days. The larva requires about 23 times as many days as the egg, and the pupa about two-thirds of the time required for the development of the larva. SEXUAL VARIATIONS. There are several factors which govern the duration of the life cycle of the weevil. The factor which is of least importance, if, indeed, it is of any importance, is that of sex. Mr. R. A. Cushman, in experiments at Tallulah, La., in 1910, in which squares were under more or less uniform climatic conditions, found that 475 males averaged in development 13.88 days, while 393 females averaged 13.49 days. The figures are so nearly equal that there is great doubt as to whether the sexes require different periods. VARIATIONS DUE TO LOCATION OF DEVELOPING STAGE. As has been stated, the tendency of the squares to hang or fall is a determining factor in the length of the developmental stage. In a humid region, however, the difference may be very small. At Alexandria, La., in 1907, it was found that the average developmental period during the first 19 days of August in fallen squares was 15.3 days and in hanging squares was 15.1 days. VARIATIONS DUE TO TIME OF FALLING OF INFESTED SQUARES, The period preceding the falling of the squares to the ground seems to be one of the strongest factors in determining the length of the developmental stages. To illustrate this, at Victoria, Tex.,in August, 1904, it was found that the average development in squares which hung only 1 day was 13 days, whereas for squares which hung 18 days, the development was 284 days; also at Dallas, Tex., in August, 1906, the average development in squares which hung 6 days was 19 days and in squares which hung 22 days was 36 days. We pre- sent Table X XVII, which shows in general that the difference in the time required for development in hanging and in fallen squares is proportionately the same in all months of the year and at all places where observations have been made. 70 THE MEXICAN COTTON-BOLL WEEVIL. TasLeE XXVII.—Table to illustrate the effect of the time of falling upon the period of development ofthe boll weevil in squares. Average period of development of weevils for eggs laid during specified periods. Alex- an- No. of days Victoria, Tex., 1904. Dallas, Tex., 1905. Dallas, Tex., 1906. dria, before falling. La., 1907. July | July | Aug. | Sept.| Aug. | Sept.} Oct. | June |June29-| July | Aug. |July 28- *) 1-15. | 15-30.} 2-11. | 10-29.) 12-28.) 11-30: 2-8. | 14-21.) July 6. | 16-21.) 12-17.) Aug. 19. Days.| Days.| Days.| Days., Days.) Days.| Days.| Days.| Days.| Days. | Days.) Days.| Days. 1 0 25. OL om asec cane alosoeer ome eee 12.5 .0 3. Cia | SOMERS bo Oec.4| heecncas, Sees eo S5 12.6 eas he = Di| ee soeerae | Lin ON aae ses 12.3 Se esee| eas iy) Wareesce BAU) |S. Se ate 13.5 Average... : ; : .§ b : Bit : 18.3 | 18.3 No. of stages.... B 5 : 9 69 The average for the 664 stages covered in the table is 18.4 days, which may be taken as the general average period of development in squares. Figure 11 graphically illustrates Table X XVII. DAVS - PEPIOO OF DEVELOPMENT VARIATIONS DUE TO TEMPERATURE. It will be noticed that the average period of development in squares which have hung on the plant for the same length of time varies with the season, but an increase of tem- perature regularly lowers the aver- age developmental period. The following diagram (fig. 12) has been constructed from the average curves determined for each of the stages in the development and shows that the range is from 13 days at 88° F. to 51 days at 62° F. Fic. 11.—Diagram illustrating effect of time of falling of infested: squared upon period of de- By using the quantities deter- velopmen 7eeV ictoria, Tex., . . : Ania a4 (Corea eee mined by the curves in figure 12 it is possible to chart the mean or nor- mal developmental period by months for any given place with known mean temperatures. This has been done on the following diagram (fig. 13) for Victoria, Tex., Ardmore, Okla., and Vicks- SEASONAL HISTORY. Gl burg, Miss. The curve obtained for Victoria is the widest which can be obtained in the United States with the exception of Texas points to the south of Victoria. It is interesting, however, that Fig. 12.—Diagram illustrating sank maa SST of developmental period of the boll weevil. (Original. ) Fie. 13.—Diagram illustrating normal developmental period of boll weevil in squares, by months, at Victoria, Tex., Ardmore, Okla., and Vicksburg, Miss. (Original.) Pensacola, Fla., would show almost as wide a curve, but there the weevil would show less rapid development in the hottest months. The Memphis, Tenn., curve is slightly wider than that for Ardmore, Okla., an Dallas corresponds almost exactly with Vicksburg. It is 72, THE MEXICAN COTTON-BOLL WEEVIL. interesting to note that Ardmore shows only four and one-half months in which the developmental period can be under 30 days. Adding the preoviposition period to the developmental period, it is evident that unless the weevil adapts itself to the northern conditions latitudes north of Ardmore can have only a fraction over three generations in a year, whereas Victoria, with seven months in which the develop- mental period is less than 30 days, frequently has six generations. VARIATIONS OF DEVELOPMENT IN BOLLS. It is of interest to note the variation in development in bolls due to the length of time the boll hangs on the plant. At Victoria, Tex., in June the development was 15 days for a boll hanging 1 day and 39 days for a boll hanging 26 days, while in bolls which did not drop, it frequently took over 60 days, with 67 as the maximum. The average developmental period of 67 weevils at Victoria and Dallas was 41 days, or more than twice the average period of weevils in squares. This difference may be considered as due to a combination of the factors of lower temperature, greater humidity, and less nutritious food. MISCELLANEOUS VARIATIONS. There are also some variations in development which can not be attributed to any of the causes cited above. Undoubtedly the insect adapts itself to the supply and condition of the food available. Con- sequently, under the same climatic conditions weevils in very small or delayed squares develop more quickly than those where the food is more suitable. Such variations are illustrated by Table XXVIII, which relates to the developmental periods of weevils of the third generation at Alexandria, La., in 1907. Taste XXVIII.— Table showing variations in the developmental period of boll weevils in the third generation at Alexandria, La., m 1907. Num- | Total By ee Total = set Total | AV€l | Total | Aver- Date of oviposition. ber of egg a larva eet pupa Din weevil toral Stages. | days. | neriod.| FY: | period. | 28YS: | period. | 4S period September 25... .....-5--s--5| 1 1 AS ts oa ea ibm a cyeteed |e ae | a ae eee e cee Rees IDA) ae aR 4 4 1 24 (5S es | Ae oe SA | etc oes WOS a see. Sac aict 7 7 1 42 6 28 | 4 77 ll DOvsoasaecs ssa ek 4 4 1 28 ((\ossc¢32- | Sosa eed py Secs | Jere: 2 Moxsiss- i/ 7 1 49 7 28 4 84 12 September 1-4......... 54 108 7 ee Pee Ses SR) * SE | EE Oe Se September 1........... 1 2 2 td 7 3 3 12 12 September 4.......-.- & as 3 3 1 24 8 12 4 39 13 September'5$.2..2... cece ens 2 4 Di | ate ow eto ea 8 ee pee eS 2 Se 26 13 Septenmrbers: 2222222 hereer2 2 4 2 10 5 12 6 26 13 HELEN Per 425: - cet o ene 10 20 2 60 6 50 | 5 130 13 September 1-5............... 30 60 2 210 7 120 4 390 13 Sapremiberi2 9. -6255-82-2..- ‘5 iB 1 20 4 45 9 70! 14 DOSS ea See eee De ee ee | 16 16 1 112 7 96 6 224 14 LD (o}-4e gpa: Sprague eanegee| 4 4 1 40 10 16 + 56 14 1D foe oA ee ee ee 12 24 2 72 6 72 6 168 14 September 3-4............--- 3 6 2 21 7 15 5 42 14 September 2-4.........-.-... 18 36 2 144 8 72 4 258 14 September 2 on ae 9 18 2 81 9 27 3 126 14 AUSUStOlss~ See. a oe eee 14 42 Ol eee oes Solita ee eee ee ite tosis eee cee ee BIO SS ES. a 3 9 al epee teed Raine ctel beastie ih Pe ep eee 42 14 Dome fi oe 3 9 3 24 8 | 24 3 42 14 September ee... eee eee 2 4 2 14 7 12 6 30 15 Agi@ast Oh ants: bees sacar 4 12 3 32 8 16 4 60 15 BODIipIMDeI et anaes eee 6 12 2 42 7 42 7 96 16 AvgHBD OIE. - .Fo8ks usse-. 28] 2 6 3 16 8 10 5 32 16 1D fo NPS RE SR ee HS aie sh | 3 9 3 24 8 18 6 51 17 AUpUStI2G6S. 24. 52 BS: 22 ee. 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7 a|ee. ee tee ee eee eee Larval period........-.:--..-+ MAG) ast BA he dete 1, 096 Teo s2ecccs)| J: sea ealanse - Hee ee ree. Pedal pemOGe:.---- 22-60. 5s sal lags | phe ee re Neate || regs ete 717 SOW 5. Secs digs Ames Potalypenigds 2. 2s-4 sL347.2 23 LSPA }/2 Em cea 3 AA Bk Ao Sees ee ye Be ee |e =<|) 2198 14.4 l | DEVELOPMENT OF WEEVILS IN THE SQUARES WHICH NEVER FALL. It is generally true that squares seriously injured by the weevil sooner or later fall to the ground. The form of the absciss-layer grown when the square is injured determines whether it is to fall or to hang. (See Pl. XV.) This will be explained fully in connec- tion with the discussion of parasites (pp. 143, 144). Certain climatic and ‘oilinneal conditions seem to increase the tendency of the cotton plants to retain the infested squares, although this tendency seems to be very largely of a varietal character. In the hanging position the square dries thoroughly and becomes of a dark- brown color. Although exposed to complete drying and the direct rays of the sun, the larvee within are not destroyed by the sun in the same proportion as those which are exposed to the sun on the hot soil. However, control by parasites is much greater in the hanging squares than in the fallen squares—so much greater at times that the total mortality from all causes in hanging squares surpasses that of fallen squares. This matter will be dealt with more fully in a later section. Owing to the much smaller number of squares which hang on the plants, we have been unable to obtain a sufficiently large series of records upon the development of the weevil in this class of squares, but the records available show that the development is slightly shorter in hanging squares than in the average fallen squares. DEVELOPMENT DURING WINTER. As is normal with many species of weevils, there is some develop- ment during the winter months. This development, however, is frequently cut short by severe freezes. In southern Texas larve and pupe of the boll weevil which are in squares when frost comes are not always killed thereby, but slowly finish their development if the weather is warm enough for any activity, and the adults thus devel- oped may live through the winter without feeding. Mr. J. D. Mitchell took a number of live larvee, pup, and adults from bolls in a field at Victoria, Tex., on December 26, 1903, after two hard frosts and one freeze. Two weeks later, from a field in the same locality, after three hard frosts and two freezes (30° F.), he took another lot of live specimens in these three stages. On February 7, 1904, Mr. Mitchell took 32 adults, 1 pupa, and 4 larve, all alive, from standing stalks, and on February 14 he found 32 adults, 2 pupe, and no larve. The material collected at different times up to February 14 7A THE MEXICAN COTTON-BOLL WEEVIL. included 197 specimens, 23 larve, 30 pupx, and 144 adults. It is therefore evident that large numbers of weevils go into the winter in the immature stages, and there is every probability that, in the southern part of Texas at least, many of them live and mature, emerging in the spring. It may be that this gradual maturity of the hibernated esti is one of the reasons why they emerge so irregu- larly from their winter quarters. Prof. Sanderson, in Bulletin 63 of the Bureau of Entomology, mentions that in March, 1903, Mr. W. P. Allgood sent aim from Devine, Medina County,Tex., a quantity of bolls, which were examined March 12. Twenty per cent of the bolls contained weevils, alive or dead, in some stage. In 40 bolls there were 40 live and 11 dead pup, 30 live and 40 dead adults, and 5 dead larve. Many of the adults had just transformed from pupx. One live larva was found in the material. Estimating the survival of weevils in the plants in this field, Prof. Sanderson calculated that there would be about 10,500 weevils per acre in the spring. The lowest temperature which the weevils experienced in the locality from which these bolls were sent was 23° F. in February. SEASONAL ABUNDANCE. BROODS OR GENERATIONS.! The term ‘‘brood”’ can hardly be applied in its usual sense to the generations of the weevil, as was pointed out by Dr. L. O. Howard in the first circulars of the bureau dealing with the problem. For several reasons no line of distinction can be drawn between the genera- tions in the field at any season of the year, not even between hiber- nated weevils and the adults of the first generation. As has been shown, the period of oviposition among hibernated females is in some cases fully 3 months, while it averages 48 days. The average period of the full life cycle for the first generation 1s 25 days, and as the time for the second generation would be slightly less, it is evident that the first eggs for the third generation may be deposited at the same time as those for the middle of the second generation, and also with the very last of the eggs deposited by hibernated females for the first generation, as shown in figure 14. The great overlapping of generations thus produced prohibits the application of any of the common methods of ascertaining their ee The complexity indicated for the first three generations becomes still further increased as the season advances, so that in October, for example, a weevil taken in the field might possibly belong to any one of five or six generations. Duration of life and the period of reproductive activity are important factors in determining fife average number of genera- tions. Periods of greatest abundance can not be regarded as giving any reliable information upon this point, since the number of weevils developed soon comes to depend largely upon the supply of squares. In the vase of the boll weevil, therefore, the information upon the number of generations must be drawn mainly from laboratory sources, but the results are supported by observations made in the field. Man of the hibernated weevils continue to deposit eggs until the middle of July, and some are active for fully a month longer. In 1903 the last eggs from hibernated weevils were deposited on August 27. In the course of rearing experiments made in 1902 it was found that many 1 The following two paragraphs are taken from Bull. 51, Bureau of Entomology, pp. 95, 96. SEASONAL HISTORY. 15 weevils which had become adult about the 1st of August would con- tinue to deposit eggs until the latter part of November. Considering the longest-lived weevils and their last-laid eggs, therefore, it is easily possible for two generations to span the entire year. The weevils developing after the middle of November may go into hiberna- tion, and from their last deposited eggs produce weevils whose last offspring will be ready for success- ful hibernation again. This con- clusion is based upon actual dem- onstration. The maximum number of gener- ations will be found by taking the first instead of the last eggs de- posited in each case. In order to ascertain the maximum number of generations which would be pos- sible, the figures for the develop- ment at Victoria, Tex., have been taken. Figure 14 is a diagram which shows the maximum num- ber of generations possible and also the minimum number possible. This is based upon the mean tem- peratures of the various months at Victoria and the known period of development at such mean tem- peratures. The maximum number of generations of course begins with the first egg laid by the first weevil to begin oviposition in the spring and continues with the first egg of the first developing weevil from each generation. In this manner it will be seen that 10 generations are possible for weevils reared on squares. The last egg laid by the first emerged weevil and the last eggs laid by the following genera- tions allow only three generations from the first emerged weevils, which might be considered the | minimum. Themaximumnumber & of generations from the last emerg- - ing weevils by the same system can only be eight generations, whereas = the minimum number of genera- 4 tions from the last emerged weevils will be two generations. There is no basis for the idea that there is a distinct hibernation brood. The activity of the adults and the development of the imma- ture stages is gradually retarded by the decline in temperature until HIBERNATION HIBGLEANATION ams W741 HIBERNAT/ON TIONS FROM LAST EMERGED WEEVILS HIBERNATION a 7/724 LS FIRST EMERGED WEEVILS ‘ if DEC. . Nov. BREEDER. VOTH. eg 32 —ON BOL SAI IIIISS/ 14. STH. VA ( Original.) — SQUARE 97TH [YZ 77H. BY i] 2ND-ON BOLLS Ma LE | SEPT. OCT. | STH. CZ AGED WEEVILS | FURST EPTE/ CYZA 57H. 67H. CZ AUG. | | OF GEMERATIONS FRO/7 0. GRO, 4TH. CY 2N0. CZ YZ SKLY OM 2ND.\ 3RO. 4TH, STH. 6TH. TTH. CZ | CEH ST. (Pia z MAXIMUM NOYEER OF GENERATIONS F? CW MAXIMUM NUMBER OF GENERATIONS FROM LAST LIURCEO WEEVILS CEE, LEZ =z Z S5| IMUM NUMBER OF GENE MINIMUM NUMBER CE) BWM APR. | MAY | SOME 15% MZ LEGEND CI 4665 ZB LARVAE Me SOUAAE Fic. 14.—Diagram illustrating seasonal history of the boll weevil at Victoria, Tex. MAR. : & x S "6 THE MEXICAN COTTON-BOLL WEEVIL. hibernation time arrives. Most of the weevils of the first two or three generations have probably died, or then do so, while most of the adults of later generations, still having considerable vitality, go into hibernation. It is certain that every generation may have some direct part in the production of weevils which are to hibernate. All weevils which are still strong and healthy when cold weather comes on may be expected to go into hibernation, so that there can be no special brood for this purpose. POSSIBLE ANNUAL PROGENY OF ONE PAIR OF HIBERNATED WEEVILS. One of the most important factors in the development of an insect is its capacity for very rapid production. The conclusions as to the ability of the boll weevil in this respect are drawn from the following data, summarized from what has been set forth in preceding pages of this bulletin. The starting point is considered to be the average date of deposition of one-half of the eggs for the first generation at Victoria, Tex., which, under the usual conditions, seems to be about June 10. The average number of eggs deposited by a female was found to be 139. For the purpose of this computation 70 is the assumed number. The difference may be considered as an allowance for mortality or failure to hatch. The average period of development for each generation is 19 days. The average period between emer- gence of the adult and deposition of the first eggs is 6 days. The average period for the deposition of one-half the eggs for each genera- tion is 18 days, thus making the average period for each generation 43 days. The sexes are produced in approximately equal numbers. For the sake of conservatism allowance has been made for only four generations: in a season. The following table shows the rate of multi- plication and the corresponding dates: Annual progeny of one pair of hibernated weevils. Weevils. First generation, average adult June 29, numbering...................--- 70 Second generation, average adult Aug. 10, numbering............----.--- 2, 450 Third generation, average adult Sept. 22, numbering. ....---.--.----.---- 85, 750 Fourth generation, average adult Nov. 4, numbering. .........--......-- 3, 001, 250 PROMS w. 522s. 1 AOS T Ages BU he PE oe eee 3, 089, 520 As a matter of fact, the multiplication during the early part of the season is so much more rapid that it is very certain that a large part of the third generation becomes adult by the middle of August. Pos- sibly a more definite idea of the significance of this ability for repro- duction may be obtained if we consider that, at the conservative rate given, the progeny from one fertile hibernated female might, in the course of four generations, number one weevil for every square foot of area in a 75-acre field. As a matter of fact, the possibility of the multiplication is controlled primarily by the abundance of food supply. The maximum infesta- tion is usually reached some time in August. If we assume that there are 6,000 plants on each acre of ground, and that each plant produces 100 squares for weevil attack up to August 1, we would find that if the usual percentage of these squares produces weevils, the actual Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE VIII. Fig. a.—Newly planted cotton field, with sprouts from overwintered cotton roots. (Original.) Fig. b.—Fallen infested squares. (Original.) FIELD CONDITIONS IN TERRITORY OCCUPIED BY THE BOLL WEEVIL. SEASONAL HISTORY. ai multiplication would be limited to about 250,000 weevils per acre. It has been shown in this bulletin that on the average over 50 per cent of the weevil stages are destroyed by natural conditions. This means that the theoretical possibilities are never reached. In fact, it is doubtful whether the actual increase from a single pair exceeds 2,000,000. Prof. Sanderson, in Bulletin 63, of this bureau, estimated that the actual increase in the number of weevils from the Ist of June to the ist of September is about 50 times and certainly not over 65 times, where theoretically it would be 625 times. PROGRESS OF INFESTATION IN FIELDS. It is of considerable importance to understand the rate of increase of the infestation in the fields. Normally, in a given cotton field the infestation when the squares have just begun to form is under 10 per cent, but this percentage increases very rapidly in proportion as the hibernation was successful. The infestation generally starts in a given field in the vicinity of timber or of buildings where cotton or cottonseed was stored during the winter. It then progresses in increasing circles until the entire field is seatteringly infested. From then on the increase is general until it is almost impossible to find an uninfested square. Table XXIX may be used to illustrate the progress of infestation in a given field. Taste XXIX.—Progress of infestation by the boll weevil, field 1, Victoria, Tex.' | etre Number D>, Block. | Date. squares. of E ercent- Remarks. Baca Squares age. eaede infested. | | 1903. JiIne' 8; O'S. 2. 4, 200 675 16.0 | Work of hibernated weevils only. July se se tech 467 211 45.0 | Second generation at work. DALY 220 5-2 -- 249 193 77.5 | Third generation beginning. August 4...... 278 224 80.6 August 29. .... 91 85 93.5 | About four generations now working. JytoOe. coe arP| Sor |Fae o >-aQl|b>as| & Z Z m4 qe |< He |< =I < \s < i —— oo oes 1904. Calvertars: 343.235.2522 12 2] Aug.23to| 2,754 | 94.0] 251] 9.1] 1,175 | 94.7] 1.8 4.2 Sept 9. Corsicana: Ago RE SEP eae ee 12 5 | July 29to | 6,951 | 72.4) 376) 5.7] 2,506 | 71.9 -6 | 27.0 Sept. 12. B eee iactesteee fee 11 5 | July 28 to | 4,534 | 80.4] 407] 9.0) 3,261 | 64.9 6] 19.0 Sept. 12. Mexia ss . Ue LOS 15 5 | July 30 to | 6,445 | 64.4 | 317] 5.0] 4,618 | 64.9] 12] 34.5 Sept. 13. Palestine. ---. aS 35 22 2| Aug. 26 to | 3,719] 91.3 | 274] 7.4 | 2,456 | 92.8 7 8.2 Sept. 14. WiCtOrla ... -o22< =. = see ok 11 18 yup 18 to | 13,227 | 54.2 | 170] 1.3 544 | 66.9] 6.1 44.6 ept. 24. Wihartont <.-o25 4545-6. 4 4| July 22 to | 5,005 | 65.0} 167] 3.3 230 | 46.4] 10.2] 25.3 Aug. 25. MOtdlesensn-asoa5=< tif (a SEE June 18 to | 42,635 |..---- G26 een 145790 |5.2-6-|-=a5c-]eee eee Sept. 24. AST eTAPe =o seer ee clinca ser Giles. 2 betes ah See eee TOS AS sere ASO. |bereeee st 80.0 | 2.2] 27.7 1 From Bull. 51, Bureau of Entomology, p. 116. Prof. Sanderson! has estimated that usually 50 per cent of the squares will be punctured by about two months after the cotton com- mences to square, at which time there would normally be about 100 squares to the stalk. When one-half of the squares are punctured it may be readily concluded that there are probably sufficient weevils present to prevent any more squares from forming fruit. It will be seen, therefore, that the critical period in the relation between natural increase of squares on the plant and increased injury by the boll weevil is during the period of six to eight weeks after the first squar- ing, which usually coincides more or less closely with the time between the appearance of the second and third broods of the weevils. Thus, if we consider six weeks as the average time for cotton to begin to square after planting, it will be seen that the bulk of the fruit must be set in 85 or 95 days after planting. In other words, to escape injury by the boll weevil, cotton must be so grown that the bolls will commence to open in about 100 days after planting and that all the fruit which will probably be secured must be set within 45 days after the squares begin to form. The advantage of early planted cotton and rapid-maturing varieties becomes, therefore, very apparent. Field examinations have shown that the period of maximum infes- tation is reached between August 1 and 20, and that from 6,000 to 10,000 adult weevils per acre is sufficient to cause maximum infesta- tion within a few days. The highest number of weevils per acre which has ever actually been recorded from a locality during the summer was 1 Bull. 63, Bureau of Entomology, p. 38. SEASONAL HISTORY. 79 24,347 adult weevils at Port Gibson, Miss., in August, 1911.'| With this number of weevils there was a record of only 37.03 per cent infes- tation of the remaining squares and bolls. Higher percentages of infestation have been recorded with much smaller numbers of adult weevils per acre. EFFECT OF MAXIMUM INFESTATION UPOM WEEVIL MULTIPLICATION. At the time of maximum infestation the majority of the third- generation weevils are becoming adult and many of the hibernated weevils have died. About this time also a decrease in square pro- Fig. 15.—Status of the boll weevil in Texas in August, 1906; percentage of infestation of all forms. (Original. ) duction accompanies the maturity of the bulk of the crop, owing to the fact that the assimilative power of the plant is largely consumed in maturing seed. If dry weather occurs at this period, which is frequently the case in Texas, there is a further decrease in the number of weevils present. Not only are there fewer squares to become infested, but each square is also subjected to greater injury, and many which would otherwise produce weevils are unfitted as food for the larvee by the decay which follows the numerous punctures. Several eggs may be deposited in each square, but as a rule only one weevil 1 During the late fall the number may be much larger. See p. 76. 80 THE MEXICAN COTTON-BOLL WEEVIL. will develop. These general, conditions frequently bring about a reduction of the number of weevils present in the field. This becomes evident to the planter by the number of blooms seen. Of course, the ra soon change and the weevils become more abundant than efore. STATUS EXAMINATIONS. In order to become fully acquainted with the conditions of the weevil during the most important parts of the season, it has been the custom to conduct an extensive series of observations in the latter part of Fic. 16.—Status of the boll weevil in Texas in August, 1908; percentage of infestation of all forms. (Original. ) June and first part of July and again in the first half of August in order to learn the extent of damage being done by the weevil. These examinations have been made so thoroughly and have been distrib- uted in such a manner that it has been possible, even in June, to determine the probabledirection of the greatest movement of the weevil during the season, to point out the regions in which the damage to the crop will be greatest, and also to indicate where the control of the weevil during the winter has been of greatest consequence. The first ‘status’ of the year frequently gives very definite evidence of natural control or an absence of it. While certain general methods of SEASONAL HISTORY. §1 control have been contrived, it is still true that some of the most important methods of control are those which are devised to suit particular emergencies. These have been indicated from time to time in connection with the status reports. RELATION OF WEEVILS TO TOP CROP. After considerable cotton has been matured fall rains often stimu- late the production of a large number of squares, and many planters are misled by the hope of gathering a large top crop from this growth. Fic. 17.—Status of the boll weevil in Texas in August, 1909; percentage of infestation of all forms. (Original. ) The joints of the plant are short, and the squares are formed rapidly and near together. Though weevils may have been exceedingly numerous in the fields, their numbers will have become so decreased by the dispersion and by the limited quantity of food that they can rarely keep up with the production of squares at this period of rapid growth. Many blooms may appear, and the hope of a large top crop increases. It has been a very rare occurrence that planters have gathered top crops, even in years of no injury from insects. The chance of its development, though always small, becomes prac- tically inconsiderable wherever the weevil is present in numbers. 28873°—S. Doc. 305, 62-2 6 82 THE MEXICAN COTTON-BOLL WEEVIL. In the seniorauthor’s experience of 10 years only oneexample of a top crop in a weevil district has beén seen. This happened in the vicinity of Brownsville, Tex., in 1911. The production of a few bolls on the tops of the plants was due to a rare combination of exceptional influ- ences, including very dry weather during the summer, defoliation at an early date by the cotton worm, and late rains after the weevils were greatly reduced in numbers. Neither the very remote chance of gathering a top crop nor the actual injury which is being done to the crop of the succeeding year by allowing that growth to continue until frost kils it is generally . ae MefcESeLeL Pee Py wig es PHAR AS wy GK apt ial Ag SES mgt \ Ror om 7 ee Fig. 18.—Status of the boll weevil in Texas in August, 1910; percentage of infestation of all forms. (Original. ) appreciated by planters. Because of the apparent abundance of squares and the presence of many blooms the plants are allowed to stand long after they might have been destroyed to the great benefit of the next crop. As is the case in the early spring, however, the abundance of squares increases greatly the production of weevils, and though a few bolls may set, they are almost certain to become infested before they reach maturity. Every condition, therefore, contributes to the production of an immense number of weevils very late in the season and at just the right time for successful hibernation. As a result, far greater injury is done to the crop of the following SEASONAL HISTORY. 83 season with no actual gain in the yield of the current season. Plants standing until frosts kill them are often allowed to remain throughout the remainder of the winter and easily furnish an abundance of favor- able hibernating places for the weevils. The consequence of this practice is that so many weevils are carried through the winter alive that the yield of the next year is much less than it might have been but for the farmer’s indulgence of the forlorn hope of a top crop. It is far wiser to abandon the uncertain prospects of a top crop and destroy the stalks in order to insure a better crop the following year. LAA SOL. Fia. 19.—Status of the boll weevil in Texas in August, 1911; percentage of infestation of all forms. (Original. ) VARIATIONS IN ABUNDANCE OF THE WEEVIL FROM YEAR TO YEAR. The decrease in damage by the weevil in Texas in the last few years has led some observers to believe that the insect will finally disappear altogether. Investigation shows that this belief is erroneous. In 1897 the French entomologist, Dr. Paul Marchal, published a paper which set forth some of the essential factors governing insect abun- dance from year to year. This author called attention to the more or less regular periodicity in the abundance of certain well-known injurious insects. In this country the cotton leaf worm, Alabama argillacea Hiibner, is an example of such periodical abundance. The 84 THE MEXICAN COTTON-BOLL WEEVIL. application of Dr. Marchal’s law to the abundance of the boll weevil will be discussed in the followmg paragraphs. When the boll weevil entered the United States, it was released from most of its natural enemies and was in the portion of the cotton belt most resembling its natural home. ie oe it increased with great rapidity. In fact, the weevil was on what may be called the upward curve of numerical abundance from 1892 to 1896. In the meanwhile, native parasites began to adapt themselves to it, and we may assume that their abundance might be indicated by a curve par- allel to but behind that of the boll weevil. In 1896 a severe drought was the cause of a very sudden decrease in the numbers of the weevil and of course also acted upon the parasites. Following 1896 the increase in abundance of the weevil was comparatively slow, owing to the unlimited opportunities for spread. The maximum point in this increase appears to have been reached in the autumn of 1904 and may have been partly due to the fact that in that year the abundance of the parasites was on the decrease. In the winter of 1904 a severe cold period turned the curve of abundance downward, but the decrease was slow until the fall of 1907, when another severe freeze caused a sudden falling off. Floods in the spring Boole =o of 1908, drought in Rib | |g thesummer,afreeze ® ay a talon eo I OIRO oe Ld X in the fall of the 8 aol [¢ MPBESEESEP TOES ate bwe: fz same year, and droughtsinthesum- mers of 1909, 1910, and 1911, followed in 1909 and 1910 by severe winters, a combined to reduce the weevilstill more. On the other hand, from 1904 to 1908 the influence of the parasites was in- creasing and from then until 1911 decreasing. As Dr. Marchal pointed out, it is very rare that some condition does not intervene just before the number present has reached zero and save the species from extermination. The weevil will undoubtedly frequently be Scraay reduced in large regions, but in such areas the inflow from oe age will serve to bring about early reestablishment. (See ig. 20 Rirmacubtsdis the adverse seasons of recent years will be followed by others which will allow the weevil to reach approximately its former abundance. This alternation of years of scarcity and of abundance will continue indefinitely. Naturally, no definite predic- tion can be made as to the number of years which will be included in the alternating periods. The series of Texas maps presented herewith (figs. 15-19) illus- trates the variations in the percentage of infestation in August during a series of years in which the weevil abundance was at a low ebb. They also show very plainly how the areas of heavy damage are shifted by more or less local causes. FERCENTAGE WEEVIL S Ss PERCENTAGE FA, EEE EEE EEE SA ay 0 Fic. 20.—Curves of numerical strength of the boll, weevil and its para- sites. The boll weevil curve is at the scale of 2 to 10 and represents the percentage of infestation in August in Texas. The parasite curve is at the scale of 1 to 1 and represents the percentage of mortality of the boll weevil due to parasitism. (Original.) NATURAL DISSEMINATION. 85 The status examinations upon which these maps were based show the following average percentages of infestation in Texas. (See Table XXXI.) Taste XXXI.—Percentage of infestation by the boll weevil in Texas in August; years 1906 to 1911. = Percentage of Year. infestation, 1906 50. 11 1907 38. 09 1908 32. 32 1909 14.78 1910 20.79 1911 fete NATURAL DISSEMINATION. The natural movements of the boll weevil are of several more or less distinct kinds. For several months in the spring there is a general dispersal in search of food. After the cotton commences to square there is a steady spread across the fields from the vicinity of the places where the insects have hibernated. This may become a spread from field to field. In late summer there is a sudden and wide dispersal, which is shortly followed by asearch for hibernation. SPRING SEARCH FOR COTTON. After a quiescent period of from five to eight months the weevils leave ihicdelerantiott quarters and start insearch for food. During a warm period, such as was experienced in March, 1907, many weevils come out of hibernation long bakes any cotton has made its appear- ance. Without doubt these weevils wander considerable distances and finally either die or reenter the quiescent state on account of lower temperatures. As the emergence from hibernation covers a period of about three months there is little or no regulation of the direction of flight, such as might occur if all emerged at the same time during a high wind. Elaborate tests have been made by releasing marked weevils fresh from hibernation in the vicinity of cotton fields. Invariably after careful search a very small percentage of these wee- vils have been found in the nearest cotton. The experiments of Mr. A. C. Morgan in 1906 at Victoria, Tex., give the most specific data on individual flight. Seven hundred and eleven weevils were used in the experiments, of which 355 had been fed and 356 were unfed. Of the fed weevils 179 were male and 176 female, while of the unfed weevils 183 were male and 173 female. This gave a total of 362 male and 349 female weevils. The maxi- mum flight by a fed male was 775 yards, by a fed female 350 yards, by an unfed male 225 yards, and by an unfed female 500 yards. The experiments also showed the average distance per 24 hours for a fed weevil as 63.3 yards, and for an unfed weevil, 66.6 yards. It was generally observed that the weevils flew with the prevailing wind. Observations on the early spring movement of the weevil in Mis- sissippi in 1910 showed the utility of the rotation of crops. During 86 THE MEXICAN COTTON-BOLL WEEVIL. the two status examinations made in 1910 in southern Mississippi it was very evident that in these fields in which cotton followed corn there was a conspicuous absence of infestation until the fall dis- ersion of 1910, whereas in neighboring fields in which cotton fol- a cotton the infestation was in some cases extremely high, even in June. These circumstances and many others which have been observed in the spring indicate a rather irregular dispersal from the places of hibernation which may carry the weevils considerable distances in all directions. On the extreme border of the infested territory this may result in the infestation of entirely new territory. SPRING SPREAD WITHIN THE FIELD. The spread from plant to plant begins in the portions of the field adjacent to tavorible hibernation quarters. It has usually been found that the early summer infestation begins at a point adjacent to timber or near farm buildings where seed or seed cotton has been stored. From these centers it is generally easy to trace the infesta- tion to other parts of the field. The movement of the weevils from these centers, however, is not regular. They occasionally fly to rather distant portions of the field and then start new centers, but on the whole the progress is steady and soon brings about a complete infestation of the field. A number of observations were made to determine the degree of movement of hibernated weevils in a field at Victoria, Tex., in 1904. The weevils were marked so that they could be recognized, and frequent examinations were made to determine the location of each specimen from day to day.1. It was found that the maximum time one weevil remained upon a single plant was 18 or more days, the observations having been discontinued after the eighteenth day. The average time positively found in 73 cases was 4 days, with a possibility for this same number of observations of 63 days. Prob- ably a true average lies approximately between these results, and, if so, we may assume that about 54 days usually intervene between the movements of each weevil. In the whole series of observations, extending over 25 days, for weevils which were found after bei liberated, only 57 movements were recorded. The total of these movements averaged only 62 feet each in 177 movement days. This would give us an average movement of but 0.35 foot per day for each weevil in a field where stubble plants were quite abundant, where squares were forming upon fully one-third of the plants, and during a period for which the mean average temperature was 78.6° F. SUMMER FLIGHTS. During the summer there is more or less general movement within the cotton fields and also from field to field. These flights are at first weak, but gradually become more pronounced and finally lead into the great dispersal of the late summer and fall. During the summer the conditions on the border of the infested area are peculiar. Many of the weevils which arrived late in the fall of the preceding year are unable to survive the winter on account of 1 The remainder of this paragraph is from Bulletin 51, Bureau of Entomology, p. 112. NATURAL DISSEMINATION. 87 their exhausted condition. Therefore, the line of continuous infesta- tion may be considerably behind the line of continuous infestation resulting from the last movement of the preceding year. Outside of this continuous line is a strip of considerable width in which the weevil is found scatteringly. The summer flights cause these isolated infestations to coalesce. FALL DISPERSION. All movement of the weevil at other seasons is insignificant in comparison with the great dispersion of the fall which carries the insect far into new territory. It is this movement which causes the more or less regular annual advance in the cotton belt. In one sense this dispersion is merely an overflow from territory in which the insects have become so numerous that there remain no oppor- tunities for breeding. In another sense it appears to be the result of a strong instinct which the weevils possess to invade new regions. At any rate, they show great activity in the late summer and fall. The main causes of the fall flight, therefore, appear to be (1) a scarcity of food and breeding places due to maximum infestation, and (2) an instinct to invade new territory. Several conditions may tend to precipitate the movement or strengthen it. Among these are damage by other cotton insects, which Fabens maximum infestation, and drought, which may have the same effect by pre- venting the continued fruiting of the plants. There seems to be no special tendency to fly in any particular direction, although prevailing winds frequently cause the majority of the insects to follow one course. This has been observed to be southeast, north, and east in different localities. If not governed by the wind, any weevil which takes flight is as likely to fly toward the old infested territory as in any other direction. It is, therefore, only a portion of the dispersing weevils which enlarges the infested territory. The distance any weevil will fly in this movement depends upon how soon it finds uninfested cotton. If on the first flight it finds only heavily infested cotton or none at all it will take wing again. In this way a succession of flights may carry the insect over a wide territory. In one case a distance of over 40 miles has been known to be coy- ered in this manner. If, on the other hand, the first flight carries the weevil into an uninfested field it remains there. Consequently, the advance is slowest in regions where cotton fields are numerous. The occurrence of the leaf worm, Alabama argillacea, in great numbers in any locality destroys the food and tends to cause decidedly longer flights of the dispersing weevils. So far as we have been able to discover, the weevil has no sense by which it can locate cotton. Such a sense may exist, but the general aimless flight of thousands upon thousands of individuals seems sufficient to account for the infestation of all fields in new territory. An interesting observation was made by the junior author and Mr. G. N. Wolcott near Meridian, Miss., that the early dispersing weevils, in flying through hill country with heavy woods, foun only the patches on the tops of the hills and from these gradually spread downward to the denser cotton. THE MEXICAN COTTON-BOLL WEEVIL. 88 } fee ES x - rans (‘1O}UNFT VIO) “TIGL 0} Z6ST WLOIJ [TAVAA\ [[OG-10}}.00 ey} Jo peords ey L— TZ “OLA “8/40 NOSPIS FHL WE) ONY O16/ MI ware jd /SS1S S14 AO “FENLTINOWMOL AO LNINLSOLIO ST) KIOTONOLNI 0 IAN AG CIMPAFIAS “1/61 OL 2681 WOU WARIM VIOG NOLLOD LO GDeaeesS ONMOMS dkw mal SN eB ea at NO mS L LAS = & cae Teena el e y NATURAL DISSEMINATION. 89 The fall movement of the weevil has been studied carefully each year since 1904. (See fig. 21.) The circumstances have been differ- ent each season, but with uniformity within certain limits. Several examples will be given. In the fall dispersal of 1904 the weevils seemed to have crossed the line of continuous infestation in southern Louisiana about August 1, and a little later toward the north, but in all cases the movement had crossed the line by the 20th of August. In this year there were two very well-defined dispersals with about a month intervening. This might indicate that the first dispersal was caused by the lack of food and that in another month a new generation found itself confronted by the same conditions as its redecessor and was also forced to disperse. In 1906 the movement seems to have been more irregular, for the first serious new infestation was in central Louisiana rather than in the southern part of the State. In the light of present knowledge this was Arébably due to the smaller amount of cotton grown in the pine woods of southern Louisiana, which naturally gave rise to comparatively few weevils for the flight. The year 1906 was the last in which any appreciable movement into western Texas was observed until 1910. In 1907 and 1908 the eastward and northeastward progress of the weevil carried it far into regions where much cotton is produced. The year 1909 exhibited some very striking features. There had been a considerable loss in the infestation during the winter of 1908 in northern Louisiana and eastern Arkansas, a region of very exten- sive cultivation of cotton. During the autumn of 1909 the almost continuous movement in southern Mississippi from field to field in the rather sparsely cultivated areas amounted to 120 miles for the season. In the delta region of Louisiana, Mississippi, and Arkansas, where the weevils encountered a belt of extensive cotton culture from which they had been driven back during the previous winter and were stopped by the large amount of food available, they were unable to gain more than 20 miles of new territory. In 1910 a peculiar situation developed. It was discovered that high winds had caused an extensive movement into central Mississippi in May or June. In the entire history of the weevil there had pre- viously been known but one occasion when a severe storm caused a dispersal of the insect. A study of the records of the Weather Bureau brings out the fact that there was a series of cyclonic storms about May 7, 1910, passing northeastward across Mississippi from the heavily infested regions around Natchez. We have been unable to find any other explanation of such an extensive movement in the early spring. Studies conducted during the summer and fall of 1910 revealed the existence of many sporadic infestations throughout central Mississippi, probably due to the storm. From these isolated infestations the weevils spread in concentric circles until about the end of November, when the intervening territory became covered. The winter of 1909-10 was unfavorable to the weevil in the Delta. When the dispersion season opened it was noticed that in strong contrast to the rapid movements in central Mississippi, the weevils in the Delta advanced slowly. During the entire season there were only two courses of considerable movement in the Delta region. One of these was along the Mississippi River through the fields adjoining the levees. The other extensive movement in the Delta country 90 - THE MEXICAN COTTON-BOLL WEEVIL. was in a belt coincident with a strip known locally as the ‘‘dogwood ridge.”’ . The winter of 1910-11 also was unfavorable to the weevil. It began with a sudden freeze on October 29, which extended over almost the entire infested region and destroyed the food supply. Severe cold weather in January also contributed to the ae Examinations made in June and August, 1911, demonstrated that the weevil was in the lowest average condition numerically that it had ever reached. It was completely exterminated in the northern portion of the Texas and Oklahoma black prairie, but west of this was a region which escaped the first frost, and where the weevils occurred in more or less normal numbers. The defoliation by the leaf worm was so widespread that a condition of maximum infestation was reached with much smaller numbers of weevils than usual, and the scarcity of proper food supply forced a phenomenal advance along the Mississippi eee toward Tennessee. In Texas and Oklahoma there were some gains made in the lost territory, but even with these gains 24,000 square miles of territory were not reinfested. The northern limit of cotton production im western Arkansas was reached, and the line of infestation stopped only about 10 miles short of the southwestern corner of Tennessee. Great gains were made in northern Mississippi, and western Alabama and Florida became invaded for the first time. HIBERNATION FLIGHT. The fall dispersion movement continues more or less regularly until frosts occur and mark the beginning of the hibernation period. Thus, in many cases the fall dispersion is a fight into winter quarters. However, a period of feeding seems to be necessary for successful hibernation. Therefore, few of the dispersing weevils which are forced into hibernation by cold weather survive. Those that do survive seem to be supplied from a distinct movement into hibernation quarters at the end of the season. The most striking observation on this point was made by Mr. J. D. Mitchell in the winter of 1906. ‘Aihogh there had been no lowering of the temperature, he found on entering the cotton fields on November 18 a very restless activity among the weevils. Adults were observed upon the squares with their wings open and flew at the least disturbance. He observed many hundreds of weevils rising into the air and disappearing. The weather was warm and pleasant, and there appeared no reason at the time for this flight, which continued for about two days. In a few days the temperature became decidedly lower, and Mr. Mitchell was able to find only a very few weevils remaining in the fields. This note is of special interest in connection with the observations on cli- matie control, which will be discussed later. OTHER FORMS OF NATURAL SPREAD. Heavy windstorms, hurricanes, and cyclones are powerful agents in the spread of the weevil. It is believed that the great storm of September 8, 1900, in Texas, carried the infestation northward many Be As has been stated, the storms of about May 7, 1910, in Missis- sippi, were instrumental in causing a considerable increase of the infested territory in that State. ARTIFICIAL DISSEMINATION. 91 There is another method of natural spread of some local importance. In hill lands, especially, rains sweep immense numbers of infested squares to the lower parts of the fields. Cotton squares are remark- aig impervious to water, and weevils may develop in them after decay is far advanced. These squares may be carried many miles from their source and deposited under favorable conditions for the emergence of the weevils. ARTIFICIAL DISSEMINATION. While the natural dispersion of the boll weevil is by far the most important means by which new territory becomes invaded, there are certain artificial means of dissemination which are of some importance. The more noteworthy of these are connected with the handling of the cottonseed and cottonseed products. Many weevils are carried to the gins with the cotton. From the gins dissemination may take lace in several ways. The weevils may be carried back to the farms in cottonseed to be used for planting, or they may be shipped by rail to the oil mills along with the seed. Moreover, weevils are likely to secrete themselves during cool weather in the wrapping of cotton bales. In this manner transportation along with the lint is possible, although experience has shown that the danger from this source is inconsid- erable. When the cottonseed arrives at the oil mill there is chance of infestation from flight into neighboring cotton fields. The greater damage, however, is in the shipment of weevils beyond the oil mills in the ears which have been used for the purpose of carrying the seed to those establishments. Among the means of minor importance may be mentioned the inci- dental carriage by vehicles, including railroad coaches, by the move- ment of plantation laborers, and by intentional carriage for the urpose of experimentation or exhibition. The possibility of spread ie ae various means will be discussed in the following paragraphs: MOVEMENT OF SEED COTTON. Many immature or teneral weevils are carried to the gins with the seed cotton. Adults are frequently found crawling over the wagons filled with unginned cotton. The devices for removing foreign matter from cotton in the process of ginning are numerous and effective. Many of the weevils are removed or destroyed, but adults, as well as larvee and pupe, are likely to pass through the gin with the seed. This has been determined by the Bureau of Entomology by running gins experimentally. Many of the weevils, consequently, are carried into the seedhouse along with the cottonseed. Moreover, many of those that are removed by the cleaning devices are not injured. They pass along with the motes into a barrel or box, which is generally uncovered, and from there they frequently fly about and find their way into the cottonseed, or they may secrete themselves in the bagging of the bales standing in the gin yard. Furthermore, many ot the adult weevils are not taken into the gin house at all. Being on the cotton in the wagon, they are disturbed by the process of unload- ing and may fly to any portion of the plant. Consequently, cotton- seed in storage at the gin may become infested by any one of the 1 For a full account of these experiments see Farmers’ Bulletin 209. 99 THE MEXICAN COTTON-BOLL WEEVIL. following means: (1) By passage of weevils through the gins along with the seed; (2) by the weevils finding their way into the seed house from the receptacle containing the discharge from the cleaner feeder; and (3) by flight from the wagons during the process of unloading. Thus, gins may serve as important agencies in the dis- semination of the boll weevil by the shipment of the seed or possibly of baled cotton. That the danger in baled cotton is slight is shown by the fact that no colonies have been found to have become estab- lished in spite of extensive shipments out of the infested territory which have been made for several years. In many localities the unginned cotton is carried for a distance of 20 miles or more to the gins. It frequently happens that this car- riage is into uninfested territory. Under such conditions it is evident that an important form of artificial dissemination of the weevil occurs. ‘Two examples will be given of the possibility of the dissem- ination of the weevil by such means. In October, 1904, a shipload of unginned cotton was carried across Lake Calcasieu, La., from Grand ake and Lakeside to Cameron. The latter place was free of the weevil and isolated by extensive stretches of swamp lands. Shortly after the shipment reached Cameron, however, an infestation was found in the gin yard. It was in all probability due to the carriage of the cotton from the opposite side of the lake. In the other case a shipment of unginned cotton was made from Yucatan, Mexico, to Gain Ala., in 1909. The Mexican locality was infested by the boll weevil, while the region about Mobile was free of the insect. No infestation resulted in this case for the reason that the shipment from Mexico was accidentally delayed in transit and did not reach Mobile until all of the weevils had died. If the shipment had been made according to the regular schedule there is little doubt that an infesta- tion in the vicinity of Mobile would have resulted. MOVEMENT OF COTTONSEED. In ginning districts on the edge of the infested territory the custo- mers are composed of those whose fields are infested and those whose fields are not infested. The inevitable result is that weevils are constantly brought into the gin yards by the farmers, and in the subse- quent movements of the cotton are spread broadcast. Some of them may alight upon the wagons filled with the seed to be returned to the farm and consequently may be frequently carried to uninfested farms. The most striking illustration of infestation by this means was found in Shelby County, Tex., in 1904. An establishment on the border line ginned for farmers in a radius of 10 miles or more. Some of the customers had the weevil. The ginner himself had a few weevils on his place, but had raised an exceptionally large crop of big-boll cotton, for the seed of which quite a demand arose. An investigation of the farms in this district showed that all the custo- mers who had purchased this seed had infestations near their seed house. Very few of the other farms in the vicinity were found to be infested. Cottonseed is frequently shipped considerable distances from the gins to the oil mills. As has been shown there are abundant chances that the seed may become infested at a gin within the infested terri- tory. (See Plate IX.) At the oil mills the cars are unloaded and Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IX. RELATION OF BOLL-WEEVIL CELLS TO SEED. a, Boll-weevil pupa found in cotton seed; b, boll-weevil pupa in cell of lint from boll; ¢, weevil cell in dwarfed cotton boll containing live pupa taken among seed; d, weevil cells in bolls; e, cotton seeds. (Original.) ARTIFICIAL DISSEMINATION. 93 passed on to the railroads for other uses, frequently without being swept out at the mills. It is common in the lumber country for cars to pass from oil mills to lumber mills. Such cars are often found containing several pounds of seed in the corners. The lumber men sweep out this waste before loading their cars. In case cotton grows near the mill the danger is quite apparent. An interesting example of the shipment of the weevil in cotton- seed came to notice in Mexico a few years ago.!. On January 5, 1903, it was discovered that Texas-grown cottonseed was being imported into the southeastern part of the Laguna district in Mexico.2, Exami- nation of this seed, made by Prof. L. de la Barreda, revealed the fact that six lots had been received from infested points in Texas and that each of these lots was at that time infested with live boll weevils. The results of an examination of samples from three consignments are given in Table XXXII. TaBLeE XXXI1.—Result of examination of infested cottonseed shipped to Mexico. Number Boll of aac of | weevils Alive. Dead. examined. found. 8 27 2 25 4 11 2 9 2 57 10 47 14 95 14 } 81 The results of these careful examinations show very clearly the possibility of transporting live weevils in shipments of cottonseed. Unless the oil mill is within the infested territory and ships hulls to points outside there can be very little danger from this product. In fact, it is hardly possible that weevils are ever spread by means of cottonseed hulls. BALED COTTON. One of the writers has found live weevils in bagging about bales consigned to Liverpool on the wharves at New Orleans. However, as has been pointed out, experience has shown that the danger from this source is very slight. PASSING VEHICLES. Carriages, wagons, and railroad trains, in passing fields where the weevils are numerous, may carry them great distances, although few specific observations have been made on this matter. MOVEMENT OF FARM HANDS. Many laborers frequently pass from infested territory to uninfested territory. Their practice is to use cottonseed for packing breakable household articles. If the movement takes place late in the season 1 The remainder of this and the next paragraph are from Bull. 51, p. 125. 2 Boletin de la Comision de la Parasitologia Agricola, vol. 2, pt. 2, pp. 45-58. 94 THE MEXICAN COTTON-BOLL WEEVIL. this cottonseed or sacks used in infested fields may easily be the means of spreading the insect. It is thought probable that a sporadic infestation at Jackson, Miss., in 1908, originated by such means from the heavily infested district around Fayette, Miss. UNEXPLAINED SPORADIC OCCURRENCES. Infestations at Wichita Falls and Paris, Tex., in 1904, far removed from other infestations, can not be explained. A reported infesta- tion in 1909 at Temple, Okla., is also of the same nature. INTENTIONAL TRANSPORTATION OF THE WEEVIL. On several occasions it has been found that the boll weevil has been carried into uninfested territory purposely. In some cases the inten- tion has been merely to exhibit ee specimens and in others to test supposed remedies. Whatever the purpose of these introductions may be, the practice must be strongly condemned. It is very likely to result in the infestation of localities many years in advance of the time the weevil would reach them by natural means. The result would be a great and unnecessary loss, not only to cotton planters, but to merchants and others dependent upon the cotton trade. In this connection attention is directed to the fact that a Federal statute pro- hibits the interstate shipment of the boll weevil, as well as other important insect pests, and prescribes heavy penalties.t. This act is reprinted in part, under the heading ‘‘Legal Restrictions,” on a sub- sequent page. In addition to the Federal legislation on this subject practically all of the States in the cotton belt have statutes which prohibit the importation or having in possession of live boll weevils for any purpose whatever. (See the section at the end of this bulletin.) HIBERNATION.’ There are many popular misconceptions regarding the manner in which the boll weevil passes the winter. For this reason we take the opportunity to point out some general considerations about hiber- nation. Many forms of animal life suspend activity during the winter. This is the case with the boll weevil and many other insects, as well as with certain other animals. During this period of inactivity the animals which hibernate derive sufficient nourishment from a supply stored within the body to maintain life. They obtain no other form of food. In fact, the hibernation period coincides more or less with the periods in which the native tock supply is absent. The temperatures which kill the cotton plant force the boll weevil into winter quarters, where it remains with suspended animation until spring. Almost coincident with the first sprouting of cotton we find the weevils leaving their winter quarters ad moving about in the fields. 1 An act to prohibit importation or interstate transportation of insect pests, ete. (Act of Mar. 3, 1905, ch. 1501, 33 Stat. L., 1269.) 2 Two excellent publications on the hibernation of the boll weevil have been issued. These are: ‘The Hibernation of the Boll Weevil in Central Louisiana,’ by Wilmon Newell and M. 8. Dougherty (Cir. 31 La. Crop Pest Commission), and ‘‘ Hibernation of the Mexican Cotton-Boll Weevil,” by W. E. Hinds an W. W. Yothers (Bul. 77, Bur. Ent., U.S. Dept. Agr.). HIBERNATION. 95 The long absence of the weevils from the cotton fields has led super- ficial observers to believe that the weevils pass the egg stage in the cotton seed. Such persons point out the fact that the weevils are found in seed houses and appear most abundantly in the fields near these buildings, and also that they have found insect larve in the seed. Asa matter of fact, the insects found in the cotton seed are not boll weevils, but other species which feed upon dried seeds and similar vegetable matter. The appearance of the early weevils in the vicinity of seed houses is due entirely to the fact that the protection offered there attracts many in the fall. Careful observations through- out the winter have shown that the boll weevil remains inactive except for very slight movements during very warm periods and that it does not breed in or feed upon cotton seed. As explained in another portion of the bulletin, the hibernation period is defined by the continuance of mean temperatures within what we define as the zone of hibernation. This zone has as its upper limit the mean temperature above which, if continued for any con- siderable period, the life activities must be resumed, and has for its lower limit the absolute temperature below which no weevil can live for even ashort time. For all practical purposes the hibernation zone lies between 56° and 12° F. METHODS OF STUDY OF HIBERNATION. In studying several features of the hibernation of the boll weevil the practice has been to utilize large cages covered with wire screen which were placed in the cotton fields. (See Pl. X, 6.) No cotton was grown in these cages, but at different dates in the fall large num- bers of weevils collected in the adjoining cotton were placed in the cages. It has been considered that the rate of survival of weevils in these cages installed chronologically is an index to the number of weevils that actually survive under natural conditions. It has thus been considered that with 1,000 weevils in a cage installed October 1, which showed a survival of 10 per cent, and a cage containing 1,000 weevils installed on September 15, which showed a survival of 5 per cent, twice as many weevils would have survived the destruction of the plants on October 1 as on September 15. Although there is no doubt that this method gives a fairly accurate index, there is one objection that can be das to it. This objection is that the number of weevils leaving the field to go into hibernation as the season progresses, the number dying in the fields, and the number maturing there are not taken into consideration as the calculations have been made. On September 15 none of the weevils in the field would have entered into hibernation. By the 1st of October, however, a certain number would have left the field, and such weevils would not be represented in the collections made for the cage installed on October 1. It is not known whether the weevils which remain in the fields late are more or less hardy than those which leave early to find hibernating quarters. The indications, however, are that the stronger and more active weevils—that is, those more likely to survive the winter—are the ones which do not go into hibernation at an early date. Nevertheless the number that may have gone into hibernation between the dates of the installation of the various cages, the number that died from natural causes, and the number that matured in the fields during that 96 THE MEXICAN COTTON-BOLL WEEVIL. time must be considered. As a matter of fact, the total number of weevils in a locality on October 1 would be the number present in the cotton fields on September 15, less the total number dying between September 15 and Qctiber 1, and less the number leaving the field to enter into hibernation during that period, plus those that matured during the same time. It is likely that the number of weevils matur- ing is generally sufficient to offset the number that die from natural causes. This leaves only the weevils which escape collection by entering into hibernation to be considered. As there is no way in which this number can be determined, the method we have followed, which ignores them altogether, is the closest approximation we can make to a determination of the actual number of weevils which suc- ceed in passing the winter after the destruction of the food plants in the fall. It is to be noted that the possible error in the interpretation of the results of hibernation experiments becomes greater in the case of the cages installed late in the season. As the season advances more and more of the weevils leave the fields and thus pass out of considera- tion in connection with the number collected and placed in the cages. The hibernation experiments conducted have dealt with 181,932 weevils utilized in seven different seasons in seven localities through- out the infested territory. ENTRANCE INTO HIBERNATION. SOURCES OF WEEVILS ENTERING HIBERNATION.! Following the maturity of a considerable portion of the crop of bolls, and usually in connection with the occurrence of a heavy rain- fall, a renewed growth of the plant commonly produces an abundance of squares. It is this late top growth of the plant, which serves no good purpose so far as further production of cotton is concerned, that is primarily responsible in most fields for the needlessly large number of weevils produced between the time of maturity of the crop and the usual time of destruction of the plants by frost. A large proportion of the weevils which become adults before September 1 may be ex- pected to die, either as cold weather comes on or during the early ely of the winter season. There is no particular hibernation brood, ut representatives of all generations may survive and enter hiberna- tion, as has been shown by figure 14 in the discussion of the life cycle. STAGES ENTERING HIBERNATION.” The reproductive activity of the weevil continues steadily until the plants are destroyed by frost, but it gradually decreases coinci- dently with the gradual decrease in temperature. All stages from the egg to the adult may be found in both squares and bolls, even after frosts have occurred. The immature stages in squares are not immediately killed unless the freeze is exceptionally severe, and in some localities many of these survive to reach maturity and to emerge during the following spring. Usually, however, only those which are nearly adult at the time frost occurs may be expected to 1 The matter in this section is mainly extracted from Bull. 77, Bureau of Entomology, pp. 12, 13. 2 The matter in this section is largely extracted from Bull. 77, pp. 13, 14. HIBERNATION. 97 emerge. These might emerge upon warm days following the colder weather, but in the absence of a fresh food supply would soon die. In the fall of 1903 Prof. E. D. Sanderson, in an examination of 700 squares at the middle of November, found 79 eggs, which means that 11 per cent of the squares contained eggs. In an examination of 1,600 squares he states that 366 larvee were found, showing that about 23 per cent of the squares contained larve at the time of entrance into hibernation.t Some stages may survive in squares for a short time after the freeze, but there are few records of weevils entering hibernation as immature stages in squares and surviving to emerge therefrom in the spring. These stages are therefore unimportant from an economic point of view. With immature stages entering hibernation in bolls, the case is quite different from that in squares. Very large numbers of weevils enter upon the period of hibernation as immature stages and during many seasons, especially in the southern part of the State, a large percentage of these complete their development, and many survive until time for their emergence in the sprmg. Immature stages in bolls have been found alive at Victoria, Tex., as late as February 17. TIME OF ENTERING HIBERNATION. Hibernation begins when the temperature reaches a point between 60° and 56° F. The exact point ens higher with a high percentage of humidity and lower a a low percentage of humidity. According to the observations of Messrs. ‘Newell and Dougherty.” at Mansura, La., in 1908, entrance into hibernation began on October 28. The mean temperature for 10 days preceding that date was 63.7° F., but the minimum dropped from 46° to 31° F. on the day the weevils began to enter into hibernation. The action of the weevils in securing shelter from approaching cold is instinctive rather than intelligent. It is probably true that they have no such sense of sight as we commonly understand from the use of that word and that their selection of shelter is not at all guided by that sense. We mean by this that a weevil on a cotton plant can not see at any distance shelter which might be attractive to it and thereupon fly from the plant to the shelter. Cold nights with a temperature between 40° and 50° F., succeeded by warm still days, such as occur commonly in the fall, seem to stimulate the weevils to an unusual activity both in flight and in crawling. It seems possible that they have an instinctive knowledge of the approach of temperature conditions from which they must secure shelter, but it is also true that many weevils remain active upon plants for some time after the plants have been destroyed by frost and frequently until several weeks after other individuals have entered hibernation. In speaking of entering hibernation, therefore, we mean the entrance of the weevils upon a period of comparative if not complete inactivity. Their action in securing shelter is gradual and governed primarily by the degree of protection from the cold which they may receive. If early in the season a weevil accidentally finds shelter which gives it exceptional protection from the cold it will likewise be exception- ally protected from heat and therefore less likely than are other less 2 Cir. 31, Lousiana Crop Pest Commission, p. 170. 28873°—S. Doc. 305, 62-2——7 1 Bull. 63, Bureau of Entomology, U. 8S. Dept. of Agriculture, 0 98 THE MEXICAN COTTON-BOLL WEEVIL. fortunate individuals to resume its activity upon warm days. If at first the shelter which weevils find is only slight they will be easily influenced by succeeding warmth, and in another period of activity will be likely to find better protection. Their flight upon warm days undoubtedly leaves large numbers of them outside of the cotton fields, where they are more likely to find favorable shelter than within the fields themselves. From this explanation it will be understood that it is rarely pos- sible to indicate by a single date the time when weevils enter hiber- nation. It may be better expressed as a period within the limits of which a large majority, though possibly not all, weevils may seek shelter. Naturally this time varies according to the seasonal tem- perature conditions, so that in a certain locality it may occur several weeks earlier in one season than in another. It is also evident that differences in temperature conditions due to latitude or altitude will cause a similar variation in the time when weevils enter hibernation. In Table XX XITI areshown the times of the yearin which the weevils entered hibernation in the experiments of 1903 to 1906, together with the temperature conditions prevailing. The table shows the relation- ships between humidity and temperature and the length of the period of entrance into hibernation. In short, it may be stated that the lower the mean temperature the shorter the period of entrance. Sufficient information is not at hand to show positively the influence of humidity, but it is evident that there is a decided influence. TaBLE XX XIII.—Period of entrance of the boll weevil into hibernation and meteoro- logical conditions. Period. : Mean Moar Year. Locality. = tempera- humidity Limits. Days. ture. out. Per cent. 1905y|/Dallas. Lex. dean Sette. Bh Nov. 29-Dec. 8......-- 10 40.5 ; £903" | 'Colleze Station; Tex=. = 2-2... 282 ee INOW. 10-27 te emcee nee = 13 401 Dal Saco. opeeee LOOSHI Victoria ylex ken seee | se ee eee the eee Nove iSO ede sn. 16 D302 eee 1905s Reece CO oar a or eh ye ee ae eee Nov. 30-Dec. 18.....-. 19 5050) |. she nee 1904 WCorsicanas Text. Letk . £Pe ee Nov. 10-Dec. 5........ 26 5520). 2: eee 1006) iD alas «Tox... S66 Ff tote Sane aa eee ae Nov. 12-Dec. 8...-..... 27 53.0 73.1 1OD4S| *VactOpiay Voxt em ns acre Seca eee Nov. 11=Deel8-2. on. 28 5745 79.3 1906 |..... Gol A rss SR baste ek ee Nov. 9-Dec. 21........ 43 GO84i Ak Eee Weevils can not be forced to hibernate when conditions do not nor- mally induce hibernation. If kept without food, they will starve. The real bearing of this statement will be brought out later in con- nection with the summaries of the survival in its relation to the time of beginning hibernation. (See Table XLVI.) NUMBER OF ADULT WEEVILS ENTERING HIBERNATION. Of course the number of adult weevils entering hibernation is a variable quantity, owing to the differences in the percentage of infes- tation in various regions and seasons. Examinations in heavily infested regions have shown averages as high as 58,000 adult weevils 1 This and the preceding paragraph are remodeled from Bull. No. 77, Bureau of Entomology. HIBERNATION. 99 per acre in the middle of November. In this connection it is inter- esting to note the pees of entrance into hibernation as shown by Table XXXIV, based on investigations made at Dallas in fields with an average of 8,300 plants per acre. Taste XXXIV.—Number of boll weevils per acre upon stalks at different dates at Dallas, Tex.' Plants Living | Livin Date. exam- weevils | weevils ined. found. | per acre. 1906. OCt 2s eae scence 110 122 9, 205 Oct. 31 to Nov. 3....- 84 190 | 18,774 WovadOn. erecta 60 106 | 14,663 INO Ver oU eis aes 2 35 29 6,877 NOVs 225 nmc-seecde~e 35 27 6, 403 Deowl sto 2 4-52. es 36 10 2,306 DECwIa eet sot Sonss 35 5 1,186 1907 A 4 Bee eee 35 3 711 1 From Bull. 77, Bureau of Entomology, p. 18. In connection with this subject we include also Table XXXYV for the same period, showing the occurrence of the weevils under shelter on the ground in the cotton fields. TaBLeE XXXV.—Number of weevils under rubbish on ground at Dallas, Tex.? Weevils Portion found— : Percent- Field. paler of acre rol age Remarks. * | examined. Pp ‘| alive. Alive. | Dead. 1906. A......-.-| Nov. 15 | 22 plants. 4 0 1, 450 100.0 | In oe of ground around bases of plants. Ac eee = Os Ss 1/264 4 0 1,056 100.0 | Under rubbish on ground. Ae Loose -|eINOVs 22 1/347 8 0 2,776 100.0 Do. ‘ALsE. ee} Deck 18 1/264 5 14 5,016 26.3 Do. 1907. ByitS. % Jan. 11 10/8384 5 2 5, 870 71.4 | Northeast corner of field. Cxsnc see: Jan. 29 10/6236 1 1 1, 247 50.0 | Middle of field. CRA TE Stefi hear 10/8384 2 2 3,354 50.0 | Near southwestern edge. 2 This table and the following paragraph are taken from Bull. 77, Bureau of Entomology, p. 20. The sum total of weevils found both on plants and on the ground on November 22 shows an average of slightly more than 9,000 weevils per acre, all of which were alive. On December 18 the number that could be accounted for was between 6,000 and 7,000 per acre on the same ground which had been previously examined. On the former date more than two-thirds of the weevils were still upon the plants. On the latter date nearly five-sixths of them were on the ground, and among those on the ground only 26 per cent were living. These fig- ures show that between November 22 and December 18 a very large mortality had occurred among weevils which had entered hiberna- tion, and especially among those which had sought shelter under rub- bish upon the surface of the black-waxy soil of field A. 100 THE MEXICAN COTTON-BOLL WEEVIL. SHELTER DURING HIBERNATION. Boll weevils in seeking shelter from the cold will enter all kinds of places which might afford shelter. The following statements are quoted from Prof. KE. D. Sanderson: ' The observations by Prof. Conradi at College Station, Tex., in the early winter of 1903, probably indicate some of the normal places for hibernation—that is, under dead leaves, in old cotton brush, and under loose bark. In the hibernation cages, where the weevils were furnished an abundance of rubbish, it was found that many of them which were hibernating successfully had crawled into the cavities made by borers in dead wood and in similar positions where they were well protected. It has been often noticed that in a wooded country the weevils appear first in spring along the borders of fields next to the woods and gradually work inward from the edges, so that it seems probable that in a wooded country most of them hibernate in woodland. Around outbuildings and barns also are found favorable places, as there is always more or less rubbish and protection in such situations. In 1903 more than five times as Many weevils were found in a piece of cotton near the college barn, where cotton had been grown the previous year, than were found in any other locality in that neighborhood. It is also noticeable that weevils are always more numerous near gins than at a distance from them. It is noticeable that weevils are much more abundant where cotton is planted in fields where sorghum stubble has been allowed to remain all winter adjoining a last year’s cotton field. : Professor Mally has given the observations of Mr. Teltschick upon finding weevils hibernating in the crevices of the soil around the cotton stalks and roots, at a depth of 3 inches. On March 7, 1901, a raw, windy day, upon 35 stalks, he found 7 live and 2 dead weevils from 1 to 3inches below the surface. In September, 1902, he stated that he had again found weevils in a similar situation during the previous spring, but not as many of them asin 1901. Mr. Teltschick recently writes as follows: “T found but few weevils in crevices around stalks during the last two winters, partly because there were no crevices (frequent rains filling them up as soon as formed) and partly because freezes were severe enough to: keep cotton from coming out during any part of the last two winters; whereas in 1900 we had neither rain enough to fill up crevices nor frost enough to keep cotton from budding out at intervals at the base of the stalk, which latter fact accounts, no doubt, for the relatively large number of © weevils found within the crevices.”’ Where the cotton stalks are allowed to stand throughout the winter they furnish the weevils both the means of subsistence late in the fall and an abundance of favorable hibernation places through- out the field. The prospects of successful hibernation are thereby multiplied many times, and, furthermore, the weevils are already distributed over the field when they first become active in the spring. The grass and weeds which almost invariably abound along fence lines are exceedingly favorable to the hibernation of many weevils, so that it will be found generally true that the worst line of infesta- tion in the spring proceeds from the outer edges of the field inward. Where cotton and corn are grown in adjacent fields, or where, as is sometimes the case, the two are more or less mixed in the same field, many weevils find favorable shelter in the husks and stalks of the corn. An especially favored place is said by Mr. E. A. Schwarz to be in the longitudinal groove in the stalk and within the shelter of the clasping base of the leaf. Perhaps the most favorable of all hibernating conditions are to be found among the leaves and rubbish abounding in the edges of timber adjoining cotton fields and in Spanish moss. From such sources the weevils are known to come in large numbers in the spring. Sorghum stubble, which collects débris blown about by the wind, is also very favorable for hibernation. 1 Bull. 63, Bureau of Entomology, U.S. Dept. Agriculture, pp. 18-19. Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XII. Tig. d.—Standing dead timber and forest environment favorable for hibernation of weevils. (Original. ) Fig. b.—Litter in forest, suitable for hibernation of weevils. (Original.) HIBERNATION CONDITIONS FOR THE BOLL WEEVIL. PLATE XIII. Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. “MASSM 10g SHL C[VULsQ) “WOT Ruleqriy UL S[[A90.M1 0} UOTJO9}01d BSB ssOuL YsTUBdS JO AJISUBd—4q “VET YO4 SNOILIGNOD NOILVNYSEIH JO UOT}VUIOIY 1OJ ( 1B OTQBIOA ULSIIO) “S[LA vy AJOA ‘soed} UO SsouL YSsTUR JOM Is—"p Bly HIBERNATION. 101 Attention has already been called to the fact that many stages enter the period of hibernation in an immature condition in unopened bolls. That adult weevils hibernate entirely within the protection afforded by the bracts and hulls of bolls has been afindantly demon- strated. Messrs. Hinds and Yothers! showed, however, that the percentage of live stages in bolls decreased rapidly during the winter, thus proving that the bolls do not furnish perfect hibernation shelter. Their results may be summarized as follows: TaBLE XXXVI.—Seasonal decrease of live stages of the boll weevil in bolls; percentage of bolls containing live stages. TS a SERS 0) Ry SS a ay ee ee ee 36. 00 RN MPI Gee eens ty heh Es Se nin 2 = 5 ea pre Ser eotsen ne as ute 1.15 NIE ee ee a Cc oe oe = oboe be Se ees 2S 0..29 eC MaRSee See ioe 20) TIO T ECs is 10. eed © oa) os. : 0.00 As would be expected, it was found that there was a greater per- centage of survival in bolls in southern localities. During an ordinary season it can not be doubted that a large majority of the weevils which survive find some other shelter than the bolls hanging upon the plants. It is not, however, as easy a matter to find weevils in rubbish scattered upon the ground as in bolls. It is necessary to collect the rubbish very carefully and sift it over cloth or paper to separate the weevils from the trash. In this way it has been found that weevils hibernate extensively in the leaf and grass rubbish distributed throughout the field. Naturally, the cleaner the field in the fall the smaller will be their chances of finding favorable shelter during the winter.? (Pl. XII, 6.) Standing trees are a common sight in cotton fields, and while the records of weevils found hibernating under bark are but few, they are sufficient to indicate that these trees may be rather important factors where they occur in considerable numbers. (Pl. XII, a.) Where the Spanish moss (Tillandsia usneoides) occurs, as in the bottom lands in the coast section of Texas and in the southern por- tions of the Gulf States generally, weevils find exceptionally favor- able shelter. Many examinations of large quantities of moss have been made to ascertain the importance of this form of shelter. The maximum number of weevils per ton of moss is recorded by Messrs. Newell and Dougherty (1909) as 3,158 in moss collected from an elm tree located in a swamp at Mansura, La., December 23, 1908. The moss was at a height of 15 feet. The tree was one-fourth of a mile from the nearest cotton field. On January 9, 1910, Mr. C. E. Hood found at Mansura 924 boll weevils and 2,156 boll-weevil para- sites per ton of moss collected at from 1 to 8 feet above the ground. The weevils seem to prefer the festoons of green-hanging moss to the dead masses. (See Pls. XI, XIII.) Cornfields adjoining cotton, or cornstalks scattered throughout cotton fields may shelter many weevils. This was first noticed by Mr. E. A. Schwarz at Victoria, Tex., in the winter of 1901-2, and has since been corroborated by a number of observers. Several examinations have been made of haystacks in the vicinity of cotton. 1Bull. 77, Bureau of Entomology. 2 This paragraph and the remainder of the discussion in the present section is modified from Bull. 77, Bureau of Entomology, pp. 30-33, 41, 42. 102 THE MEXICAN COTTON-BOLL WEEVIL. This is a task quite comparable with that of seeking for the pro- verbial needle, and it is not surprising that the results have been very meager. The fact, however, that traces of weevils have been found in these examinations indicates that weevils may find shelter under such conditions. : Farmyards, seed houses, barns, ginneries, and oil mills also afford favorable shelter for weevils. Especially in ginneries and seed houses the weevils become concentrated with the cotton or seed and frequently may be found in large numbers within or around these buildings. In connection with this subject the reader is referred to a fuller discussion of the significance of ginneries and oil mills in the distribution of weevils and of the methods recommended for con- trolling them.! In order to have a basis of comparison of the various kinds of shelter, many cage experiments have been conducted. In Table XXXVITI will be found a comparison of the survival in the cages at Keatchie, La., for weevils installed November 23 and 29. TaBLeE XX XVII.—Favorable conditions for hibernation determined by rank in per- centage of weevils surviving at Keatchie, La., in 1905-6. Weevils survived. Weevils Nature of shelter. put in Number. | Per cent. Ordinary; field'stalks}igrass ete: .% 22. 2k eee. deeb eb el- sehen = aoe 2,000 93 4.65 Brush, leaves, stumps, logs; stalks standing.........-..----.------------- | 2,500 99 3.56 Same'as above, butistalksiremoved -38--c 0 sense aoe cee eee eat 3,300 70 2:12 Cotton seed, piled but uncovered; stalks standing.................--.---- 2,000 30 1.50 Apsolubely, Dare PrOuUnNG S205 oat ones. Scene sea =e Soe tee oe 2, 000 30 1.50 Cotton seed piled and covered; stalks left standing ............-...--.---- 2,000 23 T5 1 From Bull. 77, Bureau of Entomology, p. 42. It is evident from these observations that ordinary field conditions where stalks are allowed to stand together with the grass and leaves littered over the ground are as favorable as any other for successful hibernation. One fact should be emphasized in regard to classes of shelter which have been mentioned as occurring within cotton fields, i. e., that it is possible, as a rule, to destroy or remove practically all of them. Undoubtedly the burning of cotton stalks, weeds, grass, and other rubbish is the easiest and most effective method of destruc- tion where it can be practiced. Next to this in importance would be the destruction of the stalks by a stalk chopper and plowing under alltherubbish. In the latter case it must be stated that many weevils which, under dry conditions, are buried not more than 2 inches will be able to escape through the soil and may then find shelter near, if not within, the field. 1 Farmers’ Bull. 209, U. S. Dept. of Agriculture, “‘Controlling the Cotton Boll Weevil in Cotton Seed and at Ginneries.”’ HIBERNATION. 108 ACTIVITY DURING THE HIBERNATION PERIOD. It is natural to expect that during warm periods of winter the tem- perature will rise to a point which forces the weevils into activity. Of course, the weevils under the lightest shelter are the ones which first become active. It is these warm periods which cause the inter- mittent development of the immature stages in dry bolls left in the fields. In some winters the hibernation is incomplete throughout the cotton belt, and in the extreme South it is probably so almost every winter. This same temperature condition is responsible for the growth of sprout cotton, which affords food in the warm periods. Observations were made in January, 1907, on weevils feeding on sprout cotton at Victoria, Tex., at a mean temperature of 67° F. DURATION OF HIBERNATION PERIOD. AVERAGE LENGTH OF HIBERNATION PERIOD. Many factors must be considered in arriving at the average length of the hibernation period. The time of entrance, condition of the weevils on entering, temperature and humidity before and during hibernation, and nature of shelter, all have a decided effect upon the duration of hibernation. Im a series of condensed summaries we have attempted to show how some of these factors act. In Table X XXVIII is to be found a general summary of the nine large experiments conducted, with the extreme variations in each series. From this table it appears that in the years 1906 to 1911 the hibernation period has ia between 62 and 255 days, and that in 1909 the range fell short only 1 day of this maximum range. It also appears that the average duration in Texas is 26 days shorter than in Louisiana. The period of emergence extends from Feb- ruary 15 to July 1. TABLE XX XVIII.—Extremes of variation in duration of hibernation by the boll weevil. Total Total Mini- | Maxi-| Aver- Place number | number oe ae a mum | mum | age of Earliest Tapes 5 weevils | weevil eriod.|period.| 2V€r- | @ver- | aver- | emergence. ence emerged.| days. P [ee ‘| age. | age. | ages. 8 , Days. Days. | Days. | Days. | Days. Keatchie, La., 1906.... 731 | 114,192 108 222 136 178 156 | March 22....| June 28. Mansura, La., 1909... .. 516, 067 62 254 94 199 156 | February 21.) June 29. Mansura, La., 1910... .. 170, 212 86 232 114 217 164 | February 15.| June 15. Tallulah, La., 1910...-. 58, 245 103 237 126 224 183 | February 15.| June 27. Tallulah, La., 1911 6, 587 107 231 118 158 143 | February 15.) June 4. Louisiana aver- BPO Me. a. Le 5,392 | 865,303 62 254 94 224 160 | February 15.) June 29. Victoria, Tex., 1907....| 3,028 | 383,797 92 223 95 146 126 | February 28.| June 15. Calvert, Tex., 1907..... 1,842 | 255, 831 91 285 100 195 138 | March 4..... July 1. Dallas, Tex., 1907... ... 3,462 | 481, 271 85 233 98 168 138 | March 1..... June 19. Dallas, Tex., 1908... ... 118 17, 839 113 217 121 170 151 | March’ 2. --.: June 16. Texas average...| 8, 450 |1, 138, 738 91 255 98 195 134 | February 28.| July 1. Grand total..... 13, 842 |2, 004, 041 62 255 94 224 144 | February 15.) July 1. THE MEXICAN COTTON-BOLL WEEVIL. 104 *90TIOS.1NUIO ON 1 a ee Wa OSBIOAG peyysIoa puely is io i OSBIOAB poyysIom sexo, Raby te 8061 “Xay, ‘selled AS ee as | Sie sais eke Siam = L061 “xa, ‘seed prriote is siais's yeaa ce eal | ania L061 “XAT “WWeapeg Bhar hai we =| | fae aad CRS SOG A IOS LOGBL “XO, “BIIOJOLA Bee aie OSBIDAB Po -JUS1IOM BUBISINO'T seer a). Rea alls 2S “TIGL “OT URINE L 7 OT6T “BT “YRINITRL, 1% OL6I {eT feinsueA apse 6061 “BT ‘vinsueyy “o08[ I inal 9% “IBN | ¥6 et “ady | 931 @ “adv | 0&1 4B “ABW | GET 6 ‘Ady | Sor b “idy | 081 81 “TVW | 9LT pol ete tee or eeler = op PI “JEW | 86 6 “AW | 91 &% “Ie | SEL €% “LEW | 1ST 1% “Je | 991 LI ‘JeW | OLT Oa i OE oS a aa a eee ee ae 0G “LEW | ZT Og “Ie | IFT I ‘idy | 291 1% “IeW | O9T LT ‘teW | OLT pL teen ee ee a PI “IEW | 86 66 “LEW | SCT 9% “Ie | S&T 0G “LEW | 6FT 6G “JVI | 891 1 ieee a Nina eal ti ABE &1 “ABW | OOT oS “IVI | GIL I ‘adv | GFT 8I ‘ady | S2T 83 “ABW | 991 ee ial a ele ee cl ee |e 61 “IEW | &1i @ “IVW | C&T PI “ew | 6&1 me FS oor, | 9% “EW | ¥6 91 “Ady | 621 €% “idy | IST gt “ady | 8st FZ “Ady | €8T gt “adv | 061 € ‘adv } Sst aes ciak Gree oe | eee £8 aS |e AT) eae eee a | ECT) at lin tae me ee SN. OO 0G “BW | 9ST pie os eel oe |e ee Dodi 9 7) Oc evi eae 91 ‘idy | Zot gt tidy | 21 LT Av | 612 g Av | Fez Speedy ipl ae o> FR g ACW | OFT 96 “Idy | 6ST @ ‘idy | Zor 4 ‘ady | SOT 8 ‘aidy | 08T € Avy | LIZ raat 9% “IVW | 6 I ‘ady | FoI cI “idy | FI IL ‘ady | 291 og “idy | ost 4G “IeW | OLT Tg “Iv | E81 ae Pee aoe eee ae IT “tex | OFT T Avy | 8ST ST pio giet 30 Se iS DOE OSI Sr (SD IS | BIS OI BRO Po GRO RE Se ay rece ay Ap aRE NI “shoqg “sing “shod ‘shoqg ‘shng ‘shog “shoq shoqg “HOIeU “TOIYeU “Ole “mOT] eu “HO1Ieu bm ocoaucied “Ole ‘poSiourg] -Joqiy Jo |‘postourg] -loqry Jo | *postourg| -reqry Jo | *pesiourg]} -loqry Jo | ‘pos1oug| -1eqry Jo *posioury| -Lloqry Jo | :pesieurg]) -1oqiy Jo “doneu qysue'T qysue'T yysue'T q3ue'T yysue'T yysue'T, yysue'T -10 1 OsvloA V “TS-9T “000 "ST-T “00 “08-91 ‘AON "ST-I "AON “T8-9T “390 *ST-I "220 “0g-91 “3dag “WOL}RI[BISUT “WOr}RTTRISUT “UOl}BI[BISUT “HOT; BI[BISUT “MOTB I[BISUL “MOL}EI[BISUL “UOTzeI[eISUT JO Oull [, JO OUILT, jO OUILT, JO OUIL, JO OUI], JO OUIL YT, JO OUlL |, ‘woynynjisur fo app 0} pajnpa. sp quaaam qj0q ay) fo porsad uoynusqu fo ybua) abvi0dp— XT XXX AMV, HIBERNATION. 105 Knowing that the time of entrance affects the percentage of sur- vival, it is also reasonable to expect an effect upon the duration of the hibernation period. Table XX XIX has been constructed to show the average duration and average date of emergence at each locality for all weevils entering hibernation in each half month during the several seasons of the experiments. It will be noted that the length of the period, with a few minor exceptions, decreases in accordance with the lateness of entrance. It is very strikingly shown that in any given period of entrance the duration in Texas is considerably shorter than in Louisiana. On the other hand, it is impossible to show from this table any progression in the average date of emergence. The diagram (fig. 22) shows graphically the correspondence between date of installation and period of hibernation and emphasizes the differences between Texas and Louisiana. RELATION OF SHELTER TO DURATION OF HIBERNATION. That the nature of the hibernating quarters has a direct bearing upon the duration of the period is to be gathered from the records of essrs. Newell and Dougherty made at Mansura, La., in 1909, which are abstracted below: TaBLe XL.—Comparison of length of hibernation of the boll weevil in different shelters at Mansura, La., 1909.3 Number | Number | Average Average Nature of sate of of number Date started 1908. hibernation on of weevils | weevils | of days cate a J quarters. Be. con- | surviving] in hiber- EnGe tained. | winter. | nation. 8 ‘ October 26b7 <= sa soeinaee Pasion Average...| In open field. . 1, 294 325 169.1 | April 13 DOs Fe ee SL do....| Inswamp..... 1,142 162 173.3 | April 17 ID 0 a yeaa perm sa veut opera 1) oN SS gan In open field... 1, 214 409 190.9} May 4 1) Yo tart Geeeeeee ereee, eee ie eee do ....| Inswamp..... 938 408 199.4] May 13 Potaliase £3 59S eas Pees Aes ss- 55s ee ee AS Bebyai3 4,588 SOS: epee + ek hee Seat ake ASVOPARC ros cc Sresdreeee ee oe eee esses ts Ste otoossrse rest aces secesd|>eeecdssws 185.0 | April 28 _ 1 This table and the following statements are extracted from Cir. 31, State Crop Pest Commission of ‘Louisiana. Consideration of Table XL reveals the interesting fact that weevils hibernating in the cool, shaded situations in timber remained in hi- bernation an average of about seven days longer than those hibernating in the open field. Weevils which hibernated in moss in the swamp remained in hibernation practically 200 days, and those which passed the winterin moss on trees in the open field remained in hibernation 191 days. In marked contrast to this the weevils that hibernated in a general assortment of materials in the open field remained in hibernation only 169 days, though gathered from the cotton fields at exactly the same date in the fall of 1908. This proves the dangerous nature of the moss, for it really causes the weevils in it to remain in hibernation for nearly a month longer than they would if hibernating in other’ materials. Table XL also illustrates the influence of temperature upon the dura- tion of the hibernation period, for there is no doubt that it is the temper- 106 THE MEXICAN COTTON-BOLL WEEVIL. ature prevailing in the exact spot where the individual weevils are hiber- nating that determines the date of emergence from hibernation. Piles of grass in the open field are warmed by the sun in February and March, and the weevils emerge from them at that time. The shaded places of the forest or swamp are cool and damp, and they do not reach an NOVEMBEF? DECE/VELA—— > gO 70 20 gO /0 20 3O —_ SEPTEMBER 20 JO OCTUSEF. 40 20 = eerie mies Corenar CoACCP RENE 90 Pee alc | ete ee Fig. 22.—Diagram illustrating average length of hibernation period of the boll weevil as related to date of entering hibernation. (Original.) 120 7/0 100 equivalent temperature until some weeks afterwards, and the wee- vils cunsequently emerge later in such places than in the open fields. The bunches of moss are so resistant to heat that even in the hottest days of summer they are very noticeably cooler than the air. EMERGENCE FROM HIBERNATION. TIME OF EMERGENCE. The time of emergence of the boll weevil from hibernation ranges from February 15 to July 1. It is necessary to discuss the conditions which cause this stirs a A careful study of all the series of experiments to determine the immediate causes for the first decided impulse to emerge has resulted in the following conclusion: That the HIBERNATION. 107 time of emergence varies with the total effective temperature and the rainfall. Computing the total effective temperature from Jan- uary 1 in daily units of mean temperature above the mean of 56° F. (average zero of effective temperature) it is found that approximately 172.6° F. of effective temperature and 5.1 inches of rain are necessary to bring the weevils out of hibernation in comparatively large numbers. If the rainfall is greater than 5.1 inches the necessary effective INCHES PRECIPITATION 4 a a 8 ual co) N mas LINE OF wm Es [—"_ DALLAS, /908 ~ ~ es! Mp2 pee =e — TALLULAH, OR/A, 1907 145° 470 195° 220° 245° 270° 295° be GREES EFFECTIVE TEMFPERATUAE. Fic. 23.—Diagram illustrating relations of effective temperature and precipitation to date of beginning emergence of the boll weevil. (Original.) temperature usually will be less than 172.6° F., and, on the other hand, if the total effective temperature is greater than 172.6° F. the necessary rainfall will usually be less than 5.1 inches. This may be seen by reference to Table XLI and by the diagram (fig. 23). Dis- crepancies will occur with regard to this formula and will in a large pugpe tte be due to the type of shelter or to great irregularities in the climate TaBLe XLI.—Relation of effective temperature and precipitation to date of beginning emergence of the boll weevil. Tota : Total | Dateof effecti¥e 4. | precipita- first Place. ae al tion Faun extensive iESteal: Jan. 1. emergence. oir. Inches. BIPIEII Eel OLO note sects ee ene Se keer ac ans nas soe See Sam 65 10.5 | March 1. Mansoura, 1010s4-2% 36... S2- - ee ee ee ee tn ons Sn ee hi 7.3 | March 2. EYES 1 GO re ee one ae cate gee Pe ae 5 ioc se 160 6.5 | March 12. EVERLAST OU Semen te ohn cn aie ote ea cise Ge. ane 170 2.2 | March 3. Sears, Ue Rec eteettis we a satee oa neee rds sec cmon ce minmie se ke pecans 185.5 oe ee 21. pe NV ENS oe See. Ree oe Seen ee See ae 260 1. ebruary 23. ELS, TBS ea Tg RR SR : 303.7 | 2.35 | March 5. 108 THE MEXICAN COTTON-BOLL WEEVIL. Figure 23 shows graphically that climate influences the time of — beginning emergence. It also has a decided effect upon the sub- sequent emergence. In Table XLII is shown what effect the daily mean temperature has upon the hibernating weevil. Taste XLII.—The relation of emergence of the boll weevil to increase in temperature at Keatchie, La., and Dallas, Tex., 1906. Keatchie, La. Dallas, Tex. Tote eer cent number | based on Range of temperatures (° F.). Nogteee Per cent Number Per cent of grand aK of total eile of total | weevils total emerg- emer- emerg- emer- | emerged. | emerged. ing. gence. ing. gence. 20 27 0 0 20 2.5 52 Tal 2 3.6 54 6.8 116 16.0 25 45.5 141 17.8 127 ARG 18 32.7 145 18.5 309 42.4 10 18.2 319 40.7 84 1S 0 0 84 10.7 20 2.7 0 0 20 2.5 728 100.0 55 100.0 783 100.0 1 Modified from Bull. 77, Bureau of Entomology, p. 44. The number of weevils emerging under 57° F. is very small indeed. From that point the emergence increases with the increase in tem- perature until a majority of the weevils have emerged. Most weevils have been found to leave their winter quarters during a temperature averaging between 64° and 78° F. At Keatchie 75 yer cent and at Dallas 96 per cent of the total emergence took place etween these limits. At Dallas the largest emergence occurred between temperatures of 64° and 68° F., while at Keatchie the largest emergence occurred between 74° and 78° F. In a preced- ing paragraph we have shown that higher temperatures are neces- sary to affect the weevils hibernating in Louisiana, apparently because of the heavier shelter. RATE OF EMERGENCE. With a long-continued emergence period it is important to deter- mine whether the rate of emergence is equal at all times or has its periods of retardation and acceleration. Upon charting the per- centage of total emergence for each week it was noted that the Texas and Louisiana points differed considerably. On the accom- panying diagram (fig. 24) the four Texas series are consolidated to give the average rate, and likewise the four Louisiana series are consolidated, while in Table XLIII the records for each locality are given. It is immediately apparent that the emergence begins much HIBERNATION. 109 more abruptly in Texas than in Louisiana. In Texas 25 per cent have emerged by March 12, 50 per cent by March 21, 75 per cent by April 8, and 100 per cent not until June 19. On the other hand, in Louisiana 25 per cent have not emerged until March 30, 50 per cent until April 27, 75 per cent until May 16, while 100 per cent will have emerged only by July 3. Herein lies a powerful argument for early planting. With 50 per cent of the weevils emerging after March 21 in Texas 700 FEB. MARCH AVF L. MAY SUNE SULY PLEA CENTAGE OF TOTAL ENIEPPGENCE 8 2g, ‘ G & ‘ ' ‘ ‘ Fic. 24.—Diagram illustrating average rate of emergence of the boll weevil from hibernation in Texas and Louisiana. (Original.) and 86 per cent emerging after the same date in Louisiana, or with 75 per cent emerging after April 8 in Texas and 64 per cent yet to emerge after the same date in Louisiana, it becomes evident that every day gained in Texas before March 21 or in Louisiana before April 8 is of immense importance in the fight against the weevil. Even later than these dates every day counts a great deal, because it is apparent that the longer planting is deferred the more weevils will be out to attack the cotton when it comes up. 110 THE MEXICAN COTTON-BOLL WEEVIL. TasLe XLIII.—Percentage of total emergence of the boll weevil out at given dates. | Keatchie,| Tallulah, Mansura,| Mansura,} Dallas, |Calvert,| Dallas, | Victoria, | Tallulah, Date. La., a. wal ape La., Tex., | Dex ieTex., Tex., La., 1906. 1910. | 1910. 1909. 1908. | 1907. | 1907. 1907. 1911. February 21. ...-. 0.00 0.31 1.64 7.20 0.00 0. 00 0. 00 0.00 36.95 February 28... .. 00 sal 3. 28 10. 61 00 00 00 12.01 36.95 Marche-peneeee 00 6.62 10. 56 19. 22 W.20 | 22.80 | 24°48 27.92 39. 92 March 14...._... 00 10.09 15. 69 19.73 | 23.63} 31.90 | 36.36 48.23 63.83 Marchi2) 27-6 00 13.56 21.19 23.24 | 45.45 | 44.30] 57.14 66. 24 70. 35 Marchi28..2...-2% 3.93 23.34 38.05 B0n95.| 55.45ieoore2ON) TL.72 79.35 72. 52 April 4s 6.87 35.95 46.53 38.16 | 63.63 | 64.20] 75.70 84.16 74.69 Atoril (lepers 24.54 41.95 49. 42 43.87 | 68.18 | 70.40] 81.28 89. 58 81.21 Ujoi mila ksjee Sede ee 32.11 46. 05 52. 41 47.78 | 74.54 | 77.70 | 84.46 93.80 87.73 SATU ID5 ota ees 40.67 48.89 53.86 56.39 | 87.27] 79.51 | 85.74 95. 02 96. 42 May. 26 nrccrscrnorcnns 52.73 61.83 60. 41 61.30 | 90.91 | 82.62] 88.62 95.88 96. 42 May 9S 88a oo 60. 44 70. 66 72.35 67.51 91.82 | 88.73 | 92.30 97.50 98. 59 May 16% 54-2-25-- 72.22 75.39 75.64 75.12 | 94.55 91.94 | 95.78 98.36 98. 59 May 23...22...-+:- 86. 41 88.64 84.77 82.43 | 98.18 | 94.95 | 98.76 98. 92 98. 59 May i305 S25. 5.5- 91.60 93.69 92.77 89.73 | 98.18 | 97.56 | 99.34 99.18 98. 59 JUNGOR seem oer 97.36 99. 05 98. 43 96.83 | 99.09} 99.17 | 99.73 99. 90 100. 00 iricls) bee eee 99.19 99. 68 99.89 97.83 | 99.09 | 99.68 | 99.88 99.97 100. 00 Jume'20= 5. 8s .5- 99. 61 99. 68 100. 00 98.74 | 100.00 | 99.99 | 100.00 100. 00 100. 00 SMG ico one 99.89 100. 00 100. 00 99.94 | 100.00 } 100.00 | 100.00 100. 00 100. 00 pulyrae se 100. 00 100. 00 100. 00 100.00 | 100.00 } 100.00 | 100.00 100. 00 100. 00 The nature of the shelter in which the weevils are hibernating has a decided influence upon the rate of emergence, as is shown in Table XLIV, based upon the experiments of the Louisiana Crop Pest Commission at Mansura, La., in 1909. Taste XLIV.—E fect of nature of shelter upon rate of emergence of the boll weevil, at Mansura, La., 1999. Dates by which certain percentages of the surviving weevils were out of hibernation. Character of hibernating quarters. 100 per 25 per cent.| 50 per cent. | 75 per cent. cent. Average quarters (cages Sand’ 51)2s22.22- 2222-2222. 22-22. March 19..| April 12...| May 15....| June 27. @pentfieldl(GageswAVald p)igocns sees sees ee een eee ee March 31..} April 29...| May 24....| June 21. Swamp (cGagessBand5l)).2 ee. e seeps ee ee ee April 8....| May 20....) June1....} June 29. Moss; (Cages :AtandiB) ase 0_. 2 eae ee eet cr cck April ose Wa >. june 25. --| +05 It will be noticed that only four cages entered the consideration, cage 5 being average quarters in open field, cage 51 being in average aperiere in swamp, cage A being Spanish moss in open field, and cage being moss in swamp. SURVIVAL OF HIBERNATED WEEVILS. The central idea in all the hibernation experiments has been the determination of the percentages of weevils which survive under different conditions and different treatments. In obtaining the facts which have been discussed in the preceding and following paragraphs on hibernation the grand total of 181,932 weevils has been used. With such a large series it is reasonable to suppose that the average ercentage of survival must very nearly approximate the normal. his survival in nine series of experiments conducted in seven years at six localities representing the principal climatic, shelter, and other conditions of the infested region has been 7.6 per cent. Table XLV presents the final summaries of each ot the nine series. HIBERNATION. a i | TaBLE XLV.—Summary of survival of the boll weevil in all the more important expervments. Total ; Total : number of | number o Places weevils weevils See : entering | surviving | .rvival hiber- hiber- 3 nation. nation. Isa PLEAS. Lush ET Se 6 epee aeeiieeies © obey Sa One pao Ae ee ea 24,700 731 pa | WEE STE TOA) SS ee pe eee ee ee ee 16, 281 3, 260 20.0 Raeetaniiet mar LOL OM Cocos 2 eaters < ee 5 ie eee mins sede aa nee se's se 22,179 1,038 4.6 UUPUMIpaL Ibs ol kts Sethe OS ee Re eae ee eee ee 21, 835 317 1.4 ADELE YG: TD RST EN Mle Mies ieee Sl eee ae ey a ee ee ee a ee 8, 439 46 at) IPRS LLORES Lato aC SC ee ae eee eee be 93, 331 5, 392 5.7 TORE SE CEES alk Oy Se teeta SSO ROE Se ers eee ee 32, 439 3, 464 10.6 Malvert. Lex, 1907-. = 5.5.2. 2-20< 2s te ee ey RE eee 20, 430 1, 834 8.9 AVAL ESS LOO | tetas tans saree oe ac se acis.w'= spn cc eje.= m= aeide cme ees oe 23, 645 3, 026 12.8 PBL Sih Ome SUG 2 Set ie ae AS eet = ae ee es - Seiss we. '5 58 eee oan 12, 087 118 9 Four Texas series......- pet tae Se a OOS ae Ie ee ee ee Sea 88, 601 8, 442 9.5 WROUAL Of MIN CISETICS sr... «a2 2 n= <= o..ms.« Baek. Sees Monee ee ae eee 181, 932 13, 834 7.6 The highest average percentage of survival for any locality is 20 per cent, at Mansura, La., in 1909, and the lowest average is 0.5 per cent, at Tallulah, La., in 1911. The highest percentage of survival in any cage was 47.72 per cent of 767 weevils, at Mansura, in a cage with average conditions established December 14, 1908. The lowest percentage of survival is no weevils, from 408, at Tallulah, in two cages with average conditions, established November 15, 1910. RELATION OF FALL DESTRUCTION TO SURVIVAL. One of the most important recommendations for boll-weevil con- trol is that of early destruction of the cotton stalks. It has long been known that the earlier the stalks are destroyed the less chance the weevils have of surviving. Table XLVI, showing the percentage of emergence by dates of installation, affords an incontrovertible argu- ment in support of this recommendation. TaBLE XLVI.—Percentage of emergence of the boll weevil, by dates of installation. ince Sept. 16-| Oct. 1- | Oct. 16- | Nov. 1- | Nov. 16-| Dec. 1- | Dec. 16- 5 30. 15. 31. 15. 30. 15. 31. Texas points. Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent. | Per cent. Dallas 007s... £2959. 2h ee | eee SS 2.61 6. 67 20. 57 a eo el be ee, oe OSV Gat 1 2aae SSeS Oe See Cee Se eee 3.15 3.98 10. 33 Fe GO| a ae S| PSE ere NYT E LTP tL SSPE 2 Re ag i ily le | 6.17 17.69 16522) | Senay a2] a oe AAS L908. so. etek ates ne Se 0. 23 -39 2.8 1.68 0. 20) |. ee SPEER. eee Texas, weighted average | percentareres 2 2... 23 2.33 5. 62 15. 42 1G. O5))|Ger= 4S ele eee Total weevils installed.......... 5, 213 7,729 27, 806 30, 431 EY | Ben | | ee Louisiana points. ISCALCHIGNLODO Ro oer etoss oe = Sera, eee) RES DS gees ere Fey oo! 2.71 3. 23 0.8 Manniina 1000s. -..* <2 2555 -e 2.7 3.31 23.9 23.8 24. 56 43. 23 37. 06 Maninuras O10 eascs seco e. tli 5? . 23 1.31 6.58 9.95 6.31 Ge OM eee cere SDANUUADS LOLO So8e on see tee 3. | 34 2. 23 1.16 1.53 2.4 (1,0) | eee tS SUSE AB OLY Soe eee no acne case eee 1.15 -54 SOUR acre So! (Ul Ee aese eee Louisiana, weighted aver- ; age percentage. .:....... 37 2. 00 8.04 8.82 6. 07 10. 65 12.61 Total weevils installed.......... 8,186 14, 218 24, 464 9,620 24, 252 10, 208 1, 483 Grand weighted average r percentage... 2. ..5.....-: 0.31 2.07 6.58 14. 26 9.00 |e 10.65 12. 61 Total weevils installed....| 13,309 | 21,947] 52,270 | 40,051 | 36,425 | 10,208 1, 483 112 THE MEXICAN COTTON-BOLL WEEVIL. Converted into terms of the number of weevils in every thousand which would survive the winter if stalks were destroyed on a given date, we can see the force of Table XLVI. It is even more evident from the arrangement of the data given below in Table XLVII. Taste XLVII.—Number of boll weevils in each 1,000 which would have survived destruction of stalks on a given date. : In Loui- Date of destruction. In Texas. ania September 16-30 2 3 October 114.2): ccs eee eee eee 2 23 20 October 16-31... 354-525 22 ease ee 56 80 November 1-15». < =<. 2she is Se ee ES a Ss ne rs hd tes Sp Se Sates ses ees a a 154 88 November 16-30 160 60 December 1-15. --......-- De ee hsp tad cI SE SE Ae oeps aae ie es eeere ga (?) 106 ‘December Col. . znd se PA ae ack ce 26 oh ee dete cee ee cet eee Ree eee eee ere ee be (?) 126 RELATION OF SHELTER TO SURVIVAL. It has already been stated that the density of the shelter has a bearing upon the survival. This is best shown by the following records (Table XLVIID): Taste XLVIII.—Relation of shelter of boll weevils to their survival. Place. Date installed.| Weevils. Shelter. Survival. Per cent. Mga SUIS if Se eas Sc ee ae Se ee ete October 26.... 2,436 | Average....... 20. 00 1D Yo Ae egy petal ase sis peeps ha gees che wh Meo? Bap (0 oem Seger 251580 MMOSSe see cee 37.76 Victorias Nex. 73r7. .43.7 2 LER grey ee ie PE ee October 28... . 2,375 | Average....-..- 5.61 1D) SRR 9 3 See ES rei oe ce) ieee yk cee pe November 6... 2850) |. MOSS: ae. cake 23. 65 DOR SAAC ee SEP ISIA IANS, Sek LA November 10.. 2,850 | Average....... 12. 70 RELATION OF CLIMATE TO SURVIVAL. Another important consideration in determining the causes for high or low survival is the climate. Some of the principal relation- ships are brought out in Table XLIX below: TasBLe XLIX.—Relation of climate to survival of boll weevils in hibernation. Rainfall and tempera- ture, Oct. 1—Mar. 15. Number | Per cent : Place and year. Description. of. of sur- eet! aca Aigsos | iDotal weevils. | vival. Rain- | lute jdegrees fall. mini- | below mum. 32, Inches.| °F. oe Tallulah, La., | 10 cages, variety of 8, 439 0.5 | Feb. 15-June 4...) 8.30 9.5 199.5 1910-11. shelter, installed : Oct. 15-Dee. 1. Dallas, Tex., | 9 cages, variety of 12, 087 -9 | Feb. 19-June16..| 22.61 15.0 233.0 1907-8. shelter, Sept. 21- | Nov. 18. Tallulah, La., | 19 cages, great variety 21,835 1.4] Feb. 15-June 27..| 19.34 13.0 378.5 1909-10. of shelter, Sept. 16- Dec. 14. HIBERNATION. Li3 TaBLe XLIX.—Relation of climate to survival of boll weevils in hibernation—Con. Rainfall and tempera- ture, Oct.1-Mar. 15. Number | Per cent Periods of emer- Place and year. Description. on of sur- ane, sit gence. Abso- | Total weevils. vival. Rain- | lute | degrees fall. mini- | below mum. 32. Inches.| °F. ort Keatchie, La., | 18 cages, variety of 24,700 2.1 | Mar. 22-June 28..| 18.87 21.0 91.0 1905-6. shelter (1 bare), in- 2 stalled Nov. 18- Dec. 18. Mansura, Tex., | 19 cages, great variety 22,179 4.6 | Feb. 15-June 15...) 15.37 19.5 151.5 1909-10. of shelter, Sept. 16- Dec. 14. Calvert, Tex., | 10 cages, variety of 19, 408 8.9 | Mar. 4-July 1...) 11.87] 26.0 47.0 1906-7. shelter, Oct. 1-Dec. 10. | Dallas, Tex.,| 10 cages, variety of 30, 864 10.6 | Mar. 1-June19...| 8.52] 22.0 145.0 1906-7. shelter, Oct. 13- Dec. 6. Victoria, Tex., | 10 cages, variety of | 22, 463 | 12.8 | Feb. 28-June 15..) 11.25 | 27.0 5.0 1906-7. shelter, Oct. 25- Nov. 29. Mansura, La., | 19 cages, great variety 16, 281 20.0 | Feb. 21-Jume 29..) 10.44) 23.0 81.0 1908-9. - shelter, Sept. 28- lec. 21. One of the most striking features of Table XLIX is the disparit between the percentage of survival through the six winters considered. A special effort has been made to discover the factors that cause this disparity. Among those that have been considered are the absolute minimum temperature, the daily accumulated degrees below 32 during the hibernation season, the number of times a temperature below 32° was reached, and the rainfall. Contrary to our expecta- tions, it appears that the number of times the temperature descends below 32° has no direct effect. However, there seems to be a direct relation between the absolute minimum temperature and the rainfall, taken together, and the percentage of survival. As the absolute minimum ascends and the rainfall decreases the survival seems to increase. The greatest survival (Mansura, La., 1908-9) was accom- anied by the third highest mintmum temperature and the third owest rainfall during the hibernation season. In the same way the next to the highest survival (Victoria, Tex., 1906-7) was accom- anied by the highest absolute minimum temperature and the fourth owest rainfall. Conversely, the lowest survival (Tallulah, La., 1910-11) was accompanied by the lowest absolute minimum tem- perature and the lowest rainfall. The next to the lowest survival (Dallas, Tex., 1907-8) was accompanied by the third lowest absolute minimum temperature and the highest rainfall. It thus appears that a moderately cold winter, with temperature frequently near the zone of fatal temperatures and excessive precipitation, is very unfavor- able for the weevil, but a winter with little precipitation and a tem- erature within the zone of fatal temperatures is by far the most atal. Conversely, a winter with temperatures always above 20° and moderate precipitation is the most favorable for the weevil. 28873°—S. Doc. 305, 62-2——8 114 THE MEXICAN COTTON-BOLL WEEVIL. Certain climatic phenomena are likely to occur which will empha- size still more the effects produced by extreme cold and great precipi- tation. At Tallulah, La., in 1910-11, the early freeze on October 29 cut off the food supply and was followed by warm temperatures in November which required feeding. The minimum experienced in January completed the control and was low enough to counteract the small precipitation. LONGEVITY OF HIBERNATED WEEVILS. From the beginning of the hibernation experiments in 1905 it has been the custom to place the emerging weevils in rearing jars or cages to determine the average and maximum longevity with and without food. The data obtained have a bearing upon the proper time for planting and upon other practical points. In these experiments 9,295 weevils have been used, as shown in Table L. The fed weevils were furnished cotton squares as soon as they became available. Before that time they were given fresh cotton leaves daily. The unfed series was supplied with water only. Both series were placed in small cages where general conditions closely approaching those in nature were maintained. It should be especially noted that fed weevils show over double the longevity of unfed weevils throughout the season. TaBLe L.—Longevity of hibernated boll weevils after emergence. Unfed series. Fed series. lace. Longevity. L ity. nee Number aes Number eee, of 3 T | of weevils. | yraximum. Average. weevils. | Waximum. Average. Days. Days. Days. Days. Keatehies ia. 01906. 4.eais sei 412 62 WgTD | Pee ese eas Aen ee ee ee Dallas Mex O07 ot cot ee ys 2,179 90 12. 50 901 130 38. 20 Calvert; Dex, N90 o 6 ees 1,079 48 8.07 715 118 30. 00 Victoria, Tex i007 pleee pak. 1,360 44 8. 20 1,349 86 14.70 Mansiras lia, 1 O09 cnr ee ee nem nee 261 44 11.09 360 36 10. 42 INStChez #Miss., LONG: 29 8: Sarat ees Mies 19 8.75 36 25 12. 20 Mansura; oa. 90s 8 - seen Sens 175 28 8.7 146 81 36. 50 Pallnighs Wa: TOO 4k fetes. ae kN 179 21 5.70 121 105 22. 30 Pallvilpih, Wee, AQul o£ fo. else BL. : 8 12 7.25 10 25 13.30 Motalsys.chiceee Ase eee Se Eres BGS | CSS SEee ha ae - 3;(638) 52285. 2S eee Moascimimn ses 426, eee Se oe 90 | 1p i Pe eee eae 130 38. 20 Wieighfedlaverage.” ©. soos oecelerioeciconsellten eee Bee | 10. DDR |eeeee oe faerie ee 24. 20 It will be noted that the records of longevity of weevils after emergence from hibernation referred to above are based upon speci- mens that had passed the winter in artificial hibernation cages. However, a number of observations have been made upon the lon- gevity of weevils which pass the winter under natural conditions in the field. For instance, March 1, 1906, a number of weevils were collected from cotton bolls at Brenham, Tex. These were placed in small cages and observed daily. The last one died on May 31. Naturally the time this weevil was deprived of food the preceding fall is not known, but it must have been prior to December 1, as the frosts had : HIBERNATION. 115 killed all cotton at Brenham by that date. Assuming that it entered hibernation on December 1, it lived six months without food. In another case weevils collected in the field -—-MARCH— -~APRUL -—-MAY— ,-—S UNE in the spring at Cal- vert, Tex., lived with- out food as late as June 8. This gives a duration of life without food of six months and twelve days. Similar ob- servations indicate clearly that the lon- gevity of weevils that pass the winter in artificial cages is a roper index to the ongevity of those which pass the win- ter in the field. It has become quite apparent from —— 2 = a study of therecords Fia. OTT ee Lae Con onLy weevils after that the longevity of weevils provided with food is considerably greater with weevils emer- ging in June than with those emerging in March, while, on the con- trary, with unfed weevils the longevity decreases with the lateness of emergence. (Table LI.) The diagram (fig. 25) illustrates the above statement graphically. TasLe LI.—Latest dates of death of hibernated boll weevils. Unfed weevils. Weevils fed foliage. | Weevils fed squares. Time of emergence. , Mansura,| Tallulah, } Mansura,} Tallulah, | Mansura,| Tallulah, La., 1910. } La., 1910. | La., 1910. | La., 1910. | La., 1910. | La., 1910. Mebwin—atince <2 cccye. chat sansn ke ete NS Re na tre ape lose < cian ecesee eal eote ce aus ap eae eee a 1S IEE 2 WEST I AR pile pce ete Pai ye ee ASO eACpR ert le eete eta ea a! aaiacc wevleya| oacleeew sen | aaa ee oe Min ab-sib i Leyla eo Lt ee 7. be Apr. 20 | Apr. 12 | June 20 |........-- rel Sad PERT 2 WATE LG pes ee aera eee ere meres AGE 25) (Apia 2ech Uy © 08) PUNE 2b |S. o ess Sec ee PRPS TOUT Le cease. 62s. cts 2 Bee - ay 13 ay 21 {Sune 28" /une 18tls.2.- oe eee oe. VAS ie es. ae ae ee re May 29| June 1] July 15 | July 15}.......--. pee he sec 101 bE) ig ae eh eS a ae ease June: 12 | June 15 | July 12 | July 26 j-....-...- ee 13 PUReMHIpeete «2Fse cl. eh. 9 Se. Oi eektiea: June 27 | July 29 | July 7/| July 19| July 1 BIC Olea op nance oles om win a ao ho ah Selanne earn aga tale PRE, OE ERA See ee, eee Aug. 31 Iettife BEARON .). 3.de-onmene bees Sees June 12 June 27 | July 29 | July 26 | July 19] Sept. 13 MAXIMUM LENGTH OF LIFE. In connection with Table LI it will be noticed that the latest known recorded death of a hibernated weevil is September 13. This fact, taken in conjunction with Table LII, showing the maximum longevity 116 THE MEXICAN COTTON-BOLL WEEVIL. of weevils from the time of entering hibernation to death, is of great interest. The maximum longevity of 335 days, or 11 months, gives proof of the wonderful vitality of the boll weevil. TasLe LII.—Longevity of hibernated boll weevils from installation to death. Longevity. Place, Condition. Average. | Maximum. Days Days. Mansnra, ia. tO ee ee Re cel nccas| ROEM eO ena seician.« aan ANY DOT EN Sh OV USSR SR Se Re LE oS AS SE OE SSE G5 «ne SR ot 169 243 Mansuras ies. FOO eo tte cate Bint «4 xin. ucin, yu | ROME OLN Ca cee mans 206 256 Tallulah Wier POLO Senet eereere ts oc ae ee rho oe el eee dQ. 8.5255 es 221 272 MannurasEsae SOLO | Sie tiers Sa eae eens od eeueeece Fed squares. .......... 257 267 *Padlolah Tse. Ol eas otc te ose ow oa ee wen so | ctelgs OIE arate aceae 262 335 RELATION OF EMERGENCE AND LONGEVITY TO TIME OF PLANTING. The data that have been presented show the extreme importance of early planting as a means of averting damage by the boll weevil. Early planting takes advantage of the portion of the season when the weevils are present in the fields in smallest numbers. The longer rylanting is deferred the greater the number of weevils which will 1ave emerged. The advantage of an early crop has been shown in many experiments by the Bureau of Entomology and by practical cotton planters. On the other hand, the experience in late plantings has been disastrous. The obvious explanation is in the prolonged period of emergence and the reniacenete ability of the weevils to live without food after emergence. This topic will receive additional treatment under the heading of ‘ Repression.” NATURE OF WEEVIL ACTIVITY FOLLOWING EMERGENCE FROM HIBERNATION. In the section dealing with the spring movement we have discussed the early search of the weevils for food. There are certain points connected with the spring movements, however, which are intimately related to hibernation, and these will be dealt with here. ‘In following the activity of emerged weevils at Dallas, Tex., certain specimens were marked in such a way as to make it possible to recognize them individually, and the weevils were allowed to remain practically undisturbed in the section where they had spent the winter. In making the daily examinations record was kept of the appearance or disappearance of each individual weevil. No food was supplied in any of the sections until toward the close of the experi- ments in May, when seed was planted and cotton began growing before the last weevils emerged. A majority of the weevils were seen a second time, and some disappeared and reappeared as many as eight times. The longest Bc between the first and second appearance of any individual was 43 days. 1¥From Bull. 77, Bureau of Entomology, pp. 50, 51. HIBERNATION. 1 Taste LIII.—Intermittent activity of unfed boll weevils after emergence, at Dallas, Tex., 1906. J Weevils “rehibernated’”’”— | : a Number of weevils seen— —-— ee “ ‘ =o Once. Twice. |Threetimes.| a -- a ste ees g 5 : Z a | a) < % Z ; « c fee 2 See ta 1 Fe 4s 22 . re] pe 5 e | = 3 2 5 5 5A g g g pay aa FE 5 en lee ay [P= sis S11 Se fats lesb tw Tre | @ is ia) sl 2) 3 Yas ° L e ea a Dh DL a3) Zz a Zi a Zz Ais | 46 2 | 15 1) 6 2 2 1 17 8.7 | 6 t Py 2 | 3.5 6.8 | | The observations recorded in Table LITI show conclusively that wee- vils may leave their winter quarters during warm days Le failing to find food, they may again become quiet and emerge again after a con- siderable interval. This fact has an important bearing upon the proposition which is frequently advanced by planters of starving the weevils in the spring by deferring the time of planting. While many weevils might perish in this way, it is certain that many more would be able to survive and reappear at intervals, so that there would be plenty of weevils to infest the crop, even though this might be planted as late as is possible to secure any yield. Other observations were made upon the intermittent activity of unfed weevils during the spring of 1906. Weevils from Calvert, Vic- toria, and Brenham, Tex., were tested. The weevils from Calvert and Victoria had been confined in hibernation cages throughout the winter. Those from Brenham were collected in the field early in March. None of these weevils had tasted food after emergence. The results are shown in Table LIV. In this table the date of death, unless otherwise indicated, is considered as having been the middle date between the last examination at which a weevil was found alive and that at which it was found dead. Taste LIV.—IJntermittent activity of unfed emerged boll weevils, 1906.1 | | | When , : Date of - When s When Weevils | Locality. oe ut in hi- pinches rehiber- | put in rehi- | pec ar * | bernation. hornathia: nated. rnation. | tion eee — z ere ees ae = 1905 1905 1906 1906 Calvert, TAS. ossccs 255 s-rs00srs Hae 25 a 27| Apr. 19] Apr. 23 20 | May 10 \PNov 7,13 Ov. 7,13 Wactorie, Vex: ooh 32 5252-22052 {Dec 11 | Dee il \ Apr. 6| Apr. 16 7 | Apr. 24 1906 4 LUT US a ee Nov. lh EE Pee Mar. 1 | Mar. 7 8 | May 11 : = of 3] : aS ee Average Weevils | Date of | weeviis | Date of | weeviis | Date of | jength of Locality. surviv- 4 surviv- . surviv- life in ing. Der yal ing. Larne ing longest | rehiber- nation. nation. survival. nation Days. ORI ORT, OR eraercnn ae anon coos 10 | May 22 6| June 8 0| June 8 30.4 Wictosisg: Sie oo. cocotbo 3| May 10 Ue Bere ee eee May 10 19.1 Brenham, Tex. 6. ican n-nvsacns a 2| May 23 1 | May 31 0| May 31 67.4 1 From Bulletin 77, Bureau of Entomology, p. 52. 118 THE MEXICAN COTTON-BOLL WEEVIL. The records for Calvert and Brenham show a very remarkable ower of endurance in some weevils, the average survival for the two fats of 20 and 8 weevils being over 30 and 60 days, respectively. NATURAL CONTROL. Considerable attention has been given to the study of the natural forces which control the boll weevil. These studies have revealed a large amount of important data, some of which have been used in several bulletins. In the present publication it is possible to give only a summary of the most important results. In general, the natural agencies which control the boll weevil may be classified as climatic (consisting principally of heat which kills directly and also indirectly by rendering the food supply unsuitable, and dryness, the effects of which are intermingled with those of heat), plant resistance, parasites and other insect enemies, diseases, and birds. Each of these agencies will be discussed separately, but a general summarization may be of value. Table LV is a summary of the observations made in the years 1906 to 1909 on weevil stages from many localities. It deals with the mortality of immature stages from all causes exclusive of plant proliferation. TasLtE LV.—Annual mortality of immature boll weevils in all classes of cotton forms, 1906-1909. Number stages killed Percentages of mortality : by— | due to— jotal | Total | Total : Year. ies stages | stages |- amined, | found. | dead. | Qjim- | preda-| Para- | All | Clim- | Preda-| Para- ate. tors. sites. | causes.| ate. tors. sites. LODGE TEEN Ds U2 100, 644 | 40,073 | 22,353 | 10,078 | 10,547 | 1,728 | 55.81] 25.15] 26.31 4,31 1 AS 1 Aa See ee a a 21,980 | 13, 405 1,205 3, 896 2, 263 1,116 54. 27 29. 06 16. 88 8.32 190See rece ae 72,234 | 29,546 | 13, 103 6,268 | 3,878 2, 957 44.34] 21.21 13. 12 10. 00 1909s = 2 22st eed 43 27,857 | 11, 653 4, 863 3,012 1, 231 620 41.73 25. 84 10. 56 5.32 1906-1909....| 222,715 | 94,677 | 47,594 | 23,254 | 17,919 6, 421 50. 26 24. 56 18. 92 6.78 Inasmuch as the material used in making the examinations was derived from many sources and in different proportions each year, a system of weighting the different kinds of material was devised. Table LVI presents a summarization of this weighting in terms of percentages of mortality: TaBLe LVI.—Weighted average mortality of the boll weevil, 1906-1909, due to various causes. ee Prolifera- Glinaater Preda- | Parasit- tion.! tion. ism. Total. Per cent. | Per cent. | Per cent. | Per cent. | Per cent. NOB ore avai & Rene ae aesais so ance Reptile rare pcini Se 12. 42 24. 39 24. 85 2. 94 64. 61 LOOT ee 2 cart kee Oe eee amet yeas: cen ee eter a Creal 12, 42 28. 16 16. 18 3. 83 60. 61 1908 oie, = 5 Bene, -, 23s, dee ee ee ene domes Seeiaae 12. 42 17. 83 USF 6. 34 48. 37 1909)... ooo dt setoces = Josten ene ene aes eataeee 12. 42 23. O01 10. 92 2. 63 48.99 NOOG= 1909 gaya fe 5 21 = cin ce tale Brie oe pegs wiaraiaeinh = re 12. 42 24. 45 15. 93 3. 93 56.73 1 The average determined in 1906 (see Bull. 59, Bureau of Entomology) is used to apply to other years. NATURAL CONTROL. 119 The extensive series of examinations tabulated above (Table LVI) were made upon immature weevils in all conditions of squares and bolls, the principal of which are known as hanging dry squares, fallen squares, hanging dry bolls, and fallen bolls. The conditions in these four classes of material vary greatly as does the mortality, as is shown in Table LVII. The apparent discrepancy between the totals in Table LVII and in Table LVI is due to the admission of other minor classes of material in the first table. This table (LVII) also excludes mortality from plant proliferation. TaBLe LVII.— Mortality of immature boll weevils in various classes of cotton forms, 1906-1909. Number 6 tages killed | percentages of mortality due to— Total | Total | Total a Class of infested forms asl t forms. exam- | j oe pag ined. ORIEN eI, Cli- | Preda-| Para- All Cli- | Preda-| Para- mate. | tors. sites. |causes.| mate. | tors. sites. Fallen squares....| 107,293 | 63,985 | 34,403 | 17,596 | 13,958 | 2,849 SsekOr|p ie DOs) fib ok 4. 45 Hanging squares. . 24,683 | 14,390 7,084 2,543 1,745 2,796 49. 22 17. 67 12.19 19. 43 Hanging bolls. -... 41,738 8, 737 3,328 1,709 1,054 565 38. 09 19. 56 12. 06 6. 47 Fallen bolls... ..--. 46, 200 6, 825 PSY Gl 1,128 1,148 99 34.79 16. 52 16. 80 1. 45 All classes...| 219,914 | 93,937 | 47,190 | 22,976 | 17,905 6, 309 50. 23 24. 45 19. 06 6.71 Still another extremely important aspect of this large series needs to be shown. This is the geographical differences in the control by climate, predators, and parasites. Taste LVIII.—Average mortality of immature boll weevils in various classes of cotton forms by States, 1906-1909. Total Stages killed by— Mortality due to— pce Total | Total Class of formsand State. aS stages | stages ‘ned, | found. | dead. | Cli- | Preda-| Para-| All Cli- | Preda-| Para- : mate. | tors. | sites. | causes.| mate. tors. sites. Fallen squares. Pech Pcie ace Preh ATKANSASP etre. meek 374 162 62 43 17 2 38. 27 26. 54 10.49 1, 23 ROWS aN aee se sees 28,204 | 15,177 | 4,895 | 1,990 | 2,243 562 | 32.25] 13.11 14.77 3.70 Missisaippie 22ns2 soe 4, 216 2, 661 1,070 416 263 391 40. 21 15. 63 9.88 14. 69 OBanoma soso es 657 442 238 100 117 21 53. 84 22. 62 26. 47 4.75 Southwest Texas....... 2, 757 1,390 390 186 152 52 28. 06 13.38 10.93 3.74 Southern Texas........ | 38,007 | 25,063 | 16,965 8,547 | 7,377 | 1,041 67. 68 34.10 29.43 4.15 HastPerases. oo Sek 825 464 248 136 107 5 53. 44 29. 31 23.06 1.07 Central Texas. .....0..- 14,879 7,628 4, 233 | 2,386 | 1,602 245 55.49 | 31.28 21.00 3.21 Northeast Texas....... 10, 318 6, 497 3,439 | 1,812 | 1,347 280 52.93 27.89 20.73 4.30 North-Central Texas...| 7,066 | 4,501 2,863 | 1,980 633 250} 63.60] 438.99] 14.06 5. 55 Hanging squares. ATKANSAS? = 2 << Sco see 1,612 | 1,144 494 188 60 246 | 43.18 | 16.43 5. 24 21.50 Louisiana 2 oe e Oe 8, 601 5,184 | 2,182 881 651 650 | 42.09 16.99 12.55 12. 53 Mississippi. -..... 2.2. 784 499 182 41 34 107 36. 47 8.21 6.81 21.44 Oklabomatitt.. ..- 100 63 26 6 0 20 | 41.27 9.53 0.00 31.74 Southwest Texas....... 89 46 24 6 2 16 52.10 13.00 4.30 34. 7 Southern Texas........ ) 5,740} 3,626 | 1,937 727 496 714} 53.41 20. 04 13. 67 19. 69 Rast Texas... . 0... 192 135 | 10 5 1 4 7.40 3.70 0.74 2.96 Central Texas. ......... 2,094 1,052 703 253 208 242 66. 82 24. 04 19.75 22.98 Northeast Texas. ...... f 1, 667 887 290 211 386 53.80 | 17.39 12. 66 2Z30Lo North-Central Texas...| 1,992] 1,141 766 196 88 40271 67-13") L717 7.71 43.12 120 THE MEXICAN COTTON-BOLL WEEVIL. Although the grand total of the examinations shows a higher mor- tality due to fallen squares than to hanging squares, it is noticeable that the mortality in hanging squares is greater in Arkansas, Louisi- ana, southwestern, central, northeastern, and north-central Texas, and less in Mississippi, Oklahoma, and southern and eastern Texas. As shown in Table LVIII, the highest mortality in fallen squares is 67.68 per cent in southern Texas and the lowest 28.06 per cent in southwestern Texas. In hanging squares the highest mortality is 67.13 per cent in north-central Texas and the lowest, 7.40 per cent, in eastern Texas. Climatic control is highest in fallen squares in north-central Texas, at 43.99 per cent, and lowest in Louisiana, at 13.11 per cent, while in hanging squares it reaches 24.04 per cent only in central Texas and is as low as 3.70 per cent in eastern Texas. Predatory control in fallen squares is highest in southern Texas, at 27.43 per cent, and lowest in Mississippi, at 9.88 per cent, while in hanging squares its highest average is 19.75 per cent in central Texas and its lowest no per cent in Oklahoma. Parasitic control in fallen squares is highest in Mississippi, at 14.69 ne cent, and lowest in eastern Texas, at 1.07 per cent. On the other and, in hanging squares it is highest in north-central Texas, with 43.12 per cent, and lowest in eastern Texas, with 2.96 per cent. In fallen squares it is generally the case that over half of the mor- tality is due to climate, but in Louisiana, Mississippi, Oklahoma, and southwestern Texas insect control is greater than climatic. In hanging squares the insect control is invariably greater than climatic control, and in Mississippi, Oklahoma, and southwestern and north- central Texas parasitic control alone is greater than the climatic plus the predatory control. It was shown in the table comparing the total mortality in all classes of forms (Table LVII) that the weighted average mortality due to insects was 25.77 per cent, as against 24.45 per cent due to climate. All of this evidence is cited to show that in reality the insect enemies produce a very large proportion of the mor- tality of the boll weevil and should therefore be encouraged in every way possible. Of course, it is evident that climatic control is even superior, because of the influences it brings to bear upon every phase of the weevil’s existence. Regional comparisons such as have been made above are of the greatest importance in determining what factors in natural control need to be given the greatest encouragement by cultural expedients or otherwise. CLIMATIC CONTROL. From almost every viewpoint the climatic control of the boll weevil is the most important which this insect experiences. The weevil reacts to a multitude of conditions of temperature and humidity. The time of entrance into hibernation, the length of the hibernation period, the time of emergence from hibernation, the length of the various immature stages, the rate of oviposition, and even the pro- portion of sexes are profoundly affected by these agencies. In many cases their effects are not direct. They may affect the weevil indi- rectly through the cotton plant. For example, drought may interfere with the fruiting of the cotton plant and thus deprive the weevils of food. Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XIV. NATURAL CONTROL OF THE BOLL WEEVIL. a, Pilose and nonpilose stems of cotton; b, larva of boll weevil crushed by proliferation; c, pupa of Catolaccus incertus on pupa of cotton boll weevil; d, larva of Microbracon mellitor attacking boll-weevil larva; e, /, holes gnawed by Solenopsis geminatu in effecting entrance into infested squares. é NATURAL CONTROL, Tot The most conspicuous illustration of the climatic control of the weevil lies in the failure of the pest to establish itself in the drier ortions of Texas. For several years multitudes of weevils have own from the more humid portions of Texas to the west, where the climate is drier. In fact, every year there has been a large inflow of weevils into this region. Every season, however, the conditions have practically immediately prevented the establishment of the weevil. The most important factor has been dryness, but there are others that must be considered. Among them is the fact that there is com- aratively little winter protection for the insect. In addition, an indirect result of small precipitations is the growth of cotton plants of only small size. This results in a small amount of shade and thus augments the direct effect of heat and dryness upon the infested squares which fall to the ground. Frequently the effects of climate act upon the enemies of the boll weevil. This is the case where heat destroys the weevils and their parasites in squares that fall to the ground. In several cases, how- ever, heat increases the effectiveness of the enemies of the weevil. A striking example of this was observed on September 2, 1911, by Mr. J. D. Mitchell, of the Bureau of Entomology. A succession of days in which the temperature was very high and the air exceedingly dry caused the premature opening of many cotton bolls in the vicinity of Victoria, Tex. Prior to this time the weevils had destroyed prac- tically all of the squares, and many immature stages were to be found in the bolls thus forced open. In such instances the exposed imma- ture stages of the weevil were subjected to two important destructive agencies. Heat killed many that became exposed to the air, and the ants were able to reach not only those that were exposed, but others inside of the partially opened bolls. If the bolls had not opened, such weevils would have been beyond the reach of the ants. As it was, the climatic conditions not only directly destroyed large num- bers of weevils in a situation where climatic factors rarely affect them, but also greatly increased the effectiveness of another unrelated factor of control. CLIMATIC INFLUENCES ON VITALITY AND ACTIVITIES. In the preceding pages numerous effects of climate upon the devel- opment and activities of the boll weevil have been pointed out, but these must be summarized in order to show how intimately connected the climate is with every phase of the weevil’s life. It appears that the movements of the weevil are sluggish or active in accordance with the nature of the day, cloudy days or low temperatures always causing them to be more sluggish. The number of feeding punctures per Ae eh decreases with increases in temperature, and the time before falling of a punctured square also decreases with higher temperatures. In like manner the length of life of the weevil decreases. The age of beginning copulation and the age of beginning oviposition are both increased by decreases in temperature. The activity in oviposition, which is found to begin at 75° F., is greatest in the hottest time of the day, cloudy days causing the oviposition to be less active. The num- ber of eggs per day increases with the temperature and varies for any given temperature with the humidity. The entire period of develop- ment increases as the temperature and atmospheric humidity decrease. 122 THE MEXICAN COTTON-BOLL WEEVIL. The number of generations decreases with the mean temperature and mean humidity. . Hibernation seems to begin at mean temperatures between 56° F, and 60° F., but is hastened by high humidity. Cold nights followed by warm, still days seem to stimulate the weevils to considerable activity in the fall, evidently warning them to seek hibernation quar- ters. The period of entrance into hibernation is much more rapid as the mean humidity and mean temperature become lower. The emergence of the weevil is in like manner influenced by the tempera- ture, but it must be considered that the actual temperature experi- enced by the weevil is that which affects the emergence. The time of emergence apparently depends upon an accumulation of a certain amount of effective temperature and a certain amount of rainfall, but if more than the necessary temperature accumulates less rainfall will be needed, and vice versa. The majority of weevils emerge at mean temperatures between 64° F. and 78° F. The percentage of survival seems to decrease as the absolute minimum temperature decreases and the rainfall increases. The foregoing statements are conclusions based in some cases upon more or less fragmentary information, but in other cases they may almost be considered as laws of climatic control. FIELD OBSERVATIONS ON MORTALITY DUE TO HEAT AND DRYNESS. Heat and dryness affect the weevil in a very simple manner. Un- less the square remains moist the food supply becomes unsuitable. . In other cases the heat itself causes death directly. Therefore, the hotter and drier the ground upon which the infested square falls, the more certain is the death of the weevil. In the years 1906 to 1909 an exhaustive study was made of the effects of various climatic and other agencies which control the boll weevil. In this work 222,715 cotton forms (including bolls and squares) were collected by agents of the Bureau of Entomology at 65 localities in Texas, 26 in Louisiana, 7 in Oklahoma, 6 in Arkansas, and 6 in Mississippi. Careful laboratory observations were made to deter- mine the mortality due to heat or dryness and to other factors. By reference to the series of general tables (LV-LVIII) at the beginning of the discussion of natural control it will be noticed that climatic control kills practically one-fourth of the developing stages, the average for the four years in which records were made being 24.56 er cent, which was slightly surpassed by the total insect control. he highest average climatic control was obtained in 1907, being 29.06 per cent, while in 1908 it averaged only 21.21 per cent. In rearranging the data to ascertain the condition in which the control was greatest we find the following results: Fallen squares, 27.50 per cent; hanging dry bolls, 19.56 per cent; hanging dry squares, 17.67 per cent; and fallen bolls, 16.52 per cent. The geographical distribution of climatic control is very interesting. In fallen squares the various sections ranked as follows: North-central Texas, 43.99 per cent; southern Texas, 34.10 per cent; central Texas, 31.28 per cent; eastern Texas, 29.31 per cent; northeastern Texas, 27.89 per cent; Arkansas, 26.54 per cent; Oklahoma, 22.62 per cent; Mississippi, 15.63 per cent; southwestern Texas, 13.38 per cent; Louisiana, 13.11 per cent. NATURAL CONTROL. 123 In hanging squares we find a somewhat different arrangement of the sections: Central Texas, 24.04 per cent; southern Texas, 20.04 per cent; northeastern Texas, 17.39 per cent; north-central Texas, 17.17 per cent; Louisiana, 16.99 per cent; Arkansas, 16.43 per cent; southwestern Texas, 13 per cent; Oklahoma, 9.53 per cent; Mississippi, 8.21 per cent; and eastern Texas, 3.70 per cent. In many of the records made during 1906 it became evident that certain cultural practices greatly favored the amount of control by heat and dryness. The wider the rows, the greater the amount of sunlight which strikes the ground. Consequently the fields with wide rows or in which the stand was uopariect showed the greatest mor- tality. In asimilar way, fields in which were varieties with compara- tively small amounts of leafage showed greater mortality due to heat and dryness. It did not become apparent, however, from the obser- vations made, that the direction in which the rows ran made any material difference in the mortality. The difference between the various sections in the mortality in fallen squares is especially conspicuous. This is due undoubtedly primarily to the greater precipitation in the sections with low mor- tality, which, by keeping the ground more or less moist, prevents such temperatures at the surface as are frequently reached in Texas. The greater rainfall in Louisiana also undoubtedly has an indirect effect. In that State the additional rainfall causes the cotton plants to grow to a large size and to shade the ground more than is the case in Toma, thus preventing the sun from reaching the squares on the ground. The differences in hanging squares are not quite so con- spicuous, but are probably due to some extent to atmospheric humid- ity, density of foliage, and other similar factors. Equally interesting results were obtained in 1906 with reference to the effect of heat and dryness upon the different stages of the boll weevil. It was found that the mortality in the larval stage amounted to 52 per cent, in the pupal stage to 18 per cent, and in the adult stage to 6 per cent. Nearly 70 per cent of all the mortality caused by heat and dryness occurs, therefore, during the larval stage. Table LIX illustrates the percentage of stages killed during the warm months of the year by high temperatures and is based upon all of the examinations made during the years 1906 to 1909, inclusive. Taste LIX.— Weighted average heat control of immature stages of the boll weevil, by months, Texas, Louisiana, Oklahoma, Arkansas, and Mississippi. Per cent Forms | stages | killed by Month. ae found. | heat and ; drying. Ls aes Bk ERE se see oe ee Pe es ee oe ee ee oe: 100 56 7.20 LT BARE, So. Seton es oe aes a aed Page. les Oe 2 Oc ge ee aie a 16, 930 10,708 28. 33 Rh, eee ees el Se Nae Se tae ES eae Be ee Cee es ee Ee 5059] 21,7 25.61 IMIG et 2 eee he SORES ROE pic - eee See tae, Cee Sener | 80, 923 33,170 24. 62 SISONP SVEN 27 LTP ye ee pel aire he we tn cae te Aan eI nC Re NS A ANT - 37,378 17,107 22.87 (OOO on Sots Sao Sa ae eh SENS UE Ee 7 OE ee 17,344 8, 283 16. 59 ANCES oo Se eee aaa ee Se ae ee 195,734 91, 082 23.80 Many illustrations are available to show the powerful effect of heat and dryness in the reduction in the numbers of boll weevils in cotton fields. The action of this agency is so powerful that it may check the 124 THE MEXICAN COTTON-BOLL WEEVIL. weevils in a single season so that a crop may be obtained. This was shown in a field which was under observation in Victoria County, Tex., in 1906. It was found in April that a very large number of hibernated weevils appeared in the held. This month was reasonabl moist, so that the cotton germinated promptly and made a rs growth. The month of May, however, showed a decided deficiency in precipitation, being more than 3 inches below the normal for the month. This checked the weevil at the time the first infested squares began to drop. The control continued during the month of June, which also showed 3 inches less than the normal rainfall. These conditions resulted in such a checking of the weevils by June that the cotton plants were able to put on a large number of squares. The month of July showed a precipitation above the normal, which caused the plants to grow rapidly. The setback experienced by the weevils, however, during the preceding dry period was so great that they were unable to overtake the production of fruit, so that a yield of about one-fourth of a bale per acre was obtained. Examples of such complete control within a single season are not common. It frequently happens that a drought continues so long that the plants are seriously affected. In general, however, the plants can recover more rapidly from a drought than the weevil. This results in an advantage to the crop from even a short drought. Of course the advantage becomes greater as the drought is prolonged, provided it is not prolonged to a point where it seriously affects the growth of the plants. Examples of the control of the weevil in one season from heat and dryness of the preceding season are common. Table LX shows a striking instance of this kind. It will be seen that the effects of the drought of 1902 extended into the following season and brought about a marked increase in production. By the follow- ing year (1904) the recovery of the weevils from the drought of 1902 was indicated by a decreased production of cotton. Taste LX.—General illustration of drought control of the boll weevil, Nueces County? Tex., 1901-1904. Rainfall. Temperature. Cotton | nan DO CuGe Annual. Mar. 1-Aug. 31. Annual. Mar. 1-Aug. 31. ioe a sss ee Conny, Year. equiva- Depar- Depar- Depar- Depar-| jent in Mean ture Mean ture Mean | ture | Mean | ture 500- aver: from aver. from aver- | from | aver: from pound age nor age nor- age. nor. age nor bales mal mal. mal mal Inches.| Inches. | Inches.| Inches. oF. oR. OF. Was LOO Uses Ye Biosys Ses ae 17.49 —11.90 6.74 — 7.42 70.7 0.0 76.2 | +0.83 601 OOD Ss SES cree aoe 22. 22 — 7.98 5.57 —7 71.5 +1.4 77.3 | +1.85 480 TOSS e522 eA EN 36. 92 + 6.72 | 25.97 +11. 38 69.1 — .9 74.5| — .9 4,099 UT LE a ae 28. 54 — 1.66 13. 56 + .83 70.5 + .4 76.0] + .5 1,556 NATURAL CONTROL. 125 GENERAL DISCUSSION OF THE RELATIONS OF TEMPERATURE TO THE BOLL WEEVIL. Our studies of the boll weevil lead us to the conclusion that there is a certain degree of temperature above which, under any condition of humidity, no individuals can exist even for a limited time. This point is known as the maximum fatal temperature. Below this there 1s a zone of varying width of temperatures which may be fatal in cases of long exposure or under certain conditions of humidity or insect vitality. This may be known as the upper zone of fatal tem- peratures. Below the zone of fatal temperatures is a zone of tem- peratures which, when continuing for any length of time, force the insects to shelter. This zone may therefore be fitly called the zone of xstwation, and it must be understood that the relative humidity will have a strong influence in moving this zone upward or downward, according to regional conditions. This zone is limited by the point at which effective temperature ceases. Below this point is the zone of actwity. In this zone will be found the degree of effective tem- perature, a long continuance of which is necessary to draw the insects out of hibernation. This is not an absolutely fixed point, for it varies with humidity. Possibly the relation could be stated in a definite formula if a sufficient amount of data was available. The temperature which causes activity is usually known as the zero of effective temperature. It is assumed that active metabolism begins at this point and that a certain amount of effective tempera- tures accumulated in daily units is necessary to bring about a given transformation or function. This sum is known as the total dicate temperature for any given function. It will vary in accordance with the humidity. Below the zero of effective temperature there will be no necessity of feeding, and locomotion rapidly becomes impossi- ble. On the approach of the zero of effective temperature the insects will nant considerable activity in finding winter quarters. We therefore designate the zone below this zero as the zone of hiber- nation. The lower limit of this zone is the highest temperature which may be fatal under certain conditions of humidity or rapid alternation of temperatures. Below this point occurs a more or fess restricted lower zone of fatal temperatures. The lowest point at which life can exist is known as the minimum fatal temperature. 1 Of course the manifestation of the absolute temperature which draws the weevils out of hibernation is dependent upon the density of shelter. Certain forms of shelter prevent the weevils from being affected until long after the outside air has been sufficiently warm to cause activity. 126 THE MEXICAN COTTON-BOLL WEEVIL. These zones are illustrated in the accompanying diagram (fig. 26). UPPER ZONE OF FATAL TEMPERATURE. Numerous experiments have been conducted in dropping adult boll weevils upon the soil at different temperatures to determine the 140 —MAYMUM FATAL TEMPERATURE UPPER ZONE OF FATAL TEMPERATURES 0 ZONE OF AESTIMATION 100 90 K NY G0 a ZONE OF ACTIVITY S70 W €0 <—£000 15 REQUIRED ABOVE THIS POINT N <—ZERO OF LEFFECTWE TEMPERATURE Q ZONE OF HIBERNATION FOR WMATURE STAGES N <—/ATAL TEMPERATURE FOR E665 AND YOUNG LARVAE ZONE OF HIBERNATION FOR ADULTS 8 LOWER ZONE OF FATAL TEMPERATURES SS <—MINIMUNT FATAL TEMPERATURE Fic. 26.—Diagram to illustrate the zones of temperature in their relations to the activities of the boll weevil. (Original.) effects upon the insect. In this work 119 tests were made at soil tem- peratures varying from 110° to 140° F. Below 122° F. none of the wee- vils were killed, but from 122° F. upward death re- sulted in times varying from 1 second to 900 seconds. In a general way the exposure neces- sary to cause death de- creased as the tempera- tures became higher. From these experiments we conclude that the upper zone of fatal tem- perature for the adult boll weevil may be con- sidered as from 122° to 140° F. In the series of exper- iments to which refer- ence has been made a number of observations were made upon humid- ity. The atmospheric humidity during the time the experiments were under way, however, was rather constant, ranging from 37 per cent to 40 per cent. Within this narrow range it was not determined that humid- ity either decreased or increased the length of time necessary to cause the death at any fixed temperature. It is interesting to note that the zone of fatal temperature for adult weevils which fall to the ground will be reached under general conditions when the temperature recorded at the usual distance above ground at which thermometers are placed reaches 95° F. NATURAL CONTROL. 127 ZONE OF ZSTIVATION. During 1906 and 1907, in southern Texas, Mr. J. D. Mitchell ob- served that many adult weevils were on the ground near the cotton stalks under clods of earth and dead leaves, seeking protection from the intense heat. This indicates a distinct zone of estivation, although such temperatures may exist only for a few hours at a time. The exact limitations of this zone are undeterminable. Astivation is a very common habit among weevils. As throwing some light on the probable action of the boll weevil under high tem- eratures, it is of interest to state that Prof. C. H. T. Townsend, of iura, Peru, finds that the Peruvian cotton square borer, Antho- nomus vestitus Boheman, estivates during hie Hint months in the fallen squares both as pupa and adult, but remains practically inactive. ZONE OF ACTIVITY. The temperatures at which most of the functions of the boll weevil are exercised lie between the means of 91° F. and 56° F. It is prob- able, however, that this zone approaches very close to the zone of fatal temperatures. In the spring effective temperature ' begins to accu- mulate at approximately 56 degrees, but the total necessary to bring the weevils out of hibernation may be low if the rainfall and humidity for the same period are high, and it must be correspondingly high if the humidity is low.2, When the two factors have accumulated enough between them they bring about emergence. It is roughly calculated that 172° of effective temperature and 5.1 inches of rain are necessary. A deficiency of effective temperature must be balanced by additional rainfall; a deficiency of rainfall must be balanced by additional effec- tive temperature. For a fuller discussion of this subject see the section on emergence from hibernation (p. 107). When the weevils have emerged and found food they require a cer- tain number of days of feeding before oviposition can take place. This preoviposition period for hibernating weevils and for the succeed- ing generations is determined largely by temperature and humidity. As these two factors decrease the period increases. In like manner we have shown on preceding pages how the egg and larval and pupal stages are governed by the same laws. We have also shown that even the daily rate of oviposition is accelerated by increases in temperature and probably also of humidity. The common impression that ‘‘rain brings the weevils”’ has its basis in the natural increase in the numbers of weevils shortly after a rainy period, due somewhat to the fact that increased humidity reduces the developmental period. A more important factor, however, is that humidity reduces the effects of sunshine in killing the weevil stages. ZONE OF HIBERNATION. The behavior of the weevils in hibernation is fully discussed else- where. In ice-box experiments at 45° F.it was found that the weevils would not emerge, but Dr. W. E. Hinds found that 10 weevils which had emerged from hibernation and which were confined 303 weevil 1 That is, the temperature at which activity begins. 2 Ina former publication (Bull. No. 51) we adopted the assumption made by other writers that 43° F. Is the general zero of effective temperature for insects. Recent experiments have shown conclusively that this is an error, so far as the boll weevil is concerned. 128 THE MEXICAN COTTON-BOLL WEEVIL. days at 44° to 45° F. made 36 feeding pe or at the rate of one puncture every 8.4 days. Itis probable that these punctures were all made possible by the removals from refrigeration for examination. LOWER ZONE OF FATAL TEMPERATURES. In 1904 Dr. W. E. Hinds conducted experiments in the effects of low temperature on eggs and young larve. He found that 34 eggs at 45° F. for 13 to 14 days did not hatch when kept later at a temper- ature of 69° to 70° F. Recently hatched larve, however, were killed by nine days’ exposure to 45° F. By experiments conducted with adults in 1905 it was ascertained that 32° F. was not fatal; 24° F. benumbed the weevils, but they could revive; 18° F. killed. In experiments conducted by Mr. H. P. Wood 32 weevils were exposed to a minimum of 15° F. and an average temperature of 18.6° F. for seven and one-fourth hours and then placed in the refrigerator at a higher temperature, but none sears In similar experiments Mr. W. A. Hooker exposed 11 weevils for six hours to temperatures varying from 15° to 20° F. The weevils were quiet, but later showed signs of life, although they died within two days. Between 7 and 10 degrees, five weevils were killed in six hours. One degree below zero was absolutely fatal. Observations on the effects of low temperatures upon the weevils in the fields leads to the statement that all places experiencing a tem- perature under 12° F. in the early part of the winter will profit by an almost complete extinction of the weevil, depending somewhat, of course, upon the amount of protection the weevils may have secured before the freeze. Regions having a normal minimum temperature of zero need have little fear of serious continued depredations from the weevil until the insect has proved itself able to adapt itself to colder temperatures than it is now able to withstand. In this connection it will be of interest to submit Table LXI, giving the average winter mortality from cold since the beginning of our records. TaBLE LXI.—Weighted average cold control of immature stages of the boll weevil, by months. : Killed by Formsex-| Stages Month. F cold and amined. | found. wetting. Per cent. {GTEC 9 earn: Seeree re Cees Sees ole nce Rope epemdaci sce se: Se 5, 687 1, 285 36. 42 MEDIUALY sus 2. SEE Se SPS ee sae ben Oe oa Jo acon oo eee 13, 597 665 67.36 (MarGh es <8 6 cisicn chet otas oct ese eeeeeeene ta eerie aaeiee tiga Wen sage eee 2, 500 159 31. 44 INGVEMIUDOI es. = of snck. Poe eke core ne Sec oe nee onesie oe el io ree 2,534 798 41. 40 MBCOMDED Sasi 5 ais 54S sree w wns See wee eae ee ee eee Cee | 2,663 688 38. 37 Ota Sosa t=ciatein loose siodstecas See ee eer eee ee ee oe 26, 981 3,595 44.61 It should be noticed that winter cold is, on the average, almost twice as effective as summer heat. The history of the boll weevil furnishes several examples of winter control, principal among which are the early freezes of November, 1907, November, 1908, and December, 1909, which greatly reduced weevil damage in large sections. NATURAL CONTROL. 129 FATAL VARIATIONS OF TEMPERATURE. It has long been known that one of the most potent forces in insect control is abnormal variation of temperature. Probably no stronger illustration of such control could be produced than that afforded by the conditions of the winter of 1910-11. ft ee Ry! ene" MISS Fig. 27.—Map showing dates of first killing frost in the area infested by the boll weevil, in the winter of 1909-10. (Original.) t------2.. (After Fig. 28.—Map showing normal dates of first killing frost in the southern United States. Weather Bureau Bulletin V.) On October 29 to 30, 1910, a freeze occurred throughout the cotton all but a narrow strip of territory along the Gulf coast T by the accom- belt affecting and two small interior areas of Texas, as illustratec Another map (fig. 28) is presented to show panying map (fig. 27). 28873°—S. Doc. 305, 62-2——9 130 THE MEXICAN COTTON-BOLL WEEVIL. the normal dates of the first killing frosts. Comparison of these two maps will show at a glance that the first killing freeze of 1910 was over a month earlier than the normal. Such a natural phenomenon is an exact equivalent of artificial fall destruction at the same date. The temperatures were not fatal to the weevils, but were such as to force hibernation and at the same time cut off food supply. If tem- peratures compelling hiber- nation had continued, the weevils would haveemergep in about the same propor- tion as would be expected if they were artificially de- } prived of food on the same Missa date. However, another SG climatic factor intervened. Almost the entire month of November was warm, and throughout Louisiana, at least, the mean temperature Fie. 29.—Map showing minimum temperatures on Octo- stood at above56°F. for the ber 29 and 30, 1910, the date of the first killing frostin Month. We have already Louisiana. (Orieinal.) shown that a continuance : of mean temperatures over 56° F. will force the weevils to take food, and that in the absence of food at effective temperatures starvation occurs in a few days. If all of the cotton had been killed by the freeze, the control would have been complete, but there are al- ways sheltered areas on hillsides or near buildings that escape two or three \ VA ARS severe freezes, and these Bre eh: areas no doubt harbored Was a x many weevils until the aee ,; cold wave of November 29 drove them to a normal hibernation. Inthe map (fig. 29) show- ing the Louisiana minimum temperatures of October 29 and 30, 1910, on which dates the first killing frost occurred, it will be noticed that no fatal temperature was reached, but that a freezing temperature oc- ey athab Petite Tale Bee ce eiares Thee curred in practically all of °°" “Sr ioi0-11 in Louisiana. (Original) the cotton-producing terri- tory. The other map (fig. 30) illustrates the minimum temperatures of the entire winter of 1910-11 and shows that fatal temperatures (7° F. to 22° F.) occurred throughout the State. These minima NATURAL CONTROL. 131 occurred, however, early in January, at which time all weevils which had survived the starvation of the fall were deeply hidden in hiber- nation shelters, where sudden changes of temperature have little effect. The survival from hibernation at Tallulah, La., was only one-half of 1 per cent, as shown in the hibernation statistics, and this, no doubt, must be attributed to the rare combination of early freeze, subsequent long duration of effective temperatures without food, and finally a period of minimum fatal temperatures. One of the most interesting features of the fall of 1910 in Texas was the presence of two small areas in which the first freeze was delayed from one to two months. (Fig. 27.) We call attention to the most interesting of these cases. The freeze of October 29 was felt in all Texas above the latitude of 31°, except-in Erath, part of Comanche, part of Brown, Eastland, Callahan, Taylor, Jones, and Haskell Coun- ties in central-west Texas. In this frost-free area in the following October, 1911, a very heavy infestation was found at Cisco, in East- land County, and at Brownwood, in Brown County. The infestation diminished in every direction from those places. At Lampasas, 60 miles southeast of Brownwood, where we would naturally expect a much higher infestation than at Cisco, very slight damage occurred, and at Granbury, in Hood County, 60 miles east of Cisco, where the weevils have been present since 1904, they were extremely difficult to find. Thus, it is seen that a territory which had had the weevil much longer than either Brownwood or Cisco had fewer weevils in 1911, because it experienced an earlier killing frost. EFFECTS OF FLOODING UPON THE WEEVIL. Tests at Victoria, Tex., in 1904, were divided into two parts, each of which included both the immature and mature stages. In each part floating and submergence were tested. In the tests made upon the floating power of adults, weevils were isolated and placed in water in tumblers. They were dropped from a considerable distance above the surface, so that they became entirely submerged, and they rose to the surface naturally. The surface tension of the water was found to be sufficient to float weevils which were placed upon it carefully. The generally hairy condition of the surface of the weevil’s body prevents it from being readily wetted, so that it may struggle for some time in the water without becoming really wet. When dropped, as described above, weevils float head downward, with the tip of the abdomen above the surface. In the submergence tests weevils were held down by a wire screen, and all bubbles were removed from their bodies by a pipette, thus making the tests as severe as possible. Sixty squares believed from external examination to be infested were floated in a driving rain for six hours. They were then removed and left for several days, during which time 75 per cent of them pro- duced normal adults. Ten squares which were floated in driving rain for six hours were opened at once, and in every case found to be only slightly moist on the inside. These contained six larve and four pupe, and all were in perfect condition. As squares float normally, submergence tests were considered extreme. Five squares were submerged for six hours, and after that produced three normal adults; one pupa died, and one square was found 132 THE MEXICAN COTTON-BOLL WEEVIL. to have been uninfested. Five more squares were submerged for 31 hours. These produced two normal adults, and one pupa died in the process of molting after removal from the square. Death was prob- ably caused in the last case by drying; one square was found to contain a dead pupa, and one was not infested. To test the possibility of its living, should the square be penetrated by water, a naked pupa was submerged for six hours, but m spite of this unusual treatment it pro- duced a normal adult. Numerous larve removed from squares and placed in water pupated in one or two days, and several pup remained alive, though floating for several days in water before they transformed into adults. In the case of squares floating normally it is evident that they might remain in water for several days without injury to the weevil within. Very slight wetting of the cell takes place, even under the extreme conditions of submergence. The effect of a brief flood would not, therefore, be at all injurious. As adults float as readily as do squares, they may also be carried long distances, and, further- more, they are able to crawl out of the water upon any bushes, weeds, or rubbish which they touch. Even when floating for several days continuously they are able to live and may be carried directly to: new fields. The floating of adults and infested squares explains the appearance of weevils in great numbers along high-water lines immediately after a flood. Field observations were made to supplement the laboratory experi- ments recorded in the preceding paragraphs. In July, 1904, many fields in the vicinity of Victoria, Tex., were partially and some wholly submerged. This condition lasted for several days. Examination made after the recession of the water showed that many fallen squares which had been in the water for some time contained unin- jured larve and pupe. Naturally, eggs and larve found in squares upon the plants, even though under water for some time, escaped unharmed. Weevils were working normally upon the plants. No diminution in their numbers could be seen, and it was apparent that the overflow caused no check either to the development of the imma- ture stages or to the activity of the adults. PLANT CONTROL. While climate is the foremost factor in the control of the boll weevil and also of the behavior of the cotton plant, there are certain kinds of control which the plant itself exerts. One of the most important of these is proliferation, which will be discussed in the fol- lowing paragraphs. PROLIFERATION. Early in the investigation of the boll weevil it was noticed that the immature stages and sometimes even the adults are frequently killed by a form of reaction of the plant known as proliferation.’ It appears that this property of the plant might be emphasized by breeders. For this reason special studies were conducted in 1905 1 Dr. O. F. Cook, of the Bureau of Plant Industry, has published a number of papers in which references are made to proliferation. The reader is referred to these papers, which are included in the bibliography at the end of this bulletin, for a full discussion of the botanical aspects of the phenomenon. NATURAL CONTROL. 133 and 1906. The results were published in Bulletin 59 of the Bureau of Entomology from which the following statements are abstracted. For the present purposes proliferation may be defined as the devel- opment of numerous cells from the parts of the bud or boll of the cotton plant which are injured by the weevil. It is clearly a mani- festation of an inherent tendency on the part of the plant to counter- act irritation by the growth of large numbers of new cells. This owth usually begins in the layer of cells adjoining the lining of the boll or in the staminal column of the undeveloped bloom. Part of the formation may project through the rupture made by the weevil or may form a hemispherical mass protruding from the inner side of the carpel of the boll and pressing into the lock. The reaction on the part of the plant begins generally before the egg hatches. In some cases the egg itself may be moved a considerable distance by the growth. In other instances the egg becomes enveloped and the larva emerges in the proliferous mass. Under such circumstances it may be destroyed early in life, although it often makes its way through the mass into portions of the fruit which have not been affected. As the larva feeds it continues and increases the irritation, and the response of the plant is immediate. In this way it often happens that the space the larva has eaten out becomes filled by the proliferous mass, al the pressure becomes so strong that eventually the larva or the resulting pupa or adult is crushed. It is clear from the observa- tions made that it is this crushing effect that destroys the weevil. (See Pl. XIV, 6.) A number of experiments in which weevil larve were placed in proliferous tissues showed that they could develop normally upon this modification of their natural food. The frequency of the occurrence of proliferation was determined by the examination of 1,870 squares and 2,042 bolls of a large number of American and several foreign cottons. In the case of squares, it was found that in the averages for all seasons and localities proliferous rowth followed feeding punctures in 48 per cent of the cases. The oben percentage, 75, was in the case of the Jannovitch, an Egyptian variety. In the case of bolls, proliferation followed in 81 per cent of the cases of feeding punctures. It is consequently apparent that proliferation occurs more frequently as a result of feeding punctures in bolls than in the case of punctures in squares. No very satisfactory results followed a study of the effect of climatic conditions upon the frequency with which proliferation follows the attack of the weevu. The observations included a number of varieties growing in two localities during two seasons, but there seems to be no special relation between the locality and the season and the number of cases in which proliferation was found. In fact, the maximum percentage of formation of proliferation in bolls and the minimum in squares occurred at the same time in the same locality and with the same variety. Table LXII shows the weevil mortality due to proliferation in squares and bolls under natural conditions. 134 THE MEXICAN COTTON-BOLL WEEVIL. Taste LXII.—Summary of observations showing increased mortality of the boll weevil in squares and bolls caused by proliferation. > ‘ Bee Mortality | 2; f : Mortality | 22 ey Se Squares examined. | ;, squares. | = & Locks examined. | j,, locks. | 38 2 | 2 ES : ES iS) j O¢ Ko] on Yearsof] © | 5 . : refit ‘ BI 5 ; 3 mites i a) observa-| S | © 3 = 5S ce 8/5 Bae AS =| | sa js & 2 ES eee olqd = Be on SE! a, qo oe SS Aad|iae tions. | 3 | -4 BS | FS |S a | 8s g 3 See Bast lees te a | Se o | 2 = al eS er rei lows = o s = we les |] og |/sS] om 6/38 5 28 |a5/a98|389 |] Bo * As | 290] a5 | a2 | BS |] we =} ia 2s | os S| oS | 3s ¢ ae | OS | om S/coe | se Salen teats! AS |} oo (ee |S2|/ 20) 213 #3123 /82°/88 1] 80 $/8/ 5 | BR|BEI|S |33/858] 51/5 |SElSEIS | 35/45 Oe cae Melee cs ane sta) Oe cone rege sy mad awl) ia eS FS J EAS (Ei lel Der [eal 27 SP SCha | EsCbel RE ee 9022-228 4 ea fees LUUES 44 | 41591-3025 %| AO: 5 | L150) || 221] See ei eee oe ee eee eee ee 1903S. == 1 1 Bae Sen F: oo g2s| Motes |S See) seee=|becas- 246 | 1,033 434 | 42.0 | 15.0] 5.0 10.0 1903 1 ME Mer Rees cl Fe eye ac (8 Rem 2 Ie | ae Oe Be ee 2 452 | 1,898 | 995 | 52.4 | 28.4] 12.8] 15.6 190455445 1 9 |. 2,954 | 1,480 | 50.0 9.6 6 9:0 yh). - spo 3 ore atl ce mee SR eee 1904e ee Pl Vda eg as al Se eh el | ie Ua -\2.se2|ee2=|oe2 lec AES eel Pat Blue jay ( Cyanocitta cristaia).......-.--.------ fohal|al a ae ee ila See ae Cowbird ( Molothrus ater)......-.-------------- 92) 4 GAS ee oe 84] 3 3 Red-winged blackbird (A gclaius pheniceus)....| 79 | 4 PS ict a fs La bs i | ad Eh oel Meadowlark (Sturnella magna).....----------- Bea |e 0)) else al eee ith | Ss | ees Western meadovy lark (Sturnella neglecta)... .- - Ey (ee Je) ame rn Ve ed eee |e eh ee A allseeae Oréhard fombla(icterus spurius)s 222-2. 6 fe = lassen ene aloo ae 203) e590") 10P) | 30" 64 Baltimore‘oriole (Jctenus:galbula))- <---- 2-2 =---.|-seee)|-es4|Peere Myles 50 | 11 | 24 iBiullockoniolendcrerus CUllockt) menace sence nee ee teen eee see neers 149 | 40 | 133 Rusty blackbird ( Luphagus carolinus).....--- 60 ag eae eee lee oes er se ee ees Brewer blackbird ( Huphagus cyanocephalus)...| 189 | 24 | 40} 1 |_-..]--..|.--..|..--|---.- Bronzed grackle (Qwiscalus q. eneus)...-----.-- 36 | 5 5] 19 3 |S |e Great-tailed grackle ( Megaquiscalus major MAMET OUPUS) =e Ss See Pe ee ee 32 | 2 74] aed fing | al 1 LF) ie el bea Vesper sparrow (Powcetes gramineus)...------- 29 | 1 0 ses (eee le ee (yee esl ees ee oo Savanna sparrow (Passerculus sandwichensis, SUNOS PECICS) easton a qee ce re eee tes Mere enters GSAS Smt 228 ees |e | eee Sotiemeee Lark sparrow ( Chondestes grammacus)......-.--|-----|----|----- L3dm| ele 54a an 1 W hite-throated sparrow (Zonotrichia albicollis).| 53 1 LA ae ess | Seer Sse Field sparrow (Spizella pusilla)......--.------ 25 | 2 3 eee | See he ta ee ee Swamp sparrow ( Melospiza georgiana).....-...- yf) at 7 alors ee eperl are peas ject Fox sparrow (Passerella iliaca).......---.----- Syne Pe esto enol ese panes Son ee Towhee (Pipilo erythrophthalmus)....--.------ LOFT ak Afr (Sill | re |S es |e peal eels Cardinal ( Cardinalis cardinalis).......---.-.---- ADK ass (Eee ee fol estes ts 39 | 3 4 Texan pyrrhuloxia (Pyrrhulozia s. terana).....|----- Boab earn ace eres 64] 2 2 Painted bunting (Passerina ciris).........----|----- Gee este eee eealle 109 | 18] 19 Dickcissel (Spiza americana)......--.---------|----- Beasie tee 1 sl ieee silt 26| 3 a) Purple martin«(Progne subis)! 22.2.1 -----225---|22-:- a7 aslneeee ey Tee ak ti fe lt 1 Cliff swallow (Petrochelidon lunifrons) ......--- 1 Eel aaage Ltd ideal = 35 | 34 | 638 Barn swallow ( Hirundo erythrogastra)......---|----- Bel eo tae ee zoe WAS, | ec hie] See Bank swallow (Riparia riparia).........--.---|----- oe ese sane ae 25} 11] 68 Loggerhead shrike (Lanius ludovicianus)....-- eG ll Ao | va Eee 19) |232-|>2ne- Yellow warbler (Dendroica xstiva)....--..-.--- hak Se Lee als ea! ey fs pt 25h 1 Myrtle warbler (Dendroica coronata)....--.---- nee eal Fa) |-weel E el e N e e | ee. ee Maryland yellowthroat (Gcothlypis trichas)....| 2) 1 MARIS Be a Gy Ped en Yellow-breasted chat (Icteria virens)..-.-..----|----- Bast 4eerals. 33 exe 5] 1 1 American pipit (A nthus pensilvanicus) ...----- WTB oul e20n | es eee |e eee eee fe sees Mockingbird ( Mimus polyglottos).....-..------ 43 | 2 Duly Seas 85} 5 5 Brown thrasher ( Toxostoma rufum).....------ Op |e sale Se... (Gt Books| cee Somer Sol eeene Carolina wren ( Thryothorus ludovicianus) ..-.--- 37 | 6 9} 31 ne) 1 ay bee ere Bewick wren ( Thryomanes bewicki)......-.---- Pal 1 oll Gseelscse eee Bip be ee Barc Winter wren ( Nannus hyemalis)........------ 1 ee! Di hee ULES Eee eg se eee ee Tufted titmouse (Bxolophus bicolor).......---- | 14] 5 Tal i03 || 522 3% oe ae gl eee Black-crested titmouse (Bzxolophus atricristatus)|..-. - Set | 8S) Se | See i Bae eee Carolina chickadee (Penthestes carolinensis)....| 6 | 1 1 We lefevre ae ees During Octo- ber, Novem- ber, and December. n bo et uo} A % suis 2dlen! & wtIYPl\os a Pd a BHIS EES 2g |eniae gs |8el\83 3) |p@) Ss 4 |4 I4 — oh 108 1 i EN 24 AS 49 2 2 183 | 28 | 32 66 | 12] 18 i (i ae Pe 5 2 2 Sule E ae A i |/2 . 18) |e 1 sg Oa BT bl oe Gin aes BV ele oh Tctlaeae | Bee ee 29) || i (Elle ts 6 24) 22a Vigi| HOT hy | Sloe It will be noticed that the largest numbers of boll weevils were eaten during the months of July, August, and September, and also that a considerable number are consumed during the hibernating season. The most important birds are those that capture the boll weevil during the winter. According to this table these are the three species of blackbirds, two meadowlarks, six species of native sparrows, the pipit, the three species of wrens, and the two species of titmice. It will be noted that only one of the 108 quail stomachs examined showed remains of the boll weevil. THE MEXICAN COTTON-BOLL WEEVIL. 147 REPRESSION. EFFECT OF BURIAL OF SQUARES AND WEEVILS. The effect of the burial of squares and weevils is of considerable importance for the reason that some degree of burial can be sag mee in the ordinary processes of cultivation. If it were to be found that the weevils could be killed by a depth of burial which could be accomplished without interference with the root system of the plants this process would be of vast importance. At Tallulah, La., in 1910, Mr. G. D. Smith conducted an exten- sive series of burial experiments. The infested squares were placed in sereened cages in the field. In each of these cages 2,000 infested squares were placed on October 10. A careful estimate showed that there were 250 live weevil stages for each 2,000 squares. In the first of the cages the infested squares were placed upon a sheet of wire screen 2 feet above the ground. These squares were kept constantly moist. In the second cage the squares were placed on the surface of the ground. No artificial moisture was supplied. In the third cage the squares were on the surface of the ground but were kept moist constantly. In the fourth cage the squares were buried to a depth of 2 inches and the ground was kept moist. In the fifth cage the squares were buried 4 inches and the ground was kept dry. The artificial moisture was applied three times each day during the course of the experiment. The “‘dry’’ cages were cov- ered with canvas so that rains could not reach the squares. The soil in the locality was the typical ‘‘buckshot” of the Mississippi Delta. Immediately before the institution of the experiments several rains had made the soil moist. Observations on emergence were made from October 10 until November 15. Table LXVIT summarizes the results of these experiments. Conditions. (weevils). Emergence. | Per cent. Carvel... 2 feet above sunagesmoisto. os o-oo aioe nin = a See ees = 119 | 47.6 Cage:2s. <;|7 Onisuritee) dryics: = 232. =. tee - 222-0 e ss Rane Se wpe a: ts Bae 157 62.8 Cage's. -=+)) On sumacesmoisipmeess: pore enn annie Be hoe 147 | 58.8 Gage 4.0 Li MBurtedionnchess Giyeit. secrete sne-c os oe ss oan so soem ease 62 24.8 Core ot... .|PBuriedi2ghess moist 2924 se: 2 3. teaee 328 a ae 5c eee ee gest 6 .2 Cage 6s) 2 MB UrieGrs THGHESS Obs ees 5 Eee as Re sini ae ie cc ew ene 18 Ai Chgey7i- ss eB unennn ches moist 27 ees eke om acne n seen = =n = 0 .0 It will be noticed that the greatest emergence was from the two cages in which the squares were placed upon the surface of the ground. At 2 and 4 inches beneath the surface the emergence was very small. When kept dry beneath 2 inches of the soil 24 per cent of the possible emergence occurred, but at this depth when moisture was provided less than 1 per cent emerged. At a depth of 4 inches 0.7 per cent emerged in the dry cage, but none from the same depth where mois- ture was provided. It may be concluded from these experiments that burial beneath 2 or more inches of dry soil of the “ buckshot” variety will prevent the emergence of a large portion of the weevils. If the soil is kept moist with burial at 2 inches or more below the surface the emergence is practically negligible. This is shown most clearly by comparing cages 4 and 5 in the table. 148 THE MEXICAN COTTON-BOLL WEEVIL. LABORATORY EXPERIMENTS IN BURIAL. In an experiment performed at Victoria, Tex., in 1904, 1,000 infested squares were buried under from 2 to 5 inches of well-pul- verized earth.1 Seventy-five weevils emerged. Twenty-seven wee- vils were found which had been unable to reach the surface. Their location varied from the bottom of the receptacle to just beneath the surface. The weighted average of the distances covered by the weevils which failed to reach the surface was 2 inches. In another series of experiments at Victoria, Tex., 74 squares were placed under wet soil. It was found that 16 per cent of the weevil stages were killed. Of the weevils which became adult 30 per cent emerged from the squares, but only 23 per cent reached the surface or escaped from an average depth of 1 inch. In these experiments, considering all the weevil stages present, 35 per cent died without escaping from the soil. In 1904 Prof. E. D. Sanderson performed a number of burial experiments at College Station, Tex. At from 0.5 inch to 1.5 inches below the surface 26.7 per cent of the weevils emerged; at from 2 to 4 inches 4.7 per cent reached the surface. It will be noted that these laboratory experiments substantiate the conclusion drawn from the field experiments described previously regarding the greatly increased mortality brought about by deep burial and by moisture. BURIAL OF ADULT WEEVILS AT TIME OF HIBERNATION. On or after November 23, 1903, at Victoria, Tex., 1,000 adult weevils were buried under from 2 to 6 inches of soil which contained from 9 to 19 per cent of water. Only five of these weevils succeeded in reaching the surface. Four of those which escaped and one which was still buried in the earth were found alive when examination was made on March 16, 1904. All the remaining weevils appear to have died where they were buried. CONCLUSIONS FROM BURIAL EXPERIMENTS. The field and laboratory experiments to which references have been made indicate that the boll weevil has comparatively little ability to emerge from moist soil, while dry, partially pulverized soil offers small obstacles to their emergence. The experiments also show that burial, even under moist conditions, would have to be as deep as 2 inches to bring about very decided results. The practical question therefore is whether in cotton fields the soil can be turned over to a depth of 2 inches during the growing season without injury to the crop. As is well known, one of the most important cultural methods in producing cotton is shallow cultivation. The reason for this is that the plant sends many lateral roots almost at right angles from the rows and at a very short distance beneath the surface. Many of these lateral roots le only 2 or 3 inches beneath the ground. If they were disturbed, the plants would react by shedding the squares. Undoubtedly the loss of fruit from this cause would more than offset any possible advantage accruing from the destruction of the 1 Much more thoroughly pulverized than would be the case in the field. Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XIX. Fig. a.—Cotton before treatment with Paris green. (Original.) Fig. b.—Cotton one week aiter treatment with Paris green. (Original.) EFFECT OF PARIS GREEN ON COTTON. Ai oi ss wa _ cee peebaise Penk: Var Br ae i oe i a S : ~~ owe la t REPRESSION. 149 weevils by burial. It is thus clear that as a means of controlling the eval during thie growing season the burial of squares is imprac- ticable. There is a time, however, when the burial of the squares can be carried on to excellent advantage. This is in the fall when the maximum infestation has been reached. Under these conditions it makes no difference to the planter whether the lateral roots of the cotton plant are cut or not. The fruit already set on the plants will develop in either case, and any additional fruit imevitably will be destroyed by the insects. Consequently the planter may destroy many of the weevils which would mature in a short time to feed, multiply, and enter hibernation, to emerge and damage the crop of the succeeding season. In this way deep fall cultivation is a pre- liminary step that should be practiced in connection with the destruc- tion of the plants. It should precede that process and should by no means be depended upon to take the place of it. After the plants have been uprooted and brought into windrows previous to burning it is advisable to plow the fields to a depth of at least 2 inches. This will result in the burial of many squares which were on the ground at the time of the uprooting or which fell during the process. The experiments show that the effectiveness of burial either before or after the uprooting of the plants will increase greatly if rains occur after the work is done. Likewise it is evident that the destruction of the weevils will be much greater in heavy soils than in lighter formations. In the Mississippi-Yazoo Delta the general nature of the soils is more or less heavy. This and the heavy precipitation in that region indicate a means of destroying the weevil that is especially important on account of the scarcity of direct means available. INSECTICIDES.! From the very beginning of the work on the boll weevil much atten- tion has been given to testing the more promising insecticides. As one result of the offer of a $50,000 prize by the State of Texas for an efficient remedy for the boll weevil, large numbers of supposed reme- dies have been proposed. Doubtless the inventors have been per- fectly sincere in their faith in the efficiency of these compounds. As was fully anticipated by the entomologists when the reward was offered, the commission charged with awarding the money was deluged with applications therefor, the claims in a large majority of cases being based upon some concoction supposed by the inventor to possess marvelous insecticidal properties. In comparatively few cases had the new product been tested in any way. Often samples were sent with the request that tests be made. Many of these inven- tions found their way to the various laboratories of this investigation, where it has been the uniform policy to give every thing of this kind a fair test and report the results to the originator. Tests were made in the field upon weevils confined by cages. This work has required a great deal of time, and the results have failed to indicate a single new compound having real value. Many of the substances tried had abontasale no effect on either plant or insect life, while others were equally fatal to both wherever they came in contact with them. The primary difficulty with all such insecticides lies in the fact that, { The first two paragraphs under this heading have been modified from Bull. 51, Bureau of Ento« mology, p. 156. 150 THE MEXICAN COTTON-BOLL WEEVIL. owing to the peculiar habits and life history of the weevil, the poison can not be so applied as to reach the immature stages at all, and it can not reach the adults so as to cause sufficient mortality to result in any considerable benefit to the crop. Much work has been done in thor- oughly testing the effect of Paris green. The most important results of this work have already been published in Farmers’ Bulletin No. 211 of the Department of Agriculture. They will be described briefly on a subsequent page. Among 40 other compounds tested, none proved worthy of even passing consideration for field use. As a fumigant for seed, among the eight gases or vapors tested, carbon bisulphid was found to possess considerable value when applied in the special manner described on pages 162, 163. POWDERED ARSENATE OF LEAD. In 1909 Messrs. Wilmon Newell and G. D. Smith, then of the Louisiana Crop Pest Commission, published the results of certain work with powdered arsenate of lead as a remedy against the boll weevil. This work was done in central Louisiana during the season of 1909. The principal experiments were located on three different plantations on plats provided for the PRED OS, From 1 to 10 appl- cations were made, consisting of a total amount of poison of from 1 to 51 pounds per acre. The treated cotton yielded an average of 71 per cent more than similar cotton which was not treated. In all except one of the plats there was a net profit from the use of the poison (that is, after deducting the cost of the poison and of the labor from the value of the increased yield) of from 27 cents to $23.54 per acre. In the one exception there was a loss of $7.07 per acre. These striking results led to extensive work on powdered arsenate of lead by the Bureau of Entomology. The services of Mr. G. D. Smith, who was directly connected with the Louisiana work to which reference has been made, were obtained. The bureau instituted numerous experiments in Louisiana, including several which duplhi- cated the previous work in that State. This investigation has now extended through two seasons in Louisiana, and considerable work has also been done at Victoria, Tex., by Mr. J. D. Mitchell. In the experiments of 1910, 32 plats were utilized on plantations at Livonia, Shaw, and St. Joseph, La., and Victoria, Tex. In the work in Louisiana there was a profit from the use of the poison on 20 of the plats and a loss on the 12 remaining plats. The average loss on the plats which failed to show a profit was $6.99 per acre. The average profit on the remaining plats was $5.83 per acre. Twenty- two of the 32 plats showed an increased yield of from 35 pounds to 403 pounds of seed cotton per acre. A striking result was the fact that invariably the plats upon which small amounts of the poison were applied showed profits. The work at Victoria, Tex., in 1910, con- sisted of four experiments. In only one of these experiments was a gain, in yield obtained, and this amounted to only 59 pounds of seed cotton per acre. In all of the experiments at this place there was a loss from the application of the poison of from $1.55 to $6.52 per acre. In 1911 the work on powdered arsenate of lead was continued. In some respects the results were contradictory of those obtained pre- viously, But there was agreement in that profits were obtained on all REPRESSION. 151 plats where small applications were made. On account of the apparent contradictions and the variations due to the seasons it is considered necessary to continue the work another season before definite conclusions as to. the practical value of arsenate of lead can be drawn. MACHINES. FIELD MACHINERY. Many attempts have been made to perfect machines that will assist in the warfare against the weevil. The only one of direct value that has been perfected is the chain cultivator (Pl. XX, 6; Pl. XXI) invented by Dr. W. E. Hinds, formerly of the Bureau of Entomology, and patented by the Department of Agriculture for the benefit of the people of the United States. Its construction is based upon the discovery that the weevils in the infested squares that fall in such position as to be reached by the sun soon die. In a cotton field many of the infested squares fall within the shade of the plants, and are thus protected. The chain cultivator is designed to drag the fallen squares to the middles of the rows and leave them exposed to the sun. This it has been found to accomplish in a satisfactory manner. In fact, in tests the use of the machine has been found to result in a decided gain in production. Although the chain cultivator was designed primarily for bringing the squares to the middles, it was found in field practice to have a most important cultural effect. The chains (so-called ‘‘log chains’’) are heavy enough to establish a perfect dust mulch and to destroy small weeds that may be starting. In fact, it is believed that this cultural effect would more than justify the use of the machine, regardless of the weevil. In view of the effect against the insect and the important cultural effect, it is believed that this implement or one similar to it should be used by every farmer in the weevil territory. The chain cultivator is now regularly manufactured by one of the large dealers in farm implements, but a satisfactory machine can be made by any blacksmith. Full directions are to be found in Farmers’ Bulletin 344, a copy of which may be obtained upon application to the Secretary of Agriculture. Some forms of cultivators now in use allow the attachment of boards which drag on the ground and carry the infested squares to the middles. In fact, the principle of the chain cultivator can be incorpo- rated in many implements now in use. It is strongly boibmentel Lee this be done for weevil control as well as for obtaining a dust. mulch. ‘Many machines have been designed to jar the weevils and infested squares from the plant and to collect them, to pick the fallen squares from the ground, to kill by fumigation, and to burn all infested material on the ground. The Bureau of Entomology has carefully investigated the merits of representatives of all of these classes, beginning in 1895 with a square-collecting machine that had attracted considerable local attention in Bee County, Tex. Up to the present time none of these devices has been found to be practical or to offer any definite hope of being eventually successful. At one ! The following three paragraphs are modified from Bull. 51, Bureau of Entomology, p. 157. 152 THE MEXICAN COTTON-BOLL WEEVIL. time there seemed some hope that a machine designed to pick the squares from the ground by suction might be perfected. The experiments, however, have indicated probably insurmountable difficulties; and a large implement concern, after having experimented with the matter fully, has come to the conclusion that mechanical difficulties will always prevent the perfection of such a machine. The ultimate test of all methods or devices for controlling the weevil is to prove through a series of seasons, and under a large variety of conditions, that by their use there is produced an increase in the crop treated or protected of sufficient value to more than repay the expenses of the treatment or protection. As a general rule, where machines have been used or poisons applied, plaice have provided no check upon the results obtained and have kept no close records as to the expense involved and net gain or loss resulting from the treatment. The result of such applications is, therefore, merely a general impression of gain or loss which may not agree at all with the facts. In this connection it must be stated that all machines which assist in more satisfactory methods of preparation of the land and cultivation of the crop are of indirect advantage. This is especially the case with devices which increase the amount of work that a single hand or team of mules may do. In fact, the boll weevil has been the cause of much commendable improvement of agricultural machinery throughout the infested territory. GINNING MACHINERY:! The more important results of studies upon this class of machinery were presented in Farmers’ Bulletin No. 209 of the Department of Agriculture. Modern cleaner feeders were found to be quite efficient in separating the weevils from the seed cotton, as they removed fully 70 per cent of the weevils passing into them. Of the weevils removed, over 80 per cent were still alive when taken from the trash. This fact shows the necessity for the use of some additional device which will crush or otherwise destroy all weevils taken from the cotton by the cleaner feeder. (See Pl. X, a.) For the weevils escaping the action of the cleaner feeder and passing into the ginning breast with the roll there are two avenues of escape— one with the seed, the other with the motes. In these two ways it appears that over 85 per cent of the weevils passing into the gin breast escape alive, while the remainder are killed by the saws. From these facts it is evident that some way should be provided for properly caring for the motes so as to confine the weevils which are thrown out among them and secure their destruction with those removed by the cleaner feeder. Some method should also be devised for separating from the seed the weevils that pass the saws before they reach the seed house or the farmers’ seed bins. When we consider the important effect that gins have been found to possess in spreading the weevil, especially near the border line of infestation, it appears exceedingly desirable that improvements in gin machinery should be made in the following particulars: First. The area and distance through which the action of the picker roll in the cleaner feeder is continued should be considerably increased, 1 This section is modified from Bull. 51, Bureau of Entomology, pp. 158, 159. Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XX. Fig. a.—Early fall destruction of stalks, the fundamental method for controlling the boll weevil. Windrowing stalks for burning. (Original.) Fig. b.—Chain cultivator passing through cotton rows. (Original.) CULTURAL CONTROL OF THE BOLL WEEVIL. Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XXl. (Original.) ffect after passage of cultivator. 7.. 0. —E Tig J. .—Space between cotton rows before passage of cultivator. Fig (Original. ) Use OF CHAIN CULTIVATOR. REPRESSION. 1538 compression rollers or some other device being employed to destroy the weevils separated by the cleaner. Second. Some method should be devised for keeping under control the weevils escaping alive with the motes, as under present conditions they have free range through the ginnery. Third. Possibly the most important of the devices needed is an apparatus which may be applied near the gin (possibly as the seeds leave the gin breast and drop into the seed chute) by which the weevils may be separated from the seed and brought under control, so that they may be destroyed. With these improvements the oil mills would almost cease to be a factor in the dissemination of weevils, and the movement of seed, either for planting, stock feeding, or fertilizer, would practically cease to be what it is at present, a factor in the spread of the weevil. FUTILE METHODS WHICH HAVE BEEN SUGGESTED.:! MINERAL PAINT AND COTTONSEED OIL. The very serious nature of the boll-weevil problem is constantly illustrated by the manner in which various useless devices and nos- trums are brought to public attention. At one time it was widely alleged that mineral paint would act as a specific against the weevil. An equally fallacious theory that also received considerable popular attention was to the effect that cottonseed meal exerted a powerful attraction for the pest. SPRAYING. Probably the most important useless recommendation has been that of spraying. It was supposed for some time by certain parties that it might be possible to poison weevils economically by attracting them to some sweetened preparation. The experiments conducted to determine the attraction of various sweetened substances demon- strate the fallacy of the theory. Even if these substances exerted as much attraction as was supposed, there would be insurmountable difficulties in the application of the method in the field. It is true that it is possible to destroy a certain number of weevils in regions where stubble cotton occurs by heavily spraying the earliest plants, but this method is of immeasurably less importance than the simple practice of cultural methods. SULPHUR. The old idea, the fallacy of which has been explained repeatedly by economic entomologists for the past 50 years, namely, that sulphur can be forced into the system of the plants to make them immune to insect attack, sometimes crops out with reference to the boll weevil. It is scarcely necessary to call attention to the fallacy of attempting to destroy the boll weevil by soaking the seed in chemicals with the hope of making the plants that are to grow from them distasteful or olsonous to the insect. Any money expended by the farmer in ollowing this absurd practice is entirely wasted. 1 This section is greatly modified from Bull. 51, Bureau of Entomology, pp. 159, 160. 154 THE MEXICAN COTTON-BOLL WEEVIL. PARIS GREEN. One of the most important fallacies regarding a remedy for the boll weevil was that which received great attention during the season of 1904, namely, that Paris green is a specific for the pest. The urgent demand for a specific was evidenced by the very extensive use of this substance. A portion of the great attention that it received pub- licly was due to the fact that early in the season a certain number of weevils may be killed by it. Applications made by spraying are even less effective than dusting with the dry Paris green. As was pointed out in Farmers’ Bulletin No. 211, which deals with exhaustive field and laboratory experiments with Paris green, the number so de- stroyed in the spring really means nothing whatever to the crop later in the season when the plants have put. on squares and the poison is no longer effective. As a matter of fact, the uselessness of Paris green was quickly discovered by planters. Since 1904 prac- tically none has been used in the warfare against the pest. (See PLEX Xe) TRAPPING AT LIGHT. There is still, in many quarters in Texas and Louisiana, a supposi- tion that it is possible to attract the boll weevil to lights. A number of machines have been constructed based upon this idea. Whether or not the boll weevil can be attracted to lights was one of the first matters that was investigated by entomologists. During September, 1897, Mr. J. D. Mitchell, of Victoria, Tex., a naturalist and cotton planter, set out trap lanterns in a cotton field in Victoria for one night, and sent the insects captured to this bureau for examination. In all, 24,492 specimens were taken, representing approximately 328 species. iecea according to habit, whether injurious or beneficial, the result was: Injurious species, 13,113 specimens; beneficial spe- cies, 8,262 specimens; of a negative character, 3,117. The interest- ing point in connection with this experiment was the fact that not a single specimen of the boll weevil was found, although the lights were laced in the midst of fields where the insects were very abundant. Since that time other investigators have looked into this matter fully. Lights have been kept burning in cotton fields night after night for several weeks. In no case has a single specimen of the boll weevil been discovered, although thousands of species of insects have been captured. The popular misapprehension about the possibility of capturing the boll weevil at lights is due to the fact that somewhat similar insects, Balaninus victoriensis, and other acorn weevils, differ from the boll weevil in that lights exert a strong attraction for them. Dur- ing occasional seasons the acorn weevils are exceedingly common in Texas, and great numbers of them fly to the electric lights. OTHER PROPOSED REMEDIES. Hundreds of proposed remedies, in addition to those which have been mentioned, have been carefully investigated. The claims of their advocates in practically all cases are based upon faulty obser- vations or careless experiments. The strong tendency of the weevil to die in confinement, which has been referred to, has caused many REPRESSION. 155 honest persons to suppose that the substances they are applying have killed it. Moreover, an insuperable difficulty that these special preparations have encountered is the impracticability of the appli- cation in the field. Hundreds of known substances will kill the weevil when brought into contact with it. The difficulty is to apply them in an economical way in the field. The claims made at different times of the repellent power of tobacco, castor-bean plants, and pepper plants against the boll weevil have no foundation whatever. In fact, none of these plants has the least effect in keeping weevils away from cotton. REQUIREMENTS OF A SATISFACTORY METHOD OF BOLL-WEEVIL CONTROL. ' The difficulties in the way of controlling the boll weevil lie both in its habits and manner of work and also in the peculiar industrial conditions involved in the production of the slaidle in the Southern States. The facts that in all stages, except the imago, the weevil lives within the fruit of the plant, well protected from any poisons that might be applied, and in that stage takes food normally only by insert- ing its snout within the substance of the plant; that it frequently requires only 12 days for development from egg to adult, and the progeny of a single pair in a season may exceed 3,000,000 individuals ; that it adapts itself to climatic conditions to the extent that the egg stage alone in November may occupy as much time as all the imma- ture stages together in July or August, are factors that combine to make it one of the most difficult insects to control. It is, conse- quently, natural that all the investigations of the Bureau of Ento- mology have pointed toward the prime importance of methods of control which involve no outlay for materials and very little for labor. Methods which involve some direct financial outlay for material or machinery are not in accord with labor conditions surrounding cotton production in the United States. Moreover, the indirect methods advocated are in keeping with the general tendency of cotton culture; that is, to procure an early crop, and at the same time have the great advantage of avoiding damage by a large number of other destruc- tive insects, especially the bollworm. Nevertheless it must not be understood that attention has not been paid to the investigation of means looking toward the direct extermination of the pest. Much work has been done, but the results have all been negative. BASIS FOR MEANS OF REPRESSION. In spite of the many difficulties involved in the control of the boll weevil certain generally satisfactory means of repression are at hand. They consist of both direct and indirect means. Those of an indi- rect nature are designed to increase the advantage gained by the direct measures and to increase the effectiveness of the several natu- ral factors which serve to reduce the number of weevils. Thus, the control measures constitute a combination of expedients, the parts of which interact in many ways. Naturally, the best results are obtained when the planter can put into practice all of the essential parts of the combination. 1 This section is greatly modified from Bull. 51, Bureau of Entomology, pp. 160, 161. 156 THE MEXICAN COTTON-BOLL WEEVIL. It is obvious that any method of controlling the boll weevil must depend upon full knowledge regarding its life history and the natural forces which tend to prevent its multiplication. Certain practices which upon stipenticiak observation might be considered important in the control of the insect upon investigation may be found to be of no avail whatever. In fact, in some cases what appear to be feasible means of control are worse than useless, because they tend to nullify the effects of natural forces which act against the weevil. This is notably the case with the practice of attaching a bar to a cultivator to jar the infested squares from the plants. As will be explained later, this practice is of advantage only under very restricted conditions. Throughout the greater part of the infested territory it is an assistance rather than a hindrance to the boll weevil. There are seven features of the life history of the weevil that are of cardinal importance in control. These are indicated below. 1. The weevil has no food plant but cotton. 2. The mortality of the weevil during the winter is very high. 3. The emergence from hibernating quarters during the spring is slow and prolonged until well into the summer. 4. Karly in the season, on account of comparatively low tempera- tures, the development of the weevil is much slower than during the summer months. 5. The drying of the infested squares, as the result of heat, soon destroys the immature stages of the weevil contained therein. 6. The weevil is attacked by many different species of insect ene- mies, the effectiveness of which is increased by certain practices. fe The weevil has but little ability to emerge when buried under wet soll. Exactly how each of these features of the life history of the weevil affects plans for practical control will be explained in the following paragraphs. In the case of many of the important injurious insects the problem of control is greatly complicated by the fact that the pests can sub- sist upon more than one food plant. In some cases a single species attacks several cultivated crops. In other cases the pests can sub- sist upon native plants practically as well as upon the cultivated species. All these Aafia ties are absent in the case of the boll-weevil problem. As has been shown in the preceding pages, the insect is absolutely restricted to the cotton plant for food and for opportu- nities for breeding. The problem is therefore much more simple than it would be if the weevil could subsist upon any other plant in the absence of cotton. This peculiarity of the weevil was the basis of the recommendation made in 1894 that the pest be exterminated absolutely in the United States by the abandonment of cotton. At that time only a few counties in Texas were affected. The procedure would have involved small expense. Even now the weevil could be exterminated in a single season by preventing the planting of cotton and the growth of volunteer plants. This proposal has been made at various times, notably at the national boll-weevil convention held in Shreveport, La., in 1906. Various difficulties, however, appear to render the plan entirely impracticable. In the first place, there would be strong opposition in large regions in Texas where the planters have learned to combat REPRESSION. 157 the weevil successfully. This opposition would undoubtedly be sufficiently strong to prevent cooperation in a large territory. More- over, the expense would be enormous. A large army of inspectors would be required. The work would not end with the prevention of planting cotton, but would necessarily extend to the destruction of volunteer plants which would be found along roads, railroads, about gins and oil mills, and on plantations throughout the infested region. The loss to mills, railroads, merchants, banks, and others dependent upon the cotton trade would complicate matters further. Unless a plan of reimbursement were followed there would be stren- uous opposition from these quarters, and any scheme of payment for damages would increase the cost still further. From a theoretical standpoint all the expenses involved would be justified. The saving in a few years would more than offset the cost. Nevertheless, the practical difficulties undoubtedly will always prevent the execution of the plan. All interests now seem to favor the necessary adjust- ment of conditions to the boll weevil rather than total eradication— once practicable but now little more than visionary. Under the discussion of the hibernation of the weevil it was shown that during the several years in which careful experiments have been performed the average rate of survival was 7.6 per cent. It is note- worthy that frequently the survival is much smaller. In the ex- periments to which reference has been made it ranged from 0.5 per cent to 20 per cent. The most important means of controlling the boll weevil that are available are designed to increase the tremendous mortality caused by natural conditions during the winter. The destruction of any certain number of weevils during the winter is much more important than the destruction of much larger numbers at any other season. The best means at the command of the farmer for increasing the winter mortality is through the uprooting and burning or burial of the stalks at an early date in the fall. (See Pl. XX, a.) Numerous experiments have shown the lessened mortality due to depriving the weevils of their food at early dates in the autumn. In fact, the experiments showed a practically uniform increase in the number of weevils surviving as the dates of the destruction of the plants became later. For instance, in all of the experiments per- fonod in Texas it was found that destruction in September re- sulted in a survival of only 0.2 per cent; destruction two weeks later showed a survival of 2.3 per cent; destruction during the last half of October, 5.6 per cent; and during the first half of November, 15.4 per cent. The results of the Louisiana experiments were similar. Destruction in September showed a survival of 0.3 per cent; destruc- tion in the first half of October, 2 per cent; in the last half of October, 8 per cent. . In addition to the experiments in which the weevils have been placed in cages at different times in the fall, the Bureau of Ento- mology has conducted considerable field work to show the benefits of fall destruction. The most striking experiment was performed at Calhoun County, Tex., in 1906. In this experiment an isolated area of over 400 acres of cotton was utilized. There was no other cotton within a distance of 15 miles. By contracts entered into by the department, the farmers uprooted and burned all of the stalks during the first 10 days in October, and provision was made to prevent 158 THE MEXICAN COTTON-BOLL WEEVIL. the growing of sprout cotton. As a check against this area, cotton lands about 30 miles away were used. Here the stalks were not de- stroyed in the fall, and the interpretation of the results of the experi- ment was based upon a comparison of the number of weevils present during the following season in the two localities. In May following the destruction of the plants careful search revealed only one weevil in the experimental area. In the check, however, the weevils were so numerous at this time that practically all of the squares had been destroyed. Examinations made later showed similar advantage in regard to freedom from the boll weevil of the area where the stalks were destroyed in October. The last examination was made on August 20. At this time there were 10 sound bolls to the plant on the experimental area and only 3 to the plant in the check area. The difference in yield between the two areas was about 600 pounds of seed cotton per acre. The work, therefore, resulted in an advan- tage amounting to about $18 per acre. Newell and Dougherty! have described a very satisfactory device for cutting the cotton stalks in the fall. It consists of a triangular wooden, framework, designed to pass between the rows and cut two at the same time. In the process of cutting, the machine windrows the stalks from two rows into the middle between the rows. The runners are provided with knives made of sharpened metal. Old saws have been found well adapted to the purpose. It is important to provide a metal runner at the rear end of the machine to prevent siding. This runner is designed to run an inch or more beneath the surface of the ground. The device can be made by any black- smith at a cost of about $4. It will cut and windrow from 10 to 15 acres of stalks in a day. There is a disadvantage in cutting the stalks at or near the surface of the ground: If warm weather follows, many of the roots will give rise to sprouts that will furnish the weevils food. On this account the process is less effective than uprooting the plants. Wherever the stalk cutter is used, it should be followed by plows to remove the roots from the ground. There is another important means by which the winter mortality of the weevil may be increased. This is by removing the hibernating quarters or destroying them after the weevil has gone into hibernation. Many of the insects are to be found in the winter in trash and débris found in and about cotton fields. The more shelter there is provided in the form of weeds growing about the fields, the more Scovel the conditions will be for the insect. By the burning of such hiber- nating quarters as are found in the cotton fields and in their immediate vicinity a farmer can cut off a very large proportion of the weevils that would otherwise emerge to damage the crop. The prolonged period of emergence from hibernation gives the planter another important advantage over the weevil. It has been shown on preceding pages that the period of emergence from hiber- nation extends, in normal seasons, to practically the 1st of July. In fact, except in one of the experiments that was performed, the last weevils did not appear until after the 20th of June. In the one exception the last weevils appeared on the 6th of June. In Texas it was found that 75 per cent of the emerging weevils appeared after 1 Cir. 30, Louisiana Crop Pest Commission. REPRESSION. 159 April 8 and in Louisiana 64 per cent. In Texas, after May 1, in all the experiments, from 4 to 18 per cent of the surviving weevils appeared. In Louisiana, after May 1, from 30 to 40 per cent emerged. t is obvious that the fact that many weevils do not appear until long after cotton can be planted and brought to a fruiting stage is a very great advantage to the planter. A portion of a crop at least can be set before the weevils have become active. Usually it is ossible to plant a crop sufficiently early to have it set some fruit Etats much more than 50 per cent of the surviving weevils have emerged. Attention was directed to the fact that the development of the weevil is much slower in the early portion of the season than later. For instance, at Vicksburg, Miss., the average period of development in April is 30 days and in May 19 days. In June the period is short- ened to 15 days. Consequently the planter has an opportunity to force the eecrelovinionst of fruit on the plants when the weevils are being held in check by the temperatures of the spring months. The ability of the cotton plant to grow during Aer and May is much greater than that of the weevils. This gives a margin of which the planter can take advantage. In the section dealing with natural control it was shown that climatic checks are the most important that the boll weevil experi- ences. The principal manner in which climatic factors affect the weevil is through the drying of the fruit. Naturally, the more heat - and light there is to reach the fallen squares, the greater will be the effectiveness of the most important natural means of control. This is the basis for the recommendation that the plants should be given considerable space, not only between the rows, but in the drill. Of course, it would be possible to place the plants entirely too far apart, and thus reduce the yield. There is a happy medium, however, at which planters must arrive from experience on their individual places. At the same time, varieties should be cultivated which have a minimum tendency toward the formation of leafage. The work of the insect enemies of the boll weevil is increasing from year to year. This work should be encouraged in so far as possible. It happens that several of the recommendations made for other rea- sons will result in facilitating the work of the enemies of the weevil. This is the case with early planting, wide spacing, and the use of varieties with sparse rather than dense leafage. Even fall destruc- tion is not a disadvantage, because it forces the parasites at the active season to native hosts that carry them through the winter. Wherever possible, varieties should be planted which retain a large proportion of the infested squares, because the hanging squares are more favorable for parasite attack than those which fall. Whenever the squares are picked by hand they should not be burned or buried, but placed in screened cages. In this way the weevils will be destroyed while the parasites may escape. Numerous experiments have shown that a large proportion of the weevils buried under 2 inches of moist soil can not reach the surface. Unfortunately, it is not possible to plow the infested squares under 2 inches of soil during the growing season. The operation would result in injury to the root system and cause great shedding. Never- theless it 1s possible for the planter to follow this practice after maximum infestation has been reached and after the plants have 160 THE MEXICAN COTTON-BOLL WEEVIL. been uprooted. Therefore, every means should be taken at the time of maximum infestation to plow under the infested squares as deeply as possible. ‘This method is of little use in dry regions, but fortunately is of great importance in humid regions where other means of control are comparatively lacking in efficiency. It is also assisted greatly by the occurrence of large areas of so-called stiff soils in the humid area. SUMMARY OF MEANS OF REPRESSION OF THE BOLL WEEVIL. In the preceding pages all effective methods of controlling the boll an have been described in a general way, and their connec- tion with the life history of the insect shown. Further details regard- ing the application of the methods have been published in Farmers’ Bulletin 344. In the present connection it will be sufficient to sum- marize the subject. The following are the essential features of the control of the boll weevil: 1. Prevention of the invasion of new territory by means of quarantines directed against farm commodities that are likely to carry the weevil. It is not necessary to have a quarantine applied to an extended list of articles. Only a few forms of cotton and of cotton by-products need to be considered. The most important is seed cotton. Next in importance are cottonseed and cottonseed hulls. There is no -danger in cottonseed meal and scarcely any appreciable danger in baled cotton. Cottonseed can be easily rendered entirely safe by fumigation with carbon bisulphid, as described in this bulletin. 2. The destruction of the weevils in the fall by uprooting and burning or burying the plants. This is by far the most important step in con- trol. (See Pl. XX,a.) Itis so important that unless it is followed all other means will avail little to the planter. The burning of the cotton plants is, of course, a bad agricultural practice. It should not be followed except in extreme emergencies. In all other cases the plants should be uprooted as soon as the cotton can be picked and cut by means of stalk choppers and immediately plowed beneath the surface. The ground should afterwards be har- rowed or dragged to make it still more difficult for the insects to emerge. In many cases it will be found inadvisable to wait for the uprooting of the plants until all of the cotton is picked. After only a sma portion remains for the pickers, it is entirely feasible to uproot the plants by means of a turning plow and leave them in the field so that the cotton can be picked. This will hasten the opening of the green bolls and freqenue result in a considerable saving to the planter. 3. The destruction of the weevils during the winter. This is accom- plished by the destruction of the places in which the insects hibernate. Many such places are found in the cotton fields or in their immediate vicinity. A certain number of the weevils will of course make their way into the heavy woods and other situations beyond the reach of of the planter, but many remain where they can be reached. 4. ica as an early crop. (See Pl. XXII.) The importance of obtaining an early crop has been shown to depend upon the small number of weevils which hibernate successfully, their late emergence from hibernating quarters, and their comparatively slow development Bul. 114, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE XXII. Fig. a.—Late-planted cotton under boll-weevil conditions, given same culture as early planting. (Original. ) Fig. b.—Early-planted cotton adjoining the late planting under same conditions. (Original.) RESULTS OF EARLY AND LATE PLANTING OF COTTON. REPRESSION. 161 during the early part of the season. The obtaining of an early crop is brought about by early preparation of the soil, by early planting, by the use of early-maturing varieties, by a system of fertilization which will stimulate the growth of the plants, and by continuous shallow cultivation during the season. 5. Increasing the effects of climatic control. As has been shown, practically 50 per cent of all the weevil stages throughout the infested territory are destroyed by climatic influences. This means that the power of reproduction of the weevils is reduced by one-half. A planter can increase the advantage in his favor by providing a suitable distance between the plants and between the rows. It is also impor- tant to use varieties, where possible, which have a comparatively small leaf area. The use of the chain cultivator will be found of great value in connection with obtaining the full effects of climatic control. 6. Encouraging the insect enemies of the weevil. This is accom- plished in part by procedures already recommended and further by the use of varieties which have a well-developed tendency to retain the fruit and which also have a comparatively open structure and small leafage. 7. Hand picking of weevils and squares. This is a practice of little general importance. Although under some local conditions it may be highly advisable, everything depends upon the cheapness with which the work can be done. On crops produced by wage hands it is doubtful if the hand picking of the weevils or squares will ever result in any profit. Where the crop is produced on the share basis, and the acreage is sufficiently small to allow considerable work in the picking of the squares, the practice will undoubtedly pay. It is, therefore, a matter that must be taken into consideration by each individual planter. It can not be recommended generally, for the reason that under many conditions it would result in loss. Wherever square picking is practiced the squares should not be burned. They should be placed in cages, so that the parasites may escape and continue their work. As a matter of fact, under most conditions it is likely that the encouragement that can be given the parasites by this means is of much more importance than any direct checking of the weevil by the process of hand picking. Wherever squares are burned the planter is merely destroying the enemies of the weevil and consequently working against his own interest. 8. Control at gins.—The use of modern cleaner feeders will eliminate practically all of the weevils from cottonseed. Such devices should ‘ be used at least in the ease of all seed that is intended for shipment into any infested localities and especially along the outer border of the infested territory, where wagons may carry infested cottonseed some distance into territory that has not been reached by the weevil. It is important in connection with the cleaner feeders to provide some means for the destruction of the insects that are captured. In some cases where the cleaner feeders are in operation the discharge is allowed to accumulate in an open barrel or box. From such recep- tacles weevils readily make their way into the seed cotton in storage. It is a simple matter to provide compression rollers through whick the discharge from the cleaner feeder is passed. If, for any reason, the use of compression rollers is impracticable, the trash should be 28873°—S. Doc. 305, 62-2——11 162 THE MEXICAN COTTON-BOLL WEEVIL. fumigated at frequent intervals by means of carbon bisulphid or col- lected in a closed chamber and burned before the weevils have an opportunity to escape. (See Pl. X, a.) 9. Fumigation of seed (fig. 34). This is a means of repression that will be of avail only in the case of shipments of seed into uninfested territory. It has been found that carbon bisulphid is the most sat- isfactory agent to use. Great care should be taken to insure thor- oughness of application. The use of a crossbar attached to the cultivator to jar the infested squares from the plants has frequently been recommended. Under some conditions this practice should be followed, but under others it is worse than futile. It was shown, in the treatment of the subject of natural control of the weevil, that in the humid region, including Arkansas, Louisiana, and the eastern portion of Texas, the mortality in hanging squares is greater than in fallen squares. For this reason it is better for the squares to remain on the plants. There is another reason why they should be allowed to remain on the plants which applies especially to the moist region in which the boll weevil is now doing great damage. This is, that the hanging squares are much preferred by the boll-weevil parasites. The records have invariably shown a higher rate of parasitism in hanging squares than in fallen squares. In this way the hanging squares furnish a means for the breeding of parasites, thereby enabling them to establish themselves in the field. It will be noted that the means of repression of the boll weevil may be divided into two classes, namely, direct and indirect. The direct means of control are the destruction of the weevils in the fall by destroying the plants and burning or burying the immature stages, hand picking of weevils and squares under some conditions, the burial of the infested forms at the time of maximum infestation, and the burning of the hibernating weevils in their winter quarters. The indirect means of control are early planting, the use of early varieties and of fertilizers that will accelerate growth, the selection of fields where the soil is suitable to rapid development, frequent shallow cultivation, the encouragement of the parasites of the weevil by placing the infested squares that may be picked by hand in cages instead of burning them, and the use of machinery which facilitates the various operations in preparing the land and cultivating the crop. These have the effect of increasing the acreage that a hand may cul- tivate. In view of the fact that the boll weevil forces a reduction in the acreage per hand, this is a consideration of some moment. DESTROYING THE BOLL WEEVIL IN COTTON SEED. It has been shown in this bulletin that adult weevils are frequently to be found in cotton seed and that there is danger in the dissemina- tion of the pest through the shipment of the seed. A number of experiments have been performed to discover means of killing the weevils found in seed. There are great difficulties to be overcome on account of the density of the seed and its practical impenetra- bility by certain fumigants. It was shown, for instance, that hydro- cyanic-acid gas has practically no penetrating power whatever. Carbon bisulphid was found to be satisfactory, aishouelt a special apparatus and special manipulation of the seed are necessary to insure REPRESSION. 163 success. The method described below, from Farmers’ Bulletin 209, is that which has been used by the bureau in cases where it has been necessary to free cotton seed of the weevils. The following plan for this work is proposed: A tight matched-board box should be provided having sides 4 feet high, open on top, and of other dimensions to accommodate 12 or more 100-pound sacks of cotton seed placed upright upon the bottom. Another tier of sacks could be added if desired. Into each one of these sacks about 1 ounce of carbon bisulphid should be forced by an apparatus for volatilizing the liquid and mix- ing the vapor with air. The accompanying illustration (fig. 34) will give an idea of this apparatus. It should consist of three essential parts, as shown in the illustration. A is an air pump having sufficient storage capacity to enable it to maintain a steady discharge of air for several minutes without continu- ous pumping. The stop- cock at a, regulates or prevents the escape of air, as may be desired. B is an ordinary 2-quart bottle fitted at 6! with a tight stopper of good length, having two openings, through which the inlet and outlet pipes pass. These pipes may be of glass or metal and should be as large as can be used. The inlet pipe, 6,, reaches nearly to the bottom of the bottle and is provided at the lower end with a per- forated metal cap as large as will pass through the neck of the bottle. This allows the escape of the air in small bubbles and insures rapid evaporation. The outlet pipe, b,, reaches only through the ‘stopper. Upon the outside of the bottle is pasted a paper marked with l-ounce grad- uations. C is a piece of ordinary 2-inch iron gas : es ‘ pipe about 34 feet long, Fig. 34.—Apparatus for iis ee seed in the sack. (After but this may be any de- ge sired length. It is closed and roundly pointed at the tip, and for about 15 to 18 inches of its length provided with small perforations pointing in all directions to give free escape to the vapor into all parts of the sack of seed at once. The connections may be of rubber tubing, but as little rubber as possible should be used for this apparatus, as it is affected by the vapor of the bisulphid, and the couplings will have to be frequently replaced. This, however, will not be a considerable item of expense. With the apparatus just described one operator would be able to accom- plish the entire work of disinfection. The amount of carbon bisulphid recommended is about 1 ounce for each 3-bushel sack. It is safe to say that this can be secured for less than 1 cent per ounce when purchased in 25 or 50 pound lots, making the cost of bisulphid not over 1 cent per sack. As it requires but from two to three minutes to vaporize 1 ounce of the liquid in the manner described, the expense for labor in appli- cation would not amount to one-half a cent per sack. Fumigation with carbon bisul- phid can therefore be effectively made at the slight expense of from 1 to 14 cents per 100-pound sack. Application of the bisulphid in this manner reduces the elements of danger to a minimum, as the vapor is almost wholly confined and the slight quantity escaping, mixed with the open air, would not be in either inflammable or explosive proportions. It has been determined that the slight trace of bisulphid vapor in the air would not injure the operator in the slightest degree. The sacks should be left in the box for forty hours after the gas is injected. 164 THE MEXICAN COTTON-BOLL WEEVIL. LEGAL RESTRICTIONS REGARDING THE BOLL WEEVIL. UNITED STATES STATUTE. The statute, quoted in part below, prohibits the interstate ship- ment of the boll weevil and certain other insects, and provides penalties: AN ACT To prohibit the importation or interstate transportation of insect pests, and the use of the United States mails for that purpose. That no railroad, steamboat, express, stage, or other transportation company shall knowingly transport from one State or Territory into any other State or Territory, or from the District of Columbia into a State or Territory, or from a State or Territory into the District of Columbia, or from a foreign country into the United States, the * * * poll weevil, ina live state, or other insect in a live state which is notoriously injurious to cultivated crops; * * * or the eggs, pup or larve of any insect injurious as aforesaid, except when shipped for scientific purposes under the regula- tions hereinafter provided for, nor shall any person remove from one State or Territory into another State or Territory, or from a foreign country into the United States, or from a State or Territory into the District of Columbia, or from the District of Columbia into any State or Territory, except for scientific purposes under the regulations herein- after provided for, the * * * boll weevil, * * * in a live state, or other insect in a live state which is notoriously injurious to cultivated crops; * * * or the eggs, pupz or larvee of any insect injurious as aforesaid. (33 Stat. L., 1269.) Sec. 2. That any letter, parcel, box, or other package containing the * * * boll weevil * * * inalive state or other insect ina live state which is notoriously injurious to cultivated crops; * * * orany letter, parcel, box, or package which contains the eggs, pupze or larvee of any insect injurious as aforesaid, whether sealed as first class matter or not, is hereby declared to be nonmailable matter, except when mailed for scientific purposes under the regulations hereinafter provided for, and shall not be conveyed in the mails, nor delivered from any post office, nor by any letter carrier, except when mailed for scientific purposes under the regulations here- inafter provided for; and any person who shall knowingly deposit, or cause to be deposited, for mailing or delivery, anything declared by this section to be nonmail- able matter, or cause to be taken from the mails for the purpose of retaining, circulat- ing, or disposing of, or of aiding in the retention, circulation or disposition of the same shall, for each and every offense, be fined, upon conviction thereof, not more than five thousand dollars or imprisoned at hard labor not more than five years, or both, at the discretion of the court: Provided, That nothing in this Act shall authorize any person to open any letter or sealed matter of the first class not addressed to himself. (33 Stat. L., 1270.) Sec. 3. That it shall be the duty of the Secretary of Agriculture and he is hereby authorized and directed to prepare and promulgate rules and regulations under which the insects covered by sections one and two of this Act may be mailed, shipped, transported, delivered and removed, for scientific purposes, from one State or Terri- tory into another State or Territory, or from the District of Columbia into a State or Territory, or from a State or Territory into the District of Columbia, and any insects covered by sections one and two of this Act may be so mailed, shipped, transported, delivered and removed, for scientific purposes, under the rules and regulations of the Secretary of Agriculture: Provided, That the rules and regulations of the Secretary of Agriculture, in so faras they affect the method of mailing insects, shall be approved by the Postmaster-General, and nothing in this Act shall be construed to prevent any State from making and enforcing laws in furtherance of the purposes of this Act, pro- hibiting or regulating the admission into that State of insects from a foreign country. (33 Stat. L., 1270.) Src. 4. That any person, company, or corporation who shall knowingly violate the provisions of section one of this Act shall, for each offense, be fined, upon conviction thereof, not more than five thousand dollars or imprisoned at hard labor not more than five years, or both, at the discretion of the court. (33 Stat. L., 1270.) QUARANTINES OF THE SEVERAL STATES. Quarantines designed to prevent the importation of the boll weevil are now in force in the following States and Territories: Alabama, California, Georgia, Louisiana, Mississippi, North Carolina, Okla- LEGAL RESTRICTIONS. 165 homa, Porto Rico, South Carolina, Tennessee, and Texas. They are directed against all infested counties and States, as well as against all counties which may become infested in the future. The following pages give the substance of the present restrictions. For further particulars the quarantine officers of the several States should be addressed directly. Alabama.—The present quarantine regulations in Alabama were promulgated by the Alabama State board of horticulture on April 4, 1911. The quarantine applies to cotton seed, seed cotton, hulls, seed-cotton and cottonseed sacks (which had been used), cotton- ickers’ sacks, and corn in the shuck. Importation of these articles into uninfested territory from infested territory, or from any point situated within 20 miles of the area known to be infested, is pro- hibited. However, between January 15 and July 15 shipments of these articles originating within or ginned within a zone 20 miles in length immediately adjoining the infested territory may be made to pomts not more than 40 miles outside of the line of infestation. Between October 1 and June 30 shipments of Spanish moss, baled or unbaled, originating in infested territory, are prohibited from entering or passing through uninfested parts of the State. Cotton lint (loose, baled, flat, or compressed) originating in infested locali- ties is prohibited except during the months of June, July, and August. The shipment of household goods is prohibited - unless accompanied by an affidavit attached to the waybill to the effect that the shipment contains no cotton, cotton seed, seed cotton, hulls, seed-cotton and cottonseed sacks, cotton-pickers’ sacks, corn in the shuck, or loose Spanish moss, except that in shipments of household goods made during the months of July, August, and September corn shucks or Spanish moss may be used for packing. All shipments of quarantined articles must be made in tightly closed box cars. No person except the entomologist of the State board of horticulture and his deputies is allowed to have in possession outside of the weevil-infested territory any live stages of the boll weevil. The penalty provided is a fine of from $100 to $500. Californa.—tin California the boll-weevil quarantine is in the form of an order issued by the State commissioner of agriculture on April 23, 1908.. This provides that all cotton seed shipped into California shall be consigned through one of the State deputy com- missioners of horticulture. These shipments shall be fumigated with carbon bisulphid for a period of 24 hours by a deputy com- missioner. Deputy commissioners are located at El Centro, San Bernardino, Riverside, Los Angeles, and San Diego. Florida.—The restrictions in effect are authorized by a statute passed in 1911 which established the office of inspector of nursery stock. Dr. EK. W. Berger, Gainesville, is the present inspector. Georgia.—Previous to August 15, 1904, the Georgia State board of entomology had authority, by virtue of the legislative act which created it, to enact such regulations as it deemed necessary to pre- vent the introduction or dissemination of injurious crop pests or diseases. On August 28, 1903, this board adopted a regulation prohibiting the introduction of cotton seed from Texas except under a certificate from an authorized State or Government entomologist stating that the seed had been fumigated in such manner as to kill any stage of boll weevils which might be contained therein. On 166 THE MEXICAN COTTON-BOLL WEEVIL. August 15, 1904, an act of the General Assembly of the State of Georgia was approved, but. further amended August 23, 1905, whereby cotton seed, seed cotton, cottonseed hulls, or cotton lnt in bales or loose, corn in the husk, or all material, including house- hold goods packed in any of the above quarantined products, are prohibited from being brought into the State except when there is attached thereto a certificate signed by an authorized State or Government entomologist to the effect that said material was grown in and was shipped from a point where, by actual inspection, the Mexican cotton-boll weevil was not found to exist. Through ship- ments of quarantined articles may be made in cars which must be tightly closed, and no unloading is allowed during transit through the State. No common earrier shall use for bedding or feed for live stock any of the quarantined articles when the shipments originate in regions infested with the boll weevil. Mr. E. L. Worsham, capitol, Atlanta, is the present quarantine official in Georgia. Louisiana.—The State entomologist of Louisiana is, by a law passed December 15, 19037 empowered to quarantine against the cotton- boll weevil whenever it seems advisable. At present the State is entirely infested, but if in the future portions of the State should be freed the entomologist is fully empowered to restrict dangerous ship- ments into such portions. Mr. J. B. Garrett, Baton Rouge, La., is the quarantine officer of this State. Mississippi.—The State legislature in 1908 passed a law giving the entomologist of the experiment station considerable authority in regard to the quarantines against the boll weevil. As only part of the State is infested, and it may be possible to save certain portions several years of injury, the rules established in 1904 should be con- sidered in force as restricting shipments into uninfested counties. An absolute quarantine is established against cotton seed, seed cotton, hulls, seed-cotton and cottonseed sacks (which have been used), cotton-pickers’ sacks, corn in the shuck, unsacked corn, unsacked oats, unsacked wheat, and unsacked cowpeas from the infested terri- tory. Through shipments of quarantined articles must be in tightly closed cars, which must not be unloaded while in transit through the State. Household goods to be shipped from infested territory into uninfested parts of the State of Mississippi must be accompanied by an affidavit to the effect that no quarantined articles are contained as packing or otherwise in the shipment. Baled cotton can be shipped into the uninfested parts of the State only in tightly closed cars. Prof. R. W. Harned, Agricultural College, Miss., is the quarantine officer of this State. North Carolina.—By virtue of authority from the State legislature to prevent the importation of crop pests, the North Carolina Crop Pest Commission early in 1904 adopted rules establishing a quarantine against all localities where the Mexican cotton-boll weevil is known to exist. The quarantine was absolute and applied to cotton, cotton seed, cottonseed meal, cottonseed hulls, hay, oats, corn, rice, straw, rice chaff, and other grain or material likely to harbor any stage of the boll weevil. LEGAL RESTRICTIONS. 167 The rules published in July, 1910, are reproduced verbatim: ReGutation No. 15. No transportation company, common carrier, or agent thereof, shall bring into North Carolina any shipment of seed cotton or cotton-seed hulls origi- nating at any point in the States of Texas, Louisiana, Mississippi, Oklahoma and Alabama. And this shall likewise apply to other States when the boll weevil shall be determined to be established within their borders. ReGutaTion No. 16. Shipments of cotton destined to any points in North Carolina and which originate at any point within the States of Texas, Louisiana, Mississippi, Oklahoma, Arkansas and Alabama, or other States that may hereafter become infested with cotton boll weevil, shall only be in hard compressed bales. If shipped in any other form, it is declared to be a public nuisance and is liable to seizure by the Board of Agriculture or its agents. Reautation No. 17. Any shipment of cotton seed which originates at any point in Texas, Louisiana, Mississippi, Oklahoma, Arkansas or Alabama, and which is des- tined to any point in North Carolina, can be accepted for transportation only if it shall have attached to the bill of lading a certificate or statement signed by a duly authorized State or Government Entomologist stating that the point from which said shipment originates is a locality not known to be in the area of the boll weevil infection. Rea@utation No. 18. If any shipment of seed cotton, cotton-seed hulls, cotton, or cotton seed not in accordance with these regulations be presented to any transporta- tion company, common carrier, or agent thereof, for shipment to or delivery at any point within this State, same shall be refused, and the case shall be reported to the North Carolina State Department of Agriculture, at Raleigh, giving the name and address of the consignor and of the consignee. Prof. Franklin Sherman, jr., Raleigh, N. C., is the quarantine officer in this State. Oklahoma.—By virtue of rules and regulations issued by the State entomologist in accordance with the laws of the State, shipments of cotton seed, cottonseed hulls, seed-cotton and cottonseed sacks, cotton-pickers’ sacks, and corn in theshuck are prohibited from infested territory into uninfested territory. In the same manner household goods are prohibited unless accompanied by a certificate that no quarantined material is contained therein. Through shipments of quarantined articles shall be made in tightly closed box cars and shall not be unloaded while in transit through the State. Shipments of baled cotton into uninfested parts shall be made in tightly closed box cars. No common carrier shall use for bedding or feed for live stock any of the quarantined articles which may have originated in infested territory. All persons are expressly forbidden to send live weevils in any stage to any point in or outside of the State, either by mail, express, or otherwise. Prof. C. E. Sanborn, Stillwater, Okla., is the quarantine agent for this State. Porto Rico.—By legislative act no cotton seed, seed cotton, cotton lint, loose or in bales, shall be brought into the island of Porto Rico, from any State or county whatsoever without being accompanied by the certificate of a duly authorized State or Federal entomologist that the shipment originated in a locality where, by actual inspection of such official or his agent, the boll weevil was not found to exist. Shipments not so certified are liable to seizure and destruction. Punishment is provided for in section 16 of the Penal Code of Porto Rico of 1902. The governor of the island has direct control over the enforcement of this law. South Carolina.—In South Carolina the quarantine regulations are entirely embodied in the laws of the State, and consequently not so readily modified to conform with the changed conditions and a better understanding of the methods of dissemination of the boll weevil as 168 THE MEXICAN COTTON-BOLL WEEVIL. is the case when authority to promulgate rules and regulations is invested in a commission or in the State entomologist. The law established to guard against ‘the introduction of the Mexican boll weevil into the State of South Carolina was approved on February 25, 1904. The commodities quarantined against were cotton seed, oats, and prairie hay, shipped directly or indirectly from infested points in the State of Texas. Prof. A. F. Conradi, Clemson College, S. C., can furnish information concerning the interpretation of the State law. Tennessee.—In compliance with the requirements of an act of the General Assembly of the State of Tennessee (S. B. No. 442, chap. 466), approved April 17,1905, entitled “‘An act to create aState entomologist and plant pathologist,” etc., the State board of entomology, estab- lished by said act, announced the following rules and regulations under date of December 31, 1910. (a) No cotton lint (loose, baled, flat, or compressed), cotton seed, seed cotton, cotton-seed hulls, seed-cotton or cotton-seed sacks (which have been used), or corn in the shuck, shall be shipped into Tennessee from the infested territory of Texas, Okla- homa, Louisiana, Arkansas and Mississippi. (6) Shipments of household goods from infested areas of above named States shall not be admitted into Tennessee unless accompanied by an affidavit attached to the way-bill to the effect that the shipment contains no cotton lint, cotton seed, seed cotton, cotton-seed hulls, seed-cotton or cotton-seed sacks, or corn in the shuck. (c) It shall be unlawful for anyone in Tennessee to have in his possession live Mexi- can cotton boll weevils. The public is urged to recognize the danger of introducing unwittingly live boll weevils for inspection, observation, or experiment. Mr. G. M. Bentley, Knoxville, Tenn., is the officer in this State. Texas.—In accordance with an act of the State legislature, to pre- vent the spread and dissemination of injurious insects, the commis- sioner of agriculture designated the boll weevil as such an insect to be quarantined. This ruling i in the act makes it illegal to ship seed cot- ton or cotton seed, or any other article which might carry the boll weevil from an infested county to an uninfested county. Mr. Ed. R. Kone, Austin, Tex., is the State officer charged with quarantine enfor cement. Regulations of foreign governments.—The Governments of Egypt, Peru, and India have established an injunction against the importa- tion of American cotton seed originating in the infested localities. In all cases, however, it can be arranged to have shipments cleared in ~ case they are accompanied by certificates of fumigation by a com- petent authority. THE MEXICAN COTTON-BOLL WEEVIL. 169 BIBLIOGRAPHY. This bibliography includes only the more important writings which have been pubushed in permanent form. In the preliminary part of this bibliography a special synopsis is given of the contents of pub- lications, more particularly to outline the history of the cultural method now recognized as of supreme importance in the control of the boll weevil. No attempt is made to give a synopsis of the later titles. For a complete annotated bibliography see Circular No. 140, Bureau of Entomology. 1843. Bonrman, C. H.—Genera et species Curculionidum cum synonymia hujus familie ed. ©. J. Sch6énherr, vol. 5, pt. 2, pp. 232-233. The original description of Anthonomus grandis. 1871. Surrrian, E.—Verzeichniss der von Dr. Gundlach auf der Insel Cuba gesam- melten Riisselkifer.< Archiv f. Naturg., vol. 37, Jahrg. 13, pt. 1, pp. 130-131. Contains the record of a specimen from Cardenas and one from San Cristobal, in Cuba. 1885. Ritey, C. V.—Report of the Commissioner of Agriculture for 1885, p. 279. Contains the sentence ‘Another very large species, A. grandis Boh., we have reared at this depart- ment from dwarfed cotton bolls sent from northern Mexico by Dr. Edward Palmer.”’ This is the first published record of the food plant and method of injury of the species. 1891. Dietz, W. G.—Revision of the genera and species of Anthonomini inhabiting North America. s-.tetasthen? .< ia. sass s sce 30 ELLE REN Res] 9) 0 C621 0,0) 5 | Se eS ee © re 30 Misikenttor Doll WeEVIL. 2c adhawt us sales sce se teases 30 yulvus attacks: purple mallow buds. <<<. 2... ..<4+--+--+-:------ 30 Ini EeM OMe PWREMlies ooc0l ts =~ n-ne owe ee oe bees 30 grandis. (See Boll weevil.) signatus attacks blackberry, dewberry, and strawberry buds... -- . 30 mustaken tor bollaweeyil. 2.212 <<. sn;. 22 eeeseues See ga ae lS aed 50 causes for natural. dissemination 24 2209.2. 32922. Se ee 87 checked by altitude:.¢- 2-2-3 e ee ee 28-29 dryness) = 255) Ape A dee eta 2h ee 28 low temperature: {2:2 23-523 sh eee coer bee eee 28 climatic’ control effect oikcol dees sae ae er 19 drought =e 52eoeeeeeetee eek e een es nae 16 early trast :'o ta eeenae tees. meee oe 20 influences on: vitality and activimegue 9-2-5224 25e4-46 121-122 compensations for losses caused thereby....--.-..---------------- 26-27 control by climatic conditions: !2. 2) eee eee eee eee 120-132 parasitesics.2. 0.0 FL ye a ee ee 120 predators 3 JA 5ec Sa eee SATE Been ee 120 proliferation: <2). 3h See ee 132-135 INDEX. 179 Page Boll weevil, copulation, age at beginning. . .-.---------- SERA OEE CRETE Fone 52 mratiyn Ol aCl. 1 s52> 22-06 2 sk ss oh Ae eeh yee e's. 52 MeneEPWMON eee este Fe 2 ee nt nie cola Re oe ete 33-37 development during winter..--.--.---- nfo tate aie ele ae lager cra! bdo 73-74 GinEBR@E aig >= 125-131 NaMAOUR etal et os Sk tna win ae wale oo = 129-131 Tr OTICR ae a aes ee) eh a Re I OE CM S128 Bollworm. (See Heliothis obsoleta.) Bracon mellitor. (See Microbracon mellitor.) Bruchophagus herrere, enemy of boll weevil.........-.---------------------- 141 Buildings as hibernation shelter for boll weevil . .--.-..--------------------- 102 Bunting, painted. (See Passerina ciris.) Burial of squares, effect on boll weevil.........--...-----------+--+++-++++-- 147-149 182 THE MEXICAN COTTON-BOLL WEEVIL. Page Callirhoe (see also Mallow). : buds, duration of life of boll weevils fed thereon. ................-- 48 involucrata, tested as food plant of boll weevil........-......------- 32 Cardinal. (See Cardinalis cardinalis.) Cardinalis cardinals, ‘enemy ot polljaveevillesca oe ote een ce eee eee oe 146 Careless weed. (See Euphorbia.) Castor bean plants, futility against boll weevil ........-..-.------ LEI ep 155 Cathartus gemelidius, enemy ob bolloweevil 3. 22s. eee =< ee 138 OCatolaccus huntem: enemy otjbollaweevallass)o=-=- se eee eee eee eee 141 incertus, enomy-oLboll weevil. * 2... 2 ee ee 141 Cerambycobius cushmani, enemy of boll weevil ...............-.-.-..™-.-:.- 141 cyaniceps, enemy of boll weevil. -.-.~-- 777-822 na. =e 141 Sp eneniy oipoll weeval: 2-254. Jeo) cme asa en eee 141 Chain. cultivator, use aeaims Ol weevil: . 4.0 ee ne ee te eee ee 151 Chalcodermus xneus attacks cowpea pods.......---------+----+--+-++++-+2+---- 30 Precds IM COLON SONATCS. «5 en cn nae cee el ee ee 3 mustaken for-holljweevdl.- 32. -.75 5 eee eae soe oe oe 30 Chat, yellow-breasted. (See Icteria virens.) Chaukaqnatius.spp:,,epemies of boll ‘weevilo a). 22 ee ee ae oe ere 137 Chickadee, Carolina. (See Penthestes carolinensis.) China-berries. attacked by Arzcerus fasciculatus.- "5. 22 4 Be 30 Chondestes grammacus, enemy of boll weevil........-----..-------++----+-+--- 146 Chordeiles virginianus, enemy ot boll: weevil... -2-22---.9--s2.s--.-e5see oe 146 Chimates tactor in. boll-weevaljeconttol: 5.2 =... <.5-4aqehene aes eee 120-132 TOC AUY ve intel ei Paes i aoe eet ae eee 120-1 Climatic conditions, factor in boll-weevil control...........--..------------ 120-132 influences on vitality and activities of boll weevil...........---.-- 121-122 Cocklebur. (See Xanthium.) @otteeibeans atiackedsb ved recents | ASCICULACUS as ee ee 30 bean weevil. (See Arexcerus fasciculatus.) Cold ettect on, boll weewsl ....2 2-22 4c, dae aaene ieee =e 2S eee eee 19, 28 Colinus virginianus, enemy of boll weevil......--------------+--------------- 146 Colors, attractiveness to, boll qweewilin 2-5. Scenes © oe os eee See eee 43 Conotrachelus elegans attacks galls and nuts of pecan........-....------------ 30 mistaken for boll weevil..........:-.- Se RA TE aes he he 30 entnaceus mistaken tor bOlleweci vile ee eee ae ee 30 leucophxatus attacks stems of careless weed (Euphorbia)... .-.--- 30 mistaken tor boll’ weewils..c.245.2.0.cee eee 30 NOSO BitACkS:aCOMMS ta68 ese axe eee EI 4 Ree ee eee 30 mistaken for boll weevalic 3 -c< cop teeees Se ee ee eee 30 nenuphar (see also Plum curculio). attacks fruit of plums and peachess..-.2- 4-25. -c5----= 30 mistaken: for bollywee Vil. acacia ae ee 30 Convolvulus repens tested as food plant of boll weevil..........---..---------- 32 Cordyceps, fungous enemy of boll weevil...-..-....-...----.--+-0-+--+---+--- 136 Corn, duration of life of boll weevils fed thereon...-.......------+++-------+- 48 Cornstalks, hibermation: shelter for boll weevileua. «+a. sees eerie bee eee eee 101 Cotton, American Upland, susceptibility to boll-weevil attack.............-.-- 45, 46 baled, factor in dissemination of boll weevil........-..---..--------- 93 bolls, ‘duration of life of boll weevils fed thereon..............-------- 49 effect of feeding by boll weevil thereon......-.......----------- 45 old, attacked by Arxcerus fasciculatus 1 gel preheated paca ae 30 pendent, wmdirectietiect om boll weewallees 6 ase te eee 135 with thick wallesetiection bollitweevilesssseeeer eee 136 boll weevil. (See Boll weevil.) caterpillar. (See Alabama argillacea and Leaf worm.) Cuban, susceptibility to boll-weevil attack.......-.-.---------------- 45, 46 destruction of stalks as a means of boll-weevil TOPTessION..c2 2 2k 157-158 determinate growth, effect on boll weevil............-....------------ 135 early bearing, elteetion boll weevil ae on eae eee) - eat 135 maturing varieties as a means of boll-weevil repression....--.-. 160-161 planting as a means of boll-weevil repression............------ 160-161 Egyptian, susceptibility to boll-weevil attack. . ~ ars «Dae fall destruction of stalks in relation to survival of boll weevil from hiber- NAUON: .o de eneht pense Yee os eee we ete. Ge eee 111-112 fertilization as an aid to boll-weevil repression. . Sle We . 160-161 flowers attacked by Echthetopyga gossypwi in Philippines. ois odie ne ea 30 INDEX. 183 Page Cotton, foliage, duration of life of boll weevils fed thereon. ............-...-. 49 foods plantian avapamea argullacea. 022.2). 2. 222 PT. oe eee eee 15 eno anUsOrandis =). 2 COPEL US Ea ae a Se 1-175 IOUT nL Me iy dak hig ot Seema ee ry ge 30 minions Cornus ores 0 IL) SAO IL SINS DS 30 CRAICODENUUS CONEUS 20526 F22008 S20 OT, AE Fae 30 ichinetamgaqossypi oo 9.3 Le) AL HOY AO POOR. 30 IRA RESIOUsOlee > FESO ON Pee IS AOE I 15 hairy stalks, effect on boll weevil............-. Wisi Gd SOY Oe ee ee 135 involucral, bracts, effect on boll weevil. ...-...........0...202..2.-..- 136 “kidney,” host plant of boll-weevil in Cuba-.-.....2.......----2-.4-- 16, 31 “‘loose.’? (See Gossypium brasiliense.) nectar, Indirect effect on- boll weevil..--5. 529924 222 2 22S oe es. 135 winited by Gereus pemecelen. 0 22 Nill Osu i i 30 DUCUUIIVIULES annette oes a 22 RE eS, oS ed 30 picking of squares as a means of boll-weevil repression.............---- 161 planting early as a means of boll-weevil repression. .. - . Mee! 5 160-161 restriction an impracticable means of boll-weevil repression. . 156-157 time, effect on longevity of boll weevils..................---- 116 plant, proliferation, effect on boll:weevil- ..2.....222.......0252.-- 132-135 BirUchHres mmimMical tobolk weevils SSssek Mo. PPS S. es... 135-136 retentionol truit, effect.on bolliweevil®. 122s). See). eee. 136 Sea Island, susceptibility to boll-weevil attack...................---- 45, 46 seed, factor in dissemination of boll weevil...............-...-.------- 92-93 shallow cultivation as a means of boll-weevil repression...........-.-- 160-161 squares attacked by Anthonomus vestitus in Peru....-.--...----------- 30 Ghalcodenmius ness Tae Pie ae Os Pea 31 Ipurial, eftection: boll weevdll.= 2, -2-e- aoe an ee ee eee Trapping at lights, futihty agaist bolloweevile. 5 et 3a ee i ee Trichobaris miucorea attacks tobacco Sislkes. $2.8 ae eae tal ee eee texana attacks Spanish thistle stalks (Solanum rostratum).......-.-- mistakentor Doll Weevil. 2.2165 oe erick tee Beene yee Tychius sordidus attacks pods of false indigo (Baptisia)....................-.- mistaken for boll weevil... 2: .%: jascede cece te ee Tyrannus tyrannius, enemy of boll weevil... -4..< 32-4... --se0-ee eee Tyrogiyphus breviceps, enemy of boll: weevil .< ..22-0-ectacod = => ses ee ee United States statute reparding. boll weevil. - 242524042 =.4 te ey ee Urosigalphus anthonomi, enemy of boll weevil...............-.-------------- schwarzi, enemy of boll weevil.....-. LU Sc SRA ae sp. enemy of. boll weevil: wb oe esti ae eee ee Vehicles, factors in dissemination of boll weevil...-........-.----.-----<<--<< Warbler, myrtle. (See Dendroica coronata.) yellow. (See Dendroica xstiva.) Water, duration of life of boll weevils fed thereon.................-....--..-- hibernated boll weevils fed thereon........-.-.----- Windstorms as agents in spread of boll weevil..............----------------- Wren, Bewick. (See Thryomanes bewicki.) Carolina. (See Thryothorus ludovicianus.) winter. (See Nannus hyemalis.) Xanthiim roots,attacked by Baris transversd. ..tomcceos5- ee eae oe Yellowthroat, Maryland. (See Geothlypis trichas.) Lonotricnia alowolls, enemy of boll weevil: - <2 -t-4..4-1-)-e= ees See O US. erPARTMENT; OF AGRICULTURE, BUREAU OF ENTOMOLOGY—BULLETIN No. 115. L. O. HOWARD, Entomologist and Chief of Bureau. PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. feoN TENTS (AND: LN Dix Issuep F&bruary 5, 1915. WASHINGTON: GOVERNMENT PRINTING OFFIOE. 19165, HD NaN Ee Ce ey TE) teu " tA) | HO VFR rs ’ 480. A U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY—BULLETIN No. 115. L. O. HOWARD, Entomologist and Chief of Bureau. PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. [. LIFE-HISTORY STUDIES ON THE CODLING MOTH IN MICHIGAN. By A. G. HAMMAR, Entomological Assistant, Deciduous Fruit Insect Investigations. IL’ THE ONE-SPRAY METHOD IN THE CONTROL OF THE CODLING MOTH AND THE PLUM CURCULIO. (SECOND REPORT.) By A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations, AND E. W. SCOTT, Entomological Assistant. LILSLIFESHISTORY OF THE CODLING MOTH IN THE SANTA CLARA VALLEY OF CALIFORNIA. By P. R. JONES anp W. M. DAVIDSON, Entomological Assistants, Deciduous Fruit Insect Investigations. i C Se zt i ae Lee = "Bet Broad === = oR Beatenter October Fi@. 3.—Curves showing maturity of larve of first and second broods; band-record curve, of 1909, at Douglas, Mich... ( Original.) TaBLE III.—Band-record experiments in 1909 at Douglas, Mich., by W. Postiff; com- pleted in 1910 by A. G. Hammar. Number | Number | Number | Number | Number No. of | Date ofcol-| of larvze | of moths | of para- | of moths | of para- Ao ee record.| lecting. and emerged,| sites, |emerged,| sites, t erkilled pupe. 1909. 1909. 1910. 1910. i ODmWISokewWNe 6 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLE IV.—Summary of Table IIT; band-record experiments at Douglas, Mich., 1909. Observations. Total. ao Observations. Total. Ra Larve and pup collected from Injured and winter-killed larve. . - 363 24.6 bandS.s eee Sis 5: A are See 1,475 | 100.0 || Larve of the first brood..........- 636 43.1 Moths emerging: Transforming larvze of the first 1900 ss 4 SSR ee eee ee 194 13.2 broodie:. BSF te eee aaa 194 33.2 1910 eee oo 2 eas een eee 821 55.7 || Wintering larve of the first 1909-19102 2 é.2c2cenee ei ee 1,015 68.8 brood... - . Sie ee SS are 425 66.8 Parasitized lary: ...=252-. 2s see 97 6.6 || Larvze of the second brood... ..--. 839 56.9 In numbers the second brood of larve surpassed the first quite materially. From October 18 to 25 no larve were obtained, due to prevailing cold weather. However, during the exceptionally warm November quite a number were collected which under average sea- sons would have remained undeveloped. Of the first-brood larve 43 per cent transformed the same season, while 57 per cent wintered together with those of the second brood. Of the total number of larve, 6.58 per cent proved to be parasitized by a hymenopterous fly (Ascogaster carpocapse Vier.). The proportion winter-killed and injured by other causes was 24.6 per cent. SEASONAL-HISTORY STUDIES OF 1910. The rearing material in the spring of 1910 consisted of an abun- dance of wintering larvae, which had been collected from banded trees during the previous season. During the winter and throughout the progress of the rearing experiments the insects were kept in cages in an outdoor shelter (see Plate II), and were thus exposed to the normal temperature conditions. WINTERING LARVE. The wintering larve invariably consist of individuals of the two broods, as only a portion of the first brood transforms the same season to form the second generation of moths, while the other portion win- ters like all of the second-brood larve. In the orchards a great number of the wintering larve find protec- tion for their cocoons under the rough bark of the trees and in cracks and crevices in older trees, and many are frequently found imbedded in decayed wood. It is mainly in the latter places that the codling moth larve find an escape from woodpeckers and other birds which make persistent searches for the larvee during the winter. The cocoon of the wintering larva.—The winter cocoon of the larva is proportionately small and completely sealed, and consists of heavy walls for winter protection. In appearance these cocoons vary con- siderably, depending largely upon the place selected by the larve. Under loose bark, where the larve are not limited in space, the co- coons are more or less oval, as shown in Plate I, figure 3. A slight PLATE Il. Bul. 115, Part |, Bureau of Entomology. U.S. Dept. of Agriculture. (TVNIDINO) "HOII] ‘SVIONOG LV LLGL GNV OLG]L NI HLOW DNITGOD AHL ONINVSY NI GSS YSLISHS YOOGLNO gees Oe eeee fa der. "pe OS dhl he i} THE CODLING MOTH IN MICHIGAN. 7 depression is made in the bark, the walls along the exposed sides are constructed from fragments of bark held in place by silken threads, and the inside is finally lined with a thin layer of silk. Within the small space of the cocoon the larva will be found in a doubled-up posi- tion. In the spring, previous to pupation, the winter cocoon is partly remodeled by the larva (see PI. I, fig. 4), and provision is made for the issuing moth by the construction of an exit tube (see Pl. I, fig. 5). This is partly made from fragments of the original wall of the cocoon and partly by the addition of new fragments of bark. Depending upon the location of the cocoon, the exit tube varies in length from one-fourth of an inch to over Linch. The purpose of the tube must be to provide a safe exit at the critical period of the emer- gence of the moth. Within the cocoon over the opening to the exit is placed a thin sheath of silk which is ruptured by the pupa at the time it wriggles out (see Pl. I, fig. 6) to give issuance to the moth. The transforming larve of the first brood also make their cocoons with an exit tube. The cocoons of these larvae, however, are only used for a short time and are hence of a more primitive construction. Variation in size of wintering larve.—In size the wintering larvee vary considerably (see Pl. I, fig. 7). There exists naturally a certain amount of individual variation, but in addition there are climatic factors which tend to increase this variation. The wintering larvee of the first brood are for the most part fully developed. There seems to be a tendency for undersized larve to transform the same season, as if less fit to pass the winter. Of the second-brood larve there are always a number that fail to attain full growth in the fall, and others totally fail.to enter hibernation before frost sets in. Larve para- sitized by Ascogaster carpocapse are seldom more than half grown and lack the pink color of the healthy larva. Judging from the uniformity of head measurements, the wintering larve, though variable in size, are probably to a great extent of the last or sixth instar. (See p. 78.) Winter-killed larve.—In earlier studies of the codling moth the writer has noted that killing due to cold occurred more or less fre- quently among wintering larve. During the spring of 1910 and 1911 more definite data were obtained showing a rather high percentage of winter killing. Thus, of the total number of larve from the band records of 1909 (Tables III and IV), 27.6 per cent failed to develop. A mortality of about 4 per cent may be ascribed to injury from the handling of the insects, while the rest, 20 per cent, succumbed mainly to injury from cold. Under normal conditions in orchards the per- centage of larve killed from cold is undoubtedly lower than the above figures because a proportionately large number is always destroyed during the winter by woodpeckers and nuthatches and in the spring, summer, and fall by predaceous insects and parasites. 8 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. It is quite noticeable that larve in exposed places or in poorly con- structed cocoons are more frequently killed by cold than are those well protected. As generally recommended under the control of the codling moth, it will be well worth while in orchards to eliminate the favorable hiding places of the larve, particularly the wintering brood. Such places are old stumps, decaying trunks, and branches of ill-kept trees, where cold weather little affects the larve or where their enemies can not readily reach them. SPRING BROOD OF PUP, Methods of recording pupation.—On account of the fact that pupa- tion takes place within the cocoon it is often difficult to record this transformation without disturbing the insect by exposing the cocoon. Fig. 4.—Device used in obtaining pupal records of the codling moth. (Original.) Different workers have often used small glass vials, within which the larvee have been compelled to make their cocoons and transform. This method is very unsatisfactory when we consider the habit of the larvee under normal conditions. The larva, in the construction of the cocoon, either in cracks of wood or under the bark of trees, gnaws off a certain quantity of particles of wood or bark and from these the cocoon is largely made. Furthermore, under normal protection the larva suffers less from outside fluctuating temperatures than might be expected in a tube of glass. Formerly the writer used soft strips of wood with narrow inter- spaces of one-eighth of an inch which the larve could enter and there spin their cocoons. To observe the larvee and pup within it was necessary to pull the strips apart, thus exposing the cocoon. Later it was found that when a thin film of transparent celluloid was placed in the interspace so as to cover the wood on one side the larvee pro- duced their cocoons in a normal manner and at the same time left the THE CODLING MOTH IN MICHIGAN. 9 side against the celluloid more or less uncovered, so that the insects could be observed within their cocoons without disturbing the latter. Some larve, however, particularly when exposed to too much light, would line with silk the side of the cocoon against the film. The diffi- culty in such cases was overcome by cutting in the film over the cocoon a small lobe or flap which could be gently-lifted for the neces- sary exposure. This device is illustrated in figure 4. The upper figure shows the lower side with numbers corresponding to the posi- tion of the cocoons within. In the central figure several larvee and cocoons are seen protected by the celluloid film. The two strips of wood are held together by a pair of common paper clips which have been bent and adjusted to the shape desired. n Bb o_ o~ 8 oe 2) (au = rs) © v ae) £ =) Ze 13 6 9 22 4 22 252831 3 6b April Fic.5.—Diagram showing time of spring pupation of the codling moth in 1910, at Douglas, Mich. (Original.) Time of pupation.—Owing to the very warm weather during the spring, pupation had commenced by April 15 (see fig. 5). However, with a change to cold weather that followed, pupation was inter- rupted until the latter part of May, and most of the larvee pupated during the brief period from May 19 to May 31. The last pupa of this brood appeared on June 23. (See Table V.) TaBLE V.—Pupation period for the codling moth in the spring of 1910, at Douglas, Mich. No. of Date of No. of | Date of No. of | Date of No. of | Date of larvee. | pupation. || larvee.| pupation. || larvae. | pupation. || larvee. | pupation. 2 Apr. 15 5 May 25 || 2 June 4 4 June 14 1 Apr. 30 3 May 26 2 June 5 3 June 15 1 ay 6 2 May 27 1 June 6 2 June 17 4 May 19 9 May 28 2 June 7 2 June 19 1 May 20 8 May 29 2 June 8 1 June 22 21 May 21 4 May 31 1 June 9 2 June 23 14 May 22 1 June 1 4 June 10 13 May 23 2 June 2 3 June 12 5 May 24 2 June 3 1 June 13 10 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Length of spring pupal stage.—The results of observations on the time of pupation and emergence of 106 individual insects are given in Table VI. Those pupating in April remained in this stage for the exceptionally long period of 59 days. The majority, pupating during the latter half of May, remained in the pupal stage about 30 days, while later larve, pupating about June 15, remained in this stage only 10 to 15 days. (See Table VI.) The average for the entire spring brood of pupx was 26.02 days. TasLe VI.—Length of pupal stage of the spring brood, Douglas, Mich., 1910. No.of Date of Ritor Date of obser- Days. || obser- Days. vation. | bupation. |Emergence. vation. | pupation. |Emergence. 1 Apr. 15 June 13 59 54 May 25 June 22 28 2 Apr. 30 June 15 46 DOs | endo ae AGORA S- 28 3 May 6 June 17 42 BOS |=2edorsens 00.5 :4 6 28 4 May 19 June 18 30 Siem eee GOreee Gone 28 5 donee. June 19 31 58 dos June 23 29 6 BdO sees doz2.- 31 59 May 26 June 22 27 a do June 20 32 60 =-G05=- GOnsece a= 27 8 May 20 Or 31 61 do June 23 28 9 May 21 June 18 28 62 May 27 June 22 26 10 do June 19 29 63 =GO.-- O=c=c5 26 11 GOes 22507: June 20 30 64 May 28 doeseas 25 12 do do 30 65 rare do...: 25 13 doze do 30 66 mdons do 25 14 do do 30 67 PAdo=ses June 23 26 15 doe do 30 68 2002-22 do=: 26 16 do.. doze= 30 69 .do.. Mdolss 26 17 dose do 30 70 .do.. .do. 26 18 do.. June 21 31 71 Sdore doseeae 26 19 do.. doss-< 31 72 May 29 June 19 21 20+ do... dorset. 31 73 SAG Cae June 23 25 21 Gose eee doss.- 31 74 ..do do 25 22 xdoee dotee- 31 75 2 Xo ERE See |e dotneee 25 22 EdO sees dosg=-* 31 US Weekes don: 25 24 GO sneer ee MOneseee 31 77 May 31 do.. 23 25 do NOOum eae 31 78° W22200% doze 23 26° |-2doz222-=.|| Juner 22s 32 79 dubatsye al |e Sola se 22 OA NBL Maeve se June 24 / 34 80 Fie he? yal ea domes 21 28 May 22 June 21 30 SLAs 08s June 24 22 29 152 don. ass CO eaaaeee 30 82 June 3 June 23 20 SONG ed Ot acres EERO ee eee 30 83) a |feedor- June 24 21 Slee edoreomeee Sa toe ee 30 84 June 4 June 23 19 32 do do 30 85 June 5 One 18 33 do do 30 SGin 5 | sos se see do... 18 34 GOs: see do 30 87 June 6 Ato o eee 17 35 do do 30 88 June 7 June 24 17 36 do do 30 BO) eed Ota stele dos 17 37 do edosees- 30 90 June 8 doses 16 38 Gos 3 June 22 31 91 June 9 June 25 16 39 do June 23 32 92 June 10 June 20 10 40 do dos. ses. 32 93 d0s June 24 14 41 May 23 June 21 29 04> 2. edo eee June 25 15 yA bala 6 Ca mgr [ae 95 Co ee Me 29 95. }22 ee ese se elle see Sac’ cnee July 2) |) secaesleecesnce 7 7 JUNe 426) Ssoee eas |e er eee do.... Ere a| eee ecs 6 8 JUNO O74 Pat ee eee eee ae Trl yrs Sh | ase ae ee 6 9 JUNeS 282" | seers ee see eeree Dal ye (FA alee oa eee eneee } 6 OR ee One es ec as ences Duly 2S ae acces teers i 11 iibbet: ee! el eee July 3 Talys SA teeta 4 5 12 GOs se eee cee alee do. Daly Sale eee 4 6 13 June 30 July 3 July 5 July 6 3 5 6 14 (a) do===- ..do. digithiye ¥/ 3 5 7 15 July 1 205.2 July 6 do... 2 5 6 160) |=-2d0° dOre- 22400: July 8 2 5 7 17 July 2 July 5 July 7 doseace- 3 D 6 18 July 3 July 6 July 8 July 9 3 5 6 19 dons: =3- S2GOnce< lone doe... July 10 3 5 7 20 Tiily ed elessGom cers jiilys 9) cesed0seeee 2 5 6 21 Gos st. Mdouse see July 10 July 12 2 6 8 22 July 6 July 9 July 11 July 13 3 5 7 Dae | eo kre se Okt Ee eens eee G0: e206 July 14 3 D 8 24 July 7 do: ae erlhes GOR wae July 13 2 45 6 25 July 8 July 10 July 12 July 14 2 4 6 26 July 9 July 12 July 14 July 15 3 5 6 Daf dosss 22: July 13 dot see July 16 | 4 5 7 28 July 12 July 14 July 15 Ose eer 2 3 4 29 OSs eee do-e= ec less Gosseee. July 17 2 3 5 30 ds. sesc lx dos ae July 16 July 18 2 4 6 IAWOLAP Ore 2c ats ee ee see teeta cf Bee 2.5 4.7 6.6 Maximum mae 4 6 10 Minimum 2 3 4 The so-called ‘‘red ring”’ of the egg appeared from two to three days after egg deposition, and the ‘‘black spot” from one to two days pre- vious to hatching. The eggs used in these experiments were laid in cages on pear foliage. Records on the development of the eggs were taken once daily between 9 and 10 o’clock in the morning. FIRST BROOD OF LARVA. Time of hatching.—In the field the actual time of hatching and the relative abundance of newly hatched larvee may be fairly well deter- mined from the different data on hand relative to the time of emer- gence of the moths, egg deposition, incubation of eggs, length of feeding of larve, and the appearance of mature larve, as shown by the bandrecords. In correlating these facts the time of hatching is estab- lished as given in the diagram of figure 11. The earliest eggs were deposited June 17, the maximum oviposition was reached at the close of June, and a few late eggs were laid up to THE CODLING MOTH IN MICHIGAN, 15 the end of July. Incubation of the earliest eggs lasted nine days; for eggs laid about June 30, six days; and for later ones laid during the middle and latter part of July, only four to five days. The larve from the Saugatuck band records (fig. 9) reach a maximum July 31, and inasmuch as the average length of feeding for this brood of larvee was 27 days the date for the maximum hatching would be July 4. On the other hand, on the basis of oviposition and length of incubation the height of the hatching period would be July 6. Length of feeding.—Reference has already been made in the pre- vious pages to the fact that a portion of the first-brood larve do not transform the same year, but winter and complete the life cycle the following year. The transforming and wintering larve differ in the length of feeding, and the latter are often materially larger in size. Thus on an average the transforming larve remained in the fruit 25 days against 29 days for the wintering larve. (See Tables XVI and XVII.) For the entire brood of larve the shortest feeding period was 17 days, the longest 45 days. Time of maturity of larve.—In the field the time of maturity of the larve is determined from the band-record experiments (fig. 9 and Table XXVIII). Thus the period for the first-brood larve at Douglas, Mich., extended from July 10 to September 10. After the emergence of the moths from the band-record collection it may further be possible to determine the time of maturity of transforming and wintering larve of this brood. The last transforming larva left the fruit August 8 and the first wintering larve left the fruit July 20. Tuere is also a difference in the appearance of cocoons whereby the two sets of larvee may be recognized; the transforming larva provides the cocoon with an exit tube, while the wintering larva produces a closed cocoon. (For full description see pp. 6-7.) Percentages of transforming and wintering larve—From Table XXXI it will be found that 201 larve of the first brood transformed the same season, while 368 wintered, or 35 per cent transformed and 64.1 per cent wintered. Somewhat similar results were obtained from the rearing experi- ments, though these can not be as reliable as the data from the band-record experiments, since the former are from a limited num- ber of observations. Out of a total of 51 larve, 21 transformed and 30 wintered, or 40 per cent transformed and 60 per cent wintered. (See Table XXII.) Larval life in the cocoon.—The length of time required for the making of the cocoon depends largely upon whether the larva is to transform the same season or to winter. A slight individual varia- tion of time naturally does exist for either set of larvee. In case of wintering larve it is difficult to decide just when the cocoon is completed. The transforming larve cease to be active from two to three days before pupating. For these, then, the larval life in the cocoon can be readily determined, being considered as the period from the time of leaving the fruit to the time of pupation. 16 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. In Table XIII are given the results from observations on 117 indi- vidual insects. Further records on the same topic are found in Table XVI. The larval life in the cocoon varied from 3 to 15 days with an average of 7 days. In case of a very short period of from 3 to 5 days the larve abandoned its first cocoon and made a new one. The records, however, only show the time consumed for the making of the last cocoon. Such cocoons are very primitive in appearance and have not been completed. TaBLe XIII.—Length of the pupal stage of the first brood, Douglas, Mich., 1910. f— D — Xo. Gf seaere: Lar- | Pu- No. of pes Lar- | Pu- a : SSE ETC) TUL obser- | ae “|| obser- pane) vation.| Leaving | Pupa- Emer- EER ES, vation.| Leaving | Pupa- Emer- ena pas fruit. tion. gence. E 5 fruit. tion. gence. 7 : Days.| Days. Days. |Days. 1} July 22) July 25} Aug. 9 3 15 60 | July 29! Aug. 4] Aug. 20 6 16 2.|..-do...-.<| July 26 |:.2do..... 4 14 61 | July 30 }...do....| Aug. 17 5 13 3 |- | a SOLOS o1o ne Ome ere 4 14 (i74y mere Ge Bee amo = 5 13 4]. 2 -200ss.: |g DLE 4 14 68.) seers a): |b dene ael_ aaeOL nee 5] 13 Be edocs) Ales 13 4 18 64) S22 do. a2 |-22dOssc5| eae. 2s 5 14 6 ~4d0%...<4|) Auge sb 4 20 69 [2 I@O0e 1 GOsc=.5|) SL. Se 5 14 dale me yee ee Oaape 4 20 66) 282 doses: 222d OSee saad sens 5 14 8 |. - G0... .) Agg: £20 4 25 GiGi kao Zoe |2ssGOL as | edee se 5 14 RINE Aug. 6] Aug. 19 15 13 68°) dO... s.<|5-200....|pAnge.. 19 5 15 10 |}. -|--.do....| Aug. 20 15 14 9 Foor NOs... 5/<||snedOs- Aug. 21 5 17 11 July 29 | Aug. 13 6 15 70) }.;..do...:.| Aug. - 5 |) Aug. 18 6 13 12 |. Aug. 4] Aug. 17 12 13 tL). 50s 22 =| ZAuiey 165): S805 7 12 13 |. W0..- 4|-do; 12 13 (Pa \ Bet (oe [eras Tee Aug. 21 7 15 14 July 30} Aug. 15 5 16 73 |...do....| Aug. 7 | Aug. 18 8 11 15 Aug. 1]...do 7 14 74,\....d0...2| Aug. 19%| Aug. .21 10 12 16 | Aug. 3 do 9 12 HO aGOL ends eee ao 10 12 ie || GOs seni. o do. 9 12 76 Ado. 6... |. s2005..5|e-ndas 10 12 18 do....| Aug. 16 9 13 77 oor ee lam = Aug. 24 10 15 19 |. 20O02x-.3|/252005,2 9 13 78 | July 31| Aug. 4] Aug. 17 4 13 20 Sd0e Ss. ||-=- 002 8 13 id) |-eeuOs oo Sen doee Fdose 4 13 21 do..3-<)|..sdo. 8 13 y= 40-5 eden: Aug. 18 4 14 22 do.. --do. 8 13 SL 52 -do: 2. =| Aug! 5 do. 5 13 23 -do....|...do. 8 13 82 do...-| Aug. 6] Aug. 19 6 13 24 | Gona2-|2--d0e. 8 13 8352 G02 .2/-|= GOL 24 | Vata 20 6 14 25 do.. Aug. 18 8 15 84 @os.~:3| waug: 37 | 2.8etos- 7 13 26 Aug. 4] Aug. 17 9 13 Solas One| sends Aug. 21 7 14 27 | Aug. 3] Aug. 13 7 10 86"). .2do2...| Aug. 9 | Aate. (22 9 13 28 do. . Aug. 15 7 12 Si - Oe ase ae GOs do 9 13 29 | do.. Ee doz 7 12 88 | Aug. 1| Aug. 4] Aug. 18 3 14 30 | Fesdor te s|eee dozen. 7 12 8915-2005. Aug. 5] Aug. 19 4 14 31) d| 2AUOE 2) eo Fe 7 12 90 do....| Aug. 6] Aug. 18 5 12 32 3\2-300... = | Aug: 36 7 13 Ol endoz 2A) -2005- Aug. 19 5 13 33 | SFO S25) a2 aOs ee 7 13 §2 |.. do. : .-do....] Aug. 20 5 14 34 200225-)|-— 200" 7 13 038). 2 OSS alse e Edo: = 5 14 35 do. Aug. 18 7 15 G4 |F SdOne sc a|aee doce do... 5 14 36 do. .-do 7 15 95 |...do....| Aug. 8 | Aug. 21 7 13 37 Aug. 4] Aug. 15 8 11 96 dos 2. -Aue "9 do. 8 12 38 EdOs Aug. 18 8 14 97 GOs caval seo Aug. 22 8 13 39 Aug. 6] Aug. 20 10 14 98 | Aug. 4] Aug. 12 Osea 8 10 40 Aug. 3] Aug. 15 6 12 99 |..-do....| Aug. 13 | Aug. 25 9 12 41 do.. Aug. 16 6 13 100 do....| Aug. 14] Aug. 26 10 12 42 ido... /°8)| S a 5 BS )/dnlagio 1 & bas c o S es Sie! eH 5 5 Z | Se eae ans & | a 1|/ June 25} July 2/ July 26] July 31 | Aug. 15 7 PA oa ee 5 15) |) ot 2 GOES asl Se CO sce ee Many, BOS) lee ee Pe oe ere ei (i Seaae 260 eS -. cras [tena s eee 3 dosecer 2002. July 29| Aug. 2] Aug. 18 7 2D eee 4 16 | 54 4 eee Osea Sd0n2-73 TUL S0H|_ cake ee lee (Gare A 25 55 Serene Se | 5 do.. aOhe— = ee Ose Aug. 8 | Aug. 23 7 2S) eee 9 15 | 59 Gile=sdolaes= AdGe-3= July 31} Aug. 9 Gores 7 v9) eee 9 14] 59 Uijsseao BCs (0 eee AG Tye eee a ee ee Oe |Site 16) Eee 1S me ee es = 8} June 28] July 41] July 24| July 29} Aug. 13 6 2) | See 5 15 | 46 Oo Sedona Seeks (Oneal ree al Piero lolee salen, (ols) oe oe 6 200 bes 28e 5 15 | 46 LOM COlsee + edo eee July 26 | July 31] Aug. 16 6 ht em 5 16 | 49 My ewe Olea ss |-2-00.2. 54) OUly 27) || Ae) | pAnieanS 6 Deal becae 6 16] 51 tPA eek 6 C0 eeepc Ie 0 KOs ee Leer e OMe Se 22 2d0---- 5 Aug. 20 6 “8 yl ea 6 18 | 53 13 dost-= e-aoOse doees- -do.. Aug. 15 6 Danes eee 6 13} 48 14 dO. 22. AO Ossee- Jive 283 becee oes ee ee ee (3) epee ey ee pe ee ree elena 15 do Rilo ees 3 JY: ASO | Ge. oan oe | See epee Ga ee 26) pao Se ee | oe 16} June 30 |...do.. July 23] July 27] Aug. 12 6 Liens 4 16] 43 17 0) Tully. (is PU ily OO) Wes eee ae eee Gilat 28: Ween Ce ae eee 18 do ~=doe- JUV #305. oe saleae aoe. Orlemaats pe een see 2 P|) all 19 do Adon s ATS PEA SS eos Seles ee ee Ons dee 2612 es haere eee 20 do.. 2d0hes = Aug. 2| Aug. 6] Aug. 20 6 Ad Nerney 4 14] 51 21 dos. sat Sesoe dozs-. Aug. 12] Aug. 24 6 PA eee 10 12} 55 22 do.. =pdOsece ANTE Sue eee eee eee oe (ia eee As tal regent ee OI oh on 23 doz: = G0r- Wags 7425: ee eso cee. Ballanteee 29 22 Sel Cae oe ee PN ee loee a8 adores Aug. 6] Aug. 17 | Sept. 1 6 tl ee cee 11 15 | 63 Zh eal O eee |eere fee 6322. ee OL! eater | eee eee 26 i fe eae 1 Ay (3) ees | ee | oe 27 Veloce 20" | Soe Saleen eee 28 7 Boh Seno 2 14} 48 29 7 DOM | eee 2 15 | 49 30 if aya eee 7 14} 53 31 (ei aseatss 2Gr| aes teal a ese | eee 32 | ae oe vig he earn aera lee 33 (f Soeeee 28) secot Ake See See 34 (hl ieee at MS apres |e eee ee ey || (A oom Bade SRN ee alee | 36}. =2 00535 -\3 : ial psec oi Settee 6) epee ale 37 bs A Onace= ria emer ale aateall e e ip ee es! Cal OEY (ie = ee fae ee 38 July 11 Sad Samco eres sae oe ae Gulbemece 7S eee aoe re | 39 seed Osean 4 2] Aug. Giles 24g sere Sil et-asa|/ spi 40 |. Gozeace Aug. 6] Aug. 13} Aug. 26 6 26) eeeee ih 13 | 52 41 |. do.....| Aug. 8 Gia, = Aug. 25 6 sasOSsincoeee ial SPR Gil 42 |. -do Aug SQOn=ss sleeenecenee (iSite Se 29 ete epee bee oa se 43 |. do0s.7-= JANIE SSS iat ses eats ec nee tame Gi Roa BE ie ieee al Peper lors Je 44 July 3" | PAnis sso) a see ea | Pee eae Gileeeeee BUM Becta sae Se 45 dozcss- sec Osc slleat ces ee eet ore (ci? ee ae 6 Ua esl Fees A bie 46 |. BdOsaee= Xb Pom | eee eso ee Ae ee Galea aoe Siete aere hosts ceil see ATA 2COz. ace Seek GPa ea shearer ae] (ona e nnn Oliaee. 3 SL Nre Cearara lore Stems |e eee 48 owaeS | ed Oe ee oe ke een ees Oil] Saf ae SLU Naess. 3| ae ee eee 49 |. 05.55 3) SANI eS SIF ae econ ee eee (oh Besoar Bh eerie meee ees 50 |. dois Are ATA oad oee | bea ere ot oe ee S02 |Secetel aaa eam thes @oOsens SSCOS Galore: eee see lees Gilsodaae BO | ete ocr eee TaBLE XXIII.—Life cycle of the first generation; summary of Table XX IT. Feeding of— Incuba- rs Incocoon} Pupal Total tion. Poe w ee "| aslarva.| stage. | life cycle. larvee. larvee. ; Days. Days. Days. Days. Days. Das. AW OIOBR:< 326 = oc cue oe eee 6.37 24.7 28.9 6.0 14.5 51.5 Maxim mene poeta ole ae, | if 31 45 11 18 63 (Mite oan ae eee ee oe 6 U7 fae ee Rear 2 12 43 The results of these experiments are given in Tables XXII and XXIII. Although limited in number the results of these experiments agree very closely with those of the previous experiments for the separate stages, namely, the life-cycle experiments averaged 51.5 days, THE CODLING MOTH IN MICHIGAN. 23 and the final average for the various experiments on separate stages averaged 51.6 days. The wintering larve of the first brood, which complete their life cycle the following spring, have not been included in the considera- tion of the life cycle of the first generation. THE SECOND GENERATION. SECOND BROOD OF EGGS. Length of incubation.—On an average the second brood of eggs (Tables XXIV and XXV) required 7.5 days for hatching, which is one day longer than was found necessary for those of the first brood. The maximum length of time for incubation was 11 days, the mini- mum 6 days. The red ring became first visible from three to four days after egg deposition and the black spot two days before hatching. TaBLE XXIV.—Length of incubation of the second brood of eggs laid in rearing cages, Douglas, Mich., 1910. Date of— Duration of— No. of mil Appear- | Appear- | oer d mee ance of | ance of | Hatch- | Red | Black | Incu- Te ton red black ing. ring. spot. | bation. ring. spot. Days. | Days. | Days. 1| Aug. 2} Aug. 5| Aug. 10 | Aug. 12 3 8 10 Pues OOsen alse Oren -|5-00--<...| ATE. 13 3 8 ll a EAUSS To) fees Ons- ce) Ame. Ol) Aes DT 2 6 8 4| Aug. 4/ Aug. 10 | Aug. 11} Aug. 13 6 7 9 Gis fe auto [oa 200525. - 2.00.2 2..=)| Auge. 14 6 7 10 GhRPRUE.) BOnloe. — fo eon ecice ec tee Ue os ae pees Meters 8 7| Aug. 7 | Aug. 12} Aug. 14 | Aug. 15 5 7 8 8 do (6 Foye eee emece Ko ney Aug. 16 5 i 9 9| Aug. 8 | Aug. 13 |...do.. Aug. 15 G 6 7 10 |...do. dos: ->-|..005.~ Aug. 16 5 6 8 11 | Aug.. 9 | Aug. 12 |...do.. do 3 5 7 12 G02. 2 eys-00s- 25: do.. Aug. 17 3 Bi 8 13 | Aug. 10 | Aug. 14} Aug. 16 Goes. | 4 6 7 14 | Aug. 11 |...do.. =d0= do | 3 5 6 15 Ose. | 2 dOze 0s: Aug. 18 3 5 7 16 | Aug. 12 | Aug. 15 | Aug. 17 to) 3 5 6 17 do S02. .do.. Aug. 19 3 5 7 18 |} Aug. 13 |} Aug. 16} Aug. 18 do 3 5 6 19°): a0... -.22 do.. pe dO. | Ate 20 3 5 7 209) GAGES Late Ole S-s-2 Olas 52)2-2002.. . 2 4 6 21! Aug. 15 | Aug. 17 | Aug. 19 } Aug. 21 2 4 6 22\ee One. 42-20 OL-. =a 00... | Aug. 22 2 4 7 23 | Aug. 16 | Aug. 18} Aug. 21 |...do...-. 2 5 6 24 }...d0.....|:..d0.....}...d0...-.] Aug. 23 2 5 7 25.) Aug. V7") Awe. 191: ..do.-...)...do..-.- 2 4 6 26, |e Ose ee O=.- a] cote. 4] Aue. 24 2 4 7 27 | Aug. 18 | Aug. 21] Aug. 23 GO:225- 3 5 6 28 | Aug. 19 | Aug. 22 | Aug. 24] Aug. 25 3 5) 6 29 | Aug. 20 | Aug. 23 |} Aug. 25} Aug. 27 3 5 7 SO ATIC. Cote Gols. -2|2 002. do 2 + 6 31 ozs: ==] -2d0.. Sidoze Aug. 28 2 4 7 32 | Aug. 22} Aug. 25 | Aug. 27 |...do 3 5 6 33 te) 2002. = G0=- Aug. 29 3 is 7 34 | Aug. 23 |} Aug. 26 | Aug. 28 |...do 3 5 6 35 (9) 2d6.. do.. Aug. 30 3 ai 7 36 | Aug. 24} Aug. 27 | Aug. 29 |...do 3 5 6 37 0: d6:..52 do.. Aug. 31 3 5 7 38 | Aug. 25 | Aug.°29 | Aug. 31] Sept. 2 4 6 8 39 te) do22- | Se2dO-eeslsept. 3 4 6 9 40 | Aug. 26 | Aug. 30 | Sept. 1 .do 4 6 8 41 do. do<:..|-=-d0-....|'Sept. 4 4 6 9 42 | Aug. 28 | Sept. 2] Sept. 4] Sept. 5 5 if 8 43 do... 0. 22%:.||5 20: Sept. 6 5 is 9 44 |__.do... do.. .do. Sept. 7 | 5 7 10 45 | Aug. 29 | Sept. 3 | Sept. 5 | Sept. 6 5a) 7 8 46 do Bats (see 220: Sept. 7 | 5 | 7 9 PRrair arp temera te soles) nn an NO pai 4 5.5 |. 7.4 LACT Shi thot 67 Me irate oe nai tS ee eee 6 8 11 Ltd ee a ee ee ae 2 4 6 24. DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLE XXV.—ZIncubation period of eggs of the second brood in rearing cages, Douglas, Mich., 1910; summary of Table XXIV. Appearance of Appeemnnce of Total incubation red ring. lack spot. period. Number | Number | Number | Number | Number | Number of of obser- of of obser- of of obser- days. vations. days. vations. days. vations. 2 10 4 7 6 13 3 19 5 19 7 14 4 5 6 8 8 9 5 9 7 9 9 6 6 2 8 2 10 3 11 1 SECOND BROOD OF LARVA. Time of hatching.—The time of hatching of second-brood larve under orchard conditions has been determined by methods described on page 14for the first brood. A maximum abundance of newly hatched larve occurred about September 10. The earliest larva of the brood hatched August 12. In the cages several late-deposited eggs failed to hatch, and it is possible that eggs in the field at this time would likewise remain undeveloped. TasLeE XXVI.—Length of feeding of second-brood larve, Douglas, Mich., 1910. ; fe] | a Date of — : I Date of— ees Date of— , <= ob iS ov) 3 ob 3 B 3 a= $ & > oO > ko} be uo) 5 a 8 is : a 8 || 3 r= 3 BB |. Gee be Ge | ee eae eal ee ee Saas ia son Ped ae | Bs 1S Cl a) es Ue ee SF) Mas BS ce elas Bat (Scio ee ae 3 3S 3 Ss é 3 2 3 S) 3 S a Z jon) = A 4 jen) 4 A 4 ea 4 A 1 28 || 28 3 Oct at 43 || 55 | Aug. 24] Oct. 1] 38 2 29 || 29 4 Sept. 24 30-}],'06)/..200. 22 -2/5-300:.-2.)|) 738 3 29 || 30 |...do.. ---G05.55..| Sb) od ||=s5do05-4--| (Oot. p2yleeag 4 29 || 31 Sept. 15 25 || 58 |...do.. -do.. 39 5 31 || 32 Sept. 20 30 || 59 | Aug. 25 | Sept. 15 | 21 6 34 || 33 Sept. 21 31 || 60 |...do.....| Sept. 27 | 33 7 38 || 34 Sept. 22 32 || 61 |...do... Oct. 2 7 8 38 || 35 Sept. 23 33 || 62 | Aug. 26 | Oct. 2] 37 9 45 || 36 Sept. 24 34 || 63 |...do....-| Oct. 3] 38 10 36 || 37 Sept. 12 21 || 64 |...do... *d0z=- 38 SE 37 || 38 0) 21 || 65 |...do.....| Oct. 7| 42 1212 37 || 39 |...do.....| Sept. 23 | 32 |/ 66 | Aug. 28 | Sept. 24] 27 13 41 l\ 405. do. 52 -|—..d0.-.54|) 32:|| Gri! Sdbe-sas\"Octw nail ne 14 44} A) odo... ale sGOlcee-|) < 32a) 68a dO-2o.4|_2 GOscces| neon 15 24 |} 42 |...do.....| Sept. 26 Bo) || 69 feeedosc -cc]2.sG0-e ee lieo 16 24 || 43 ; Aug. 23 | Sept. 23 3L))) 2007. . > > y Ss + > a wa a |o Py je lf jf fe feahof 3 .l2 |$ [6 {8 |s, 2 r— R |o 3 3 4 38 ipa ra B 1° B Or iaesal a g| 5 | |FalgslPa/a/he | Ss | & |Fsiss|Falex|as E| So |S [sa SS eel es lao S| SA |S [eS /S8 3B ee) ao >) o ) iS) So Iasi} ¢ 2 ° ° OR cscs 3 3 slic fo he |io Pemtil's 3 Sialto’— Woy iver 2=) ope iors Zz A mae ees 4 A [4/4 |4 |j4 |4 Je leoke. tei 6) SL. ole wed le See ie Ott Septet: |) 13 |evasa\e cee. eal i a 2 eae 27 |) ami. g%}. ef. eee it Qk Septealoul- 18. |Cscsclenge. [\s- 15s] 38] 10 a ualy. 20') 28 || 10"|2:.- iia) (eee Pavel 23 Sepials |) 19 125s eee Onl asa ii SOME GT D3 x hee BAD) Qh ee Uebel, s 2c | 1b B4-|, Sept. 2h (226 |..-.21.2.2. Gil) 22S | 5| July 26] 54] 26 2 Dest 20us Sepulmoe pus Ze |) 16) locs-~)oscee iT Peo 5 | Bye 207) Sy 21 Pe 12 td | 10s] '26'| Sept.27 | 10:)....-|..... Pal esa Re 7, |) Ags ~ |) SB BF, A Bowes. 20:|/ 2% | Sept.30') 7 |-----|----. Sali 2t 2 0 Bean aaa a SU etn eS Peete limite OR Octs s3u|) 29 |. 22[.. 19) | #2 P| 9| Aug. 7! 49] 18 he ly DS eee es Be 20) Ootte, Gel) * 13% }s. .. Heme es ee : Tultecce HeartallerSOb ROCi es ONL 8S) lhe scle coc. it eer) ate ys") Peer Sib Sie} Oct.. 12 Ones 2 oe: 9) | 223-5 0 es Sulecaie@etes to Wes 10). Si eee 6 i)... Gras i@ebs, Til) 98 jk. -|ozs Le ng eee 3 73) Bea Tal oeawOetecote Sic cs 2|ho... 3 a Sliced) FAS WS i Oebe 24e] Ste. - = 4 5 wa ¥ y 5 aS === F § 10 15 2025 30 5 10 15 2025 30 5 10 15 2025 3 JULY AUGUST SEPTEMBER OCTOBER NOV. Fic. 10.—Curves made from band-record experiments in orchards at the lake shore near Douglas, at Saugatuck, and at New Richmond, Mich., 1910. (Original.) days. Thus the first larve of the second brood appeared August 31. Similarly, the first-brood and second-brood larve in the Lake Shore and New Richmond experiments have been determined, with due consideration given to the seasonal conditions of each locality. The results from three band experiments may be appreciated by an examination of the curves in figure 10. A difference in the time and rate of maturity of larve will be noted in considering the height of the curves representing the first brood. In the Lake Shore orchard THE CODLING MOTH IN MICHIGAN. a1 the maximum occurred August 8, in the Saugutuck orchard July 31, and in the New Richmond orchard July 18. It will not be possible to compare the dates for the appearance of first larve of the first brood, since the New Richmond experiments commenced slightly after the larvee began to appear. At the Lake Shore band experiments larvee were collected in great numbers during the month of August, whereas at New Richmond only a few were obtained. There is only a slight difference in the time of appearance of the earliest second-brood larve in these locali- ties, which would indicate the existence of a tendency on the part of the seasonal conditions to become equalized or uniform over the fruit belt at midsummer. At the Lake Shore orchard larve continued to appear one month later than in the New Richmond orchard. Part of this difference was due to the scarcity of fruit at New Richmond, but also partly because of prevailing higher temperature during the fall near the lake, which prolonged the season in the latter locality. Though limited in scope, the results of these band experiments show that the codling moth varies in the time of its development in these three localities in close relation to existing climatic conditions, thus indicating that the insect must be governed by the same climatic con- ditions that govern the plants, and it must be due to this fact that we find a corresponding difference in the time of activity of the insect in the spring, as is noted in the time of blossoming of apples in the different sections of the fruit belt. Of the total number of larve of the Saugatuck band experiment 73.2 per cent pertained to the first brood and 26.8 per cent to the second brood. Of the first-brood larve 34.8 per cent transformed the same season, and 65.2 per cent wintered in the larval stage. Of the total number of larve, 25.5 per cent developed into moths in 1910 and 39.7 per cent in 1911. Parasitism by Ascogaster carpo- capse affected 4.7 per cent, and 30.1 per cent died during the winter, killed by cold. SUMMARY OF SEASONAL-HISTORY STUDIES OF 1910. Figure 11 represents graphically the main results of the seasonal- history studies of 1910 and can better be appreciated from the diagram than by description. Except for the prolonged pupal period during the very abnormal spring of 1910 the insect developed fairly normally so that from the point of view of the activities of the codling moth the season may be taken to have been about average. ) 1 For a more thorough test, records should be taken on temperature, time of blossoming of apples, and time of emergence of spring brood of moths in the different sections in the fruit belt. ay) DECIDUOUS FRUIT INSECTS AND INSECTICIDES. SEASONAL-HISTORY STUDIES OF 1911. The results of the 1911 life-history studies of the codling moth are in many respects similar to those obtained during the previous year. a oe RE faa) = ; 5 OF Lu = O S =| Te . = SE D aS e pa ats FEE esl ous o. as wee ca) (Ss aS “ AS < ia} a E Ko ; re Ss) = = S o 9 golsa oO a Se Tat = “ a | at | et in) a = 1e) ee =| a 5 ° “ Sus =o is g | 8 z= Tao 5 S = > << fe) 2 -O £ - = i) ne ee ee 8 tabs E LS + 2 =a ES SES — — o Q cE a mS) a qe a 38 = ae 9 Le) 52 = ne =n = < a cs oO = oO als a Ovi positi in of Sprint JUNE JULY Sy Ko) heyy Yo), 25) 5) 10) 15 20) 25 AY 10 15 20 25 M Fic. 11.—Diagram to illustrate seasonal history of the codling moth as observed during 1910, at Douglas Mich. (Original.) The main difference is that found in the time of transformation and date of appearance of the different stages, which is ascribed to the prevalence of a very unusually high temperature during the spring APRIL Is 2025 | 5 THE CODLING MOTH IN MICHIGAN. 33 and summer. To a certain extent the 1911 life-history studies con- stitute a test upon the 1910 investigation and in addition show the behavior of the codling moth under the above climatic conditions. In the presentation of the observations made during 1911 on the codling moth the same plan has been followed as for 1910, and many of the details concerning methods and tabulation previously described apply equally to the 1911 studies. TaBLE XX XII.—Time of pupation in the spring of 1911. Date of | Number | Date of | Number || Date of | Number || Date of | Number pupa- of | pupa- of pupa- of pupa- of tion. pupe. | tion. pupe. tion. pupe. tion. pupe. May 9 1 || May 22 10 |} June 2} 2 || June 14 3 May 11 1 || May 23 8 || June 3 2 || June 15 | 1 May 12 1 || May 24 8 || June 4 3 || June 16 1 May 14 6 || May 25 7 || June 5 5 || June 17 3 May 15 7 || May 26 5 || June 6 4 || June 19 2 May 16 2 || May 27 8 || June 7 2 || June 21 1 May 17 8 || May 28 9 || June 8 2 || June 22 | 1 May 18 12 || May 29 6 || June 9 7 || June 26 | 1 May 19 16 || May 30 7 || June 10 6 May 20 14 || May 31 11 || June 11 4 May 21 11 | June 1 3 || June 13 | il | Total pups, 212. SOURCE OF REARING MATERIAL. , The rearing material in the spring of 1911 consisted of wintering larve, which in a normal way had entered hibernation the previous season. Practically all of the larve were from band records and represented the normal proportion of both first-brood and second- brood larve. The wintering cocoons were made between narrow strips of wood (fig. 4) and in pieces of corrugated paper (fig. 17). During the winter larve were kept in an outdoor shelter. WINTER-KILLED LARVA. The percentage of larvee killed by cold during the winter proved to be equally as high during 1911 as observed in 1910. After the com- pletion of the different band-record observations the results show the following percentages of winter-killed larve: Per cent. Newel chimond pan Ginecordse.2 =. 2.2 -ccscie ao se oes a oe eee 38.1 Eee eae Ky MRS MEO COLORS me shee oo. atc cic Sele Se was SS eee ade 30. Lake Shore band records. ....... to SSE ES Se a Se 25 From these figures should be substracted a small number of larvee injured in the course of transportation from the field to the laboratory. Those from New Richmond showing the highest percentage of mor- tality were sent in boxes through the mail and suffered more or less under transportation. The larve from the Lake Shore and Sauga- 1 During 1911 an improvement was made in the method of shipping the larve from the distant localities of the band records, by the use of mailing tubes (see page 61 and fig. 17). 34 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. tuck orchards, however, were all carefully handled, and the results of these observations show approximately the normal proportion of winter-killed larvee. SPRING BROOD OF PUPZ. Time of pupation—tIn the rearing cages pupation commenced on May 9, reached a maximum May 19, and terminated June 26 (Table XXXII). The relative rate of pupation is illustrated by a curve in figure 12. It will here be observed that pupation occurred rather irregularly and that the time when the larger number of individuals pupated extended over a longer period than in 1910. This, of course, had a direct bearing upon the time and rate of emergence of the moths of the spring brood, which,. like the pupz, appeared very irregularly. TaBLE XXXIII.—Length of pupal stages of the spring brood, Douglas, Mich., 1911. l No. | Pupated.| merged. Days.'| No. | Pupated. Emerged. Days.|| No, Pupated. Emerged. Days. 1| May 14 | May 29 15 || 42 20 83 | May 29 | June 19 21 PY Ie e(0 Ks aes Sone Pe dOssaee 15 BS | te 19 84 |5=do!= <2 doses 21 S| eee Osea May 30 16 || 44 20 85 | May 30 | June 20 21 4| May 15 | May 28 13 45 23°||| (86) |22-do:--=- | June 18 19 Hy | C0 Co ee May 39 15 || 46 20 ASV Al le fo Kote = June 19 20 6 | May 16 |...do..... 14 |} 47 19 88 | May 31 | June 21 21 eee d0teeae June’ 6 21 48 18 89) |E2e dose | Sad ose. eee! 8 | May 17| June 2 16 49 19 90)'| 52d 0:52 June 20 20 Os|2..do22e: -June 3 17 50 18 TIN Pees oc ars June 19| 19 10 -do.. PeG0-ss. 17 51 18 Pa ats Faye June 20 20 ll d0sse28 June 10 24 52 19 O37 |e a eedoreeee 19 12 doa June 2 16 53 18 94|June 2] June 22 20 13 | May 18 | June 3 16 54 13 95 OStee6 June 21 19 14 Corse ace hanes 16 55 16 96 | June 3 | June 22 19 lay |B aCoyeeee June 6 19 56 17 O7) |Seediosess- June 21 18 160|pn donee June 4 17 57 18 98 | June 4] June 23 19 17 Baars June 5 18 58 21 99 doz=-=- June 24 20 IS sdoee=- June 4 17 59 18 || 100 | June 5] June 23 18 19 (Oy nos June 5 18 60 193) 1000 |Psadorees= ee doe res 18 20 | May 19] June 6 18 61 20),||| 102) |ps dol == June 24 19 21 does June 5 17 62 20", 103! |=. edoraees ~~ -d0se5 19 22 200s-525 3200r playuauye - aungeuadwias Aprep ebeuany > 3 w AS — (e) 2. (lo to} we Q- AS! = 5) Zz oO S © ON. “oS. wm: 16 Nn 27 29 31 2 4 & 10, 12 14 16 18 20 22 24 May June Fia. 14.—Emergence curve of moths of the spring brood in 1911, at Douglas, Mich. (Original.) been due to the fact that mating had not taken place, it being difficult to find the insects in copulation or to bring about mating by confining together single pairs of male and female moths. In the stock-jar cages, where a number of male and female insects have been confined, eggs havealways resulted in abundance and mating must have occurred quite generally though it was only observed on rare occasions. It was therefore planned to remove female moths from the stock jars after the moths had been confined together two or three days, and prior to any egg deposition in the stock jars. THE CODLING MOTH IN MICHIGAN. 39 Taste XXXVII.—E£gq deposition in confinement by individual moths of the spring a brood, Douglas, Mich., 1911. Number of individual moths. 1 | 2 | 3 | 4 5 6 | 7 | 8 | 9 | 10 ll 12 | Date of egg depo- : sient Date of emergence of moths. al = S S x x te S ve) 1) Sa) Jo) — rc N N N N N N N 2 co) 2 oS 2 ) (2) 2) oy) 2 2 2 Ss - | 3 5 - = = =. Ee =} =} Lo Lor} Lo" lox) eS Lert = = Lea) Leo) La) Lo) Date of death of moths. 1 Escaped June 20. In all 160 female moths were removed from the different stock jars (Table XL) and were kept isolated in glass tumblers, covered with perforated tin covers. A small piece of sponge dipped in diluted sugar-and-honey solution was inserted to supply food. To encourage egg deposition fresh pear leaves were placed in the tumblers and were daily replaced by fresh foliage at the time the tumblers were examined for eggs. on - VY July 1 June 21. June 10 June 25. July 2. June 28. | July 8: July 6. July 6 July 6. July 8 TasLe XX XVIII.—E£9q deposition by individual moths; swmmary of Table X XX VIT. Number of individual moths. Observations. _——— oS a bee ioe | 3 4 5 6 7 8 9 10 | 1 12 Total eggs per female ....-- 70 35 26 36] 161 35 32 86} 102 49 15 38 Days before egg deposition . 7 7 4 6 6 9 4 5 4 3 5 8 Days duration of egg depo- SIMORee ccs ec ese fe ck aeee 16 9 1 4 rf 3 2 2 6 3 2 2 Days alive after egg depo- | — Shuler aaa a Ske 5 2 On esos. 2 1 3 8 3 5 4 3 Days moth lived........... 27 17 ye ee 14 12 8 14 12 10 10 12 40 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLeE XXXIX.—E9q deposition by individual moths; summary of Tables XXX VIT and XXX VIII. Observations. Average. | Maximum.| Minimum. 1 Of asjy ov eu Ge) 10 | eer Sein oo Se oo oe Seas oS Sac Smee SecesSsssossose 57.08 161 15 Eiges per'day per. temiale 52 3-5 eee eee ee eerie ee ery 16.31 58 1 Days before egg deposition per female.........-..--.--------------- 5. 66 9 3 Days of egg deposition pertemales= 4.2. 2-22 - a2 eee See ec 4.75 16 1 Days moths lived after ege deposition......-.--..--.-----2--------- apeyy 8 0 Days moths lived: =... - 2222 =e saan eae ewe eee eee saree eeaeee see 12.72 27 4 From the 160 separate experiments only 12 yielded results worth recording, and these are given in Tables XXXVII-XXXIX. The following observations are recorded in Table XX XVII: The time of emergence of the different moths, the time and amount of egg depo- sition per female, and the date of death of each of the female moths. In Table XX XVIII a summary of results will be found showing the number of eggs per female, the number of days before egg deposition, the duration of egg deposition, and the length of life of the moths. It will be noted that on an average these moths commenced to oviposit 5.6 days after their emergence; the maximum length of this period was 9 days and the minimum 3 days. Egg deposition extended on an average over a period of 5 days. The average number of eggs per female was 57.08, the maximum number of eggs per female 161, and the minimum 15 eggs per female. The moths lived, on an average, 3.2 days after egg deposition; in one instance death followed the day after the last oviposition; on the other extreme a single moth lived 8 days after the last egg deposition. The conditions under which it was necessary to keep these moths for observation were of course quite abnormal and it is doubtful whether all of the moths deposited the normal number of eggs. It is the writer’s opinion that in the field the average number of eggs per female is considerably higher and may reach an average of 75 to 85 eggs per female. Egg deposition in stock-jar experiments.—The nature of the stock- jar tests has already been described on page 13. As will be found in Table XL, the observations merely cover the date of emergence of moths in each cage and the date of the first and last egg depositions per jar, which give only an idea of the extent of the oviposition period. We find from these data that on an average the first eggs were laid four days after the date of emergence of the moths, THE CODLING MOTH IN MICHIGAN. 41 TaBLE XL.—Oviposition by moths of the spring brood in rearing cages, Douglas, Mich., 1911. Date of— Number of days— Num- > | From Cage P RS. pave Emer- First Last Before |Duration| “ate of =“ gence of | ovi- ovi- ovi- Of. oyi-ni|\ ane moths. | position. | position. | position. | position. | \ : ‘ : position. 1 13 | May 24] May 28 | June 14 4 18 21 2 20 | May 29] June 3 | June 21 5 19 23 3 9 | May 30] June 10 | June 10 11 1 11 4 10 | May 31] June 6 June 8 6 3 8 5 yale patsy aba re Cees June 9 5 4 8 6 29) | dune 2822 200-—~-— ABEL: lee 4 4 7 7 39 | June 3] June 5/| June 21 2 ii 18 8 47 | June 4]June 8 | June 20 4 13 16 9 40 | June 5]/June 9} June 9 4 1 | 4 10 43 | June 6 do... June 24 3 16 | 18 11 29} June 71} June 10 | June 20 3 11 | 13 12 56 | June 8 | June 11} June 23 3 13 | 15 13 45 | June 9/| June 12 | June 15 3 4 | 6 14 50 | June 10 | June 13 | June 22 3 10 | 12 15 14 | June 17 | June 22 | June 26 5 5 9 16 48 | June 19 | June 23 | June 27 4 5 8 17 38 | June 23 | June 25 dolt.- 2 3 4 18 44 | June 24 | June 27 | June 30 3 4 6 19 16 | June 25 |...do..... July 2 2 6 ii PAC OLA NG man ime Epes arses me sae eee! 4 8.3 | 11.3 ISTE ir hata hae Seka ee ee eee ee 11 19 23 MRE Teaeene s Sat re omcis ce eae ce wes 2 1 | 4 The shortest period before first egg deposition was 2 days, and the maximum period 11 days. Within the separate cages oviposition lasted from 1 to 19 days, with an average of 8.3 days. When we consider tlie period from the date of emergence to the date of last oviposition we find a maximum length of time of 23 days, an average of 11.3 days, and a minimum of 4 days. Period of egg deposition.—In the field egg deposition is estimated to have taken place from May 28 to July 18, with a maximum number of eggs between June 10 and June 30. This has been estimated from the records of egg deposition by moths in captivity, the time of emer- gence of the moths, and the band-record observations. Length of life of moths.—The length of life of 153 male and 177 female moths, confined in the stock jars, is given in Table XLI. On an average the males lived 9.18 days and the females 10.63 days. The maximum length of life for the males was 18 days and for the females 23 days. 42, DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TasBLe XLI.—Length of life of male and female moths of the spring brood in captivity; summary of records of 330 individual moths, Douglas, Mich., 1911. Male. Female. Male. Female. Length| Number | Length | Number || Length | Number | Length | Number of life. |ofmoths.} of life. |ofmoths. || of life. |ofmoths.| of life. | ofmoths. Days. Days. Days. Days. 2 2 2 2 14 11 14 9 3 2 3 4 15 8 15 13 4 12 4 6 16 3 16 5 5 11 D 5 || 17 2 17 5 6 11 6 10 18 1 18 a 7 14 7 13) We cmeeceealtsomeoeee 19 4 8 18 8 ASF teers ae ees 20 2. 9 15 9 207 || pease so eee ee 21 1 10 16 10 22S, || 2s setae pace ee ee 23 1 11 11 11 13 _—_—___—_—_ 12 15 12 14 || 153 177 13 1 13 3 | TaBLeE XLII.—Length of life of male and emale moths of the spring brood in captivity, Douglas, Mich., 1911; summary of Table X LI. Life of Life of Observations. male female moths. | moths. Days. | Days. AVWOTAS Ol a2 28 a eassenne clea 9.18 | 10.63 WG bate isiinere= ae as Semnaqcce 18 23 Minimums: - 3-2 s22.cc-<----5 2 2 Tt is of interest to note that in this brood, as well as in the summer brood, the females were more numerous than the males and survived the males on an average by about two days. THE FIRST GENERATION FIRST BROOD OF EGGS. Length of incubation.—Observations on the length of incubation extended over the greatest period when eggs occurred in the field (Table XLII). The high temperature which at times prevailed brought the minimum length of incubation down to 4 days, against 6 days for the same brood in 1910. The average length of incubation for the brood was 8 days, the maximum 10 days. Observations on the embryological development of the eggs were also taken as recorded in Table XLIII. The so-called ‘‘red ring” generally appeared 3 days after egg deposition, and the ‘‘black spot” 2 days previous to - hatching. THE CODLING MOTH IN MICHIGAN. 43 Taste XLIII.—Length of incubation of the first brood of eggs and average mean tempera- ture during incubation, Douglas, Mich., 1911. Date— Duration of— Average 2d No, of ‘ | Pros vation.| ©888- | Depos- | Red Black oe Red |Black) “eo emper ited. ring. spot. Hatched, ring. | spot. ice ature. ion. Days.| Days. | Days. F,° 1 Rea tiie= May 28] June 1] June 5| June 7 4 8 10 64. 27 Oy eae ae May 30| June 3] June 8] June 9 4 9 10 64. 21 SM Is ohseir June 1] June 4 Gece. < June 10 3 7 9 65. 79 Cle eee June 4]/June 7 | June 11 | June 12 3 ii 8 67.78 HPs aha June 3] June 6) June 10| June 11 3 i 8 7. 87 (2 eee PUNE 5 aude, Sse coe. <5 oe June 13 at Ioaeeee 8 66. 88 acest oeeee JUNE 2G" | ssase sea. leo omee ses Abie ee 1 Gy] eee Ee 9 65. 07 8 14| June 8} June 11) June 15} June 17 3 7 9 65. 27 9 81 | June 9] June 12} June 16 aos 3 7 8 65. 30 10 15 do 22 do: lp eego-ee- June 18 3 7 9 64. 96 ll 146;) dunes 10") Sune-ss | eco June 19 Of lease 9 63. 68 12 15 o By ee toh erl bere ae arene June 20 bo ees 10 64. 12 13 68 | June 11} June 14} June 18 (0) 3 Zi 9 62. 93 14 20 do BRGsa3 = doze June 21 3 7 10 63. 58 15 50 | June 12] June 15} June 19 doy2.-5 3 7 9 63. 29 16 8 do ssoloesece edoteens 4 15 4 13 (ACSA Coe es July 23 | Aug. 6 6 14 4 13 BONE dose PedOn nese Aug. 7 6 15 4 13 Sli dowrese Bo eee Aug. 8 6 16 4 16 32 eee O pense July 24) Aug. 3 vi 10 4 16 83! |2 2500822 July 25) Aug. 7 8 13 4 18 841 doles: Jtly; 226) ee eG Osease 9 12 4 17 Son PasCoeese= July 27] Aug. 8 10 12 BD; 16 S6uly Adosesee July 28 | Aug. 9 11 12 5 16 Sil aaedoeeee BAC ne Aug. 10 11 13 5 15 88 | July 18) July 24] Aug. 7 6 14 5 21 BO |e sad. ees: 2 G0sne-8 |S dose 6 14 5 16 ON Pa=d0es--e July 25 | Aug. 6 a 12 5 15 O14 Saedoleses esdo=e=s Aug. 7 7 13 5 15 G2 Esadoe ..do = Osten 7 13 5 16 93) 252002. - =G02-555 ACOs 7 13 5 16 94 \l.- sdoL esse daly 26:|5- go H S < ee 80 co 84 0 zo 70 8 - : 08 ra bo 78 = 7% & A @ 50: 14 ee: wz & 5 49 pe Xe} :3 68 = = 30 E bb S =) ie 6 Zz! ; ‘a 20 2s ass 60 © 10 58 > Q. _* 6 il 4 17 2023 2b 29 | 4 7 10 15 1b 1922 25 2831 3 6 4 12 15 16 July August September Fia. 16.—Emergence curve of moths of the summer brood in 1911, at Douglas, Mich. (Original.) was practically the same for the different band records. This may be due to the peculiar climatic conditions of 1911, when the spring opened up uniformly over the entire fruit belt—a rather unusual occurrence. It may also be that during the middle of the summer the seasonal conditions became equalized over the different sections, and produced a corresponding equalizing tendency upon the develop- ment of the codling moth. The emergence records for the summer moths are remarkablo both in respect to time and. rate of appearance of the moths. The earliest moths issued July 8, which emergence was 21 days earlier then that of the more normal season of 1910. During the early part of the emergence period, from July 10 to July 14, moths appeared in abundance. During the later half of July, however, they were less THE CODLING MOTH IN MICHIGAN. 51 numerous, while during the first half of August they were again During the remain- ing part of the emergence period, which exteneled to September 18, very abundant, reaching a maximum August 7. comparatively few moths appeared. TaBLE LI.—Oviposition of moths of the summer brood in captivity, Douglas, Mich., 1911. Date of— Days— Num- Num- ber | From ber of time of of moths | Emer- First Last Before Of emer- cage. per | gence of | ovipo- ovipo- | Ovipo- | ovipo- |gence to cage. moths. sition. sition. | sition. | sition. \last ovi- posi- tion 1 29| July 10| July 14] July 20 4 7 10 2 ZA auly Us. do--.-- July 24 3 11 13 3 10 | July 12 |...do..... Aug. 1 2 19 20 4 29} July 13] July 16} July 27 3 12 14 5 26 | July 14| July 23] July 24 9 2 10 6 15 | July 15] July 18) July 26 3 9 11 7 10] July 16] July 20} July 28 4 9 12 8 14| July 20] July 26} July 31 6 6 11 9 15 | July 21} July 28) Aug. 5 7 9 15 10 16)|, July 22 |...do-.... July 30 6 3 8 ll 15.| July 23 do-.222 Aug. 4 5 8 12 12 13 | July 25 | July 27 dos = 2 9 10 13 25 | July 26} July 31.) Aug. 1 5 2 6 14 11 | July 27 dos. --| Aug: (2 4 3 6 15 14| July 28| Aug. 1] Aug. 7 4 7 10 16 17 | July 29 | July 31] Aug. 14 2 15 16 17 18 | July 30) Aug. 1] Aug. 10 2 10 11 18 36 | July 31 | Aug. 2] Aug. 18 2 17 18 19 37 | Aug. -1} Aug. 6| Aug. 7 5 2 6 20 15} Aug. 2| Aug. 5] Aug. 9 3 5 7 21 38 | Aug. 3] Aug. 6] Aug. 15 3 10 12 22 Si Ane, “40/27 do.--.- Aug. 16 2 11 12 23 64) Aug. 5 | Aug. 7 | Aug. 12 2 6 7 24 35} Aug. 6] Aug. 8 | Aug. 13 2 6 7 25 88 | Aug. 7] Aug. 9] Aug. 16 2 8 9 26 55 | Aug. 9] Aug. 11} Aug. 17 2 7 8 27 54| Aug. 10] Aug. 12} Aug. 31 2 20 21 28 27 | Aug. 12] Aug. 13; Aug. 23 1 ll ll 29 19 | Aug. 13 | Aug. 17 | Aug. 21 4 5 8 30 47 | Aug. 14] Aug. 16 | Aug. 25 2 10 ll 31 21] Aug. 16] Aug. 18} Aug. 28 2 ll 12 32 16) Aur. Lescdo... 5. Sept. 3 1 17 17 33 27 | Aug. 18| Aug. 21 | Aug. 28 3 8 10 34 23 | Aug. 21} Aug. 22} Sept. 14 1 24 24 35 15 | Aug. 22} Aug. 25 | Sept. 3 3 10 12 AVEIAUG=25 nae eee ee wane semen see oe a 3.2 9.4 11.6 MRT UT eee eee ee ee So ee ache 9 24 24 Minimum...-.. el VN EG 2 se eee 1 2 | 6 Time of oviposition.—Observations on egg deposition by the sum- mer moths in captivity were made under conditions already described on page 14 for the spring brood. The results as presented in Table LI show that on an average the first eggs were laid 3 days after the time of emergence of the moths and that oviposition extended on an average to 9.4 days. Within the various cages considerable variation will be noted; in one instance the first eggs were obtained the following day after the emergence, in another instance the ninth day; in one cage the last eggs were deposited the sixth day, and in another cage the twenty-fourth day after the time of emergence of the moths. 52 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. On correlating the above observations with the time of emergence of the moths it will be found that the oviposition period extended from about July 11 to September 25. However, very few eggs were laid during September, and not all of these hatched. The great majority of eggs were deposited during August. TasLe LII.—Length of life of male and female moths of the first brood; summary of records of 1,019 individual moths. Male. : Female. | Male. Female. Length | Number| Length | Number || Length | Number] Length | Number of life. |ofmoths.} of life. |ofmoths.|| of life. |ofmoths.| of life. | of moths. Days. Days. Days. Days. 1 1 1 i 18 6 18 10 2 8 2 5 19 2 19 9 3 16 3 6 20 5 20 10 4 22 4 15 21 7s 21 13 5 22 5 24 22 1 22 9 6 42 6 32 23 2 23 2 7 46 7 27 25 1 24 2 8 48 8 62 26 1 26 4 9 50 9 46 32 1 28 1 10 41 10 Se ll ceases ee eee oes ee 29 2 11 30 11 7 el erent eae Ie ee 30 1 12 32 2 A | Sears Sees alae ee toe 32 1 13 18 13 BOR lsc cease cae oleae es 33 1 14 24 14 Bair) | eee ee eee eee 37 1 15 12 15 26 16 11 16 22 Total. = AG Lcswe tee 563 17 12 17 14 TaBLE LIII.—Longevity of male and female moths o of the first brood; summary of Table LIT. Life of Life of Observations. male female moths. | moths. Days. Days ANGTAGO - 2 acca steteneeee 9. 57 11.49 Maxaimuminns ose o see 32 37 IME Ean eee ae i 1 Length of life of male and female moths.—A summary of observations from 1,910 individual moths is recorded in Table LIT. The condi- tion under which the moths were kept has already been referred to on page 39. As observed for the previous brood, the longevity of the males was shorter than that for the females. On an average the males lived 9.57 days and the females 11.49 days; the maximum length of life for the males was 32 days and for the females 37 days. It is of interest to note that the results obtained by the writer at North East, Pa., in 1909,’ are almost identical with those given above; the average length of life for the males being 9.79 days and for the females 11.47 days. 1 Bul. 80, Pt. VI, Bur. Ent., U. S. Dept. Agr., p. 91, 1910. : THE CODLING MOTH IN MICHIGAN. Ne The females were found to be more numerous than the males, which was 2lso observed in the spring brood of moths. Length of life cycle of the first generation.—In Table LIV are brought together the average results from observations for the separate stages of the first generation. These data show that on an average there elapsed 53.59 days from the time of appearance of eggs of the first brood to the time of appearance of eggs of the second brood. Com- paring these results with those of the complete life-cycle series (Tables LV-LV1I), there will be found a difference of results of less than one day. In the life-cycle tests 75 individual insects were under observation from the time of the deposition of the eggs to the time of emergence of the moths that resulted from these eggs. TasLeE LIV.—Summary of results from experiments on the separate stages of the first generation of the codling moth in 1911. Number of days. Life eycle of first generation. Average. | Maximum.} Minimum. INGA Dao OMeRESS are oes sen a nate aac ok ascent secceesinn so86 7.94 10 4 Feeding period of larvee ........-.....-.--- SR ee serie Ee eee eye ie ae 21.25. 29 15 Melis IO NCOCOONS Se ar Ae ae Ne. Ss cas: He coeea cc sae a eeeees ese tee 18 3 Prpalistaressc. asec. 2. one So 5S. a eee OF GO. Se Be See cee eae ee 14.0 21 6 ENMENOLOre GFP CEPOSIMOM: = s.cisee | ho sca te oe setae ee cease esa 32 9 1 SRG oS hh 5 ee ean to ee 2 ee ee 53.59 87 29 TaBLe LV.—Life cycle of the first generation of the codling moth, as observed by rearing at Douglas, Mich., in 1911. Date of— Days for— No. ass he eee | Lu E | | M Total serva- gg Tatah. arva a mer- | _| Feeq. Making Nota tion. | deposi- | ee leaving pre gence of at Heed of pupal life tion. 8: the fruit. =e moth. | 8: 8: |eocoon. | Pe 3 "| cycle. | 1| June 1/] June 10} July 4] July 9/| July 22 9 24 5 13 51 | ee. .= on doses ep aolia sss Aft yaa li | ee aes 9 24 7H eee (Ses ee 3 dos Be: ee Gow) |Fsdo-. 22 July 27 9 24 7 16 56 4|June 3 June ll dots: ULAR Silos ae aee 8 23 re) (Bae Ree aes) | ne eee 5| June 5] June 13] July 8| July 26| Aug. 8 8 25 18 13 64 6 do:2-2- dos. 5: July 9] July 14] July 31 8 26 5 17 56 17| June 6] June 15} July .6| July 9] July 23 9 21 3 14 47 DeSales dO: .- ae 0s: July 8} July 11] July 26 9 23 3 15 50 MOG) || en Os 225» sa0Oe 22% BdOscrae ee dOs.cac Go=-2-. 9 23 3 15 50 110 does... Osea Goxe--- aac es doses 9 23 3 15 50 111 do-*=-< EeGOLo=== do.....| July 18] Aug. 3 9 23 10 16 58 112 dows =s005 3: July 9] July 16] Aug. 1 9 24 7 16 56 113 dese. CO oat | Sot neem ol mene ene 2July 31 [8 ee ee as eae ME 55 114 do: =:-. PO ec) ante Sac e Eau s 2July 25 ON Ses SO Oe Gamera 49 115 | June 8 | June 18} July 8 | July 11 }.......... 10 20 S}p| Pe Anpear | eer sec) 116 Gor... i to eee July 12} July 24] Aug. 7 10 24 12 14 60 Ree sune 8 2dols se: July 8} July 12| July 31 9 20 4 19 52 118 dos: eek: [Rees July 9] July 13) July 30 9 21 4 17 51 119 sG00s5.5 SedOe es dG: ==. July 18} Aug. 3 9 21 9 16 55 120 dol.-.- dots: July 12} July 14] July 31 9 24 2 17 52 21} June 10 | June 19} July 8| July 13] July 29 9 19 5 16 49 pS | 28 Cena doe igrige etl laoths Ol he ee Same 9 24 10; |2.o9n2e| aes 23 adO2 S256 do xX; WOly sid: |2das:o:.|Sseec a an 9 25 te Ee Ea one: 24 GOL.te- Gece Bed ouesas July 21} Aug. 5 9 25 7 15 56 25 do co fa ee VLy Won etlyer ee |< 226 oeecee 9 26 (fa ee ees [te 26 | June 11! June 20! July 6) July 10! July 228 9 16 4 13 2 1 Bagged fruit; average feeding, 20.9 days. 2 Pupated in fruit; average feeding, 21.4 days. 54 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TasLe LV.—Life cycle of the first generation of the codling moth, as observed by rearing at Douglas, “Mich., in 1911—Continued. Date of— Days for— No. of ob- = e = serva- gg f arva G mer- 2 Makin Total tion. | deposi- eee | leaving pi gence of ee hs of : ee life tion. 8. | the fruit. moth = 8- | eocoon. | Pete. cycle 27 | June 11 | June 20 | SUL ya eyo Ueys 2s | Sac eee 9 17 5p cs aeeecs| eee 28) |22edossee- Eee OMe alieee GOs steele. oss July 29 9 17 5 17 48 D0) Read onsees dokeee July 9] July 13] Juiy 30 9 19 4 17 49 30 |...do. doweee July 13} July 18] Aug. 4 9 23 5 17 54 3h) |e2do" do BGO". a6 July 20} Aug. 5 9 23 7 16 55 132) |Eedouse dor July 7] July 12| July 28 9 17 5 16 47 133 doz-=a5 dou... | July 9] July 13] July 31 9 19 4 18 50 1 34 danse dowtezt Gozs2.2 July 12} July 28 9 19 3 16 47 135 Goi dos. July 13] July 19} Aug. 4 9 2B) 6 16 54 36 | June 12 | June 21} July 6] July 9] July 22 9 15 3 13 40 37 doe Gores July 8} July 14} July 31 9 17 6 17 49 38 Gose= dois | July 10] July 16} Aug. 1 9 19 6 16 50 39 doz-a4 dozeane dos eee July 15} July 31 9 19 5 16 49 40 dors: does. ROWS = 8 July 16} Aug. 2 9 19 6 17 Sail 41 do Gores Ulysse dokeres ug. 9 9 20 5 24 58 At eed ose Govcaas ado2== July 15} July 31 9 20 4 16 49 HAS erdossse= dos Tulyson|seadoss =e domsees 9 18 6 16 49 DAA dor enne dos dilate eaasasoue Aug. 8 9 Dh eee |e ee 57 APR ome eee les (6 Ca peel Fees orate Se [Es ee come 2July 31 Oe Peeoeetel Ms serra bomen ac 49 46 | June 13 | June 22 | July 11] July 20/ Aug. 4 9 19 9 15 52 47 dozexe- dows. = GOseas July 18 dora 9 19 7 17 52 48 Gos-=2 Goss July i242 2do2 =e Aug. 3 9 20 6 16 51 49 do Got edoMes: July 21} Aug. 5 9 20 9 15 53 150 | June 14 GOkse.- July 10} July 15] July 31 8 18 5 16 47 151 Ob: <2:: does July 11] July 16} Aug. 1 8 19 5 16 48 152 Gos ee doles Edo July 17 Gliese 8 19 6 15 48 153 dom: Kole ae July 21] July 29] Aug. 10 8 29 8 12 57 154 (OE ee (6 La aera es |e patel |e era oe 2Aug. 1 8) eciecs- sales eh ale eee ee 48 55 | June 15 | June 23 | July 9} July 14] July 30 8 16 5 16 45 56 Goze dow s:- Angle 14 eafbllyy ay |e eS eo 8 19 (Beeps iene oe 57 do!-.2- dataa July 18] July 26| Aug. 8 8 25 8 13 54 158 | June 16 Goss. July 12} July 17} Aug. 2 i 19 5 16 47 LE | Pe 6 too = dome GOssse- July 19} Aug. 4 af 19 7 16 49 ECG) Pears (oR dosse. July 13} July 18} Aug. 1 7 20 5 4 46 61} June 18 | June 24} July 12} July 27 |....__...- 6 18 LD, 12 eect ee ee 62 doit = do.....| July 17] July 30] Aug. 10 6 23 13 11 53 63 do=2.-5 Goleeer July 1S) | See Goe ses Eanes 6 24 1 eee eS as 64 dose. doses July 20} July 28} Aug. 9 6 26 8 12 52 65 Go. = Edoleaee July 23; July 29] Aug. 10 6 29 6 12 53 66 | June 19} June 26} July 15]! July 26] Aug. 9 7 19 11 14 51 67 | June 20 | June 27 | July 12} July 20] Aug. 5 7 15 8 16 46 68i|-22d02---= Chee sme July 24} July 29} Aug. 10 7 27 5 12 51 69) |/psedoureas (6 (oa 5 [ee Aug. 4] Aug. 18 W NeeAnesae boacess* 14 59 |~ DIONE 3s GOb see Goths July 14) July 21} Aug. 5 7 17 7 15 46 LA ead Oss Cokes Obese] ili 28) |) Ae id 17 9 14 47 TEA | hee One dome July 20} July 29} Aug. 10 7 23 9 12 51 73 | June 26| July 3] July 28| Aug. 3. Aug. 15 ie 25 6 12 50 (aa iee: ¢27) | Dolly* As |. Osean eee One me eee Genes 7 24 6 12 49 7 eo (eee seedou te: 5 -200b22:5| Auge “6:|Auee 19 7 24 9 13 53 1 Bagged fruit; average feeding, 20.9 days. 2 Pupated in fruit; average feeding, 21.4 days. TaBLE LVI.—Length of the life cycle of the first generation; summary of Table LV. Days for— Observations. IRS ; 9 Hatch- adi Making of} Pupal | Total life ing. | Feeding. |’ cocoon. | period. cycle. AVe@rare le Sateen oe ena | 8.33 21.25 6.54 15,18 51.10 Maxam tints so sons Sete nce 10 29 18 24 64 Mining eae sene eens 6 15 2 11 42 THE CODLING MOTH IN MICHIGAN. 55 It is of interest to note the extent of variation in the length of the life cycle of the first generation. The figures of Table LIV show a maximum length of time for the entire life cycle of 87 days and a minimum of 29 days, or a range of variation of 58 days. From the above results it becomes evident that reliable conclusions can not be made from a limited number of observations no matter how accurate the records may be; they only represent the results under limited conditions. Such conclusions may readily become extremely mis- leading when used as a basis for timing spray applications. By using the average length of the life cycle of 51 days it will be found that three broods of the codling moth could have existed in the Michigan fruit belt in 1911. Or should we, on the other hand, choose to use the records for the minimum length of the life cycle we could on that basis account for the existence of a fourth brood of the codling moth. Our observations, however, only show evidence of two broods, since out of several thousand larvee of the second brood not a single insect pupated in 1911. THE SECOND GENERATION. SECOND BROOD OF EGGS. Time of incubation.—Eggs of the second brood occurred in the field for about three months. During this long period the different eggs were often subjected to strikingly different climatic conditions, which resulted in an unusual degree of variation in the time of incu- bation. In Table LVII are included the records for 110 observa- tions. The time of incubation here varied from 6 to 16 days and averaged 9.35 days for the whole period. During the latter part of July and first half of August, when the greatest abundance of eggs was found, the time of incubation varied from 6 to,8 days. As for tlie first brood of eggs, observations were also made on the embryo- logical development of the second brood of eggs, namely, the time of appearance of the “red ring” and the “black spot.’ The summa- rized results in Table LIX show that the red ring appeared on an average within 3 days after egg deposition and the black spot 2 days previous to hatching. A number of eggs deposited during the middle part of September failed to hatch, mostly due to the prevailing low temperature. The fact that the red ring had already appeared in these eggs proved them to be fertile. All of the eggs used in these tests were laid in the rearing cages, and there were 4,643 eggs under observation as listed in Table LVI. 56 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TasLe LVII.—Length of incubation of the second brood of eggs, and average tempera- ture during incubation, Douglas, Mich., 1911. | | Date of— Duration of— j No.of | Num- eee . obser- | ber of _ | Appear- 5 ‘vation.| eggs. | Egg dep- py ance of | Hatch- | Red | Black | Incu- i es osition. | req ring. | black ing. ring. | spot. |bation.| ‘T°: | spot. Days. | Days. | Days. °F, 1 18 | July 14] July 18] July 20) July 22 4 6 8 66. 96 2 23 | July 15} July 19] July 21 | July 23 4 6 8 66. 83 3 35 | July 17} July 21 | July 23 | July 24 4 6 7 66. 00 4 59 | July 18} July 23 | July 25 | July 28 5 7 10 64. 60 5 67 | July 19} July 24] July 27 |...do.... 5 8 9 64.18 6 (ojeeadoss- ale do_-2-|---doL- 3) July, 29 5 8 10 64. 67 if 64 | July 20 | July 26 Juilye 28s doses. 6 8 | 9 64.35 8 8 he dow seul as COs ea iee Goren holy oO 6 8 10 64.73 9 5.| July 22 July 27 July 29} July 31 5 7 9 65. 41 10 Sil edores| -cdosaes lame do.. Aug. 1 5 7 10 66. 47 1l 27 | July 23 July 28 | July 30} July 31 5 7 8 65.09 12 25 do... .|...do. July 31] Aug. 1 5 8 9 66. 30 13 15 | July 24} July 29 |_..do. doses 5 7 8 66. 63 14 17 | July 26] July 31 | Aug. 1] Aug. 2 5 6 7 69. 20 15 12 | July 27 |..-do.. 2dOsm. Osea 4 5 6 70. 33 16 An edowe alten One ane Ones me eer 4 5 7 69. 76 17 12 | TJuly 28 | July 30) Aug. 2°|..-do.-= 2 5 6 70.7 18 4 .do. pane Saotss Aug. 4 2 5 i 70.08 19 14 | July 29| Aug. 2] Aug. 3 do: =<. 4 5 6 70. 23 20 3 do Bess Osis qx=|| AUg010 4 5 7 70. 22 21 72 ly SO eed os ne cette. Ando seer 3 5 § 70. 55 22 TRE sdo: ee edone eae dossse | PAE 6 3 5 7 71.00 23 Osa ily, (olelsee done oP Atenenos eed Oc eer ¥ 5 6 70. 54 24 30) |G odowk,--- | 22 dota: sedan ser) Aled 2 5 7 71.07 25 AG) Avie do Auges See dor TdO ssc 2 4 6 70. 25 26 22 dOsco.|peedO-e--| Aue. 6a Aue eS 2 5 7 71.22 27 72 | Aug. 2 Aug. A Ane: G7 |. -2d0-25 = 2 5 6 71.29 28 AG SN dom oa seed Osten Os eres eA SnD) 2 5 7 71.01 29 40} Aug. 3]| Aug. 57} Aug. 8 |...do.... 2 5 6 71.81 30 Siipe-dos- Aug. 6 |...do...-| Aug. 10 3 5 7 71.74 31 30 | Aug. 4 |...do....] Aug. 9 | Aug. 11 2 5 {i} 72.61 32 111} Aug. 5 Aug. 8 | Aug. 10 |: ROO aie 3 5 6 73. OL 33 T7AEe domes aI CANIES dale On ere onn kee, 2 5 7 72. 20 34 146} Aug. 6 | Aug. -8] Aug. 11 |.--do.... 2 5 6 71.95 35 60l| Ssdossss|aendOeeaaleae doz ==.) Aug. 13 PB) 5 7 71.00 36 188 | Aug. 7 ]}...do....} Aug. 12 | Aug. 14 1 5 7 69. 97 37 18 2d0s22— |S 2-C0see Aug. 13 | Aug. 15 1 6 8 70. 39 38 309 | Aug. 8 Aug. 11 Aug. fA} |S. Onerr 3 6 7 66. 59 39 Bi PAG bse) eocto Onoetel actlah Aug. 16 3 6 8 69. 47 40 3] Aug. 9] Aug. 12 |...do- Aug. 15 3 5 6 69. 47 41 99 Ones Ao loa) eco (eee | es Go Fernie) 3 5 7 69. 49 42 13)]o22dote saloon COseae Ate LomPATIon ens 3 6 8 69. 96 43 298) Aue. 10: Ame eedore-.|a4200- tr 3 ii 7 69. 86 44 AN AGO no nel 2 dO sao | see dOnis Aug. 18 3 5 8 69. 99 45 310 | Aug. 11 -do...-| Aug. 16 | Aug. 17 2 5 6 69. 33 46 130 do. Aug. 14 ]...do.. Aug. 18 3 5 i 69. 56 47 37 do. sae MOb ora) Avie sal7: | eAnion 19 3 6 8 69.15 48 128 | Aug. 12 | Aug. 15 |.+.do.. Aug. 18 3 5 6 69. 92 49 37 |b adoneee|taedosse- [tes do....| Aug. 19 3 5 7 69. 40 50 130 | Aug. 13 Aug. 16} Aug. 18 | Aug. 20 3 6 7 68. 65 51 102) | edo ss 24) esdorn ae |see do... -| Aug 21 3 6 8 67.68 52 87 | Aug. 14 Aug. Ly |) Aig. 19") S22dols ss: 3 5 7 67.77 53 58 |..-do....|...do....] Aug. 20 | Aug. 22 3 6 8 67.86 54 198) | Ate. 5 |Siidos- ce PATE ete ead Omer at 2 6 7) (67.07 55 68 do COs rer | vate do.. Aug. 23 2 6 8 66.85 56 Bile doe alee Gomer paoe do...-| Aug. 24 2 6 9 66. 08 57 Sileaidowne |beaGoes 2. eAtip 22) Arieee 25 2 7 10 65. 40 58 37 | Aug. 16 Aug. 19} Aug. 23 | Aug. 24 3 7 8 65. 63 59 Ais PE OOe se) | Se do. Sed Owes eRe 2p 3 7 9 66. 04 60 QIAN ed0ee- =| AME. 20 Aug. 24 | Aug. 26 4 8 10} 64.23 61 Sul. dors... does: a vdowsee Aug. 27 4 8 iii! 64.16 62 21 | Aug. 17 | Aug. 191 Seedotsee Aug. 26 2 7 9 63. 22 63 39 |...do....] Aug. 20 |} Aug. 25 | Aug. 27 3 8 10 63. 24 64 AQ) |e 2d02 ea lae dO cer lees do....| Aug. 28 3 8 1 63. 72 65 206 | Aug. 18 }...do...-| Aug. 26 |...do.... 2 8 10 62.99 66 18 ees Cores) Mee do....| Aug. 27.) Aug. 29 2 9 11 62.97 67 26} Aug. 19 | Aug. 21 | Aug. 28 | Aug. 30 2 9 11 62.00 68 4 2300: <-%\-=- doXac= |= do. Aug. 31 2 9 12 61.69 69 119 | Aug. 21 | Aug. 23 ABE. 30° Sept. 1 2 9 lat 61. 71 70 7 eens Cpa) Bee dose st. -.d0.. 2 ..<| Hepte 2 2 9 12 62.36 71 32 | Aug. 22! Aug. 25 !.. ..do....! Sept. 1 3 8 10 61.03! ‘ THE CODLING MOTH IN MICHIGAN. 57 Taste LVII.—Length of incubation of the second brood of eggs, and average tempera- ture during incubation, Douglas, Mich., 1911—Continued. Date of— Duration of— No. of | Num- . ANETAES obser- | ber of Appear- fee vation.| eggs. |Egg dep- ABneee ance of | Hatch- | Red | Black | Incu- pee toe osition. | od ring. fone ing. ring. | spot. |bation.| ‘UT: Days. | Days. | Days. Fs 72 80 | Aug. 22} Aug. 25 | Aug. 30 | Sept. 2 3 8 11 61.81 73 50 | Aug. 24] Aug. 26] Sept. 2 | Sept. 4 2 9 11 61. 96 74 SSO. are Pee dOene | a5 00sec -lpept. 2 9 12 62. 23 75 210i PAuigs 26) Ante. 3001. -do...-|-2.do--2- 4 7 10] 62.95 76 46 | Aug. 27| Aug. 31 | Sept. 3 |_..do....- 4 7 9| 62.90 77 16 do. 2.2|-2200:; -32|2.:dos..=2| Sept. 6 4 if 10 63.17 78 26) | Aue. 28) j2.2do:-..) pept. (5/2 do... 3 8 9 62.59 79 Stee doz a~5|se-C0seeritendaue. | pept: 7 3 8 10 62.41 80 12 |...do....] Sept. 1] Sept. 6] Sept. 8 4 9 a 62.39 81 Biles GOs sa.5] se. Obes ..€0...-| Sept. 9 4 9 12 62.84 82 8 | Aug. 30] Sept. 2] Sept. 8 |...do.. 3 9 10 63. 58 83 else OOsee al-5-005— do... -.| Sept. 10 3 9 11 63. 27 84 6 | Aug. 31 | Sept. 3] Sept. 9 |...do.. 3 9 10 63.77 85 i) eae Ge -J005— .-do....| Sept a) 3 9 11 63. 60 86 10 | Sept. 2| Sept. 6 | Sept. 12 | Sept. 15 4 10 13] 62.14 87 40 | Sept. 8 | Sept. 11 | Sept. 16 | Sept. 18 3 8 10 62. 46 88 V0) | eset Ko aes =G0..--|--.d0_.. || Sept. 19 3 8 11 62.85 89 5 | Sept. 9 | Sept. 12 | Sept. 17 do.. 3 8 10 62. 34 90 3) jess G0.- o...-| Sept. 18 | Sept 20. 3 9 11 62. 06 91 ae Gose do....|...do...-.| Sept. 25 3 9 16 61.09 92 1| Sept. 10 | Sept. 13 | Sept. 19 | Sept. 21 3 9 11] 61.86 93 2) ee GOs Se edoe. -|25-00= Sept. 22 3 9 12 61.39 94 Seeedos 5 do... -.| Sept. 20 | Sept. 24 3 10 14 61.09 95 29 | Sept. 11 | Sept. 15 -do....| Sept. 22 4 9 11 61.35 96 16 |...do do>.- do....| Sept. 23 4 9 12 60. 92 97 1 |...do Sept. 16 | Sept. 21 | Sept. 24 5 10 13 61.03 98 1 (oe (eee do...-.! Sept. 22 | Sept. 25 5 11 14 61.11 99 3 | Sept. 12 GO=25-|2--G0-=- =| sept. 24 4 10 12 60. 71 100 tle dops2 do....| Sept. 25 4 10 13 60. 81 101 19 | Sept. 13 | Sept. 17 do....| Sept. 24 4 9 ail 61.19 102 Gil d0an= we Onos do... -.| Sept. 25 4 9 12 | 61.27 103 Allie 00s c do. . Sept. 23 | Sept. 26 4 10 13 | 60.93 104 ily 2 Sac koe do: =. .|---d0-...-| sept. 27 4 10 14 60.43 105 Uesedos. dove -do....| Sept. 28 4 10 15} 60.47 106 5 | Sept. 14 do. Sept. 22 | Sept. 24 3 8 10 61. 68 107 1 0.. do.. Sept. 23 | Sept. 28 3 9 14| 60.76 108 7 | Sept. 17 | Sept. 25 | Sept. 27 | Sept. 29 8 10 12 59. 60 109 1 Edo. -do.. S200ssee | OChae ul 8 10 14 58. 55 110 2 |eesdoz.. 2-005. pede] MOCtsS 8 10 16 57.80 Tasie LVIII.—Length of incubation of second-brood eggs laid in rearing cages, Douglas, Mich.,1911; summary of Table L VII. Appearance of red | Appearanceofblack} Total incubation ring. spot. period. Number Number Number Nae of obser- neve of obser- Nariber of obser- YS: | vations. YS- | vations. YS: | vations. 1 2 4 1 6 13 2 27 5 30 7 22 3 41 6 15 8 13 4 24 7 12 9 9 5 11 8 18 10 17 6 2 9 22 11 15 8 3 10 11 12 9 ae A eal SE eae ll 1 13 4 nee PORE ee a balls c.cttciceaaa|ee cictene ce « 14 5 58 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLE LIX.—Length of incubation of second-brood eggs laid in rearing cages, Douglas, Mich., 1911; summary of Tables LVII and L VIII. Number of days— SLES RES: Forappear- |For appear-| por incu- ance of red ance of eran ring. black spot. 7 ASVOTASC =e a see = eo 3.33 7.19 9.35 IW bra leskth aces a eee Re 8 11 16 Minimum@ 225-2 - == 25.55=2 1 4 “6 Effect of temperature upon the time of incubation.—The general effect of the temperature upon the time of incubation of the codling moth eggs has already been considered on page 44 and the results for the second brood of eggs have there been given in the diagram (fig. 15) together with those for the first brood. In Table LVII the average daily temperature is given for the 110 separate observations. These temperature records have further been summarized to averages for the respective days of incubation as given in Table LX. The range in variation of average degrees of temperature for the different days is shown in the same table in the columns of maximum and minimum. TaBLeE LX.—Average mean temperature during incubation of second-brood eggs, Douglas, Mich., 1911; summary of Table L VII. AVeTra re ie) Ta ce. Daysiot iMrambee Average mean temperature ineuba- | ef obser- meas aes: Average. | Maximum.| Minimum. | | | Sek. ca is oF. 6 13 70. 72 73.01 69.33 7 22 69.79 72. 61 66. 00 8 13 67.88 70.39 65. 09 9 9 64.56 66. 30 62.59 10 WN 63.51 66. 47 61.03 11 15 62. 46 64.16 61.19 12 9 61. 45 62.84 59. 60 13 4 61. 23 62.14 60. 81 14 5 60.39 61.11 58. 55 15 1 GOUST j\es oo ee aoaleene = ceeeiee 16 2 9. 44 61.09 7. 80 SECOND BROOD OF LARV. Time of hatching.—In the field the hatching period extended from July 18 to October 3. The great majority of larve hatched during the latter part of July and throughout August; during September only a few appeared. The period of hatching of larve of the second brood, extending over two months and a half, is very exceptional in compari- son with the records for a normal season. During 1910 the period of hatching of eggs of the second brood was less than ene month and a half. THE CODLING MOTH IN MICHIGAN. 59 TaBLeE LXI.—Length of feeding period of second-brood larvx, Douglas, Mich., 1911. Date of— Date of— 2 ; No. of ont Ce No. of sag ke Days ne of | = is a Days 0S a aT bee obser- Ser PaO tee |Obser-|———_ =], of 4 va- | watch- | Leaving | 4" |] Ya | qatch- | Leaving | © |) .Y® | Hateh- | Leaving | ed | tion. ing. Gut ing. || tion. ing. | fruit. ing. tion. ing. frit: ing. j 7 July 23 | Aug. 18 26 ¢9 | Aug. 12 | Oct. 10 59 137 | Aug. 20 | Oct. 7| 48 Qe 00s. 525 Aug. 19 27 70) | 22c0o.- Oct. 12 61 ASB ht . O22 2). 5 Ole =. 48 3 26 WL |252002 2250 Oct. 20 ae) aBOLE S GO-5- onl. - GOlss- 2 48 t 4 5 : | 5 |. 4 : ih 8 Oy; 35215°—Bull. 115, pt 1-125 60 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLe LXII.—Length of feeding period of second-brood larvx, Douglas, Mich., 1911; summary of Table LX I. l } Number | Days of | Noaeer| Days of | Number | Days of | Nake Days of of larvee.| feeding. || of larvee. | feeding. | of larvee.| feeding. of larve. | feeding. fe | | a 2 2 = ara ! : | | | tS) 20 7 32 apy 44 2 56 | 1 BA aN 9 33 Sint} 45 2 58° | 4 22 5 34 5 46 1 59 | 5 23 4 35 2 47 1 60 6 24 || 13 36 | 3 48 3h | él 2 25 9 37 Ot 3 49 1 62 | 5 26 || 9 38 4 50 2 64 | 2 27 a 39 3 51 7 69 4 28 8 40 2 52 3 70 | i 29 il 41 3 53 1 fil 3 30 3 42 3 54 | 1 76 | 10 31 | 8 | 43 || 2 55 2 84 Length of feeding period.—The feeding period of the second-brood larve is considerably longer than has been recorded for the first-brood larve and is mainly the result of prevailing low temperatures during the late summer and the fall. The data from 199 observations (Table LXI) cover a long period of time extending from July 23, when the earliest larve hatched, to November 13, when the last larve left the fruit. There was a range in the length of the feeding period of from 20 to 84 days, with an average of 40 days. Time of maturity.— In the rearing cages the first larve of the second brood left the fruit August 18, but these were not from the earliest eggs. Considering the time of feeding and the date of earliest ovi- position, it is evident that in the field the first larve left the fruit about August 13. As noted from the band records, the last larve left the fruit November 13, which was also the last date of observation in the rearing cages. BAND RECORDS OF 1911. During 1911 the band-record tests were extended to the following five localities: Benton Harbor, New Richmond, Douglas, lake shore (near Douglas), and Pentwater. The purpose of these tests in the widely separated sections of the Michigan fruit belt was to determine the possible existence of differences in the time of development of the codling moth. The different band-record orchards were located respectively near Benton Harbor, 7 miles from the lake; at Douglas, on the grounds of the station 2 miles from the lake; at the lake shore, west of Douglas; and near Pentwater, about 7 miles from the lake. Most of the apple trees were old and none of them had been sprayed with poison. The number of trees and varieties of apples, so far as could be determined, were as follows: At Douglas, two trees Golden Russet, one Rhode Island Greening, one crab apple; at the lake shore, one King, two Canada Red, one Wealthy, one Astrachan, two winter varieties not determined; at New Richmond, two Baldwin, one Transcendent crab apple, one winter variety not determined; at Benton Harbor, one Golden Russet, one Canada Red, one crab apple, three fall varieties not determined; at Pentwater, six Ben Davis. THE CODLING MOTH IN MICHIGAN. 61 TaBLe LXIII.—Band records at Douglas, Mich., 1911. | | Emer- | Num- : Emer- | Num- | 7 Emer- = Emer- Date of | Num- gence of, ber of |) x. Date of | Num- gence of ber of eo collect- | ber of gates of para- | win- ee collect- | ber of rae para- | win- | | ing. | larve. | "jo17.’| Sites, | tering | ing. | larve. |"9i7,’| Sites, | tering 1911. | larve. | nie 1911. | larve. a | | 1] June 25 Wee oer bees J 26 | Sept. 8 Nera cel. eeon 9 | 2| June 28 2 72 a i) 27 | Sept. 11 1a ea a eee 13 | 3} July 1 3 hl ESS Se 1 |} 28 | Sept. 14 ie are le ee in 4| July 4 Dileeese-|e a Se Se: 0 29 | Sept. 17 7 ae a Deen 20 5| July 7 2 > eae 0|| 30) Sept. 20 ia | oes CS 17 6| July 10 15 G 1 9 || 31 | Sept. 23 1D} 2 25 ce 3 [oak Aa 19 | 7| July 13 9 False 8 2e 2 32 | Sept. 26 | el Le ee 20 | 8 | July 16 21 | 14 6 1 33 | Sept. 29 Cj ae a a | 9| July 19 18 | re (a 4] 34| Oct. 2 Bie se le. .ec 8 10} July 22 21 20 1 0) ay | Oct. 5b 1! 1] PA Pat ae 10 11} July 25 11 3! 2 6! 36 | Oct. § dl cesar eee 6 12} July 28 13 5 4 4 Si) er, LiL 11 Ee RE ee ee 16 13 | July 31 17 1 3 13 38 | Oct. 14 ROM eee oe alates siete 10 14} Aug. 3 7 3 1 3 39 | Oct. 17 1/2) (ee ae! bp e e | 17 15] Aug. 6 16 Giles veneers 10 40 | Oct. 20 al Eee ae |e re 8 16} Aug. 9 20 3 1 16 41 | Oct. 23 DEN SS Ss Oe See 2 17| Aug. 12 28 Cn Se ee 24 42| Oct. 26 ed Fe ees (Oy ee eae 1 18 | Aug. 15 A la FS! (Bae ese 21 43 | Oct. 29 Ou ee ee seen oe oon 0 19 | Aug. 18 1 (OS) ae el eae ie 12 44| Nov. 1 Gl |e taoan eek 6 20 | Aug. 21 11d Pees ae aa | ee bea 10 45| Nov. 4 OS eet ee 0 21 | Aug. 24 1 el Re od) | eee ey 14 46 | Nov. 7 (0 RAD ee | eee ee 0 22 Aug. 2 8 aie: sees 8 47 Nov 10 Hdl eeeeeeel eee 2 23 HE UE a Tl Eee eee 3 48 “9p 6) | a SS peep (2 ae er 1 24| Sept. 2 ne oo ae 9 —— 25 | Sept. 5 11 Jol eee oer 13 orale seo 517 91 19 407 At Benton Harbor, New Richmond, and Pentwater the larve were collected respectively by Miss Clara Jakway, Mr. G. W. Tibbits, and Mr. 8S. J. Taylor, who sent the collected larvee for each observation to the station at Douglas. Mailing cases (see fig. 17) containing small blocks of corrugated pasteboard were used and proved very satis- factory. Very few larve were injured during transportation, and not a single shipment was lost during the whole season. At the Douglas and lake shore orchards the larve were collected by the staff of the station. Tapie LXIV.—Band records of 1911 at Benton Harbor, Mich.; larvx collected by Miss Clara Jakway. l | Emer-| Num- Emer- | Num- 2 Date of | Num- Emer- gence of berof | x Date of | Num- Emer- gence of ber of No. of | } f gence of|e- fe No. of Il 1 f \gence of a record.| “Ollect- | ber of \rioths, | Pata | Win Il recora., Coect | ber of rioths,| Para | win- | ing | larvee 1911. | Sites, tering ing. larve. 1911. | Sites, | tering | 1911. | larve. | ; 1911. | larve. | || -- — — 1] June 25 12 4 1 7 24| Sept. 2 OF: |S. R eee lee oleae 67 2| June 28 58 a7 2 19 25 | Sept. 5 a8 Jal | erp Pepe he 53 3} July. 1 71 47 | 8 16 26 | Sept. 8 il Roe ae] Ee ee 65 4| July 4 120 66 | 9 45 27 | Sept. 11 Ob lene SS oe oe 37 5] July 7 103 52 | 1 5D 23 | Sept. 14 AS son So. | eee Es 48 6] July 10 94 43 7 44 29 | Sept. 17 Belnesen es oeensee 32 7| July 13 61 45 3 13 30 | Sept. 20 | EG eS A ees 24 8| July 16 46 28 7 16 31 | Sept. 23 | Vi lege tle eer S 15° | 9] July 19 36 i a oe 6 32 | Sept. 26 | VY ee oe eee 16 | 10! July 22 37 27 2) 8 33 | Sept. 29 | PORE Ae a 8 | 11 | July 25 20 CA er ee 4 34| Oct. 2 2S Se Wee 4 12} July 28 19 sales tees 4 35 | Oct. 5 CES Ee A ee 4 13 | July 31 22 D cis 13 36| Oct. 8 A A ee Corte 3 14} Aug. 3 20 “fh eee 3 14 37 | Oct. 11 oS eis ee eee ee 4 15| Aug. 6 | 25 D lnttte ned 27 33] Oct. 14 ey See Oe ee 5 16} Aug. 9 76) Nel OS 5 alata 4 39 | Oct. 17 9 See lig Reo 5 17} Aug. 12 41 i eae 2 33 40 | Oct. 20 Le an Cees 4 18 | Aug. 15 57 1) ear 54 41| Oct. 23 hy ees Pees > 5 19 | Aug. IS 59 I aT SE 53 42|.Oct. 26 if | ee ie ees | 1 20} Aug. 21 60 2 oe 58 43 | Oct. 29 WS Ss aro | GRE. 55 1 21) Aug. 24 OAR ee iow! Con iar 42 ——— 22| Aug. 27 49 | Yl eee: 48 Thee aa | 1,567 441 | 35 | 1,091 4 a 7 Deane (eis 67 | 62 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. The results from the above band records are presented in Tables LXIII and LXVIII, in so far as same could be completed in 1911. The time of appearance of larvee and their relative abundance in the respective localities have been graphically shown by curves in figures 18 and 19. It will be noted here that there is practically no differ- ence in the time of appearance of the first larvee in the five localities; nor is there any difference in the time of appearance of the earliest second-brood larvee, so far as this could be determined. In account- ing for this uniformity in time of maturity of larve it should be remembered that the seasonal conditions during 1911 were quite Fic. 17.—Mailing case used for shipping codling-moth larve. (Original.) unusual. The spring opened up suddenly and uniformly over the entire fruit belt, and the prevailing high temperature must have started the development of the insects more or less at the same time in the different sections. During 1910, it will be recalled that in these localities a slight difference was observed in the time and rate of appearance of the first brood of larvz and practically no difference in the time of appearance of the second brood of larve. We may deduce from these observations that the seasonal development may in years become more uniform in the different sections of the fruit belt than is generally the rule, and that these differences are more in evidence during the early spring than during the rest of the season, while at midsummer conditions are more or less uniform for the whole belt. THE CODLING MOTH IN MICHIGAN. 63 TaBLE LXV.—Band records at New Richmond, Mich., 1911; larvx collected by G. W. Tibbits. x | Emer- | Num- Emer- | Num- Navot Date of | Num- kane? gence of} ber of No. of Date of | Num- — gence .| ber of | erord collect- | her of moths, | P2ta- win- lrecord,.| Collect- | ber of ae para- | win- =e pie le larvee. 1911, | Sites, | tering || “aM ing. larve. 1911. Sites, | tering "| 191. | larvae. | 1911. | larvae. | | | i | UPTa ey eae | See |e ea) PS ee eee eee eee 24 | Sept. 2 id Cee Fert 7 2 | June 28 12 fi Saree 1 25 | Sept. 5 : a CAR eres Baiee By = 12 3| July 1 8 2 1 5 |} 26 | Sept. 8 | BRR Nie eri 8 4|July 4 6 el See 4 | 27 | Sept. 11 Ta Saeed 12 5|July 7| 17 10 | 1 6 28 | Sept. 14 124) Sass Ae x oe ae 12 6 July 10 18 10 4 4 29 | Sept. 17 jC See PRS oe 11 7| July 13 17 Gl Bebe coat 12 30 | Sept. 20 15 tan da (iN Tek 8 14 8 July 16 21 73) Gee 14 31 | Sept. 23 iit |e lee aan 11 9 July 19 16 A tse 2s 6 32 | Sept. 26 A se ctl oe we ok 16 10 | July 22 19 11 rt 7 33 | Sept. 29 TN es a ek 2 eee ll 11 | July 25 17 5 i ‘1 34 | Oct. 2 | i [Ee ap Rae eae 4 12 | July 28 7 4 i 2 35 | Oct. 5} a Le ee (Se eee 4 13° July 31 210 Bae Sees Bape 5 36 | Oct. 8 Se cereae eadan Goel 3 14. Aug. 3 9 ieee 4 37 | Oct. Il Hh] PeSeeecs ameenes 5 15 | Aug. 6 14 Ae ee 12 38 | Oct. 14 ra EE ese a 16 | Aug. 9 ll = jt he Ep | 8 39 | Oct. 17 < RE SEeee Roe 4 17 | Aug. 12 20 A oe Be mpc, 7 40 Oct. 20 | ee eee 1 18 | Aug. 15 | 8 iS eee taka Jee 14 41 | Oct. 23 Bibione Oye ate ae SOM 19 | Aug. 18 | i Peon [A ak See 12 42| Oct. 26 Ty oe eee ee eee 1 | 20 | Aug. 21 i ida] eae Ses ae 12 43 | Oct. 29 I eee poe ees 1 21 | Aug. 24 iP yi eet a a 13 44| Nov. 1 It aoa Pe tes 1 22 | Aug. 27 PR eee oo to 10 —|———_ 23 | Aug. 30 iNT Ree 2p | cree ll Motsle = 2 | 434 ' 90 9 335 The band-record curves in figures 18 and 19 are of further interest in that they show a marked irregularity in the rate of appearance of larve in the different orchards, and none of the curves show any natural demarcation between the two broods of larvae which could be used as a basis to separate the two broods. TaBLE LX VI.—Bamnd records at the lake shore near Douglas, Mich., 1911. ree | : mae Num- || Emer- | Num- N Date of | Num- | Emer- gence of) ber of |). Date of | Num- |,Emer- ‘gence of, ber of 9. of | cottect- | ber of (8°22 f"para- | wia- |) N°-°f! coltect- | ber of |8°2¢° of para-°} win- tecord.| ~~ moths, | 2: rs record.| ~; moths f P ing. larve. 1911 *| sites, | tering ing. larve. 191 ’| sites, | tering “> 1 1911. | larvee. * | 1911. | larvee. = I}- ees | ae SS 1 | June Wl Geena al 2 eee O|| 26] Sept. 8 il eee eee Me nce 15 2 | June 12 4 5 3 | 27 Sept. 11 7g eee ae serene 25 3 | July / 11 8 1 2 | 28 | Sept. 14 7 Fh | Pepe | Sy) ae 28 4| July 14 i 01 |S e | Pah 29 | Sept. 17 7 fl ea earl ores 28 | 5|July 7 | 57 cy ee | 25 || 30 | Sept. 20 32 32 6 July 23 12 1 | 10 | : 7 | July 19 ified (oe ome 4 8 | July 23 ig ree 6 9 | July 49 71h sade 24 12 | July 43! PVA i eel Fie 21 13 | July 44 | 2 eens 18 14 | Aug 43 | 19 : 23 15 | Aug 59 NR ee ede 44 44 9 64 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Some of the band records might even become misleading were they not supplemented by’ observations from the rearing experi- ments. For instance the great drop in the curve of the Benton Harbor record (fig. 19) was due to the exposed condition of the apple trees and to severe storms during the latter half of July. Owing to the dropping of over half of the apple crop that resulted, a large number of larvee failed to reach the bands, and many immature larve MOT AN L IM in ae ATE il TAT | HAT HAN EL AAT 25 30 5 10 15 20 2530 5 10 15 2025305 10 15 20 25305 10 15 JULY AUGUST SEPTEMBER OCTOBER NOV. Fa. 18.—Curves made from band-record experiments in orchards at the lake shore near Douglas, at Douglas, and at New Richmond, Mich., 1911. (Original.) were materially delayed in their normal growth in apples on the ground. There is also to be noted a marked difference in the relative abund- ance of first-brood and second-brood larvee in the different localities. Of the total number of larve of the Douglas band records 50 per cent were of the second brood, while of the Pentwater records only 31 per cent pertained to the second brood. For a comparison of the details of the results for the five band records reference is made to Table LX VIII. THE CODLING MOTH IN MICHIGAN. 65 Taste LXVII.—Band records of 1911, at Pentwater, Mich.; larvx collected by S.J. Taylor. } | | | Emer- | Num- Emer- | Num- Emer- 5 Emer- z Date of | Num- gence of} ber of || 1 Date of | Num- |, ence of ber of oot collect- | ber of pends of para- | win- pipet collect- | ber of gence of *ara- win- i, ngs larvee 1911. sites, | tering ole me larv2 ar tie sites, | tering i 1911. | larve. ‘ 1911. | larve. 1} June 25 6 es 5 27 | Sept. 11 FF eee Pacis oe 18 | 2| June 28 10 EN (Aa oe 5 28 | Sept. 14 1 AR bane. Bae | | a Bn ce 12 3| July 1 56 Ad 2 10 || 29 | Sept. 17 A lest 6.0 s eee } 14 4|July 4 24 a ok rs 15 || 30 | Sept. 20 (Gece ea eee le 16 5| July 7 18 1 a 7\|| +31] Sept. 23 ie ee Ine ee ee Ty 6} July 10 17 7d Sree 13 |} 32 | Sept. 26 77 i aes | aa is ae 7| July 13 37 Jil oa eeay 6 || 33] Sept. 29 Pind a Dea Weds Ware Net ee 8| July 16 46 od ees 12 34 | Oct. 2 NSMA Ass tes |oom mene 13 9| July 19 57 DO! lees ace. 19 || 30. | Oct. 5 UO eee eee eos ats 10 10 | July 22 73 | fl Pee 6 |) 36 | Oct. 8 SY) Sere ern | 5 11 | July 25 38 | 7 Ill BP aeree 9] 37 | Oct. 11 1834) Seen Mcp 13 12} July 28! 39 | Ol ocs ae aes 8! 38 | Oct. 14 CEMA apse eee ee an | 11 13 | July 31 52 | | a eee 27 |) 39 | Oct. 17 PAA ER ch beats meee 22 14/| Aug. 3 45 | 3 Oh | ae eee 24 40 | Oct. 20 LDF tes oe ceo re ocr | 15 15| Aug. 6| 38 ee (pistes o7 41| Oct. 23. Dy Pot ate (Eee Ihiguees 2 16 | Aug. 9 | 32 Ne ae 27 || 2} Oct. 26 | Di acc eae a | 3 | 17 | Aug. 12 | 16 | 77g) oe ee eae 14 43 | Oct. 29 | PAN See ions | Hels ee ae | Zell 18 | Aug. 15 | 2, BN as amie 38 | 44 Nov. 1 Ol eee seam aaa } 0 19 | Aug. 18 On ee wae Gs Sess 28 45 | Nov. 4 | Out ce St De 0 | 20 | Aug. 21 i iate se kee 26 46 | Nov. 7 | Te ee Te | 21| Aug. 24 ie ea an 17|| 47| Nov 10| ry esetelg lite, see 0. 22 | Aug. 27 Cty ae Bee 25 || 48 | Nov. 13 | (esas eae eee te 0 | 23 | Aug. 30 74d oh SaaS (Se eee 26 | 49 | Nov. 16 Oo | 258s Se Bes 0 24 | Sant. 2 wi beet oars Pees 25 50 | Nov. 19 Lal. Bersh See see | 1 25 | Sept. 5 1b eee ee 15 — 26 |-Sept. 8 Tey pe he 3 Cena 16 | Totals: .... | 1,044 372 2| 670 | | TaBLeE LXVIII.—Band records of 1911; summaries of Tables LX III-LX VII. Douglas. Lake shore. | ea base sa | on Pent water. jee Sey a Me | ais Aver- Observations. | | age per a Per | Total] po, | Total] po, | Total] po, | Total] po, | cent. - num- num- + | num- num- her, | cent. | “ber, | cent. Dien COBO eae) | eats be. | com. Larve collected from BHEWIADOS ce. 517 | 100.0 | 1,125 | 100.0 434 | 100.0 | 1,567 | 100.0 | 1,044 | 100.0 100.0 Moths emerging, 1911. . 91 17.6 | 287 29. 5 | SO 20.7 441 28.1 372 | 35.6] 25.5 Parasites emerging ,1911 19| 3.7 9 8 9 ral 35 2.3 2 2 18 Larve of the first ) DYIGOO Se os SS 261 50.5 775 | 68.9 | 268] 61.7] 1,008 | 64.3 717 68571). 62.8 Transforming larve of / RG ECOG. 222258 91 34.9 287 | 37.0 90} 33.6) 441 43.7 372 | 51.9 40.0 Wintering larve of Hist PLOOd =. =.=. s5:- 170 | 65.1) 488] 63.0 78 | 66.4 567 | 56.3 345 | 48.1/ 60.0 Larve of the second } DPIOGd HS 733529223 256 | 49.5) 350] 31.1 166 | 38.3 559 | 35.7 327 | 31.3 37.2 Wintering larve of first and second DPrOodsy=-4 "252." S35 407 | 78.7 829 | 73.7 335 | 77.2} 1,091 | 69.6 670 | 64.2 ret The averages for the different observations show that from the total number of larve only 25.5 per cent transformed and issued as moths in 1911; adult parasites issued in 1911 from 1.8 per cent of the codling-moth larve; 62.8 per cent of the larve were of the first brood and 37.2 per cent of the second brood; of the first-brood larvee 40 per cent transformed and 60 per cent wintered; of both the first and second broods 72.7 per cent of the larvee wintered. SUMMARY OF SEASONAL-HISTORY STUDIES OF 1911. The prevailing high temperature of the season produced a marked shortening in the time of development of the codling moth. The deviation from the average conditions is only slightly noticeable within the separate stages, but becomes strikingly marked for the 66 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. whole life cycle. Thus the time of hatching of the earliest larvee of the second brood came 21 days ahead of those for the previous year, and the time of hatching of the second-brood larve extended over an unusually long period of two and a half months. The second-brood larve were exceptionally abundant, being in some orchards equal in numbers with those of the first brood. In figure 20 a summary is given in a graphical form to illustrate the progress of the development of the codling moth in the course of the whole season of 1911. WHE) ia ==5 = t+—Sy = Ee SSeS KS a yoece SH aS <= Sass! Ss ees $< a — ‘ 26 eee eee eee eee ee = eS ea EEA ri 1 == a == fay === ma — =: Fz Be oe Sasa es SSS: === eS a =o r= a {+} SSS 3 ——¥ SS BS rs ne. rae = = a Soe == == =, SSS masS== —— = —- a> AQ = = oe 2 SSS eS SSS Sa = : ps ae === SS ey 4: ae Ne. 20730 3) 1015. 20 (0) "15: 20) 25.90) MOIS 20) 255 JULY AU GUST SEPTE MBER Fig. 19.—Curves made from band-record experiments in orchards at Pentwater, Douglas, and Benton Harbor, Mich., 1911. (Original.) WEATHER RECORDS FOR 1909, 1910, AND 1911. Considering the variation in the time of transformation of the cod- ling moth during the three years of observation, it -becomes evident that the insect is largely governed by climatic conditions. This is only natural, since phytophagous insects, depending upon the development of their host plants, must to a certain degree be governed by the same phenological laws that govern these plants. The earliest codling moths of the spring brood generally appear at a THE CODLING MOTH IN MICHIGAN. 67 time shortly after the blooming period of apple, so that the early lar- ye will hatch after the setting of the young fruit. A full considera- tion of climatic conditions during the years 1909, 1910, and 1911 is therefore given for a better interpretation of the life-history studies. 10 15 20 25 $ NOVEMBER +9194 ( Original.) ér| brood brood d nd broo | mer, 10 15 20 25 5 SEPTEMBER | OCTOBER 10 15 20 25 AUGUST 5 Hilgnacd oR] = = == 7) G— QE ie) = Ur ™ Le » Ipasi os ie) re) = Oo Lop] ‘S c a Y)_ qe 12) pupatidn JUNE JULY 5 10 15 2025 | 5 10 15 20 25 Diagram illustrating seasonal history of the codling moth as observed during 1911, at Douglas, Mich. 20. Fia. MAY 5 10 15 20 25 A self-recording thermometer of the type generally used by the United States Weather Bureau was kept in the rearing shelter throughout the seasons of 1910 and 1911, and the records of the tem- perature conditions are given in Tables LXIX and LXX in degrees Fahrenheit. The average daily temperature in these tables repre- sents the averages from hourly readings for each day. The readings 68 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. of maximum and minimum degrees of temperature were taken from a special maximum and minimum instrument. Daily record was also kept on the general weather conditions. For the preparation of the following account of climatic conditions the writer has in addition made extensive use of thereports of the United States Weather Bureau. The season of 1909 was characterized by a cool and wet Apri, by heavy rains during July, and by an exceptionally warm Novem- ber. During the month of May rather cold and dry weather pre- vailed. During June the temperature as a whole was seasonable, although there were an unusually large number of rainy days. The temperature for July averaged slightly below normal, and the pre- cipitation was far in excess of normal. During August the tempera- ture averaged several degrees above the normal and the rainfall was slightly in excess in the southern parts of the peninsula. September, on the contrary, was marked by a somewhat low temperature and a deficiency of precipitation, October was unseasonably cool and rather dry, while November as a whole was unusually warm. The spring of 1910 in many of its features was unprecedented, as is well stated by the United States Weather reports for March: The excessive warmth, the extreme dryness both as regards precipitation and rela- tive humidity, the large number of clear days with bright sunshine, the early disap- pearance of snow and ice, the light wind movement, and the absence of serious storms makes a history for the month (March) without parallel since the beginning of the official records. Never since the Weather Bureau was established has there been such an early opening spring. As a whole, the conditions that prevailed at the close of the month were those usually experienced from three to five weeks later. The warm weather of March continued through the first two weeks of April, when many deciduous fruit trees were out in full bloom. Following this warm weather, at a very critical period for the orchards, a drop of temperature occurred, which was accompanied by a storm with rain and snow and severe freezing. The cool weather which prevailed during the latter half of April continued with slight interruption throughout the month of May and the first half of June. Vegetation was not merely greatly retarded, but badly damaged, and the season was exceptionally backward. In striking contrast to this low-temperature condition came warm weather, which was rather above normal, extending over the latter half of June and all of July. August was fairly normal. During these last months precipitation was below the average, and clear bright weather prevailed mostly throughout. The weather conditions during September and October were fairly normal. A marked drop in temperature set in during late October, which brought most insect activity to a standstill for the rest of the season. The month of November, in striking contrast with 1909, was cloudy and cold. The uniform spring of 1911 was very favorable for the development of fruit and leaf buds, which were not unduly forwarded. The weather during April was rather more severe than usual until the last THE CODLING MOTH IN MICHIGAN. 69 week of the month, when a pronounced warm spell set in, which advanced rapidly the growth of vegetation. The mean temperature for May was decidedly above normal, and an abundance of sunshine prevailed. The United States Weather Bureau pronounced the heat for the month unprecedented. Thunderstorms were frequent, accom- panied by high winds and excessive rainfall. This weather condition continued without interruption throughout the greater part of June, when severe storms occurred, which caused great damage to orchards and the fruit crop. During the period from the 11th to the 18th, at the height of the emergence period of the spring brood of moths, a markedly low temperature prevailed, accompanied by frequent rains, which caused a sudden and prolonged delay in the appearance of the moths. The weather conditions during July were also very excep- tional. The first week of the month was marked by excessive heat and great dryness, while during the latter half of the month decidedly cold weather prevailed, with frequent local showers. August in most _respects was normal, while September was marked by sharp alterna- tion of warm and cold periods and a frequency of rainfalls. During October, and particularly during November, cool weather prevailed, which delayed considerably the time for the maturity of many second-brood codling-moth larve. TasLte LXIX.—Temperature records taken in the outdoor rearing shelter, showing maxi- mum, minimum, and average daily temperatures, Douglas, Mich., 1910. April. May. June. July. August. |September.| October. |November. Ae sd ee (eta [eee =f eG = ae a a = = = = s/s] /8l8lalelelelelelsl2] 2] ells slalsl elaial s \HlS/S/E/B1eIEl 8 2/818) 8/8181 21818] 2 | S/8| F818 SIlBia eet =| We hie ee be otal a= a | 4 £ a | & 5 a| & 5 a|& 5 Sy ee a pl ies i (erste eye | mcctea felon = te Pees [ache Pcie lene eziel beste |ilech WESh URS Sey mete be! oF of oF, Ey SRK Se 7 otk OL Coy ih °*#F ° a M4 Ly ff hy 2 °o 7 °o [7 A ° = 9) 7 ° 7 OH 1 58] 32) 41.5} 70} 49] 61.0) 89 7| 79.2) 7 66} 70.8} 83) 55) 69.5) 54) 50) 51.8) 41] 28) 35.3 2 44] 33] 36.5} 69] 48] 63.0} 89] 75] 80.8] 73] 59) 66.2) 77] 54] 67.1] 60} 46] 52.7) 33] 25] 29.7 3 52) 35) 42.9| 80) 60] 66.9} 92, 73) 81.2) 76) 55) 66.3) 70) 49] 59.8! 69} 44! 54.0) 41] 30) 34.92 4 59} 38} 48.3) 84) 62) 70.8) 94 88) 83.1) 81) 63) 70.2 81) 47| 65.2) 60) 49 55. 4) 40} 31) 35.9 5 59} 31) 43.6) 75) 52) 65.2) 95) 78} 86.0) 85) 69) 73.7) 75] 61] 65.7) 50) 37] 46. 7; 48) 38) 41.8 6 72) 26) 51.9) 70} 59) 63.2! 7 68] 73.7} 86) 61} 74.3) 63> 59] 60.8} 62! 46) 52.3, 50) 42) 49.5 7.--| 74! 43] 59.7) 68) 54! 60.8) 85; 65) 74.4) 88] 64] 77.0) 73) 57] 62.2) 55} 36] 46.0) 44] 40) 41.8 8--.| 75) 51] 61.3) 75] 53) 65.9) 89) 65] 78.9} 74) 69] 69.4) 70) 56) 67.9] 56) 31] 44.5) 50} 33) 40.2 9..-| 76] 55) 62.4) 84! 62! 75.3] 89, 73] 79.7] 84] 57] 70.7] 64) 53! 60.1] - 63] 38] 49. 6, 47) 33) 41.3 10..-| 82) 54 68. 9) 86} 67) 74.9} 89 73) 77.2) 87] 62) 73.1] 71) 53] 61.9) 60} 48 52. 7) 59) 48) 52.4 11...) 64) 55) 60.3} 78] 64) 66.2) 87) 71] 78.2) 78 64] 67.4] 73] 58] 64.9) 60) 46) 59. 0) 72| 46} 62.4 12 68) 42) 52.5) 64) 53) 59.2) 78 60) 67.1) 73) 57| 65:3) 62) 52) 55.4] 59} 43) 50. 0, 39] 1 20)! 23.1 13 65} 36) 48.5; 66) 51) 58.8) 78) 59) 70.8) 78] 60) 67.0) 67| 48] 56.3) 64) 42 51.9) 25] 1 20)! 23. 2 14 75| 47] 61:4) 72) 53] 61.2) 79 68) 69.1] 81! 67] 73.4] 70) 50) 60.6] 59] 48] 53.2) 33] 24) #29 15 79| 55] 68.7) 72) 53) 63.3] 82 57] 70.6) 76) 67| 69.6) 72) 61] 66.2) 63) 47 53. 0) 34] 26) 304 16 79| 58) 68.8 68 60) 63.4) 72 63] 65.7) 81| 69] 73.3] 73] 50) 62.8] 76] 50] 63.1) 34] 21 220 17 79| 64 71. 9} 69] 60} 62.3} 72) 54! 61.9) 77) 67) 70.9] 82) 53! 68.5) 57] 42) 53. ‘ 48| 30) 35.5 18 84) 64) 74.7) 73] 55) 63.7] 79) 54] 68.4) 78) 65} 66.3] 74) 61] 66.7} 64) 41] 53.3] 34] 26) 28% 19 86) 72) 79.2) 78) 55) 68.1] 75) 64] 67.7} 69} 51! 60.0) 64) 48) 59.2) 54! 46! 50. 2| 32) 27 29.8 20 85} 59} 70.0) 76) 62) 69.5] 77) 53] 66.4] 70} 49] 60.9} 68] 45] 57.9| 53] 45! 47.9) 34) 28) 3156 21 74| 61] 69.8) 79} 55) 70.1) 72) 64] 66.0) 80} 53] 68.5) 68] 47| 56.3] 51] 43] 45.9) 34] 28! 31.3 22 76| 60) 65. 0} 85; 65) 76.9) 75 53) 68.0) 72) 66] 65.3) 70 44) 56.2) 48) 42) 44.3 37] 28) 33.0 23 70} +60} 61.4) 87| 67) 77.3) 76, 56] 63.7) 71] 51) 59.9) 72) 50) 62.4) 46) 49) 44. 5, 38) 28) 32.6 24 72| 654) 58.0) 82) 59) 69.7) 68) 53) 59.6) 70) 56) 59.3) 67} 59) 62.0) 51} 41) 45. 3, 31} 26) 28.0 25 82} 57) 70. 3) 80} 69) 73.1] 66) 53) 59.8) 72} 45) 57.9} 60! 50) 56.9] 57) 41] 47.4) 39] 30) 34.7 26 82) 63 72.1) 83] 68} 74.9 71} 51] 62.3) 78] 49) 63.4] 63] 43) 53.9] 50} 32) 39.1) 48] 34! 38.4 27 89} 64] 78. 2) 77| 67) 68.6] 77) 49] 64.2) 79) 59) 68.5) 68] 47] 61.0} 44! 30) 35.3) 47] 32] 38.6 28 68} 61] 62. 9 64) 58) 60.3 78; 56} 69.2} 69} 59) 62.7} 63) 42) 54.2] 47] 33] 40.7) 38] 26) 33.6 29 74| 55 64. 5) 74, 48) 63.1] 78> 61) 63.3} 66) 46) 55.7) 62) 47] 53.9] 51) 42! 46.5! 32) 21) 27.7 30 75| 52) 65.3) 83) 47) 74.3) 82) 62) 73.7) 74} 44) 58.2) 56! 46] 50.6) 48] 41] 43.9) 34] 27] 31.2 31 67) 58 ee Jee eee SO) bale 26201) S74l Salo Ono sesso eee 44) 38) 40: 13833) 22 see 1 Temperatures below 20° F. not recorded. COMPARATIVE LIFE-HISTORY STUDIES FOR THE SEASONS OF 1909, 1910, AND 1911. On considering the seasonal variations in the time of transforma- tion and the relative abundance of the codling moth it is evident that the climatic conditions, and mainly the temperature, are the direct governing factors. Sometimes a scarcity of fruit may mate- rially reduce the normal abundance of the codling moth. The effect of climatic variations upon the life of the insect is particularly noticeable in the spring, when the relative earliness of the season is followed by a corresponding change in the time of emergence of the moths. [rom the curves of figures 1, 6, and 14, which represent the time of emergence of the spring moths for the respective years of 1909, 1910, and 1911, with temperature records for the last two years, it will be noted that under prevailing uniform temperatures the emergence for the main portion of the moths becomes limited to a short period, as occurred in 1910, while on the other hand under fluctuating temperatures the emergence is very irregular and extends over a much longer period of time, as observed in 1911. THE CODLING MOTH IN MICHIGAN. él The time of the emergence of the earliest moths has closely fol- lowed the time of blossoming of apples and occurred from 5 to 10 days after the blossoms dropped (Baldwin apples). By adding to these figures the time of flight of the moths previous to oviposi- tion and the time of incubation of the eggs it was found that fully three weeks elapsed before the hatching of the earliest larvae of the first brood. In 1909 the moths commenced to appear at a normal time, but were somewhat delayed in reaching a maximum of emergence. The season as a whole was fairly normal. The late fall, together with MAY JUNE LILY EEE aed dete 5 10 15 2025 | 5 10 15 2025 | 5 10 15 20 25 10 15 20 25 wes j b “Od OD D 4/o drs 6 VG pies /| Pn. ; | i ot tl Fig. 21.—Diagram showing time of emergence and relative abundance of spring-brood and summer-brood codling moths, and blooming period of apple trees, during 1909, 1910, and 1911 at Douglas, Mich. (Original. ) other favorable influences, produced a development of a very large second brood of larve. Of the total number of larve for the year, 43 per cent were of the first brood and 57 per cent of the second brood. This occurrence was perhaps directly due to the unusual rate of emergence of the moths of the summer brood. These com- menced to appear at the normal time, but already reached a maxi- mum during the early part of August (fig. 21) instead of the latter part of the month, which is the general tendency as shown for 1910. In the band-record curves of figure 22 is shown a corresponding rate in the time of maturity of larve of the second brood. The maximum in the first brood of larve occurred comparatively late, 72 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. which in turn reduced the-percentages of transforming larve as against the percentage of wintering larve of the same brood (see Table LXXI). The occurrence of an early maximum of larve in the second-brood larve was due to the early rate of emergence of the moths of the summer brood, and to favorable climatic conditions. During 1910 the codling moths of the spring brood were delayed in the time of emergence of the earliest individuals. The larger number of moths, however, emerged Very soon after the first appear- ance of moths, so that for the rest of the season the dates for the occurrence of the separate stages were about normal. The summer moths commenced to appear July 26 and reached a maximum of ra le AUGUST |SEPTEMBER| OCTOBER [NOVEMBER 5 10 15 2025 | 5 10 15 2025 | 5 10 15 2025 | 5 10 15 2025 | 5 10 15 2025 Haul JUNE 5 10 15 20 25 Pg i 2% Brod Fig. 22.—Diagram showing time of leaving the fruit by the first-brood and second-brood laryz of the cod- ling moth during 1909, 1910, and 1911, at Douglas, Mich. ( Original.) abundance during late August, which has been observed to be the general rate of emergence for the brood. In 1910 the codling moth was naturally limited in numbers as a result of the small crop of apples, and to this must be ascribed the reduced size of the second brood. Of the total number of larvee from the band records, 73.2 per cent were of the first brood and only 26.8 per cent of the second brood. In some sections of the Michigan fruit belt the apple crop was so limited that only one brood occurred, the fruit having dropped before the second brood developed. The spring of 1911 opened at a normal time. The temperature during the latter part of May and all of June was on an average exceptionally high, and this condition forwarded’ the development of both plants and insects In a very unusual manner. The moths commenced to emerge at a normal time, as comnared with pheno- THE CODLING MOTH IN MICHIGAN. 73 logical developments. In the course of the emergence period part of the moths of the spring brood were hampered by cold rains, which set in during the middle of June and caused a somewhat pro- longed delay for about one-half of the moths. This irregularity in the development of the insect produced an unusual effect upon the time and rate of occurrence of the separate stages for the rest of the season. This is noticeable from a study of the curves of figure 21 for 1911. In the summer brood there occurred an abundance of moths at the very start of the emergence, which was followed by a decrease in number as a result of the delay found in the spring brood; then again an abundance of moths appeared during the first half of August as a result of the emergence of the later half of the spring brood of moths. The prevailing high temperature advanced the earliest developing insects to the extent that the second-brood larve appeared three weeks ahead of those of 1910, and further prolonged to a very unusual extent the time of emergence of the summer moths, the period of egg deposition, and the period of hatching of the second brood of larvee. The large fruit crop, together with the high temperature, favored the development of a large second brood of larve. For the total number of larvee collected at the Douglas band records 50.5 per cent were of the first brood and 49.5 per cent of the second brood. TaBLeE LXXI.—Summary of results of band records for 1909, 1910, and 1911, at Douglas, Mich. a= 3 a > 7 7 | | Percentages for— Observations. | a | 1909 | 1910 | 1911 ay = =: MOLDS eInereine The Same SEASON a= fo. cock cone acces toe ack ete motceleemses ees 13. 2 25.5 17.6 Mothe emereinpsthe fOuO WINE SCUSOMs. - oS. cca. osc b clace ss dinasae vee ans -ecsee-e. 50.7 Bey ial ae ee Motalomearconbe Ol MO lUS=s eee Nee sce fe See cok. eo ose ck Sues sess weetaaces 68.8 Gazal pear as bY Interns larves of total band) collection: .-2 22-4 2.2.52 5. 2 2-22 se ee ees = 85.7 | 73.5 78.7 Wintering larve killed by frost»..........-.- SRE ASR ee ae er ene Ore a | 245.6) | SOF | ea ase: Or ichjire Cal ahy 055 sore eee eet aes sre ne Rohe ae Sue Mena b eats Seven cet bceemssbs LS) AO ose ee Relative proportion of irst-brood larvees.... fo... o.oo 2c en ees eee ee cee nn 43.1} 73.2 50.5 Relative proportion of second-brood larvee................-.--.-------------+--- | 56.9 26.8 49.5 MIPATIN(O LITO ah VOOM tI siy DLOOU! 2 nee ee be oe eee wn oes Hae Saas Gave eos ears Say 34.8 34.9 Wintering larve of first brood 66.8 65.2 65.1 The results from the band records for the three vears at Douglas show that of the first-brood larve about one-third transformed the same season and two-thirds passed the winter in the larval stage, as do all second-brood larve. (See Table LX-XT.) INSECT ENEMIES:! PREDACEOUS INSECTS. Several predaceous insects have been found to attack the larve and pup of the codling moth. Of these a small black beetle and its larva, Tenebroides corticalis Melsh. (PI. III, figs. 4, 5), belonging to 1 For information relative to the bird enemies of the codling moth, see Yearbook of the Department of Agriculture for 1911, pp. 199-208, ‘‘ Bird Enemies of the Codling Moth,’ by W. L. McAtee. 74 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. the family Trogositide, has been found to constitute one of the most important predatory insect enemies of the codling moth. The slender and flat form of the larva and also the depressed shape of the beetle enable the insect to penetrate into narrow cracks and crevices in search of prey. Both the larve and beetles have been found in the cocoons of the codling moth, having penetrated the walls of the same and destroyed the host. Full-grown larve and beetles have been collected in the late fall and in the spring, which would indicate that the insect passes the winter in both stages. The white and deli- cate pupa was once observed under the bark in a small cavity, which must have been made by the larve previous to pupation. There are several species of carabid beetles that have been found under the bands on apple trees. Of these Pinacodera limbata Dej. (Pl. III, fig. 3) and Platynus placidus Say were seen to destroy the . larve of the codling moth. Mr. W. Postiff collected in 1910 one specimen of Tenebroides castanea Mclsh., which also was destructive to codling moth larve. These specimens were kindly determined by Mr. E. A. Schwarz, of the Bureau of Entomology. In wind fallen apples the codling moth larve are sometimes attacked by wireworms (species not determined), which have been found in wormy fruit. In confinement the wireworm larve fed freely upon codling moth larve, even after the latter were removed from the fruit. The larvee of a lacewing fly (Chrysopa sp.) were often observed in the act of absorbing the contents of the eggs of the codling moth. In the rearing shelter these insects were regular pests, in that they would destroy the eggs in the cages under observation whenever the eggs were left exposed. In the orchards the larve of the lacewing flies are very common and no doubt they play there an important role in checking the codling moth. PARASITIC INSECTS. Among the native hymenopterous parasites of the codling moth Ascogaster (Chelonus) carpocapse Vier. (PI. ITI, figs. 1, 2) is the most commonly observed. It has been collected in the States of Michigan, Pennsylvania, Maryland, Virginia, and Nebraska, and will probably be found in most localities where the codling moth occurs. The species was originally described by Mr. H. L. Viereck * from specimens col- lected at Douglas, Mich., in 1908 by Mr. R. W. Braucher. The writer also reared the insect in abundance at North East, Pa., in 1908 and 1909. The band records in 1909 at Douglas, Mich., showed that 6.6 per cent of the codling moth larve were parasitized, and in 1910 the sep- arate band records showed the following extent of parasitism: New Richmond, 7.7 per cent, Saugatuck 4.7 per cent, and Lake Shore 7.25 per cent. 1 Proc. Ent. Soc. Wash., vol, 11, p. 43, 1909. Bul. 115, Part |, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE Ill. ea dpa eS INSECT ENEMIES OF THE CODLING MOTH. Fic. 1.—Ascogaster carpocapsx, a hymenopterous parasite of codling-mothlarve. Fig.2.—Cocoon of Ascogaster carpocapsx within a cocoon of the codling moth, enlarged twice. Fig. 3.—Pin- acodera limbata, a predaceous beetle destructive to codling-moth larve. Figs. 4, 5.—Tene- eee parce, beetle and larva, which feed upon the larva and pupa of the codling moth. riginal.) THE CODLING MOTH IN MICHIGAN. = ( 5) The time of emergence of the adult parasites coincides with the time of emergence of the two broods of the codling moth. Like the host, the parasite is evidently two- LXXII and LXXIII.) brooded or possibly has a partial second brood. (Tables TaBLeE LXXII.—Time of emergence of the spring brood and the summer brood of Asco- gaster carpocapsx at Douglas, Mich., 1910. SPRING BROOD. | Number Number | Date of | Number} Date of Dat2of _ Number| Date of of para- emer- of para- emer- || of para- emer- || of para- emer- sites. gence. sites. gence. || sites. gence. | sites. gence. 2) June 22 9 | June 27 4| July 2 1} July 9 9 | June 23 | 2] June 28 1| July 3 1} July 15 5 | June 24 14 | June 29 5| July 5 ;———— 11 | June 25 5 | June 30 3| July 6 | 86 10 | June 26 3] July 1 1| July 8 SUMMER BROOD. 1| July 26 2) Aug. 11 1} Aug. 19 || 3 | Aug. 29 1} July 30 3 | Aug. 12 5 | Aug. 20 || 1 | Aug. 30 2| Aug. 2 || 3| Aug. 13 6| Aug. 22 || 2| Sept. 5 5 | Aug. 4 3 | Aug. 14 2 | Aug. 23 ||-—— — 1| Aug. 5 |} 6 | Aug. 15 2{ Aug. 24 || 72 3} Aug. 7 4]| Aug. 16 3 | Aug. 25 | 2) Aug. 8 3 | Aug. 17 1| Aug. 26 4| Aug. 10 2| Aug. 18 1} Aug. 27 || | | || TaBLE LX XIII.— Time of emergence of spring and summer broods of Ascogaster car- pocapsx at Douglas, Mich., 1911. SPRING BROOD. Number | Date of || Number| Date of | Number | Date of || Number | Date of of para- emer- of para- emer- of para- emer- of para- emer- sites. gence. sites. gence. sites. gence. sites. gence. | | 1| June 2 3 | June 12 3 | June 19 | 2| June 28 4] June 5 2; June 13 || 7 | June 20 || 1 | June 29 7| June 6 4| June 14 4} June 21 || 1| June 30 1} June 8 5 | June 15 2/ June 22 |__| 4/ June 9 2/| June 16 6 | June 23 || 83 7 | June 10 4} June 17 | 4) June 24 || 1} June 11 || 7 | June 18 1| June 26 || SUMMER BROOD. | | 1/ July 9 6 | July 21 |! 5| Aug. 4 || 1| Aug. 15 3} July 11 1} July 23 1} Aug. 6 || 2) Aug. 16 1} July 12 | 2] July 26 1} Aug. 7 || 1] Aug. 17 3| July 13 || 2) July 28 4|/ Aug. 8 || 1| Aug. 18 2| July 14 || 2| July 30 2| Aug. 9 || 1] Aug. 20 2| Juiy 15 || 5| July 31 | 1| Aug. 10 | 2| Aug. 22 4| July 16 || P| eae 2{| Aug. 11 2| Aug. 27 1| Jul¥ 17 || 2} Aug. 2 1| Aug. 13 1| Sept. 3 2| July 19 || L| Aug. 3 3 | Aug. 14 )|}————_— | 74 | The time and stage of the development when the larve become parasitized are not definitely known. Probably codling moth many larve are parasitized after they leave the fruit and while in search of suitable places for the spinning of their cocoons. that many larve are parasitized while still in the fruit. since adult 35215°—Bull. 115, pt 1—12-—6 It is very evident 76 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. parasites have been obtained from codling moth larvee which were collected in windfallen fruit and confined in cages. At the time the parasitized codling moth larve leave the fruit they may readily be recognized by their inferior size and the absence of the pink color, which is characteristic of the full-grown codling moth larve. In the orchard on the grounds of the station, where numerous adult parasites had been liberated in the course of the season of 1911, fully 40 per cent of the band-record larvee were parasitized in the late fall. The average measurement of the head of full-grown codling moth larvee is 1.5 mm.; the parasitized larva at the time of leaving the fruit has an average head measurement of only 1.3 mm. In the spring of 1911, 15 undersized larve, lacking the pink color, were confined in a separate cage; of these, 10 proved later to be parasitized, while the rest died from other causes. The parasite passes the winter in the larval stage within the host. The following spring feeding is terminated, and the host larva is completely devoured, except for the skin and the chitinous parts of the head. Within the cocoon of the host the parasite larva makes a small oval cocoon, white in color, within which it pupates shortly after. In 1911 once parasite pupated May 21 and issued as adult May 28, having remained 7 days in the pupal stage. So far as has been observed, only a single parasite develops in each host larva. The parasitized codling moth larve that winter do not modify the cocoon in the spring as does the normal larva, which provides an exit for the issuing moth. The parasite fly is therefore forced to gnaw its way out through the walls of the cocoon. NEMATODE WORMS. On September 1, 1910, the writer collected a windfallen apple with a full-grown codling moth larva which was found to be infested with minute, white-colored nematode worms (species not determined). The entire body cavity of the larva was filled with the worms and quite a number of worms were also found in the burrows in the apple, where the mass of worms had the general appearance of mildew. growth. MISCELLANEOUS OBSERVATIONS. NUMBER OF LARVAL INSTARS AND MOLTS OF THE CODLING MOTH. The codling moth, like all arthropods possessing an exoskeleton, must shed the skin from time to time in the course of its growth. The process of casting the skin is called ‘‘molting” (eedysis) and the stages between the molts are termed ‘‘instars.”’ The determination of the number of instars of the codling moth becomes difficult because of the small size of the larva in the early THE CODLING MOTH IN MICHIGAN, 77 stages and its habit of feeding within the fruit, where it can not readily be located for observation without great care and labor. Mr. E. L. Jenne,! in his studies of the codling moth in the Ozarks, determined the number of molts of the larve by rearing them on small pieces of fruit in glass vials. The vials were frequently exam- ined for the cast skin of the head, and on this basis the number oi molts was established. Jenne encountered great difficulty in preventing the fruit from rotting and in maintaining the larve in a healthy condition. His records from 12 larve showed that 9 larve passed through 7 instars and 3 larve passed through 8 instars. At Douglas, Mich., the writer, in determining the larval molts, method of head measurements, on the basis 9 made use of Dyar’s ” that ‘‘the widths of the head of the larva in its successive stages follow a regular geometrical progression.”? By this method the necessity of finding the cast skin was eliminated and the larve could be reared in entire fruit or in large pieces of fruit. On the other hand, this practice involved a considerable amount of labor and additional difficulties both in the finding of the larve and the taking of the measurements, TaBLe LX XIV.—IJnstars of the codling moth larvx of the second brood, and head measure- ments in millimeters for each instar, Douglas, Mich., 1910. First instar. Second instar. Third instar. Fourth instar. Fifth instar. No. of ob- ar oa servation. : Mi ° Hatch- First Second Third Fourth ing. Mni. matt Min. aaah Mm. Salt Mm. sivaihe Mm. | Ue Ree epee Aug. 11 0.33.| Aug. 15 0.50 | Aug. 22 0.66 | Aug. 27 1.00 | Sept. 8 1. 40 Nh ae ee Aug. 12 .33 | Aug. 16 .45 | Aug. 20 . 66 a: | pee 1.03 (ya Einweo oa Goer Se Sh SS sdost Soe ee GE =e .50 | Aug. 23 .63 | Sept. 5 1.00 | Sept. 1 1.30 See tee Aug. 16 .33 | Aug. 21 -48 | Aug. 27 - 66 (*) -91 | Sept. 12 1.20 FiO. ae pean tl beet B30]! dors es .55 | Aug. 25 Cree CD) Ot eee tee (CR NB MEE Desc atbee- souleeece (00) ||2-C0se5- =00 |---G0..--- SHON eee) idee ls sacri) aoe ee oe Aa oee 7 eae Oe RO Onslot -oo EdOsx: - 46 B)ieghil. se3t2- Rete evace Sobconed Boose rente Meer emer hae aeae SEE ESR SE 100/005. -90 | Sept. 1 -70 6 Dipatal PRS pees ee ee eee UDR ener Aug. 20 .33 | Sept. 3 -40 | Sept. 7 -65 Sept. 22 - 87 (S) 7 ey i eke MO ee oon pedOccens .32 | Sept. 1 -48 | Sept. 5 .65 | Sept. 12 .83 | Sept. 21 1.06 ; Sixth instar. Pupation. Days duration of instars. No. of ob- |—— == = > Se = Bervation. | ritth Mm Sixth | First | Second | Third | Fourth | Fifth Sixth molt. ‘ molt. |» instar. instar. instar. instar. instar. instar. _ — | _ —_ Lewes. Sept. 20 | 1.60| & 4 7 5 12 12 Deere... Saas Eee os 4 4 | Me ae etl al so Scat Reese ey: Sept. 18 Les | 5 4 7 | 4 5 17 es eects Sept.22] 1.50] Se 5 6) 9 7 10 g he eee ee es PORT Nh J a 2s 5 isk te Cael Dee ie ler ee & He pata 3 Lee ae ees 5 5 ARERR ph oes] Se acres NS oc bs =| pee go eee ee 5 Sree eel a se eccc:|ss 25-2. ce 3 5 Tite ts eee Nl i ee ae eee = eo ah -ca eenee | aera a 14 4 | 105) || See a ol eee ees WY scar aoace | (@) |--eeee eee -¥ 12 | 4 | 7 | 9 (‘) nag 4 ! Bul. 80, Part I, Bur. Ent., U. S. Dept. Agr., 1909. 2 Psyche, vol. 5, p. 420. 3 Died. 4 Wintered, 78 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Taste LXXV.—Larval instars of the codling moth; head measurements in millimeters for each instar; duration of instars. Summary of Table LX XIV. ag easurements in .pe ; ; Head Bieasun SUE Days duration of instars. instar. | | — — Sees ae ~ a8 Ss ~ w rS re xe Ss a : 23 Observations. Het ae ie aoe Vlas! 3 iH z Ss = Bs 8 > =e Nee |) Eh eies 7a + g D S += D ” od er tt ie D omd c = n loca ae] Be SSS Se plese bere) Seal ineees 42 a roi Ince leet a = = TS Mell ae ae) a ZIRE ees a =) = a w ° I= lS = = =| = fe) S b= 4G =| = iS 3 =| 4 & wn = i mH wn I 2 my oa) THE CODLING MOTH IN MICHIGAN. 81 Taste LXXVIII.—Instars of the codling moth larvx of the second brood; head measure- ments in millimeters; days duration of the instars; Douglas, Mich., 1911—Contd. Date of hatching and molting, and pees head jeer Days duration of instars. in millimeters—Continued. No. of a4 == ] ) a os op =) Se & nN & | = & | & Nn si ks ioe AVETAPAS 2 foes cases sees | 0.35 | 0.47 | 0.70 | 0.81 | 1.14 | 1.68 A EB 7 eat es 14.2 MSSM Sexoie's see ee wei eee . 54 18) «SL } 1.08 } 1.81 16] 9 10 10 | 13 23 LW Br ebuee hb cole 58 aes Seo gee eee yaa -42| .60 | + -80)} 1.22) 1.52 4) 2 5 4; 5 5 { | | | | The records for the time of molting and the head measurements for the separate instars for the first brood are given in Table LXXVI. Of a total number of 14 larve, 8 attained full growth. Of these, 2 passed through five instars and 6 through six instars. A single larva (No. 8) that appeared stunted in its growth had seven instars, but failed to reach maturity. One full-grown larva of this brood wintered, while 7 resulted in moths the same year. Larvee Nos. 11 to 14, inclusive, were left undisturbed during their early stages in order that their development should not be unduly delayed. 82 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. The observations on the molting habits of the second brood of larve (Table LN XVIII) were not all completed, as at times some of the larvee were neglected on account of the stress of other work. TasLe LX XX.—Head measurements of jirst-brood and second-brood codling moth larve, collected from banded trees at Douglas, Mich., 1911. nee pecone vet | Second q TOOC )OOC q brooc x brood re we larvee. eee larvee. | om larvee. || ees larvee. < * | collected | collected ~- + j\eolleeted)|| 5-5 ss /) collected July 13. Sept. 17. | July 13. || Sept. 17. mm. mm mm. mm. ill ros a) S57 | 16 | 1.623 || 16 | 1.783 2 1.509 2 1.629 17 1.839 17 1.738 3 1.560 3 1.84 | 18 1.518 18 1.733 4 1.709 4 1.78 19 1.809 19 1.620 5 1.70¢ 5 ils laiye | 20 1.62¢ 20 1.739 6 1.629 6 1.84 21 1.56¢ 2 1.739 7 1.56 7 1.689 | 22 1.62 By 1.78¢ 18 1.29 8 1.62¢ | 23 1. 67 23 1.783 9 1.629 9 1.789 | 24 1.62¢ 24 1.62¢ 10° |) 70g 10 1.849 25 1.709 || 25 1.899 11 1.798 11 1.683 | 26 1.70¢ 26 1.789 12 1.569 12 1.689 | PAL 1.62¢ 197 1.279 13 1.62¢ 13 1.689 | 28 1.629 28 1.67¢ 4 1.562 114 1.299 | 29 1.809 29 1.679 15 1.569 15 ere? | | 30 1.659 3 1.89¢ 1 Parasitized larve. The results from these observations are, however, similar to those previously obtained. The pink color which is characteristic of the mature larva first appeared a few days after the final molt. A number of mature first and second brood larve collected in the field were measured for a comparison with those maturing in the laboratory. The records of Table LX XX show no material difference in the size of head of the larvee of the two sets except that the field larve are slightly larger, which is to be expected, since the latter have developed normally and without any ‘interference. TABLE LXXXI.—The average widths of the head of the larva in its successive instars and the rate of increase at each molt; summary of Tables LX XIV-LX XIX. - Average a eaers 1910, sec- 1911, first 1911, sec- s increase Instars. ond brood.| brood. | ond brood.| “Verase at each molt. mm mm. mm. mm mm BUTS GES. Ao see aioe Sere = Sa ani e Lae 0.33 0. 35 0.35 0. 34 0.13 SCCOMG Re -—) ~ ——— - EEE ee ee ioan D.., T_T ee ee ee eee ee po THE CODLING MOTH IN MICHIGAN. 85 Ege deposition commenced in the cages from 3 to 9 days after the emergence of the moths, and most of the eggs were laid within 5 days after egg deposition commenced. In one instance eggs were laid 23 days after the emergence of the moth, but as a rule the great majority of the eggs were laid within 8 days of the emergence. The number of eggs per female varied considerably in the cages— on an average, 57 eggs per female were obtained. ROX OX eK, MOR BO Mok oe x @@O® N x silk so xbocperixhaon oclix ox x @@®@ x eas XieXrae ei Xie a6 0x! wv xcsakl x96 x x @x x Ni XxX xXXXXXX XX xX XX x x @® x & MK I MAK SKK in ye eR x x x x xX \ KX KK KX ML, OF) REPS Meat Ki MX k Be OG KX KM Kh Ke x x x @® Q % Dy N XxX XXXxXXxXx xx x x/® x x O@® concn Mme KO Ry i eRe Nee x x @® x NS xxxxxx xxx x xXI@@x x x x x x NN xX xXxXxXxX XxX XxX KK Re NJ SS XxX XX XXX XRT |X x KP KF pee ine IK NE x S SS CONTINUATION OF APPLE ORCHARD ~ABOUT 15 ROWS. SOUTH Fic. 23.—Diagram showing arrangement of plats and trees in the W. F. Gilkeson orchard, near Fishers- ville, Va. Trees counted are indicated by circles, the numbers agreeing with the numbers of trees in the tables. Variety, York Imperial. (Original.) in the accompanying diagram (fig. 23). The trees of each plat from which the fruit was counted throughout the season for records are designated in the diagram by the same numbers which these trees bear in the table. The orchard is on a hillside gradually sloping to the southeast. It had a good cover crop of June grass and clover and was kept clean of dead limbs and rubbish, and the trees are headed rather low, thus facilitating spraying. The principal variety is York Imperial. There are a few Early Harvest trees scattered throughout the orchard, but none of these latter was included among the count trees. Plat I included 150 trees, Plat II 64 trees, and Plat III (the unsprayed plat) 10 trees, this last plat being in the center of the orchard. The treatments which the respective plats received are shown in Table I. ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 89 TaBLeE I.—Treatinents and dates of applications for the codling moth and the plum curculio. One-spray method. Fishersville, Va., 1910. Plat I. Plat II. Plat IIT. Dates of application. (One-spray method.) (Unsprayed.) First application, Apr. 16-18 | Not drenched. Vermorel | Drenched with arsenate of | Unsprayed. (as soon as petals fell). nozzles. Mist spray. Ar- lead, 2 pounds to 50 gal- senate of lead, 2 pounds to lons commercial lime-sul- 50 gallons commercial phur (13-50). Bordeaux lime-sulphur (1-50). nozzles. Pressure, 200-225 Pressure, 200 pounds. pounds. Second application, May 16...)..... a Ee eee Commercial per ed Do. only (1}-50). No drenched. No peonieal: Third application, June 22...-.)....- ose s £3202 O40 528 - AOSSLT i IES SIS. Do. Plat I was sprayed thoroughly three times but was not drenched. Commercial lime-sulphur wash and arsenate of lead were used for each applicatom. Plat II (one-spray method) was thoroughly drenched, Bordeaux nozzles and high pressure being used. This plat received one application of arsenate of lead and commercial lime-sulphur and two subsequent applications of commercial lime- sulphur only. THE CODLING MOTH. In Table II is shown the total wormy fruit and fruit free from injury by the codling moth for the entire season for the eight count trees of each plat, the number of the trees in the figure agreeing with those in the table. TaBLeE II.—Number of sound andwormy apples for each tree from demonstration, one-spray and unsprayed plats. Fisherville, Va., 1910. PLAT I. LIME-SULPHUR DEMONSTRATION. | Total a Total | Per Condition of | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree for cent fruit. ae 2 3 4, 5. 6. its 8. 9. 10. lat of P sound fruit. Womnny........-< 141 29 47 80 35 al 31 72 22 12 496 |....... Sound. 2 4. * 21,324 | 9,131 | 9,221 | 9,445 | 8,749 | 6,560 | 6,373 | 6,980 | 5,622 | 2,566 |85, 971 |.....-- Total: =< 21,465 | 9,160 | 9,268 | 9,525 | 8,784 | 6,587 | 6,404 | 7,052 | 5,644 | 2,578 |86, 467 |....... Per cent sound .| 99.34 99. 68 | 99.49 | 99.16 | 99.60 | 99.59 | 99.51 | 98.97 | 99.61 | 99.53 |......- 99. 42 PLAT II. ONE-SPRAY METHOD. Wormy........ 82 88 63 63 6 29 33 77 41 23 | 1 eae Sound..........| 7,282 | 6,543 | 8,044 | 7,539 | 2,023 | 3,372 | 3,777 | 5,873 | 3,065 | 3,127 |50,645 |......- Total. .-2: 7,364 | 6,631 | 8, 107 | 7,602 | 2,029 | 3,401 | 3,810 | 5,950 | 3,106 | 3,150 /51,150 |......- Per cent sound. 98. 88 | 98.67 | 99.22 | 99.17 .70 99. 14 99. 13 | 98.70 99. 68:99, 2i one eee 99. O1 PLAT III. UNSPRAYED. Wormy.-.---- 781 423 487 480 355 296 812 188 421 776 | 5,019 | : eee Sound..........| 5,159 | 1,908 | 3,067 | 2,935 | 1,874 | 1,329 | 4,413 | 1,168 | 2,285 | 3,227 |27,365 |...._.. Total.-.-* 5,940 | 2,331 | 3,554 | 3,415 | 2,229 | 1,625 | 5,225 | 1,356 | 2,706 | 4,003 132, 384 Seen Per cent sound.) 86.85 | 81.84°| 86.29 | 85.94 | 84.07 | 81.78 | 84.45 | 86.13 | 84.44 | 80.61 |....... 90 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. - Plat I, which received all three applications of arsenate of lead, gave 99.42 per cent fruit free from codling-moth injury, the per- centage for individual trees ranging from 98.97 to 99.68. The total number of apples counted from this plat was 86,467. Plat II received the one-spray treatment and shows a total of 99.01 per cent of fruit free from codling-moth injury, the percentages for individual trees ranging from 98.67 to 99.70, and the total number of apples examined being 51,150. This shows a difference of only 0.41 per cent in favor of the demonstration. Plat III, the unsprayed plat, shows 84.50 per cent fruit free from codling-moth injury, the total number of apples examined being 32,384. This shows a gain in sound fruit by the demonstration treatment of 14.92 per cent, and by the one- spray method a gain of 14.51. As will be noted, the percentages of sound fruit from the check trees is rather high. This is probably very largely due to the fact that these were located in the center of the orchard, all the surrounding trees being sprayed. In Table III are shown the places of entrance into the apple of the total larvee for the season for each tree of each plat, and also the percentage, by plats, entering the fruit at the calyx, side, and stem. There was a total of 496 larve on the demonstration plat, as against 505 larve on the one-spray plat, a difference of only 9 larve in favor of the demonstration plat. On the unsprayed plat there was a total of 5,019 larve. Comparing the percentages of larve entering at the calyx end of the apple on the different plats it will be noted that the demonstration plat shows 33.06 per cent entering at the calyx end as compared with 13.46 per cent on the one-spray plat. The unsprayed plat shows 63.86 per cent of larve entering at this point, which may be taken to indicate the normal behavior of the larvee. Table [IV shows the comparative efficiency of the demonstration and one-spray treatments in preventing infestation at calyx, side, and stem. By comparing the figures for the different plats it will be seen that the one-spray treatment was more effective than the demonstration in preventing entrance at the calyx, and less effective in preventing entrance at the side and stem. The demonstration treatment saved a total of only 0.41 per cent more of the crop than the one-spray, method, most of this saving being due to prevention of side entrances. ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 91 Tasie ILI.—Places of entrance of fruit by total larvx of the codling moth for each tree of each plat. Fishersville, Va., 1910. PLAT I. LIME-SULPHUR DEMONSTRATION. Total number of larve and place of entrance of fruit for each tree, first and second | Per- broods combined. cent- int age of | larvee | Total | | Total) enter- | num- | | | for | ing at | ber of Place of entrance. | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree |plats.| calyx, | larve. eel} 2. 3. Ae en he 6. 7. 8. 9.0.)}.10..5) side, and | stem SPS a ee aa lea aa a Se a care RE PE eae First and second | broods Calys. 24. 3.-2 49 6a. 14 25 | 5 10 16 32 4 3 T6491 Sos.00' |e =o aot 3148 (aie apa 60 20 26 40 | 22 12 11 14 12 Oni! 226."|" "abr 67" || 22-0 tem eed 32 3 if 15 | 8 Bul 4 26 6 0} 106 PANE ¥ (Al Wiens Lotallys. <-.-= 141 29 47 80 | 35 27 31 72 22) 12 | 496 | 100.00 496 PLAT II. ONE-SPRAY METHOD. : | We | First and second broods: Calyx. se. Sileid 6 7 tle oe 12 oft 4 41| SH GRh ee seo: eee Side sos se. 45| 49| 42| 30] 4] -14] 17] 40| 26] 13] 280| 55.45 |-22.22. Stems co aan o2 29 28 15} 26} te ua | 4| 26 11 | (sea Sy al hs 3 AC 2) ee Total....... 82 | 88 | 63 | 63; 6| 29] 33] 505 | 100.00 505 | PLAT III. UNSPRAYED. First and second | | | | | | | ser | 111| 251| 510 \3,205/ 63.86 |....... Calyx:.e-e-2- 487 | 252| 297, 296| 244| 196 Sidext sie! 132 78| 88) 100/ 60) 58 93 43 | 62 |''105| 819 | 16.32'|-2 22. Stemi. 45.242: 162 93 | 102 84 51 | 42°) 158 34 | 108| 161} 995) 19.82 |....... 355 | 812 188 | 421) 776 |5,019 | 100.00 , 5,019 TaBLeE 1V.—Efficiency of the demonstration and one-spray treatments as shown by the percentage of wormy apples. Fishersville, Va., 1910. Percentage of wormy apples. Total Total number Plat No. l | of nuMTiber : Ve wormy of Calyx. Side. | Stem. | Total. | apples. | 2PPles. (ePenionstration=laso--20 eee eee eee 0.19 0. 26 0.12 0.57 496 86, 467 RE TIONGISPIAYV: 2 -526-o eect ab.slule sein eels 13 .54 nou .98 505 §1, 150 Ig einsprayedscs8-t ih. Mo. ees. 9.89 2.53 3.07 15.49 5,019 32, 384 THE PLUM CURCULIO. Table V shows the effect of the treatments in the W. F. Gilkeson orchard in controlling the plum curculio on the three plats. Egg and feeding punctures are combined in the table under “ Number of punctures.” 55743°—Bull. 115, pt 2—12——2 92 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLeE V.—IJnjury by the plum curculio for entire season. Plats I, II,and IIT. Fishers- ville, Va., 1910. PLAT I. LIME-SULPHUR DEMONSTRATION. Number of punctured and sound apples, etc., per tree in each plat. Total per cent of Total | of fruit Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree | Tree for free 1. 2. 3. 4. 5. 6. tie 8. 9. 10. | plat. | from injury Number punctures... .. 1,333) 677; 618) 747) 864) 757) 835) 819) 369 210) 7,229)..7..... Number fruit punc- fred ae eee 987| 321 397} 471) 522) 483) 476) 542) 239) 123) 4,561)-....... Number sound fruit . . . .|20,478) 8,839] 8,871) 9,054) 8,262) 6,104) 5,928) 6,510} 5,405) 2,455 81,906)........ Numberirait.-5-2-5-- 21,465) 9,160) 9,268) 9,525] 8,784) 6,587) 6,404) 7,052) 5,644) 2,578) 86,467|....-..- Per cent free from in- JOTY SS o2vc sce ose es 95. = 96. a 95. 71} 95.05] 94.05] 92. 66} 92.56) 92.31] 95.76) 95.22)........ 94. 72 PLAT II. ONE-SPRAY METHOD. Number punctures. - ..- 855) 1,025) 563) 744 13, 271; 231) 314) 149 293\ 4 A883) coo eee Number fruit punc- | Guredl: soe: beet St 428) 584) 544 516 107; 156) 143) 202 90)" LIZ) | 25882)se eee Number sound fruit... .| 6,936) 6,140) 7,563) 7,086 1,918) 3,245) 3,667] 5,748] 3,015] 3,037] 48,355)........ Number fruit.........- 7,364] 6,724) 8,107| 7,602) 2,025) 3,401) 3,810} 5,950) 3,105} 3,149) 51,237|.......- Per cent free from in- Tot eae ae eee oe 94. 20} 91.31) 93.28) 93.21) 94.71) 95.41) 96.24) 96.60} 97.10] 96. 44)........ 94. 37 PLAT III. UNSPRAYED. Number punctures. .--. 917; 311) 332) 483 231 168) 683) 146) 342) 620) 4,233)........ Number fruit punc- RUIBER Com ae ese ae shes 673} 246} 297; 344) 165) 128) 463 81} 283) 434) 3,114)........ Number sound fruit... .| 5,267] 2,085] 3,257} 3,071] 2,064] 1,497] 4,762| 1,275] 2,423] 3,569) 29,270|........ Number fruit.......... 5, 940) 2,331] 3,554) 3,415) 2,229) 1,625) 5,225) 1,356] 2,706] 4,003) 32,384)........ Per cent free from in- NUDV eo eee aac ae pee 88.67) 89.44) 91.64) 89.92) 92. 4 92.12} 91.13) 94.02} 89.54) 89.15)........ 90. 38 On the demonstration plat the percentage of fruit uninjured by the curculio was 94.72, and on the one-spray plat 94.37, which shows only 0.35 per cent in favor of the demonstration plat. The unsprayed plat shows 90.38 per cent free from curculio injury. As has been noted, the check trees were in the center of the orchard and sur- rounded by sprayed trees, which no doubt accounts largely for the high percentage of sound fruit on the check plat. EXPERIMENTS IN MICHIGAN. The experiments in Michigan during the season of 1911 were carried out in Mr. Edward Hutchins’s orchard near Fennville, Mich. The entire orchard, consisting of 205 trees, was used for the experimental and demonstration spraying, the experimental part being located in the western portion of the orchard where the principal varieties are Baldwin and Rhode Island Greening. The plats were laid off across these varieties in order to have both represented in each plat. (See fig. 24.) The east side of the orchard is composed of a general mix- ture of many varieties, Trees of each plat from which the fruit was ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 93 counted throughout the season for records are designated by the same numbers which these trees bear in the tables. The orchard is almost level, sloping slightly toward the west. It was kept clean, cultivated throughout the summer, and sown to oats in the fall for cover crop. The trees are 30 years old and medium to large in size. Plat I included 18 trees; Plat II, 17 trees; Plat III, 19 trees; Plat IV, 12 trees; Plat V (the unsprayed plat), 21 trees, this last plat extending across the orchard near the center. The treatments given and dates of application are shown in Table VI. YOUNG APPLE + ~~ © OO) C7OF57 0 io ww = AK oS aA at ata Ss a OrOaD xz R OO GG S--hs ZROvGQAAORAAO HUA WOOWOOD ZFPADAATDGA Aaa Hay FIELD. 0 ww ”n a4 122) non | Qo a x OS— o Oo M@O|xxxRXRCTVILD wn 4 COD VE) NE =<: stsjs[ais Sinysiciceersiais 4 54 7 5 6465,|-.- pee cees SiGGE AG PES LER Ree Mie es ey oe Tac 65 661 153 879 89297 |0. SSSR oe PPE eee cit atac S hiceees eleaiamones 4 24 5 33 3208 The keeee TRO tea het er ee es A ede ato S ntcpate ic Mi 73 739 165 977 100. 00 977 PLAT IV. BORDEAUX-MIXTURE DEMONSTRATION. First and second broods: ; CAV S conse bis e aie sinreslaete eee ciate 3 47 5 55 QOS | ocr tees Bide RLS Lise 8 109 19 136 68134 Ces DtOM cc eee eaaacnan; muse hoa atoeee 1 5 2 AO?) | Swern Bul. 115, Part Il, Bureau of Entomology, U. S. Dept. of Agriculture. PLATE IV. Fia. 1.—PICKED APPLES FROM THREE TREES OF PLAT | (DEMONSTRATION) IN THE EDWARD HUTCHINS ORCHARD, FENNVILLE, MICH. SOUND FRUIT ON THE RIGHT; Wormy FRUIT ON THE LEFT. (ORIGINAL.) Fic. 2.—PiCKED APPLES FROM THREE TREES OF PLAT III (ONE-SPRAY) IN THE EDWARD HUTCHINS ORCHARD, FENNVILLE, MICH. SOUND FRUIT ON THE RIGHT; WoRMY FRUIT ON THE LEFT. (ORIGINAL.) Fic. 3.—PICKED APPLES FROM THREE TREES OF PLAT V (UNSPRAYED) IN THE EDWARD HUTCHINS ORCHARD, FENNVILLE, MICH. SOUND FRUIT ON THE RIGHT; WoORMY FRUIT ON THE LEFT. (ORIGINAL on Taste VIII.—Places of entrance of fruit by total larvx of the codling moth for each tree of each plat. Fennville, Mich., 1911—Continued. ONE-SPRAY METHOD FOR CODLING MOTH, ETC. PLAT V. UNSPRAYED. Total number of larvee and place of entrance of fruit for each tree; first Percentage and second broods combined. 8 of larvee Total doen fet entering at| number * | ealyx, side, | of larvee. Place of entrance. Tree 3. | Tree4. | Tree 5. and stem. First and second broods: Dalyan eee gh 577 856 1,022 2,455 iy Ge) il eee ae Biderses 5 .2f2. 258. A. eae Bee a 553 | 574 593 1,720 SISOS oes ace ase NENG et Se eS NI ars res le a 99 139 116 354 (i) | ee a Ai aN |e iy BRET Sorte ep, ae 1,229} 1,569 1,731 4,529 100. 00 | 4,529 As shown in the above table, the total number of larve on Plats I, ITI, and V were 301, 977, and 4,529, respectively. The unsprayed plat (Plat V) may be taken to indicate the normal behavior of the larve and shows that 54.21 per cent of the total larve of both broods entered the calyx end of the apples. In case of the sprayed plats, as would be expected, the proportion entering at the calyx is greatly reduced, and there is a corresponding increase in the proportion entering the fruit at the side and stem. The demonstration plat shows 13.62 per cent of total larve entering at the calyx end as compared with 6.65 per cent in the one-spray plat. Comparing the percentage of larve entering at the stem end of the apple it will be noted that this percentage on Plat I is 1.99, as compared with 3.38 per cent on the one-spray plat. It would be expected that this difference would be due to the protection of the stem end of the apple by the later applications of poison on the demonstration plat, and this is probably a correct conclusion. However, by referring to the foregoing table it will be seen that in the case of Plat IV, the Bordeaux-demonstration plat, 4.02 per cent of larve entered at the stem end. The efficiency of the one-spray and demonstration treatments in preventing worminess is shown in condensed form in Table IX. TaBLe 1X.—Efficiency of the demonstration and one-spray treatments as shown by the percentage of wormy apples. Fennville, Mich., 1911. Percentage of wormy apples.! Total Total number | number Plat No. of wormy of Calyx. Side. Stem. Total. apples. | apples. hos Demonstrations... . 224-2... e408 0.96 5.98 0.14 7.08 271 3,825 RP mOne-apray: sf cb 02. oi. os Serie 86 11.64 .44 12.94 683 5, 275 Nisew DIB ITAV OO Ns conch tk asc te nme etka 25.62 17.95 3.69 47.26 3, 081 6,518 1 Each entrance was counted in determining the percentages for calyx, side, and stem, so that the sum of these percentages exceeds the total percentages of wormy fruit. 98 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Here, as in the foregoing experiment, the one-spray treatment was more efficient than the demonstration treatment in preventing entrance at the calyx, the difference being 0.10 per cent in favor of the one-spray treatment. However, the one-spray treatment afforded only about one-half as much protection as the demonstration treat- ment against side worminess. In comparing the total efficiency of the two treatments it will be seen that there was a saving of 40.18 per cent of the crop in Plat I and of 34.32 per cent in Plat III. EXPERIMENTS IN DELAWARE. The experiments in Delaware in 1911 were carried out in the orchard of F. C. Bancroft, near Camden, Del. The part of the orchard used for this experiment was a block of about 600 trees somewhat isolated from the rest of the apple orchard. On the north side was a peach orchard, on the east and south a pear orchard, and on the west a cornfield. The orchard was almost level, having just enough slope to drain well. It was well tilled throughout the season. The main variety was Stayman Winesap, with Missouri Pippin used as the principal filler. The trees were 16 years old and were rather large for their age. The plats were laid out diagonally across the orchard, as shown in the accompanying diagram (fig. 25). Trees of each plat from which the fruit was counted throughout the season for records are designated in the diagram by the same numbers which these trees bear in the table. Plat II includes 60 trees; Plat ITI, 52 trees; Plat VII, 39 trees, and Plat VIII, 25 trees. The treat- ments to which the respective plats were subjected are shown in Table X. TaBLe X.—Treatments and dates of application for the codling moth and the plum curculio. One-spray method. Camden, Del., 1911. | | Plat II. = Plat VII. ae A ae (Demonstration. ) (One-spray method.) Plat VIII. Dates of application. Commerciallime-sulphur | Commerciallime-sulphur | (Unsprayed.) and arsenate of lead. and arsenate of lead. First application, Apr. 27 | Scab treatment. Mist spray. | Scabtreatment. Misi:spray.| Unsprayed. (before blossoms opened), Commercial lime-sulphur Commercial lime-sulphur (14-50) plus 2 pounds of alone (14-50). Pressure, arsenate of lead. Pres- 140 pounds. sure, 140 pounds. Second application, May 13 | Not drenched. Mist noz- | Drenched with arsenate of Do. and 15 (after petals zies used. Arsenate of lead, 2 pounds to 50 gal- dropped). lead, 2 pounds to 50 gal- lons of commercial lime- lons commercial lime-sul- sulphur (14-50). Coarse phur. Pressure, 140 spray. Bordeaux nozzles. pounds. Pressure, 140-150 pounds. Third application, June 7...|....-. Gosts=4- actos ees ....-| Commercial _lime-sulphur Do. } alone (13-50), ot drenched. Fourth application, July 10.|..... LO. \efoiacle'e 281-515 eee cies GON cesenee ce cen chews Do. ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 99 Both sprayed plats received four applications in all, the first before blooming, but after cluster buds had opened, to protect the fruit from apple scab. Plat II received arsenate of lead at the rate of 2 pounds to 50 gallons of lime-sulphur for each application. Plat VII, the one-spray plat, received the arsenate-of-lead treatment PLAT lV PLAT V. WEST LAST PLAT V7. PLAT VI, (ONE SPRAY, CCDs Chime (Ca? Ce CN CnC) (U)) NC ee Cieetn O) Sipm thre a Saat a ae aS Soa Ss PLAT /V (UNSPRAYED) a et a a a sas SoS Sao, Sco 9. 9 FLAT // (DEPIONSTATIONW) BORDEAUX So SUSiF"S YDNanAOnAN RY cA Ci Sica g ny N \ XN YPANKAWKDHDUVUHHUUHUHUHHHHHNUNHDUHHDHUHWYUAY LSS WEST DNMNNNUNHANA YN NHnHDYAVHNAAUNAUAUHHAUNUAAHAHAUHYNNAAWAANnN AN MANHANAYAHDAAUARNUTNA ANH ANANAUNHN A VNAUAUNAADWnDN NN YNnNOAN KHAN YHNDANAHDNHDAARAANAAAA AA AAAaA AANA AH ANNnNNANAUnHDAANUNUNUAUAnANNAAVAUNnANUNUNAAAAnANnNnA HANH AWN NDAARAANNANANAUNUNAUnHYNYNAANADHDANAAAAUnAUUAA HAA NN YPNANHNDNAMA NA NN NAANUnHNAAAUAUAUNUAADAAUAUNUNAAUAnAUHWUHAMYN NW DG ARNIS CO. O Mih.t2 G2 WAN A-W WA. 0-O.- GO) O-O@w KN ANnNnNANHA AVUNnHDAAVNnNHANAUNUHAUHA HW nan n ann nnn nnn nnn 12) SOUTH Fic. 26.—Diagram showing arrangement of plats and trees in the Thomas Fruit Farm orchard, near Wichita, Kans. Trees counted are indicated by circles, the numbers agreeing with the numbers in the tables. Trees marked X, Winesap variety. Those marked S, mixed varieties sprayed by owner. (Original.) the orchard and extend north about halfway across. The unsprayed plat was located between Plats I and II, as is shown in the accom- panying diagram (fig. 26). The trees surrounding the plats were 104 sprayed by the owner. DECIDUOUS FRUIT INSECTS AND INSECTICIDES, Plat I includes 32 trees; Plat II, 24 trees; Plat III, 36 trees; and Plat IV, 8 trees. The treatments which the respective plats received are shown in Table XV. TaBLE XV.—Treatments and dates of applications for the codling moth and the plum curculio. One-spray method. Wichita, Kans., 1911. Plat : (demonstra. Plat If (demon- van : go noe, Bt tion). Commercial stration). Bor- 5 =. Ae Dates of application. lime - sulphur and aan did. Sesh Ee on ae Plat IV. arsenate of lead. nate of lead. ccmsitoiat lead First application, | Not drenched. Bliz- | Not drenched. Bliz-| Unsprayed.......... Unsprayed. Apr. 14(beforeblos-| zard nozzles. Coarse zard nozzles. soms opened). spray. Arsenate of Coarse spray. . eee ee occ k 88. 38 89. 94 76. 54 73.86 71.52 75. 89 | eee eh, 84.16 PLAT IV. UNSPRAYED. Worry se eres as. eae 1,769 1, 890 POS} 2,709 2,072 2 PAS) PAZ OL ts= 2 ce sk ROUTO Sas) Bese ooo kee R con 25 1,114 1, 166 960 1,000 | 704 645 Sb GD eee eS LUE | a O_o 2, 883 3,056 3,192 3, 709 2,776 | 2,890 | 18,506 eee: Peneent-aound: He 22. 3.29525... & 38.64 |] 38.15 | 30.07 | 26.96 | 25.36 | 22.31 es Alay | 30. 20 By again comparing the one-spray method (Plat III) with the commercial lime-sulphur plat (Plat I), as has been done in the fore- going experiments, it will be noted that Plat I shows 95.28 per cent of fruit free from codling-moth injury as against 84.16 per cent free from this insect on Plat III. Plat IV, the unsprayed plat, shows only 30.20 per cent fruit free from codling-moth injury. Thus the commercial lime-sulphur demonstration plat shows an increase of sound fruit over the unsprayed plat of 65.08 per cent, while the one- spray plat shows an increase of 53.96 per cent over the unsprayed plat. The number of apples counted on the four plats, respectively, were 20,545, 21,334, 9,745, and 18,506, making a total of 70,130 for the four plats. One point in favor of the demonstration plat is that 106 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. there were over twice as many. apples on the count trees, which would tend to decrease the total percentage of wormy fruit. However, as will be noted later, there were 573 more codling-moth larve on the one-spray plat than on the lime-sulphur demonstration plat. The Bordeaux demonstration plat (No. II) did not give as good results as the lime-sulphur demonstration plat, the percentage of fruit free from codling-moth injury being 84.93, practically the same as on the one-spray plat. The notable difference between the two demonstration plats in percentage of sound fruit may be due to its location relative to the unsprayed plat or to some other local con- dition. Table XVII shows the places of entrance of fruit by total larve for each tree of each plat. TaBLE XVII.—Places of entrance of fruit by total larve of the codling moth for each tree of each plat. Wichita, Kans, 1911. PLAT I. LIME-SULPHUR DEMONSTRATION. Total number of larvee and place of entrance of fruit for each tree, first and second broods combined. Percentage Total | of larve Total for entering at number aA | plat. | calyx, side,| of larvee. Place of entrance. Tree | Tree | Tree | Tree | Tree | Tree and stem. 1. 2. 3 4, 5. 6. First and second broods: BYR Ecce see = eee ae 19 13 7 11 6 9 65 63:70 ahem Sides: i hed. bt oe. ae 92 | 174] 144] 149] 112) 174 845 SiA1 1). as Sie) COI eS ries br re 0 7 6 17 9 21 60 65195|< 252 eee Motal. cette. ek te et 111 194 157 177 127 204 970 100. 00 970 PLAT II. BORDEAUX DEMONSTRATION. Calyx Say ks it Se eee & 28 19 27 17 39. 26 152 5 a ee OG Sides: 2-865. Beas oot tele 496 | 354) 5385] 394] 373 | 502] 2,654 B2s05)||25 serene SAME E Eee racks ce ces aoe 55 84 89 49 66 66 409 12.02 |e = et see otal. 4° 327,. Jat Meee Seas 579 | 457 | 651 | 460 | 474 | 594 | 3,215 100. 00 3, 215 PLAT III. ONE-SPRAY METHOD. BL yey se A cada aim A De to 23 | SOME bl | PAA Sih 240 PRO 131 Bidet perce eo 236 | 323| 151| 172| 230| 134] 1,255 iain cep eee 26| 42| 28] 93| 24) 14] 157 i ae ae ee ete 285 | 397 | 193 | 213) 287) 168 | 1,543 | | | PLAT IV. UNSPRAYED. OE 2 RARE pee See Saree 1,039 |1,107 |1,338 |1,629 |1,280 |1,400 | 7,793 60. 33) [at .c eed Side: sJysctest 202-8 "415 | 493 | 557 | '662 | '499 | 530 3, 156 24. a3 ose semen SL SHHS SSBB BRntAS SaGeinn Osan Aree 315 | 290} 337] 418] 293] 315] 1,968 UGE.) | Heeenee bie Motel x. soe eo. < Sesace gos nec 59 |1, 890 see ( 709 |2,072 |2,245 | 12,917 100. 00 12,917 ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 107 In this experiment a slightly smaller percentage of larve entered at the calyx end of the apple on the lime-sulphur demonstration plat than on the one-spray plat, the percentages being 6.70 and 8.49, respectively. As will be noted under the above discussion of wormi- ness of the apples, a coarse-spray nozzle and a high pressure were used for all applications on all the sprayed plats. Such treatment would therefore be expected to result in a lower percentage of larve entering at the calyx end on the demonstration plat than if a mist spray had been used, as was done in the foregoing experiments. The total number of larve on Plats I, IJ, III, and IV are, respectively, 970, 3,215, 1,543, and 12,917. In protecting the calyx end of the apple there is shown a difference between the two treatments of 1.02 per cent in favor of the demon- stration, which is a greater difference than occurred in any of the other experiments. This result is probably largely due to the use of coarse-spray nozzles on all sprayed plats as mentioned above. The demonstration treatment saved a total of 95.28 per cent of the crop, which was 11.11 per cent more than that saved by the one-spray treatment. The efficiency of the one-spray and demonstration treatments in preventing worminess is shown in condensed form in Table XVIII. Tasle XVIII.—Efficiency of the demonstration and one-spray treatments against the codling moth as shown by the percentage of wormy apples. Wichita, Kans., 1911. Percentage of wormy apples. Total number Total Plat No. = _| number A of wormy of apples Calyx. Side. Stem. Total. apples. fe Pemonstration. 6.0 -0-'s cc. c- coe | 0.32 4.11 0.29 4.72 970 20,545 TII. One-spray...-... tse eos), 1.34 12.88 1.61 15.83 1,543 9,745 MV MS DLaVOO «sock. aan he ons 42.10 17.05 10. 64 69.79 12,917 18, 506 SUMMARY OF RESULTS. The percentages of fruit free from codling moth and plum curculio injury on the demonstration, one-spray, and unsprayed plats from the several localities are given for comparison in Table XIX. The average percentage of fruit free from codling-moth injury for the four orchards gives for the demonstration treatment 96.72 per cent as against 90.76 per cent for the one-spray method, a gain of 5.96 per cent in favor of the demonstration. The average percentage of fruit free from this insect on the unsprayed plats was 52.70, making a gain in favor of the demonstration plats over the unsprayed plats of 44.02 per cent. 108 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TasLe XIX.—Percentages of fruit free from injury by the codling moth and plum cur- culio on one-spray, demonstration, and unsprayed plats in Virginia, Michigan, Delaware, and Kansas, in 1910 and 1911. Codling moth. Plum curculio. Locality. Demon- One- Un- Demon- One- Un- stration. | spray. | sprayed. | stration.| spray. | sprayed. Fishersvilles Viaw.. 424. - das) o22 ese kee t= 99. 42 99.01 84. 49 94.72 94.37 90. 38 WOMnVile, Miche si se sscce a cate ee 92.91 87.05 D278) | Lateoaosce loess aoe eae eee Caniden, “Dek --a)shsencetee ee saree see 99.27 92.83 43.40 90.37 85.69 65.13 Wichita, Kans) cect sc ecenccen ace tee ce 95. 28 84.16 SOL20 se | Sabscehc | beemceet ee eee Average of four localities: = <5. 22 ss.-.25 2-22 96. 72 90. 76 52.70 92.54 90. 03 77.75 In Table XX is given a summary of the results of the one-spray experiments carried out by this bureau in 1909 (Bul. 80, Part VII, Revised) for the purpose of comparison with the foregoing results of the 1910 and 1911 experiments (Table XIX). TaBLE XX .—Percentages of fruit free from injury by the codling moth and plum curculio on demonstration, one-spray, and unsprayed plats in Arkansas, Virginia, and Michigan in 1909. Codling moth. Plum curculio. Locality. Demon- One- Un- Demon- One- Un- stration. | spray. | sprayed. | stration.| spray. | sprayed. Siloam Springs, “Ark... = -/2.¢<-s2-2022 555 98. 12 92.76 66.74 82.88 86.34 8.85 Crozet Wie ensued aoee sce nese eeeeceee ee 94.13 84. 07 53. 02 86. 89 73.93 54. 02 Mount Jackson; .Va..2-....= -eeese-eesteees 92.74 91.68 54. 00 40.82 57.90 27.23 Sameniick)) Michie. tc e cme e ee ieee eee 97. 66 93. 61 77.79 98. 77 97.54 87. 42 Average of four localities..........-. 96. 57 91.46 65.14 83.37 77.10 49.17 Incomparing Tables XTX and XX it will be seen that for the two sets of experiments the average percentages of fruit free from codling- moth injury on the sprayed plats were practically the same, while on the unsprayed plats the fruit was considerably less infested with this insect in 1909 than in 1910 and 1911. The average percentage of fruit free from this insect for the demonstration treatment in 1909 was 96.57 per cent as against 96.72 per cent in 1910 and 1911, a dif- ference of only 0.15 per cent. In the case of the one-spray treatment there was a difference of only 0.70 per cent in the average percentages of fruit free from codling-moth injury. Table XXI shows the total efficiency and the protection afforded. to each of the different parts of the apple by the treatments for the four orchards. It will be seen from the average of the four localities that nearly 60 per cent of the total larve on the unsprayed plats entered through the calyx, while on the sprayed plats 83 per cent of the worms entered the fruit by way of the side, showing that the poison in the calyx is much more efficient than that on the side of the fruit. ONE-SPRAY METHOD FOR CODLING MOTH, ETC. 109 The averages of the percentages of apples wormy at the calyx on the demonstration and the one-spray treatments are practically the same, there being a difference of only 0.3 per cent in favor of the demonstration treatment. The one-spray treatment was about one- third less effective in preventing side entrance than the demonstration treatment. Both methods were effective in reducing entrance at the stem end, the demonstration slightly more so than the one-spray. TABLE X XI.—Efficiency of the demonstration and one-spray treatments against the codling moth as shown by the percentages of wormy apples, Virginia, 1910, Michigan, Delaware, and Kansas, 1911. Percentage of wormy apples. Calyx Side Stem Total Locality. —eeeeeeEEeEeEeEeEeex——eE——eEeEeEEeeEeEeEeEeEeEeEE—E—E—E——————EEE——E——————— Dem- Dem- Dem- Dem- on- | One- pee) on- | One- Ane _| on- | One- we on- | One- pleas 4 stra- |spray.|SP™Y-| stra- | spray.| SP!"9"| stra- | spray.| SP™Y"| stra- | spray. | SP™@Y h ed . ’ : ed : ed tion. tion. * | tion. * | tion Fishersville, Va....| 0.19} 0.13 | 9.89 | 0.26 0.54] 2.53] 0.12] 0.31] 3.07 | 0.57 -98 | 15.49 Fennville, Mich.!...} .96 .86 | 25.62 | 5.98 | 11.64] 17.95} .14 44] 3.69 | 7.08 | 12.94] 47.26 Camden, Del....... -03 -36 | 31.67 | .62] 5.96] 18.78} .08 84) 6.15 | ..73.] +7.16 | 56.60 Wichita, Kans..... -32 | 1.34 | 42.10 | 4.11 | 12.88 | 17.05} .29] 1.61 | 10.64 | 4.72 | 15.83 | 69.79 Average.....- -37 -67 | 27.32 | 2.74 | 7.75 | 14.08 | .16 -80 | 5.89] 3.27] 9.23] 47.28 1 The figures under calyx, side, and stem for Fennvyille are based on the number of entrance holes instead of the number of apples entered. For the purpose of comparing the results of the experiments con- ducted in 1910 and 1911 with those conducted in 1909, as to the efficiency of the two methods of treatment as shown by the per- centages of wormy apples, Table XXII is presented. This table shows that the results in the two sets of experiments were practically the same as to protection of the calyx and stem ends of the apple from codling-moth infestation. The one-spray method was less effective in preventing side entrance in 1910-11 than in 1909, TABLE XXII.—/ ficiency of the demonstration and one-spray treatments against the cod- ling moth as shown by the percentages of wormy apples. Results of experiments in 1909 compared with those in 1910-11. Percentage of wormy apples. Calyx. Side. Stem. Total. Years. Dem- Dem- Dem- Dem- on- | One- Baas _| on- | One- a _| on- | One- tales | on- | One- Phe p stra- | spray. |°P9 ¥"| stra- | spray.| S209") stra- |spray. gh Y*) stra- | spray.| SP6 y tion. * | tion. * | tion. tion. ‘ 1900 oes ett so s2% 0.57 | 0.68 | 23.85 | 2.87] 7.64] 8.92] 0.18] 0.59]. 2.21 | 3.42] 8.55] 34.86 UU a eeicee ene -37 -67 | 27.32 | 2.74 | 7.75 | 14.08 . 16 -80 | 5.89] 3.27] 9.23] 47.28 110 DECIDUOUS FRUIT INSECTS AND INSECTICIDES, CONCLUSIONS. The results of experiments reported in the present paper corrobo- rate those earlier obtained by the bureau (Bul. 80, Pt. VII, p. 146) as to the efficiency of the one-spray method in controlling the codling moth and plum curculio. Bringing together the results of all of the tests which represent several seasons and varied conditions, it is found that the average of the percentages of sound fruit from a single spraying is 90.64 as compared with 96.19, the average of the percentages of sound fruit on the demonstration plats receiving from three to five applications. The unsprayed plats’ show an average of 57.79 per cent of fruit free from codling-moth injury. The variation in percentage of sound fruit is considerably greater with plats receiv- ing the single application than where the demonstration treatment was given, indicating, perhaps, a less degree of insurance from injury, especially under unusual seasonal conditions, as in case of injury of fruit by hail, etc., as occurred in Virginia during 1909. For the entire period the range in percentage of sound fruit on the demon- stration plat is from 92.91 (Michigan, 1911) to 99.42 (Virginia, 1910) and on the one-spray the range is from 84.07 per cent (Virginia, 1909) to 99.01 per cent (Virginia, 1910). In Prof. Gossard’s work in Ohio (Bul. 191, Ohio Agr. Exp. Sta.) a single spraying resulted im 91.60 per cent of sound fruit as compared with 45.80 per cent from unsprayed trees. In West Vir- ginia, Rumsey (Bul. 127, W. Va. Univ. Agr. Exp. Sta.) obtained by the one-spray method 97.40 per cent of fruit free from codling moth, as compared with 96.7 per cent sound fruit from four applications, In these tests the unsprayed trees showed 65.9 per cent only of sound fruit. Dr. Felt’s very valuable data obtained in New York State (Journ. Econ. Ent., Vol. V, p. 153, 1912), and covering three years of experi- mental work, shows for the entire period for plats receiving a single application 97.35 per cent of sound fruit; for plats receiving three applications 99.22 per cent of fruit free from worms as compared with 79.05 per cent of sound fruit on unsprayed trees. The above data, while obtained under rather variable conditions of experiment, establish beyond doubt that a single thorough appli- cation of an arsenate-of-lead spray at once after the falling of the petals will protect from codling-moth injury a large percentage of the crop, though not quite so high a percentage as by several applications designed to protect the fruit during the entire season. While the information as regards the plum curculio is not so full as desirable, it also appears that this insect is controlled by the single thorough treatment practically as well as by the usual three or four applications. Thus the six orchards where data were obtained by ONE-SPRAY METHOD FOR CODLING MOTH, ETC. yes BL the bureau on the curculio give an average percentage (average of percentages) of fruit free from injury on the one-spray plat of 82.62 as compared with 82.40 per cent of sound fruit on plats receiving the demonstration treatment. The percentage of sound fruit on the unsprayed trees was 55.50. Results obtained by Rumsey (I. c.) fully substantiate the foregoing. In his work a single spraying gave 87.5 per cent of crop free from injury as compared with 86.1 per cent of sound fruit on the plat receiving four applications, the check plat showing 67.9 per cent of uninjured fruit. In the case of the curculio the degree of protection afforded by spraying varies much more widely than for the codling moth, depending upon the abundance of the insects and the quantity of fruit present on the trees, as may be seen by reference to the tables on the subject in the foregoing pages and in the previous report (Bul. 80, Pt. VII). It would therefore appear from the foregoing that for the control of the codling moth and plum curculio under eastern conditions, a single thorough spraying is about as efficient as a schedule of treat- ment requiring three or more applications; were these the only troubles to be considered, the orchardist would hardly be justified in making additional applications. The reader should bear in mind, however, that in the experimental work reported applications have been made with an unusual degree of thoroughness. It will be evident that the value of a single spray- ing depends entirely on the extent to which the calyx cups of the fruit are filled with the poison. Perfect spraying in this regard should prevent all calyx entrance of fruit by the larve. As a matter of fact, in our plats sprayed most thoroughly we have not been able entirely to prevent calyx entrances, though such a degree of thoroughness has been obtained, as reported by other experimenters in the Western States. The point can not be too strongly emphasized that thorough- ness is the keynote in obtaining satisfactory results from the one- spray method. The necessity of filling the inner calyx cup with poison, as insisted upon by western entomologists, and the employment of a nozzle throwing a coarse spray, as the Bordeaux, has not been, on the whole, confirmed under eastern conditions. It appears that as good results follow the use of nozzles throwing a fine spray as where coarse nozzles are used. It is also clear that under our conditions there is no necessity to fill the inner calyx cup to con- trol the codling moth successfully, and indeed this is prevented by the stamen bars which remain turgid and shield the cavity below, even after the calyx lobes are nearly closed. There can be no ques- tion of the desirability of high pressure in spraying (175 to 250 pounds), and most orchardists appreciate this fact. The practical 112 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. utility of the one-spray method under eastern conditions is greatly lessened on account of the necessity in most regions of giving orchards additional applications of fungicides for the prevention of such dis- eases as apple scab, bitter rot, apple blotch, sooty blotch, ete. In regions where bitter rot and apple blotch are not troublesome and in the case of varieties little susceptible to apple scab, the single appli- cation would be most likely to have value, and orchardists thus situ- ated should determine the applicability of the method under their respective conditions. Where additional sprayings are necessary for fungous diseases, an arsenical should be added, as the additional cost is slight. One very important fact has been developed as a result of these studies, namely, the importance of great thoroughness in spraying after the falling of the petals. While this has been insisted on by entomologists for many years, yet the great extent to which the cod- ling moth may be controlled by this one treatment has not been appre- ciated. The aim should be to poison the calyx cup of each and every apple on the tree, irrespective of whether subsequent treatments are to be given. Imperfect spraying at this time can not be remedied by any number of later applications, ee COPIES of this publication may be procured from the SUPERINTEND- ENT OF DOCUMENTS, Government Printing Office, Washington, D. C., at 5 cents per copy a U - DIV. U.SSECT: U. S DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY—BULLETIN No. 115, Part III. L. O. HOWARD, Entomologist and Chief of Bureau. PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. LIFE HISTORY OF THE CODLING MOTH IN THE SANTA CLARA VALLEY OF CALIFORNIA. BY P. R. JONES anp W. M. DAVIDSON, Entomological Assistants, Deciduous Fruit Insect Investigations. IssuEp JANUARY 18, 1913. WASHINGTON: GOVERNMENT PRINTING OFFICE, 1913, BUREAU OF ENTOMOLOGY. L. O. Howarp, Entomologist and Chief of Bureau. C. L. Martarr, Entomologist and Acting Chief in Absence of Chief. R. S. Currron, Executive Assistant. ‘ W. F. Taster, Chief Clerk. I’, H. CurrrenpEn, in charge of truck crop and stored product insect investigations. A. D. Horxrys, in charge of forest insect investigations. W. D. Hunter, in charge of southern field crop insect investigations. F. M. WessteEr, in charge of cereal and forage insect investigations. A. L. QuaIntTANcE, in charge of deciduous fruit insect investigations. E. F. Putiups, in charge of bee culture. I). M. Rogers, in charge of preventing spread of moths, field work. Rouia P. Currtz, in charge of editorial work. MABEL Cotcorp, in charge of library. Decipuovus Fruit INsEct INVESTIGATIONS. A. L. QUAINTANCE, in charge. Frep Jounson, P. R. Jones,!} F. E. Brooxs, A. G. Hammar, E. W. Scort, R. L. Nouaaret, R. A. Cusuman, L. L. Scorr, J. B. Gin, A. C. BAKER, W. M. Davip- son, E. B. Buaxestez, W. B. Woop, E. H. Srecter, F. L. Stanton, entomological assistants. J. F. Zrmer, W. 8. Assort, W. H. Six, entomological assistants, employed in enforcement of insecticide act, 1910. 1 Resigned. CONTENTS “END Ta 1 Cin st Oe Oe anak ryt See meee ee eee rN. ee Seamitaninigny aiudies: Of 19005). 2... . - Benes fb... s actin dae bead wakes SErener DEOOU Gr PUP: <.. 2 -~ ants o> - Seer oats be ccanceis 2. geet SY - Bere TEOOrOL GUNS ran a, ., a ede Be ee Sng aun ne satel ss = L055), Pe i ar ermeen .- SeRe ay eee en Bere meee AEH RGOG) OL CRORE: 2 <2. 2 ie -, Se ae ocee ais attests ork E- = Porter teme MERE VE... 5c. 2. . Se eh Se Ee ee Poms DEOte OL UPS. .:..2-.... see een dd Senter Ya sets f 2 Tie ORTIGUNEY 32. 75. . eee es oo en ee ee Pete OH CMUERPCNICOS «3... =. - . ae oats ae een bine e «eg ime Ch pn pAHON 2 = ota st eae a 3 es eee ha ad weal emetr Oreprine DUDAN SAE -*. Neos fe et ats aah es 23 ae Comparative length of pupal periods of male and female larvee........ Srapipear ciate CUMCNOME ts oe 2. Se ae ne ne cetayee tre eee See Stine pinta Mino nies "=. ree os 2s See. Rees ral erg ee Time of emergence of moths in spring. ...........-+-.25.--5-+---0.4--- Time of emergence of moths in spring versus time wintering larvze leave the fruit the preceding year. . ..... 2-2 -2s4cbesedsmnenmee-- Relative percentage of larvee wintering from band material and per- centage emerging as first-brood moths the year larve were collected. . Time during the day when moths emerged. ............-..--------- GALES V2 WEST 01 a oh ee a es oe A a Le EE 02s ce ee a Se Agee ae SSeS Sk SE eo PSCC LL nel nay ee 2 che Ph eae ee reer a Pe PPMP AtOHRDURNNI tse ner. See SS S88 As oo i 8 Wee eee RSE ROGUE On lar Vsentrae tas etm. Slee te COONS: IVS Nab tne eee ie Wemeven Wackness errr.) tee he 0 aa eee ee a Number of larvee developing in one apple ...................--- Feriodjof feedinpoflarvesin fruit... ..2..-<. ..3.. 34a $e shoes Larval Life: Ti Tie ROCQOM ic. omens Seiten sy see qauaten Saeen RATE DERGU! OF PUNE. «Sno dae’. sla POE Bn Baten Nee eat AOE RA aed Eine GF PUpPalOn. <2 2.725... - -eBE Soap SUL cick ed a Se eae Length of first-brood pupal stagess. 3.02. «32: - Qed ve daesoues ox erat PrOSMAOT MONG es ¢ ~ sito, —- digs ahtane\enic piesa tie srayeticpa tics Lig) bt owe: Re OROMGrARN CE os ot... Meee ad nae a dang Seer Bata Ao Sir IGesiGn DONO 252.) .2. : . Beth $y tee iens, enacting fC ae hile Eecle OF LTHh PENSTAUION. ... . ee. 2.22.) u,ce agedtesines seers MPGOU PENG TEUOG 2 een nso.) 2. eee ben on OE te ee Serene EG Ol CURE a se oA. Ce en oa LAE Sy ete PMCR AON DEMO oo. 0 occ: - . see oo. bee done olerapes eociisa Ve we PResGHNIE DRQOU/GE IAT VER os ac. a: ~ Seep ears = x te aln ox wpaafoltth da aeisemeein’ EEO PU ENIDU <2 cea oc. 4 a tee nln ociady eet hamaed aes ime ot leaving the trib for Wilters< <<<... -< <2o-0600-----428 Review of liie-history work Of 1910... 20... ... 5. 2 eae nncceeone-tse- ‘IV DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Page Seasonal-history studies for 1911..... eNO ne AS 58 RYH a ea, Pk Se 143 Spring brood of pups... : isco. 2.05 =. sepa aie ee Eee Ee ea sees ee 143 Time ‘of pupation ..\0...t2<28 ets eens see as eo ee 143 Second! series of latves. 62.5.'. -. . ee sue cee eae ee eee ~ “143 Temperature conditions: <32-- SR ee eee 146 Spring hrood..of-moths....<1 532.52. . Bees See eters: on eae oe aa eee 147 Time of emergence of moths in the spring. - sates wa terete as eee Time of emergence of moths in the ee versus the: ue. wintonne larvee leave the fruit the year before.........:.........-..-...-2.-- 148 Time during the day when moths emerged ...........-----.--------- 148 Peniodokewapostiaonss: > 2... Be eee oe ee eee 149 Longevity of spring brood of moths: +25... 222 22 so-so eee 149 Hitshipenetation-lee: sci ose. et. ee Ee See ec cee 2 toe 150 Pirstprood of espe. 2 222 Be See ee oe ee eee 150 Imneubation ‘period «2.2. <4 2: 5 Sars Bee eee Ae ee eee 150 Firstibrood-of larvae: 2202 cea ake eee ee Pee eee ee 151 Time of hatching Pye es ey eee eee 151 Number of larvee developing in each apple...........-.......--- 151 Hirst brood iof pups: 2: 55. OSS: Se ee one oe ee 152 Time of pupation and leneth of pupalstapes sm oes eee 5 eee 152 ‘Kirst'ibrood of mother 220. 2. eet eee ee ec oe ore alae ae ee eee 154 Time‘ olemergence: see. .-: See es hee pee ee ete ee ee 154 Oviposition! period <2 f2o.2.* . Ul eas chee Cree cee ere ee 154 Life cycle of first generation. ....... WD: tia iert aad = aia) le a a are ne 155 SOCOMG SENECA LGM seers. cu nee Gene Me naia nce tie sen kaw Cte Rema au nvaaarele 156 Second brood OF eepss 2-8 220 Saas sees eset ae cee Ses aa eee 156 Incubation period): - os... TN Oo. Paces cce ees See 156 Second brood of larve.......- Ns eee ba ees SLA NA 0s oh Soe 159 ‘Time: of hatching... eo ee eee Beet oe eee ce 159 Peoding period!- 2: <<: 5232 Aes 5 De Oe eee ee eta a ae 159 Time-of-leavine-truit for-winterings 2225222 2252422-0-- +--+ eee 160 Watiral enemies of-the codling mothe....222::228: pareve ee ee ee ee 160 Parasitic insee ta... ss2rren: i: 2es8sc.8 Be Sn5et tee ee ene eee 160 Predaceous insects.ic.c2a:! 232: Slates cc 2e2 32: Se eee, Bo ee eee 161 Band recordsof 1909 42 2 say acc. 53 s2 ere: 32 Shs ee Ce eee eee 161 ibsnd Tecords Of-191O ewe a3 24's ET Oa eae niece ee ee 162 Bancrecords of LOL. so secors ste see sce st ote cee Ee ee eee 163 First-brood emergence v. overwintering emergence, 191]............-.------- 164 Review of liie-history work: of 49VPet ots doer lo 2 oee a TEs ae ct eee eee 165 Conparison of life history’ mri910'and- 1911ee sores ve ate eee nee 165 Weather records for! 190919 Osean Gi alO i epee se mee see ee ee rete 166 Comparative life-history studies for the seasons 1909, 1910, and 1911........... 170 Control of the codling moth on pears and apples in the Santa Clara Valley.... 171 TheO?Toole pear orchard at-Alviso; Cale tit 7022+. te cee oe eee nee 172 Spravanp Operations snot 2 eee Bee ee se eee ee eee 173 Deacon OLMIS 2 sms oe Se Stats Aes ET OI NOR ta Oe 172 SeasomollOd this sd ssc} 20 2S EE RRS OR ao eee ae es cee anaes 175 The Northermapple orchard :- 22 = Sess 0g et ent 5 eee eae 177 Deason: OF MGs er Aaa reo no ARS eet eee Sele shies oe ate See 177 Conclusions from experiments 'in controle: <2: 52251002) J. hoon ces ee 179 PURI REY «vo sore arerwteare ute ten Pty ip ieielns b> ose cleinatsik lame Stem ene 2 tere area 180 Fia. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. PLES ERay ELON S. Diagram showing emergence of moths, derived from band-record RPeh Oy COMCGLEU- ID LUO oe asa = «cee mdase nisin nccic aon cia 6.6 ois sales ontae Diagram showing emergence of moths, derived from band-record Minchin comected Im TOOT 632. Ses eT beet ek OR Diagram showing time of pupation of spring brood of pup, 1910... -- Diagram showing emergence of first-brood moths for 1910. ........-.-- Diagram showing seasonal history of the codling moth during the PEPSI RO UC It SRR Ta OF ee See ee eer ae ene Diagram showing pupation of spring brood of larve, 1911..........-- Diagram showing emergence of moths; overwintering brood of 1911... Diagram showing first-brood pupa, 1911............ be S475 Diagram showing emergence of first-brood moths, 1911. = hn chee aeear! Diagram showing band record of 1909...............---------------- Diagram showing band record of 1910. . 02.606 odo. 25+ -c coe s gene 5. Diagram showing band record, Northern orchard, 1911. : Diagram showing seasonal history of the codling mth during: the season of 1911.. Vv ~u she mas 3 TH Be _?. iv abs | + cr : if ng ‘ farraiaae “aot saleouty (ane v is) : ; : P eee vigtunit ‘ “ pycitl A ld) (tegen) eae), |e 1A ae) ay in » UO WONs UAC ge ; , 4 dudb-serh galyrotla alicayi i l : >) eu fA sthiTs it * Mi : 4 : - ‘ At Tiwi hie _ es): ; ul tT oS i ae ‘ P ( . “ss . P a ' ' ; Witt (curva A 7 A “ x 7 é i {POT hiv ieee 7 . - 4 irs os 4% - U.S. D. A., B. E. Bul. 115, Part III. D. F. I. I., Issued January 18, 1913. PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. LIFE HISTORY OF THE CODLING MOTH IN THE SANTA CLARA VALLEY OF CALIFORNIA. By P. R. Jones and W. M. Davinson, Engaged in Deciduous Fruit Insect Investigations. INTRODUCTION. The codling moth in California presents so many differences in life history in comparison with that which has been learned in the East, as well as so many local conditions associated with each particu- lar valley in this State, that there has been felt the need of a more comprehensive study of its life history with the temperature condi- tions influencing the same. The data presented in this paper have been collected during the past three years, 1909, 1910, and 1911, only partial records being obtained for the first year but fairly complete notes for the latter two. The Santa Clara Valley is practically one large deciduous-fruit orchard from 60,000 to 70,000 acres in extent, lying between the Santa Cruz Range of mountains on the west and the Mount Hamilton Range on the east and extending from the San Francisco Bay just north of Alviso 50 to 60 miles south past the town of Gilroy. The valley varies in width from 5 to 20 miles. According to the United States Weather Bureau the average mean temperature for the whole year in this region is 58.1° F., com- piled from a record of 36 years. The annual mean precipitation for this time has been 14.79 inches, with practically all of the rain- fall in January, February, March, November, and December. It will thus be seen that the codling moth is influenced by a low dry mean temperature with little or no rainfall during the period it is attack- ing the fruit. The data for 1909 were gathered by Messrs. Dudley Moulton, for- merly of this bureau, and J. R. Horton of this bureau; that of 1910 and 1911 by Mr. F. L. Young, formerly of this bureau, and by both of the authors. Miss Emma Weber has contributed many life-history observations also during the years 1910 and 1911. 113 114 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. An attempt has been made to follow the plan of presentation as given by Messrs. Jenne and Hammar in their respective studies on the codling moth.! SEASONAL-HISTORY STUDIES OF 1909. SPRING BROOD OF PUPA. The record for this brood was made from larvee collected January 2 in the field from under the bark on apple trees and placed in sepa- rate vials for an individual pupation record. ‘Table I records the time of pupation, time of emergence, and length of pupal period. TaBLE I.—Spring brood of pupx. Length of the pupal stage for wintering larve col- lected in January, 1909, from banded trees. Date of— Date of— No. of Length|} No. of Length individ- of pupal||individ- of pupal ual. Pupa- Emer- | stage. ual. Pupa- Emer- | stage. tion. gence. tion. gence. : Days Days. 1} Feb. 20} Apr. 17 56 17 | Mar. 26] May 3 38 2) Mar, $45)55-do..- 48 18 | Mar. 27 dozz- =: 37 3H | sen OP ci bere lees 53 19 | Mar. 29} Apr. 28 30 4 | Mar.’ .5 |J..do... 52 20 |...do.....| May 3 35 5 | Mar. 8] Apr. 28 51 2Y eG Os =. <= |pe2dOsese- 35 6| Mar. 9] Apr. 26 48 22] Mar. 30} May 6 37 ie \ ee aoe Ee (oe 48 23] Apr. 1] May 1 30 8 /=--d0:...-| Apr: 28 50 24|...do.....| May 3 32 9) Mar. 11 |...do 48 25 |...do. Bails (eS 32 10 | Mar. 12] Apr. 29 48 26 |..-do. 1-002. 32 11 | Mar. 13 ay 1 49 Pil ee Loe eel [ames (he 32 12 | Mar. 15 |-May 3 49 28 | Apr. 6] May 10 34 13 | Mar. 23 |...do 41 29} Apr. 9| May 11 32 14} Mar. 24] Apr. 28 35 30} Apr. 12} May 4 22 2153) era Coe Al (Baro (0) 35 31 |...do May 17 35 16 do.....| May 1 38 Thus the pupal stage varied from 22 to 56 days, with an average of 40.22 days. The first pupation occurred February 20 and the last April 12, while the first adult emerged April 17 and the last May 17. The pupal period, therefore, occupied the time between February 20 and May 17, or 87 days. No record was kept with regard to the sexes of either larve or adults. Table II shows the variations in the length of the pupal stage and is a summary of Table I. TABLE II.—Spring brood of pupx. Variations in the length of the pupal stage as recorded in Table I. | Number Number ae Number Number of pupe.| P8Ys- || of pupe.| P®Ys- || ofpupe.| P8YS: | of pupe.| Dys- 1 22 5 35 4 48 1 52 2 30 2 37 2 49 2 53 5 32 2 38 1 50 1 56 1 34 1 41 1 51 This record is for only 31 pupz and is somewhat irregular. 1 Bull. 80, Pts. [and VI, and Bul. 115, Pt. I, Bur. Ent., U. S. Dept. Agr. CODLING MOTH IN SANTA CLARA VALLEY. 115 SPRING BROOD OF MOTHS. No record was taken of the adult emergence of the overwintering brood in 1909 other than that recorded in Table I for the pupal stage. FIRST GENERATION. FIRST BROOD OF EGGS. No record in 1909. FIRST BROOD OF LARV®. No record in 1909. FIRST BROOD OF PUP. Larve were collected at intervals in June, July, and August from banded trees and placed in vials for pupation in lots of varying numbers. Table III shows the pupal period for 182 individuals. Tn all 207 larvee pupated, but 25, or 12.08 per cent, perished before the adults issued. TaBLE III1.—Pupzx of the first brood. Length of the pupal stage from material collected in 1909 on banded trees. Date of— Date of— Num- Length || Num- as Length pea of of ber of of indi- pupal indi- pupal F Pupa- Emer- ie Pupa- Emer- vidual. hiovt gence stage. vidual. hari gence stage. 116 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLe III.—Pupz of the first brood. Length of the pupal stage from material collected in 1909 on banded trees— Continued. Num- Se Length Num- Feet Length berof) | SS —— of ‘ per Ol eee | ) OR 4 indi- pupa indi- pupa ; Pupa- Emer- : Pupa- Emer- vidual. niGri gence. stage. || vidual. Fert gence. stage. Days. Days. 75 | June 28 | July 17 19 129} Inly 6] July 26 20 16) 2005 =~-)]=2- Ore. 19 130) | 200.5. July 27 21 77 doles. a6 (eee 19 AST |e dOrecee July 28 22 78 dots: Gore25 19 132 |2eedoles ido:---4 22 79 doses. ls dol 19 133 | July 91] July 31 22 80 do. does 19 134 | July 10; July 29 19 81 do. dows 19 135 | July 13 | July 28 15 82 (Layee [eee dO: 3-6 19 136 == 2G02-22- July 31 18 83 Gose-—- July 19 21 137) |'S2dOnzes eee 18 84 do. Gos--.0 21 138) Seiden: Aug. 4 22 85 do... do:2 22 21 139 do.. Aug. 5 23 86 do.. doiec- 21 140 | July 14 |...do..... 22 87 doze. GOs sae 21 141 | July 22] Aug. 14 23 88 do. 3.24|44 Sdoss2. 21 142 | July 26) Aug. 17 22 89 doza2. dot 2s 21 143 | July 29 | Aug. 21 23 90 do.. sdoss.. 21 144 | July 13] July 31 18 Oiviies sO. 2 . 42 |g OE 21 145 |2..d0-3--- Aug. 3 21 92 f= dots. dots. 2 21 146 | July 14 do.2222 20 oR Gn eles G02 o- 21 VAT eee Gorn Aug. 4 21 94 dots. dos 21 148} July 15] Aug. 3 19 95 do22-- (6a 21 149 |...do.....] Aug. 4 20 G6)|eeadOse=- donee 21 GO) We saC le sa = 0.53: 20 97 Gole-e July 21 23 151 | July 16] Aug. 3 18 O8-|E2 43 36 do Tog 8) | eae 44 LOG) eee Mar. 16} Apr. 25 |.--..- 40 Sti et beee GOssee Lad Ones se )|b turers 44 107 Fp) i co Fo = ae 24002 23 40 38 ee Ose sue Apr. 21 é 42 108 (0) do:=--- sidoizsie 40 39 Q .do....-| Apr. 23 fe) 44 109} @ Gor tL Apr. 27 42 AONE PEs .do Apr. 24] ¢ 43 TNO) ee ee dovtue May *16)| 2.25 61 A). Mae ec edowe- = AMI Zo seer 44 lil é =dOsee = Apr. 27| ¢ 42 42| 3 20022 .\-5| eos. 3d 44 112 Q SQObeen = Apr. 26} Q 41 43 | oO Ato) a ||e aoa = d 44 113 J Zq0ss. = Apr. 25} o 40 44 2 = COs oni AS Pie 2: Q 42 114 Q do® dos. Anes Or Ae eadoes- 4 July 110) |22-do.2) oie 010% to |oandooee 7 July 11 | July 13 2 tiny ia 1 {July 20 2 +-doz Pad se-< 4)\.. do. Aulre ed Oaac 4 EdOe BE AO seat IVE aexeloy- 1| July 21 il Daly teed oe 5. 1G ee Gomer 1 et 20 : : Seeley se ido: July 14 By EA Broo tee fe hig Aiaty 21 1 ; y 20 3 doe ess. Gor.st: 6iea-doe. 6 (ry 1 3 uly 20 3 Edozc EEdoase 10}| td ok: 8 {ral 21 5 BRC Oe eGOaa- ZileeedOne 2} July 20 2 July 13 | July 15 6 | July 20 6] July 21 6 Eedoy- wo (ora Iiteadocn 2s BOO sae 2 e=dor PadOn- iipsadore 1a |e dose ae 1 .-do. == do2 3 es Olea Si Mlice cUO eee = 3 2edo= P=do- E5yf| bgt (Oe Sul eee Gd Onset 5 July, 14) |aedo-s2= PH eee Vey 2 ied O sen 2 eEdor July 16 2} July 21 30 pedo sgea. 2 _.do. . GO. 3 | July 20 Fee Ome 3 dor ..do. PIN eto koa 1G | eeedoneer 3 ..do. =-do- 2) July 21 2) ee edOee ae 2 ..do ea dor 2 |2..do. Ail ee eG Ome 2 = =d0): ..do. 1|...do. 1S AGORs.2 1 Dido iesndos=-ee 45 eeedols 14sleadoene 14 July 15 | July 17 APS. oleae 1 | July 23 1 July 16 auly 18 1 July 22 1 aloes 1 Whos se uly 24 July 17 Vly 19 2 \ruly 23 3 {yuly 26 9 SeCOS Ss sasa0Oe Biles ed0 ert. 5 ae a : July 24 1 July 19 | July 20 2 \sJuly 25 1 |}July 27 3 July 26 1 ie ; July 22 1| July 28 2 |fiuly 29 July 21 : pe A > |\July 30 3 : try 23 3 | July 29 3 Lae 31 1 Wess 22 5 |\ 7 |f--do.... 3 --d0.---\Fuly 24 9 |f--d0---- “NW yuly 31 4 July 23 8 Pity eae ze : \ do. ; it. do. rs July? 22)|35-d0s. 2% 6 | July 31 6] Aug. 1 6 ..do. ..do. il | beexeloyne ies doe 1 ..do. ..do. lal Same Keys = 1 ae i edo -do padOn ey aie. -doe Ace 3 1 fAug. 1 6 -2dor ..do. 10 |...do 10 }\Aug. 9 4 moo) heal ar(0 Looe 7 WPS etoloye 1| Aug. 1 2 July 23 | July 25 13 | Aug. 1 15 | Aug. 3 13 Peon ndOs en ie edo.e.s! Seimeedos 8 dole -fik* don Syicedol ss S| dort 8 SAGO se Sal ye nOO a 28 2 Hieeisy; io 5 dOr. 3 z July 26 24 ug. } ; July 24 {rary 27 2| Aug. 3 10 \Aug. 4 26 d July 26 13 | Aug. 2 12) | e2does.e 12 ~ie boos Aug. 1 1s AE: 3 2| Aug. 5 2 d July 26 8| Aug. 2 2| Aug. 4 1 eee ai ali OR 6 Aug, L Aug. 5 2 July 26 17 {i ug. 2 Res (ogee 3 Aug. 3 5 |pAug. 4 9 {ray 28 4 Aug. 4 : s : 1 Aug. 3 Aug. July 25 |...do. Ibias. Ha 12| Aug. 6 7 ~ |fAug. 3 2) Aug. 5 --do. --do. 6 ree 4 6| Aug. 6 2 © ro _ 10 TaBLE XXIV.—Second-brood eggs. CODLING MOTH IN SANTA CLARA VALLEY. Continued. Red ring. Black spot. Hatched. Num- Sager Date of ~ = Length ber of | ber of | deposi- | phate of | Num- | Date of | Num- Num- | °f 688 apple. | eggs. tion. | appear- | ber of | appear- | berof | Date. | ber of | Stage ance. eggs. ance. eggs eggs } ° . Days. \sAug. 3 14] Aug. 5 11 ll 49 23 | July 25 | July 28 15 Aug. 4 9 Aug. 6 9 12 Aug. 3 3| Aug. 5 2 10 50 10 | July 26 |..-do.... 9 \Aug. 4 7| Aug. 6 61 1 ug. 5 9 10 51 a ae Oe 28 Wer 3 Aug. 6 3] a Z } 2 g- ae 7 1 12 “ O05 .ce >| Aug. 4 7 ug. 5 5 10 52 16 |...do...- July 29 8| Aug. 5 4| Aug. 7 rb ul 53 u d July 28 4, Aug. 4 5; Aug. 5 5 10 SoCs Ttly 620 6] Aug. 5 1} Aug. 7 6 12 os Aug. 4 1} Aug. 6 tL) 11 54 3 |.--do....) July 28 3 Wee 5 a Aug. 7 2 | 12 55 a ldo mdo. 2) 2 wdoeoce 3 soa: 4 a eae e 5 Wau. 6 3. pli 56 10) |zezdoe.- Bdo=. Aug. 5 2 Aug. 7 4 12 ss do 7 DiGOer. 2 4 ll 57] 11 | July 27 | July 29 va\ertias 4 yAug. 8 5) Mia oe UE: Aug. 9 3 13 58 2}...do....| Aug. 5 1 | eee ee 5 eee (Tee arya: || cee) Aug. 7 2 1] 59 4]...do....| July 28 merce g fats: 8 1| 12 t : Aug. 10 1 i yol4 60 7|.--do....|---0.-.2) 996 {ane 8 9 \Aug. 7 6; 11 61 3.| July 28 | Aug. 1 |) Auge 7 3| Aug. 9 3 12 62 Si eedoe 4; > do... 4] Aug. 5 La aaeeeaes aks ae cE 2 63 1 --do....}-do. tT) gee aS eres coe ee aa (A See | re rg 64 2 20nd vay. a / \aug. 7 2| Aug. 9 2, 1. 65 2| July 29 Sag 2 Pesos Ze eaGeren 2 11 aoe. ug. 6 5 lAug. 10 12 |) 66 14 | July 30 {ie 2 6| Aug. 9 Site ees Aug. 5 4| Aug. 10 y [Aus 1 1) 2 ge 5| Aug. 8 2 67 6 40... VA 2 1| Aug. 9 4 \Aug 10 i ~ tes 3 68 7 do...) ug 3 1 |}Aug. 8 7. eeedoseee 7 11 Aug. 4 3 ? ,, |fAug. 2 3 Aug. 11 8 11 69 July 31 Wee 3 6 \aug. 9 9 tae 12 1 12 70 TeeOOse oe moe 2 OMe . -GOmeee 7 | Aug. 11 7 1l £ ..do. 8 Wdocss 19 il “1 20 aioe? Hane. 3 12 \ do. : 20 dine, 12 1 12 : Aug. 11 1 10 72 6) Anesth |. -do...e 5 | Aug. 10 6 vers 7 ; is 73 aeLerlOSwAH gue ath yt g |- dams sek doeee OR ae Na ~ Seon. i ig) Hae SS | (See RI eek eh MES |S oy v4 4| Aug. 2 (Aug 5 S|, CCaReR ee Tes Mt a Brome ene -, ug. 4 12 \\, ; 75 16:|) “dowd Aug. 5 2 \aug. ul 16 | Aug. 13 161) oe = ug. 4 6 77 17 |...do:... Aue 5 4 ea 4 fie 14 i ? = ea: 16 ug. dds be 18] Aug. 3 {ine 2 |) does 6 | Aug. 15 4) 12 79 HM d Aug. 5 4)| .. ome 8| Aug 14 7 11 A eis’: Hea 0a 1) Aug. 13 ay aves 4 = Aug. 12 3 ug. 14 1 80 9 |-.-do....) Aug. 5 9 Wes 1B 6| Aug. 15 4 12 81 4| Aug. 4] Aug. 6 4} Aug. 14 4]...do. 4 11 82 nih) acu le be Oss oct 3 | Aug. 13 ee (ay 3 11 83 4) Ange S|) «00.2.2. i | does. 3} Aug. 16 4 11 84 193i: dese. Aug. 7 5 o 14 a 2 dObes2 73 19 11 ati Fee i 9 Osea 4 » | 85 Ly Oss es Aug. 8 1| Aug. 15 1 oe Lees - ee sOOla te 27 | =o CObstu< 86 35 Aug. 6 Aug. ll 5 | ea Sees F Hane 17 . m : Sdoveee Aug. 16 87 2 |..-do..... Aug. 8 2 \Aug. 16 1| Aug. 17 1) Bat: eee 9} Aug. 15 10} Aug. 16 88 13 |-.-d0....-1) Aug. “0 4| Aug. 16 3, Aug. 17 By) id 137 Incubation period of eggs laid in rearing cages— 138 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Taste XXIV.—Second-brood eggs. Incubation period of eggs laid in rearing cages— _ Continued. Red ring. Black spot. Hatched. ‘ —___+_____—| Length Num- Naw Date a Pile ber of | ber o epos Date of | Num- | Date of | Num- Num- Sines apple. | eggs. tion. | appear- | ber of | appear- | ber of | Date. | ber of : ance, eggs. ance. eggs. eggs. Days Aug. 9 3 i‘ Aug. 17 3| 10 89 46| Aug. 7 {ane 10 2 |v 16 46 tate a ai Aug. 9 20 Shs Tete & 24 Aug. 17 3 10 90 28°}. ..do-....- Aug. 10 4 Aug. 17 4 Aug. 18 19 11 Aug. 11 z i Aug. 19 6 12 Aug. 9 Aug. 16 fi 91 19;\|) adoses {au 10 z “Aue. 7 6 \ aug. 18 13:(() an ug. Pe d0sc.5 2 92 3 |...do.....| Aug. 10 1 he a3 a fe dong: Pueeent pas [ 4] Aug. 20] 24{ 1 93 24] Aug. 9 face 5 ‘ip Pores a ug 94 (© at aso ala do..... OH ae 19 5 \...do iff gal Aug. 1 3 95] 886 |. 2dowwi Al do... 23 HAUS: 19 ghia. 35; ll 96 6 |...do.. udoteet 3 | Aug. 18 6 hndauc.. 6} 97 10 |...do.. Go-sest Bele edosseee 10 Boe aeee iM it 98 4] Aug. 10| Aug. 13 4| Aug. 19 4taog. ot alice 4|...d d 2 |...do a ave: 20 ay ae 99 2200s22 BGOssaee eee OO. ace ‘Aug. 21 1 Aug. 20 1 10 100 a yal Ma Coe ait. dos. 5 Wee pi ra ie 101 171) dota’. < do..... menor. oe 13 |. -do..... 4) ul ug. 102 5| Aug. 11 | Aug. 14 2| Aug. 21 5 Aue, 53 3 12 ‘Aug. 22 3 103 Gb] o- chose os2tieedoecekh 9i-|2.tdo.. ee 9 AGE 53 13 » 22 6 |) Mit 104 Bildeedos.s4\esidor 26 Bi pda... 23. 8 Hane Ss Sal bees edo. 4 2| Aug. 22 Fab Odea 105 AN 8 lO aceg MRAOs.o 8 3 { ie: 3 a | ae os ate: Aug. 21 3 107 4| Aug. 12] Aug. 15 4 Cae cs ; \ do at a 108 17 do 7200! soe 10 | Aug. 21 ip lene QOUsee 17 11 109 5 dos. Aug. 16 4 eae 3 Ee ee 3 11 ug. 110 8| Aug. 13 |...do..... 6 Vaae. a 2 \..do ales, 8} 10 111 2 dose Aug. 15 1 Bue: 22 - oe 24 a 112 6 dow. Aug. 17 6 hice a 9 Aug. “35 F 12 113 27 | Aug. 14 |...do..... Dre 200. /4-b 27 ave. rs ihaear Aug. 24} 22| 10 114 80’ |. €duas st |en-do-. 2p silt. do.. 26 30 ere ca ah oan ‘Aug. 24 22| 10 115 28 |) -2donss. Peder. 2 onple Sdo.:!.. 28 ee = F rt 116 49 | Aug. 15 |..-do..... 49 | Aug. 24 49 |...do..... 48 10 117 51 ae aeake 520-225 51 co oars 3 51 aa me. 5. a 4 118 37) ib ndon es cdane amb -£dos.... 37 {Ge 38° ' =i Aug. 18 26 doe. 2: TON Gee doLe see 56 10 Aug. 18 30 | Aug ug. 26 120 60 |...do..... Aug. 19 30 | Aug. 25 31 | Aug. 27 30/11 ; Aug. 18 20 | Aug. 24 40 | Aug. 26 44| 10 121 46 |..-do..... (Aug 19 26 | Aug. 25 6 | Aug. 27 2 . SplCLOwneat AERO OTSA G oO ao Loses, ‘ 122 11 | Aug. 17 Likue 21 6} Aug. 26 1 | Aug: 28 f| 2 Aug. 19 10 | Aug. 25 Aug. 2 5 “ 23 |...do..... {aug 21 12| Aug. 26 12| Aug. 28 S| Sear ‘ hug 19 8 | Aug. 25 8} Aug. 27 12 10 ve 19 ).-.do...--'Aug. 21 11) Aug. 26 IL | Aug. 28 ra | Resa Aug. 20 e002 = wate 12 125 3| Aug. 18 { AE. 21 2| Kus. 3 Aug. 30 3 ug. 20 ug. 126 4 |...do..... ate: 21 2 Aus. 27 4 pais : % Aug. 20 P| aet ( Ses A é ug. a 4 |. s2dosss HAUS 3 2 | Aug. 28 1 | Aug. 30 1) ig ug. 2/ 11 128 11 | Aug. 19|...do..... il igre! ofl Ppt oc 11 CODLING MOTH IN SANTA CLARA VALLEY. 139 TaBLE XXIV.—Second-brood eggs. Incubation period of eggs laid in rearing cages— Continued. ; Red ring. Black spot. | Hatched. Aha eee pee of - : Length oe cue posl- | Date of | Num- | Date of | Num- Num- | of ess apple. | eggs. tion appear- | ber of | appear- | berof | Date. | ber of | Stase- ance. eggs. ance. eggs. eggs. Days. pus: at 3 | joe : Lang 30 7 i ug. 2: : ug. 3 i 129 12 | Aug. 20 {ite 23 2 ‘Aug. 29 8 Aug. 31 5 11 Aug. 5 Aug. 23 5 | Aug. 28 2) Aug. 30 10 10 100i Ge AB sede ie, 4 3 | Aug. 29 14 | Aug. 31 Our il 131 8 | Aug. 21 aon t } Aug. 30 8 | Sept. 1 8 il 132 7 does. ‘Aug. 24 2 ---do ee i ae ee Tl ee it 1) <-CLO Gea ‘ 133 9 | Aug. 22 |...do..... 5 ee oF i \ do..... 9] «40 a 2 eer --t a0 chee 3 Aug, at 5 Rolo sere 5 10 35 SOGeo eon Ose a 1 ug. 3 1 | Sept. 2 1 11 136 7| Aug. 23 | Aug. 25 4 {sep \ sdocss. S| eenio Aug. 24 + eedOree... 15 10 137 19\|_. das, .<- bes a = \ do i 2 19 sept: i i] Aug. 25 3 ’ Ne ae 10 138 By. bie 2) s b doncth: 8 Sept. 3 3 ul (Aue! 26 3 I ise ta 2 12 Sept. 2 2 |{--d0----- (| ll 139 9 | Aug. 24 |...do..... 3 {Sept, z 2 Sept. 5 1] 2 zi ept. 6 13 Sept. 2 9 | Sept. 4 9 11 140 11 |...do.. do..... 10 Sept. 3 2| Sept. 5 3 a 141 63 BAR: oe eOOseeee 1 eee 2 3 | Sept. 4 3 11 ept. 3 4| Sept. 5 2 ul 142 6 | Aug. 25} Aug. 28 4 {Sept, | 3 Sent ; 2) i 143 PAN Sars OE Gol.22< 2 ee 3 2 {een 6 1 12 144 wae Sted do..... 3 \eepinee ci Max. ba A aaa 145 4| Aug. 26 | Aug. 29 1 Heept. 6 elaeeee at a} ae 146 Bt. dov.. 21-0 -do..-2: 10 {Sent, : a does a| 12 147 1d | ats Cee Be Goxe-= 8| Sept. 5 191 ||S2d0=---~ 17 12 148 11 | Aug. 27 | Aug. 30 2 | Sept. .6 11 | Sept. 8 11 12 149 Gr doz. Doles. ayy Pc ee GuleaeGO=eo. 6 6 12 us ; Aue: 28 an a 2 ee if i papi, 9 5 12 2005203 One DA SO ec 7a ea 6 Cee 4 12 152 12 | Aug. 29| Aug. 31 3 {pent, 4 a aor 4 a. a 153 Sl orde | KLdB.c: 7 {Bept, 4 3 |\sept 10 at) St ...do. 2 | Sept. 11 12 12 154 93 | Aug. 30 | Sept. 2 19 Isnt a a Seb 12 2 13 155 4 |---do.....]...do..... 4 {Sent, 10 3 | Sept. 12 2 13 156 1 d d ul {Sept : : Baer 2 5 = 4 OE. = GOsccce ep 13 Sept. 10 8 {Set 13 2| 14 157 2 | Aug. 31 (eet. ; ; \ do... 2| Sept. 12 2|. 12 158 PAs 2 dOzeas2|_sadpt..22 12 | Sept. 11 Dike. GOs -e6 1 12 159 2| Sept. 2| Sept. 6 2| Sept. 13 2 Sept 16 2 4 » if eaOeeES 4 | Sep 2 sed 3 ee wed oar 7 Sept, id 2 | Sept. 16 4) i ani}. .sde |: Mokad 7 | Sept. 13 dis |. AAO L hl Sept. 14 6 |...do.. 6| 33 163 8| Sept. 3| Sept. 7 8 {Sept 15 2 | Sept. i7 9 14 164 ee ee eee ee 5| Sept. 14 5 (Bet. 6 2 leur = ~ |fSept. 16 2 13 165 7 star ol es (ee i mes {> Gaeeee ‘ {Se t.17 5 | Ss 166 5 |---do.....].-.do.....| 5 | Sept. 15 beep is| i] da 167 3| Sept. 4| Sept. 8 | 3 |. aes 5 {Bept a Ae 168 3 Sept. 5 Sept 9) 1| Sept. 17 2 Sept 19 2 14 =102355.| 3200s s0-- - O-5-= 2 eas “Ose 2 14 170 1| Sept. 7 | Sept. 10 1 | Sept. 19 1 | Sept. 22 1 15 7 11| Sept. 9| Sept. 11 7 | Sept. 21 11 | Sept. 24 11 15 172 a ies ee ee 1 |. -.aeeese 2|...do....- 2 15 173 rh heer eae Sept. 13 9.|_ siete 2 |. -do..... 2 15 56602°—Bull. 115, pt 3—13——3 140 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Taste XXIV.—Second-brood eggs. Incubation period of eggs laid in rearing cages— Continued. Red ring. Black spot. Hatched. Num- Naas pale of : Hengia ber of | ber o eposi- | Hate of | Num-| Date of | Num- Num- | ° €88 apple. | eggs. | tion. | appear- | ber of | appear- | berof | Date. | ber of | St@8* ance. eggs. ance. eggs. eggs. ‘ i Bl Days. : ria ept. 2 3 | Sept. 25 2 15 174 8 | Sept. 10 | Sept. 13 8 {Sept = 2 | Sent. 27 2 lear == 5 Sept. 22 2 | Sept. 25 2 15 175 3 |..-do.....}...do..... 3 Sept. 23 1 | Sept. 26 1} 16 ; Sept. 22 11 | Sept. 25 10 5 176 13° | -22dow- (Eee do:.c2 2 13 Sept. 23 2| Sept. 26 3 16 = ilies Sept. 15 (| Se (G KS sae 3 | Sept. 25 1 4 178 12 | Sept. 11 {Set 17 3 | Sept. 24 9 | Sept. 26 ib 15 179 1| Sept. 12 | Sept. 15 1| Sept. 26 1 | Sept. 27 1| 15 180 5 | Sept. 14} Sept. 18 2|...do..... 5 | Sept. 29 5p eediis 181 6 |...doee.-. eee does5: 6 conta ; domes 6 15 182 13) 5.00. --—- em Qs 28% 7 | Sept. 26 Bp aeeCOSSsae 13 15 183 1 | Sept. 15 | Sept. 19 1| Sept. 27 1 | Sept. 30 1G ET 184 6 | Sept. 17 | Sept. 20 6 | Sept. 30 GrTOet.. +2 6 15 185 3i|Eadoleas PeAdo:: .f. Syl one i |SasG0n==- dl 15 186 3 | Sept. 18 | Sept. 22 2 1 OCtay, at 3 | Oct. 3 3 15 187 5 a ees Cove ee aedO: 5 SiiLeedo:sese Dh. sdOSsa< 2 15 188 3 | Sept. 21 | Sept. 24 Sal OCcta a4 2 | LOCuNNO 2 15 189 3 | Sept. 22 | Sept. 25 3 | Oct. 6 3 }| Oct. 8 3 16 The length of the egg stage ranged from 7 to 17 days, with an average of 10.92 days. Very little difference in the length of the stage is shown by Table XXIV for the 78 days or period of oviposit- ing by the first-brood moths. The red ring appeared from 2 to 3 days after deposition usually, the black spot from 6 to 10 days. TaBLE XX V.—IJncubation period of second-brood eggs. Summary of Table X XIV. For appear-| For appear- . Observation. ance of ance of eres red ring. | black spot. ; Days. Days. Days. Average.......-- 2. 64 9. 24 10. 92 Maximum.....-.- 9 15 17 Minimum.......- 1 5 if SECOND BROOD OF LARVA. Feeding period.—As mentioned under the egg stage, eggs were obtained from July 9 to September 25, a period of 78 days, and were hatching from about July 19 to October 8. The feeding periods were observed on a number of these at various intervals and devel- oped normally and spun cocoons in the rearing cages in which they passed the winter. The details of these records are given in Table XXXVI. CODLING MOTH IN SANTA CLARA VALLEY. 141 TaBLE XXVI.—Larve of second brood. Period of feeding of larvx in rearing cages. ; ms | | Date of— Date of Have | ate of Daye No. of a Fae of, y|\onOls Sole rn 7 aE “4 | y > larva. | Hatch- Leaving cen || larva. Hatch- | Leaving ae | ying. yo) ° fruit. a4 ing. fruit. B: 1 | July 20 | Aug. 29 40 | 43 | Aug. 20 | Sept. 20 31 2 Ne dttlys 20.2 = cdO sea 39 44 |...do..... Sept. 25 36 eC Oscar eer: Osean 39 | ADM ras 20Oe- x2. Sept. 24 35 4 |...do.....| Sept. 11 52 | 46 |...do..... Sept. 29 40 5D MLedorees: Sept. 13 54s 47 |...do.....| Sept. 28 39 GulenaOre a2 Aug. 30 40 | AS) 5 .00+,..-& Sept. 23 34 (| Rents eee ee Aug. 31 41 | 49") “Aug. 21 | Oct. (7 48 8-|--2d0:.-. aes Co Beeee 41 50 | Aug. 22 | Oct. 18 57 Oni esdotes. - Sept. 2 43 | abe He--00:25.,- Sept. 25 34 VOL |e 2. Oase:- | Aug. 31 41 | Dohe= sOO- Sept. 29 38 11 | July 26 | Sept. 17 53. || 53 | Aug. 23 | Sept. 28 36 12 | July 29 | Sept. 5 38) | pata dO. a= Sept. 30 38 13 | July 31 | Sept. 28 59 | EG i hse (6 eee Sept. 26 34 14 | Aug. 10 | Sept. 15 36 |i 90 |---do:.--- Oct. 6 44 thie -dO-55-- Sept. 21 42 57 | Aug. 24 | Sept. 26 35 16 | Aug. 11 | Sept. 15 35 || Fe hel eters oko ieee Sept. 25 34 17 | Aug. 12 | Sept. 20 39 tT obo ea Oct. 12 49 18 | Aug. 11 | Sept. 10 30 G0sieaeQO: -- x: Oct. 15 | 52 19 | Aug. 12 | Sept. 13 32 61 | Aug. 25 | Oct. 10 46 20 | Aug. 13 | Sept. 26 44 | 627 |-2 dol: 2. Oct. 7 43 21 | Aug. 14 | Sept. 13 30 | (eR Ty aes (ae es Oct. 6 | 42 - 22 | Aug. 15 | Sept. 17 33 64 | Aug. 27 | Sept. 27 | 31 23 | Aug. 14 | Sept. 15 | 32 Goulee- 0-2. SIN OCtS 46: 40 24 | Aug. 15 | Sept. 25 41 66 | Aug. 30 | Oct. 7 | 38 25 |...do.....| Sept. 28 44 67 |esdol2 2) Sept. 29} 30 26 | Aug. 14 | Sept. 21 38 68 [88 -d0: = 5, Oct. 16 | 47 97 | Aug. 15 | Sept. 19 35 | ee ae Oct. 7 38 2Rt lee GOr. 2:2 Sept. 18 34 “(0 es (oe Oct. 21 | 52 29 | Aug. 16 | Sept. 30 45 | tl} Sept. 1.) Oct. 9°) 38 30))/5-4d0sse-. Sept. 19 34 | ie 7 Wee (aes ae Oct. 13 | 42 S1t a e@G0 2 oie sO... 2 34 | 73 | Sept. 2} Oct. 16] 44 32 | Aug. 17 | Oct. 1 45 74 -< Orso... e200. 553 May 14 ssdo: 222 |=. 2do-22.. Sido. May 15 Apr. 3] May 16 edo ye May 19 2=got~a04 May 16 Sas (oe May 18 Length No. of indi- vidual. Date of— Pupa- Emer- | tion. | gence. Apr. 3] May 18 700.2. May 19 doe ee May 16 =(6 (Cee 4 es doz. Eda ae | May 20 | Apr. 4] May 19 2005-25. May 17 | eJdor-=*: May 18 | Apr. 5| May 15 400.2 2 May 18 sdox> : May 19 EOOs.+ 2 May 20 AO=: Seales tape 200s. 28 May 18 Apr. 6{| May 20 Serotiheae May 18 sad On sses May 20 EaOe. ae OO. Endo we ne May 19 ..do.....| May 20 ACOs ao eRe do Apr. 9| May 21 eedos | 28 dos Apr. 10" edo seo stone Gores dobre [nee dore- Apr. 14| May 22 Apr. 15 | May 23 ALDI.) 165) ee Ose sdos ts May 22 Apr. 17 | May 24 Apr. 19 | May 27 Apr. 20| May 26 Sole | EES doz3s*: eGOs.. sal May 31 Apis 1s es dqueeee adores date Apr. 24| June 1 dO. Fe > edosese Apr. 25 | May 31 Apr. 26! June 4 Apr. 28} June 3 May 2, June 6 a Ta eee June 4 May 9, June 8 146 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLE XXIX.—Spring brood of pupx. Length of the pupal stage of overwintering larvx collected from banded trees in 1910 and reared in vials. Date of— Date of— N 0, of : Leng No, of Tense indi- | ex. indi- eX. vidual.| Pupa- | Emer- pul vidual.| Pupa- | Emer- zupal tion. gence. Be. tion gence SLeEe Days. Days. 1 | Mar. 14] May 6/ ¢ 43 34 | Mar. 31 | May 16]...... 46 2 | Mar. 16] Apr. 26; ¢ 41 tary San (ee a May 12/ ¢ 42 3 |yMar. 17 | Apr. 29)" ¢ 43 36" |)-=-d04 May 16 ° 47 4.) | Seidossos® Apr. 28| ¢ 42 BV Guelerxe lo ea May 18 roe 48 5 | Mar. 18 | Apr. 30 g 43 38) (eae GGL. May 16 cf 46 6 | Mar. 20| May 1]. 42 39) |) PADIse iL | nde Q 45 7A (sees (Oa May 3 ree 44 40. |. 22daeeee. May 18 ree 47 Sh zcdotk 3 May 2 of 43 41 dons: May 20 Q 49 Ofiacndoxtes May 1 ref 43 42 |("37 32 | 14.8 ALBAN | ats bats} C-8 | July 25 102 9 111 23 | 20.7 22 19.8 45 | 40.5 c-9 Aug. 1 41 5 46 12 | 26.1 1685) 3457 28 | 60.8 C-10 Aug. 8 18 1 19 Ou) © Taal\ 8658 7 | 36.8 cain Aug. 15 13 5 18 Det perils Tf ej BES) 9 | 50 C-12 Aug. 27 20 0 20 ipa ae 10 | 50 11 | 55 Total.| 1,108 71 | 1,179 394 | 33.4 239 | 20.3 633 | 53.7 1 Time during the day when moths emerged.—Observations on 100 moths were taken to determine what time of the day emergence was most common. Jars in which pup for emergence were kept were examined four times a day for 14 days. The times of examination were 9 a. m., 11 a. m., 1 p.m., and 4 p.m. Out of the 100 moths only 9 issued between 4 p. m. and 9 a. m., 44 emerged between 9 a. m. and 11 a. m., 42 between 11 a. m. and 1 p. m., and the remaining 5 between 1 p.m. and 4 p.m. Thus it seems that from 9 a. m. until 1 p. m. is the customary time of emergence. (See Table XXXIV.) CODLING MOTH IN SANTA CLARA VALLEY. 149 TaBLE XXXIV.—Spring brood of moths. Time during the day when moths emerged. s Number emerging before | Total Date. —s emer- | 9a.m. 1ia.m. | i pia: 4p. m. gence. Apr. 26 a 0 0 0 | 2 Apr. 28 0 | 1 3 3 | 7 Apr. 29 Us 11 12 0 | 24 May 1....| 2 3 0 oO | 5 May 2....| 0 12 5 1 18 May 3 1 4 1 0 6 May 4 0 6 4 0 10 May 6 0 0 6 0 | 6 May 8.... 1 0 oy OF} 3 May 9....| 1 1 2 0 | 4 May 10...) 1 3 > 0 | 6 May I11... 0 3 3 0 | 6 May 12...| 0 | 0 1 Ri 1 May 15...| 0 | 0 1 0 | 1 Total. | 9 | 44 42 5 100 Period of oviposition. —Although moths were placed in an oviposi- tion cage with apples as soon as they emerged, no eggs were observed until June 1. After that time there was no difficulty in obtaining eggs. In the field eggs occurred early in April. No eggs could be obtained from single pairs of spring-brood moths, and thus no data were obtained as to the number of eggs a single female could deposit. In April and May, 1911, the mean temperature was considerably below normal and. possibly this fact may account for the moths refusing to oviposit on the apples. From June 2 to 9 maximum oviposition took place. Longevity of spring brood of moths.—Records were kept relative to the length of life of 40 moths which were placed in two jars and which were fed on grape juice and brown sugar. The results of these observations are given in Table XXXV and the summary of the results in Table XXXVI. TaBLE XXXV.—Spring brood of moths, 1911. Length of life of the moths. Cage A. Cage B. | Date of— Date of— Number | _ MENS | Ae oe al Number | Vere x of Days. of Days. moths. Emer- moths. Emer- , gence Death. ‘ | gence. | Death. re 2 Apr. 29....| May 1.-.... 2 eee Viosee May 4..... 1 ee ae GOle eee May 2..... 3 7 Tl ee douecce | May 5...-. 2 Cn. Eee Osseo 55 May 3....- 4 te Rae de:4.. | May 7....- 4 tel | ep eae donee. May 4..... 5 58) ee do2=3 | May 10 7 | fe aR dos... May 5..... 6 Be lt GOs 2a | May 12. 9 it ieee Ci (ge oe May 7....- 8 | BP leon = don... May 13..-. 10 te | eA ae do.....| May 8..... 9 Low lee do..2...| | May 14. 11 Jing |S Soe Glace | May 9..... 10 —_—— TO ee do.....| May 12...- 13 17 44 Uys) legs eee dol. | May 13. 14 Ae ee ee do: <. = May 14 15 =a) Eee do.....| May 16. 17 Si eee: AO°.2: | May 17 18 23 | 124 | 150 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. The average length of life of the moths in cage A was 10.5 days, while that of those in cage B was 7.41 days. The combined average was thus 9.19 days. TasLeE XXXVI.—Longevity of moths of spring brood. Summary of Table X XX V. Observations. Days.~ AVehage. sere a-e= 9.19 Maximum.......- 18 Minimum...-...- 1 FIRST GENERATION. FIRST BROOD OF EGGS. Incubation period.—In the preceding pages the length of the period of egg deposition was considered under the habits of the moth. A record of the length of the egg stage for 34 eggs is shown in Table XXXVII. As mentioned before, the earliest emerging moths would not oviposit in the cages, and it is probable that all eggs deposited previous to June 1 required from 15 to 18 days for the egg stage. Taste XX XVII.—First-brood eggs. Incubation period of eggs laid in the rearing cages. Red ring. | Black spot. Hatched. + | Num- Dateof | | Length | No. of | ber of | deposi- | of apple. | "an? Ge Date of | Num- | Dateof | Num- Num-| egg | Bes. 10n. | appear- | ber of | appear- | berof | Date. | ber of | stage. ance. eggs. ance. eggs. eggs. | Days. | 1 | 1 | June 1/ June 7 1 | June 14 1 | June 16 1 15 | aH 3|June 2]June 5 3 | Jume 15 3 | June 17 3 15 3h 4. Jd oy = June 6 Aas = COle. = 4 Gorss=2 4 15 | PEO! so.,3 2 do.. 2 >| 3 |---do....- Kaine 8 1 | June 16 1 \ do 3 15 5 | 5 | June 4) June 7 5 rane a ; June 18 5 14 6 4|} June 5 June 8 4 | June 17 4) 4 dowes 4 13 | 2 ail SW gercra: : \June 18 2 | June 19 2 14 gs} 2|June 8 ere ao | see 2). donc. a | hy 4s Ose 2k (ee (5 (2 oe AG\Eaad0. ses 4): dots. 4 11 10 | Dil nts Gb eee | June 12 Yel ate 6 Ct eee 24/8. 2doe =< 2 11 | 11 3|June 9 tie at 4 \..do Benen 3 (Oho a oe 3 10 12 | 1 | JunemtO|22 dos 2 1 | June 19 1 | June 20 1 10 13 | 1 | June 11 | June 13 1 | June 20 1 | June 23 1 12 14 U7) Jrment2s|o adore La seGOre -<). 1b 3 dose 1 11 15 | 8 | June 16 | June 18 | 8 | June 26 8 | June 28 8 12 = ——— Table XX XVIII shows a summary of Table XX XVIT. TaBLE XXX VIII.—Incubation period of first-brood eggs. Summary of Table X X XVII. Days of Observations. incuba- tion AVCLaZes a. «acter 12.77 Maximum........ 15 Mininium sys ee- 10 CODLING MOTH IN SANTA CLARA VALLEY. 151 From Table XX XVIII it is seen that the maximum egg stage was 15 days, the minimum 10, and the average 12.77 days. The average time before appearance of the red ring was 3 days, and the time before appearance of the black spot 11 days. FIRST BROOD OF LARV®. Time of hatching —The first larva to appear from eggs laid by cap- tive moths hatched June 16. In the field at this time some full- sized larvee were noticed, which were in all probability just-hatched larve about May 1, but, as has been stated before, the captive moths refused to deposit eggs before June 1. From eggs laid after this date 16 larve hatched and were placed on apples to get data on the feeding period and post-larval stage. Only six of these transformed into the pupe and Table XX XIX records their larval history. TaBLE XXXIX.—First-brood larvx: Feeding period and length of the post-larval stage. = Date when— | Length | No. of Sie. Sie Lae of larval | larva. Larva | Feprecibed sah Larva | Stage. hatched. apple. apple. pupated. Days 1 3 June 17 | June 17 | July 12] July 13 26 | 2 fe} June 19 | June 19 | July 17} July 26 37 | 3 é |.--do....|2..do...-| July—@ | July 23 34 4 ie] PedOeeere (ea C0- s-F Ul ygeiom July Sl 42 | 5 3 June 20 | June 20 | July 17] July 27 37 | 6 ? June 28 | June 28 | July 23 | July 30 32 | | a Larva spun cocoon in apple. The average length of the total larval stage was 34.67 days, includ- ing the time taken by the larva to spin its cocoon after leaving the apple, which is the post-larval stage. As this period varies consider- ably, in the above six instances from 1 to 18 days, the true larval stage or feeding period is found by simply taking the time of larval existence until the worm leaves the apple. In the instance of larva No. 3 the cocoon was spun inside the apple, so the time spent in feeding could not be determined. The average time taken by the other five to attain full growth was 25.8 days, with a maximum of 28 and a minimum of 24 days. Number of larve developing in each apple.—Several larve entered the same apple in numerous instances, but never more than two developed. In the orchard usually but one larva is found in each apple, although the entrance holes of several often can be observed. An apple from which a larva of the first generation has issued may later contain a larva of the succeeding generation. 152 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. FIRST BROOD OF PUP. Time of pupation and length of pupal stage—The larve for this record were collected from banded trees and placed in gelatin capsules and vials to obtain pupation records. Practically no difference in length of pupal period was found in those kept in capsules and in those in vials. Of the 123 larvee placed for pupation 52 died, and of the 71 remaining 12 elected to pass the winter as larve. The pupation record in Table XL is therefore recorded from only 59 indi- viduals. The earliest pupa occurred July 8, the latest August 16; the earliest adult issued July 27, the latest September 13. Conse- quently the pupal period ranged from July 8 to September 13, a wa} Aprep aBeuony ol payusuye — aunyeda a, ‘ a. > a S ‘s 3 £ 5 Z 4 18 20 22 24 26 26 30 1 3 5 749 «UN 13 15 17 1 July August Fia. 34.—Diagram showing first-brood pup, 1911. (Original.) period of 68 days. The shortest pupal stage was 18 days, the longest 37, and the average 23.12 days. Using this average we find that probably the earliest pupa occurred July 4, and as the latest adult (see adult emergence record, Table XLITI) issued September 29 we have a theoretical range for the pupal period of 87 days. Of the larvee under observation there were 21 males and 33 females, the average pupal stage of the former being 22.95 days and that of the latter 23.45 (see Table XLI), the females thus requiring half a day longer to develop into adults. Five individuals escaped before their sex could be determined. Figure 34 shows graphically the time of pupation of the first brood. CODLING MOTH IN SANTA CLARA VALLEY. as TaBLE XL.—VFirst-brood pupx: Length of the pupal period srom material collected in No. of indi- vidual. 10'|.22 CaONOoUkRWWe 1911 on banded trees. Date of— | | Date of— | Length || No. of Length Dies of er indi- aa a pupal Pupa- | Emer- ‘period. | vidual.| Pupa- | Emer- | period tion. gence. tion. gence Days | Days July 8 | July 27 Q 19 31 | July 20} Aug. 13 }.....- 24 eds eae edGse 1" 9 19 32 | July 21 | Aug. 11 8 21 July” (Bie.sdors 25] 18 33 O-~. =| Aug. 12 22 July 10} July 31 21 34 | July 22} Aug. 17 fof 26 July -12')° do. ..: 19 BOneeily 24). | ApS Tat os 21 Sdopeee ae oues 3 20 | 36 | July 25 | Aug.17/] o 23 ..do. SOOL seit 20 Sinlaee do. .|-=.d0L.- g 23 edozs e300 52212 § 20 38 | July 26 | Aug. 19 24 200825 425-002 — 5 20 3936. G0: =| Auge 20 25 do.. PAI Neer eee = 21 40} July 29 | Aug. 21 23 Ose Seep oo § 22 41 | July 30 | Aug. 23 24 dor Aug. 6 25 AQ dos salt oadows 3 24 July 13 | Aug. 1 3 19 43 |...do. Aug. 28| o 29 220022 Aug. 3] o 21 44] July 31] Aug. 24 § 24 muilys ta eedoee.. | 20 45 | Aug. 1] Aug. 26 25 .do. -ado, é 20 | 46 \:- dos... 2] Aue. 24 26 uly. 5s|2kdo-k.k|as.4-2 19 | Aiea dOns=. |=. -Gd0u- 26 Waossea| Aes worl 21 4s | Aug. 2| Aug 26 24 rela ee CI PATIS Sy eiil= ssc... 23 49 | Aug. 3 | Aug. 30 27 July 16-| Aug. 6] o 21 50 |-:-do_.-.| Sept. 9 8 37 eado: -2 -|' Anup. 19 |g! 34 51 | Aug. 4 | Aug. 28 24 July 17} Aug. 5) 2 19 || 52 |...do....| Aug. 29| ¢@ 25 Sc ee Aug. 7 Or | 21 i} HERO. era leaedOs ae.) eS 25 July 18} Aug. 8] o | 21 54 |...do....} Aug. 31 Q 27 -do. Aug. 9} of | 22 || 55 | Aug. 6] Sept. 2 9 27 2G (Ss Aug. 8 Oo 22 |] 56 | Aug. 12| Sept. 7| o | 26 July 19} Aug. 9] Q | 21 57 | Aug. 13 | Sept. 2} & | 20 don. Aug. 14 Q | 26 58 | Aug. 16 | Sept.13 | 9 28 July 20} Aug. 11 3 22 59 | Aug. 19 |...do...-| o& 25 a8do2. Aug. 12] o | 23 || i i | The variations in the length of the pupal stage are shown in Table XLI and a summary of Table XL in Table XLII. TaBLeE XLI.—First-brood pupx: Variations in the length of the pupal period for 5% TaBLeE XLII.—First-brood pupx individuals. Pupe. _ Nono-ior Days. | Pupe. | Days. is || 6 25 19 || 5 26 20 | a 27 21 || re 28 22 || Tap 29 23 «CO 1 | 34 24 | il 37 | | : Summary of Table XL. pare aera in the Observations. | pupal | stage. ALVETALC. <2. --25 | 93.12 Maximum. .... 37 Minimum........ 18 154 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. FIRST BROOD OF MOTHS. Time of emergence.—On July 22 the first moths emerged foun band material collected July 6. The emergence reached its maximum August 19 and continued on until September 29. Most of the moths, Beuany Number of Moths 10 13 tb 22 25 28 3! 3 24 27 August ee © oa = ~ <= + 1) 3 Gs ® S 8h) + = “Ss 1) ™ 5] = By) ® = 25 &. > Fic. 35.—Diagram showing emergence of first-brood moths, 1911. (Original.) however, emerged in August and the first few days in September. As can be seen from figure 35 and Table XLIITI the emergence is drawn out so that it covers a period of 70 days: TaBLe XLIII.—Emergence of moths of the first brood: Material from banded trees. Date of | Number Date of | Number Date of | Number Date of | Number emergence. | of moths. || emergence. | of moths.|| emergence. | of moths. || emergence. | of moths. July 22 2 Aug. 11 2 Aug. 25 3 Sept 9 4 July 25 1 Aug. 12 4 Aug. 26 5 Sept. 10 3 July 27 3 Aug. 13 5 Aug, 27 3 Sept. 12 1 July 30 3 Aug. 14 7 Aug. 28 2 Sept. 13 2 July 31 2 Aug. 15 3 Aug. 29 6 Sept. 14 1 Aug. 1 5 Aug. 16 2 Aug. 30 9 Sept. 16 1 Aug. 2 1 Aug. 17 9 Aug. 31 1 Sept. 20 2 Aug. 3 1 Aug. 18 5 Sept. 1 3 Sept. 22 1 Aug. 5 3 Aug. 19 12 Sept. 2 4 Sept. 29 1 Aug. 6 2 Aug. 20 8 Sept. 4 1 Aug. 7 2 Aug. 21 9 Sept. 5 3 157 Aug. 8 6 Aug. 22 6 Sept. 6 1 Aug. 9 4 Aug. 23 6 Sept. 7 3 Aug. 10 4 Aug. 24 5 Sept. 8 1 Oviposition period.—Nearly all of the moths which emerged were utilized for securing eggs by confining them in Riley cages in which apples had been suspended on strings. The moths oviposited readily and a large number of eggs were secured. The first eggs were ob- tained on August 10, or 19 days after the first moths emerged, which was on July 22. The earliest moths did not oviposit in the cages but it is probable eggs were present in the field about the middle of July. The oviposition period continued throughout August and September. CODLING MOTH IN SANTA CLARA VALLEY. t55 LIFE CYCLE OF FIRST GENERATION. Along with other rearing experiments to obtain the length of the ege stage and the feeding periods of the larve a number of adults were reared from the egg to ascertain the complete life cycle. In this experiment only six individuals were carried through the entire period and the details of the work are shown in Table XLIV. Table XLV is a summary of Table XLIV and shows that the aver- age life cycle from egg to egg (allowing 3 days after the moths emerge before eggs are laid) was 71.3 days, the maximum 77 days and the minimum 67 days. Adding the average egg stage, or 12.77 days, the average feeding period, or 25.08 days, the average post-larval stage, or 9 days, the average pupal stage, or 23.12 days, and allowing 3 days for eggs to be deposited after the moths emerge, a total of 72.95 days is obtained, or very close to the average life cycle, from actual rearing experiments. TaBLE XLIV.—Life cycle of the first generation. Date of— = Length No. of individual. Sex. - aioe = of egg eposi- . ack arva stage. tion Red ring. spot. hatching. Days. UO eS Ee Sore ode eee Bees oe ee ie ¢ | June 2] June 5] June 15| June 17 15 2 sain Be A RSE 2 Ae eS erat eee eed Se | y | June 8 | June 10] June 18 | June 19 11 eee eee eee wee at eee ed Feats ode Sat rh -doOz= = wRne pL | dows | dave. ll ee ate te Jenene da, iin REE ee law ate afs Q ~dozsaaie.- USSR Ras (se ero ne ee il De oe ee Nc ee cance SER EI: cde adiaisage ost & | June 10 | June 12 | June 19 | June 20 10 Case ee er eee ee cee te bs Mcrae aes Sb ? |...do....| June 18 | June 26 | June 28 12 Date of— | Length ; Total : i th o Length | Emer- | Length | /e | ens No. of individual. | para | Larva of larval | gence of | of pupal teen ce cy ne ee a” | Pupa- stage. adult. stage. 8 88 entering | leaving | finn adult. egg. apple. apple. | Days. Days. | Days. Days. ocd eee oe June 17} July 12} July 13 26 | Aug. 5 23 | 64 67 J Se eS 22 5 eke eee June 19} July 17 | July 26 37 | Aug. 17 22 70 73 CS gee iad Soe See (yes eo eee July 23 34 | Aug. 13 21 66 &9 ls Ree 33 geee Oo Reel hee do July 13 | July 31 42 | Aug. 21 21 74 77 18 Ae eR ae eee eer June 20| July 17 | July 27 37 | Aug. 18 | 22 | 69 72 Danone 2 MN ye a June 28 | July 23 | July 30 32 | Aug. 22 | 23 | 7 70 TaBLE XLV.—Summary of Table X LIV. | | Total life | Total life | Observation. |eycle. Egg|cycle. Egg | to adult. to egg. Days. Days LS C2 eee ee 68.3 ree Lech Ts) eee eS ee See 74 77 MIRAE Sas egos omc 5 = ot Oe 64 67 56602°—Bull. 115 pt 3—13——4 156 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. SECOND GENERATION. SECOND BROOD OF EGGS. Incubation period.—In all, 845 eggs were deposited during the 33 days on apples in the cages used for this purpose. No record was kept as to how many eggs a single female deposited, but, judging from the number of female moths confined and the eggs deposited by them, the average for each female must have been about 40. No record was kept as to the time of day the females selected for ovipo- sition, but observation throughout the day showed moths ovipositing from early in the morning until evening. Table XLVI shows the length of the egg stage for 760 individuals. TasLeE XLVI.—Second-brood eggs. Incubation period of eggs laid in the rearing cages. Red ring. Black spot. Hatched. NowoE Num—1Datetok | | Length apple. a o se ed Date of | Num- | Date of | Num- | Date of | Num- ofcee BBS. | z appear- | ber of | appear- | ber of | appear- | ber of Be. | ance. eggs. ance. eggs. ance. eggs. | Days. 1 Su eAgr ea O |< Aug. 21 3 Aug. 23 3 13 Aug. 27 ll 2 9 | Aug. 16 | Aug. 19 9 Ge = 8 Aug. 28 Bl We > 8 Aug. 29 1 13 5 Aug. 28 6 ll - =GOsne= 39 |} Aug. 29 23 12 4 46 | Aug. 17 {Aus 20 30 |JAug. 27 3 |J Aug. 30 9) 9 13 & Aug. 28 3 ||Aug. 31 2 14 Sept. 1 if 15 Aug. 20 6 | Aug. 26 6 |, 5 Bo | cxetlnge te {age at 1 | ane é aug. 29 6| 12 6 4|...do.....] Aug. 20 2 ee. 8 rl eaeees 3| 12 SdOeeeee 4 ; Aug. 30 3 12 8 14| Aug. 18 WAug. 21 5 |bAug. 28 10 { {ane 99 1 Aug. 31 q 13 9 Po esse § KOSS ee Aug. 21 1 | Aug. 27 1 | Aug. 29 1 intl 10 iy Bae dor EOS. .< 1 | Aug. 28 1 ue 30 1 + ug. 29 5 1 2 Aug. 20 5 | Aug. 27 6 |jAug. 30 15 12 YW 25 | Aug. 28 es 21 16 | Aug. 28 19 te 31 Dy eee Sept. 1 1 14 12 2 || Avge LSa| a doe.:. = Da ean dOneoae 2 us. 30 2 12 ug. 31 12 13 4| Aug. 19 | Aug. 22 2 tae: FH } Sept. 1 | a3 8- Sept. 2 1 14 Aug. 30 3 11 14 9 (ho) 555 = Aug. 21 6 Aug 28 9 Aug. 31 6 12 15 an. or eee (Go Sae3 1 Edo see 2 |] Aug. 30 1 11 Aug. 22 1| Aug. 29 1| Aug. 31 2 12 Aug. 30 1 1 : Aug. 21 1 Aug. 31 2 12 i 16 Gua doseeese Wee 99 3 \Aug 28 5 Sept. 1 1 13 | Aug. 29 2 Set, i i 13 Aug. ept. 7 4 |---dO...02)------ 2-2 Joeeeeens hode: 30 1| Sept. 2 1b in 18 4] Aug. 20 {Ane 55 Bal doe... 4| Sept. 1 4}. 938 Aug. 31 it 11 Aug. 22 6 | Aug. 29 5 \Jc 19 (ke oe { Sept. 1 s| 12 Aug. 23 2 | Aug. 30 5 {een ; 13 20 rh eats eee Aug. 22 9 ee Be sont a | pair ise 1 15 d G0... 14 | Aug. 29 11 | Aug. 31 2 11 OW ees COSA Aug. 23 1] Aug. 30 4 Sept. 1 12 2 Mido. 35. 22 Pile sdouse . idee 2} Aug. 29 2 {sant 3 he ea 23| 3] Aug. 21| Aug. 24 2| Aug. 31 3 Sept a A ete . : | mM) m0) do {0 B) 2 fh ao..| a0 HSE 1] 8] Aug. 23 1 Sept. 1 | 5 11 25 16 |..-do..... Aug. 24 ul do veeee 16 sept. 2 6] 12 CODLING MOTH IN SANTA CLARA VALLEY. 1 ve TaBLeE XLVI.—Second-brood eggs. Incubation period of eggs laid in the rearing cages—Continued. Red ring. Black spot. | Hatched. No. of | Num- | Date of — —____—|—__—_____——_| Length apple. a i Date of | Num- | Dateof | Num- | Date of | Num- of @88 BES. * | appear- | ber of | appear- | ber of | appear- | ber of 8 ance. | eggs. | ance. | eggs. | ance. | eggs. Days. Sept. 1 1 11 26 7| Aug. 21 | Aug. 24 4] Aug. 31 6 Sept. 2 3 12 Sept. 4 1 14 Sept. 1 4 ul 28 12 |...do..... (ae pel} -= gener 12 {sent 2 7} 13 Sept. ¢ : Aug. 24 8 Sept. 1 3 11 29 20 |.--do..... Fae! 25 7 \ do..... 18 Sept, 2 | 12 "hag. 4 |{--40----- 11 30 25 | Aug. 22 |...do...-. 15 Haopte i = {Sent 3 22 12 Aug. 31 1 31 Ailecdors(Fdo:..2 6 Heont. 1 ' \sept. 3 12 qa |fAug. 31 1} Sept. 2 ll 32 3 |.. -do do..... 3 hSept. 1 2| Sept. 3 2| 12 Sept. 5 1 do... =. 5 ; Aug. 31 7 33 13 |...do..... ee 26 2| Sept. 1 5 {sept 2 : u Aug. 31 1 | Sept. 2 1 ll 34 8 |...do..... ca 25 7 {Sent. 1 7 | Sept. 3 7] 2 E=dOLs ce 3 | Aug. 3 20 | Sept. 2 1 11 35 24 |...do..... ren 26 3 | Sept. 1 4| Sept. 3 13 | 12 ' Sept. 1 1 . 36 5 | Aug. 23 |...do..... 3 {Sent i Et ee 5 u 37 Ai |\e00-s~<. do 2s 2dOuee =e 4 cept 4 ; a BtdO ts. S: 38 hl eeealepee Pees : \ doe H {seve é 4 13 ‘ ept. 39 fl ‘do Aug. 26 4 |P2sdoises: 5 | Sept. 4 3 12 Secareel Aug. 28 1} Sept. 3 1 | Sept. 5 3 13 40 14 ECOL se Aug. 26 9 | Sept. 2 14 BEDE 4 14 a =p 00cncee Zen | ain CLO ae 3 41 6 |...do ae oe $ fsept 3 1| Sept. 5 2| 13 8 : Sept. 4 1 | Sept. 6 Re 14 ~, Aug. 26 6 | Sept. 2 25 | Sept. 4 : 42 27 |..-do..... ie 28 4| Sept. 3 2| Sept. 5 7] 1 Aug. 27 116) seedotete: DEN eco aaa oe 43 29 | Aug. 24 ree 28 7| Sept. 5 3 {sept 2 Ge Sept. 3 17 | Sept. 5 9 12 44 19 don: Aug. 27 18 |;Sept. 4 1 | Sept. 6 8 13 Sept. 5 1 | Sept. 7 €, ia Sept. 5 4 Sept. 3 23 ' 45 PAs3h (tes (oP aesdOacee 19 {Sept 4 2 {sent : : = 46 10) |es-doss oes: 6 | Sept. 3 10 {Bept, 2 i a 47 20 |...do..... do... 11; Mela 20 (Bent. ; Aer 48 40 | Aug. 25 | Aug. 28 27 {eept: - i See ae 49 36 de do 29 ecp i 4 a3 Sept. c 3 z pe was eee eee ept. Sept. 4 Sept. 7 20 13 50 O12 dase sdoesct: 1s | Sept. 4 21 {Bent i y i 51 ADS. dOu-2 =. pe dO msn 3 jeer Sear 3 Sept. 7 3 8 Sept. 4 Sept. 5 1 52 3nie.dows... dow..2. sep 2. Sept. 7 1 | Sept. 7 1 13 a Sept. 5 3 | Sept. 8 13 13 53 15 | Aug. 26 | Aug. 30 9 (Sent. 4 | Sent 8 A tees 54 4 do. .- =. adoes-2, 3 | Sept. 7 3 | Sept. 8 3 13 55 23 |...do.....| do..... 20 Sent. 7 io \. do es 22| 13 Sept. 5 9 56 17 Be (a See J00n- ae 11 ahae 6 ‘ sudOnacee 16 13 Sept. 7 Sept. 5 3 d maracas 8 13 57 Ca Bees (See edouecs. 7 {sept e P tle. 9 1 14 58 Ps a saci 16 {Ber 8 if |\sept. 8 i9| 13 (Sept. 7 1 il sd0sssu2 7 \JSept. 8 6 12 59 17 | Aug. 27 | Aug. 31 u (sept. ; i lt : ei Sept. 10 2 14 158 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLE XLVI.—Second-brood eggs. Incubation period of eggs laid in the rearing cages—Continued. 7 ; i Red ring. Black spot. | Hatched. No. of | Num: | Date of | a Length apple. gl eee | Dateof Num-| Dateof , Num-| Date of | Num- _ 88S. * | appear- , ber of | appear- ber of | appear- | ber of ge. | ance. | eggs. | ance. eggs. ance. eggs. | ie apf = a = | | | Days. Sept. 6 2| Sept. 8 3 12 60 9] Aug. 27 | Aug. 31 8 |{Sept. 7 6 | Sept. 9 5 13 Sept. 8 1 | Sept. 10 1 14 61 2 Gozeeee Gort: ss 1 | Sept. 7 1} Sept. 9 1 13 62 2 doe-r-n Gore=: 2 | Sept. 6 2| Sept. 8 2 12 Sept. 8 4 lhe 7 o “4 « Sept 11 6 14 63 7 | Aug. 28 | Sept. 1 5 ae Fa 2 Sept. 12 1 15 } = - |(Sept. 10 1 13 64 7 (sa scloheet emda. 1) 6 teen: : : \eent ib 4 14 | Pept. \sept. 12 2| 15 | Sept. 7 1 Ise | f > ||Sept. 9 1 12 65 ) do ores 5 ae s : [sept 10 4 13 | ; “Vn | Sept. 7 5 66 B:| 1: adage] see do.....| 8 HSebt. 3 [hedoneen: B ea 4 67 2 | Aug. 29 ;...do..... 2 pce Sone 2 | Sept. 11 2 13 “ Fad ip ee SRCOcacee Suet Gore == 4 13 68 5 |...do pedoees. 4 5 sept. 6 Mee re ab aay 69 3 SLNCLO Seecty bee doees.: 3 | Sept. 8 3 | Sept. 11 3 13 Sept. 10 2 lia x | ae mC Oneces 1 io > |(Sept. 13 3 14 70 5 | Aug. 30 {sept 2 3 {sept a 2 (sept. 14 2 | a5 = Bul errs 4 i(eedoucens 1 | Sept. 10 1 | Sept. 13 1 13 esos aM Septet 1 | Sept. 12 1 | Sept. 14 1 14 72 | Se Ones Sept. 4 NG does 6) eet dose se 4 14 73 Ath a0 ko Jue doe (Re eee N Ine are | 2 doz...) 2) aed Oene.e 2 14 I '(Sept. 4 3 Na ©, ~ 5 74 7 | Sept. 1 {sepi. : A \sept 13 7 oe 15 THR? 1 a= Sept. 4 5 ps does = 15 14 75 22 eee Oseeee {Sent, - 10 tO secon 21 Sept. 16 1 15 76 4) Septeray| edom.s.| 4 | Sept. 15 4 | Sept. 17 4 14 77 16) (Sept. 43ls-4doe...2 | Basse seo alee cutee Sept. 18 4 14 78 A \|USep entoe se eames 1 (Yaa Sept. 22 4 | Sept. 25 4 13 From Table XLVI it will be seen that the average egg stage was 12.5 days, the later individuals remaining in the egg slightly longer than the earlier, a phenomenon probably due to the gradual lower- ing of the temperature. Out of 845 eggs deposited, 760, or a frac- tion under 90 per cent, hatched. As can be seen from a study of Table XLVI the red ring is not a constant factor in the egg develop- ment, since it could be discovered in only 610 individuals. Mortality is about equally great before and after the appearance of the black spot. Table XLVIT shows the variations in the length of the egg stage as recorded in Table XLVI. TaBLE XLVII.—Second-brood eggs: Variations in the length of the egg stage as recorded in Table XL VI. Number 4 Number | bd ofeggs. | D®YS: |! oreggs. | Days. 68 11 8 | 15 301 12 | 307 13 760 76 14 Table XLVIILI is a summary of Table XLVI and shows the aver- age, maximum, and minimum length of the egg stage. CODLING MOTH IN SANTA CLARA VALLEY. 159 TABLE XLVIII.—Second-brood eggs: Summary of Table XLVI. | Length Observations. of the egg stage. Days AVELALO = 0. «5.4 -in- 12.5 | Maximum........ 15 | ‘Minimum........ 11 SECOND BROOD OF LARV2. Time of hatching.—Eggs obtained in the cages hatched from early August until September 25, but as the first moths did not oviposit in confinement just-hatched larve in numbers were probably in evi- dence in the field from the latter part of July until the middle of October, when most varieties of apples were picked. Feeding period.—Apples on which eggs had been laid were placed in jelly glasses to obtain a record of the time taken by the larval development in the fruit. Although in most cases several larve entered the same fruit more than two full-grown larve never issued from the same fruit. The apples used were yellow Newtown Pip- pins and were large enough to provide food for several worms. The larve have a habit of coming out of the apple, wandering around the glass for a few days, and then entering the fruit again, thus extend- ing the period of their growth. This habit may account in part for the large variation in the length of the period between hatching and the final emergence from the fruit for the purpose of spinning the wintering cocoon. The maximum time spent in the fruit was 79 days and the minimum 43, with an average of 58.15 days. Table XLIX gives the record of the time spent in the fruit of 39 individuals. TaBLE XLIX.—Second-brood larvx: Time spent in the fruit. -| {| | Larva ie } | Larva . No. of | Larva | emerged Pit S || No. of | Larva | emerged | Days apple. | hatched. | from fruit, | @Pple. | hatched.| from foult fruit. wt fruit. ue =e br 13 | Sept. 1] Oct. 21 50 || 53 | Sept. 7] Nov. 22 76 28 | Sept. 2.| Nov. 7 66 o4 | Sept. 8 | Nov. 2 55 29) ||-e20Oees20 Nov. 2 61 ay eee 0 Co aa Nov. 21 74 33 } Sept. 3 | Oct. 27 54 | Beets eee Nov. 5 58 OF, (2220055222 Nov. 1 59 had es Cees Nov. 26 79 35 | Sept. 2 | Oct. 22 50 59 | Sept. 9 | Nov. 13 65 36 | Sept. 3 | Nov. 12 70 60 | Sept. 8 | Oct. 23 45 36 | Sept. 4 | Oct. 20 46 60 | Sept. 10 | Nov. 24 75 37 | Sept. 3 | Oct. 22 49 61 | Sept. 9 | Oct. 27 48 40 | Sept. 5 | Oct. 20 45 Gls Sdou-.2: Oct. 31 52 41 | Sept. 4 | Nov. 4 61 62 | Sept. 8 | Nov. 15 68 42 | Sept. 5 dG=- 33 60 63 | Sept. 11 | Oct. 30 49 43 | Sept. 4 | Nov. 3 60 64) |. . do... Nov. 11 61 45 | Sept. 6 | Oct. 14 43 65 | Sept. 10} Nov. 1 92 AG.) doses. Nov. 5 60 69 | Sept. 11 | Nov. 5 05 47 | Sept. 5 | Nov. 14 70 75 | Sept. 15 | Nov. 2 48 49 | Sept. 6 | Oct. 19 43 Coa) ee Nov. 20 66 50 | Sept. 7} Nov. 8 62 | fen eced0r 2.5. Nov. 12 58 OL, | ss2005.2 Oct. 31 54 Ud) Bee Cee Nov. 9 i) 92 gos.--2 | Nov. 12 66 160 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Table L, a summary of Table XLIX, shows the average maximum and minimum time spent by the second-brood larve in feeding. Tasie L.—Feeding period of second-brood larve: Summary of Table XLIX. = Bist | Days in Observations. | Phieteiatt | ASCLALC . yaar o 58.15 Maximum....... 79 Minimum........ 43 Time of leaving the fruit for wintering.—Table XLIX shows that the date the earliest larve left the fruit was October 19, but as these larve were not from the earliest eggs deposited and the earliest moths did not oviposit in confinement the band record will show when most of the larve cocooned for the winter. The band record for 1911 shows that after August 31 second-brood larve were un- doubtedly hibernating and that they reached their maximum from September 28 to October 5. The earliest second-brood larve prob- ably cocooned the latter part of August and since half-grown larve were found in apples on the tree as late as November 30, it is possible that the last stragglers did not cocoon until some time during Decem- ber, 1911, or January, 1912. NATURAL ENEMIES OF THE CODLING MOTH. Parasitic insects.—The egg parasite Trichogramma pretiosa Riley may be regarded as a factor in the control of the codling moth in the Santa Clara Valley. In 1909 eggs of the host were collected to obtain records on the parasites. A large number of the Tricho- gramma issued, but as there was no record of the time when the eggs were laid by the moths or parasitized by the chalcidid, the life cycle of the parasite was not determined. In 1910 the Trichogramma was very abundant, so much so that in the life-history work on the codling moth the jelly glasses in the insectary containing the eggs had to be carefully covered to keep out the parasite. In this year a record was kept relative to the life cycle of the parasite. Table LI gives notes on the life history of eight parasites. TaBLeE LI.—Life of Trichogramma pretiosa in codling-moth eggs. 5 é pays from ? | Date para- ate para- | deposition Date Cees | sitism site of eggs to : ' observed. | emerged. | hatching | of parasite. July 24 Aug. 5 Aug. 19 26 DOr. as |o25 do.-=es Aug. 20 Pw July 27 Aug. 10 Aug. 23 27 Doo 2.|252 don wsee8 Aug. 24 28 July 28 Aug. 5 Aug. 19 22 Dosss2t) oe (of eam a (ee dostee- 22 Aug. 1 Aug. 10 Aug. 22 21 Aug. 2 Udo. te salen Ghhaaess 20 CODLING MOTH IN SANTA CLARA VALLEY, 161 The date on which the parasitism was observed can have little to do with the actual date of the parasitization of the egg. As the parasites were very abundant in the vicinity of the eggs it is prob- able that the latter were stung almost directly after being deposited; consequently the parasites’ life cycle would start immediately after the codling-moth eggs had been laid. Figured in this way the life cycle ranges from 20 to 28 days, with an average of 24.16 days. A comparison with the life cycle of the parasite in earlier or first-brood eggs and in eggs of the second brood would be interesting. In 1909 several parasites were reared from the larve of the codling moth by Mr. J. R. Horton, of the Bureau of Entomology. These were all unidentified Hymenoptera. Toward the end of April, 1911, some overwintering full-fed codling moth larvae were observed by the junior author to have a whitish, distended appearance and upon closer examination proved to have been killed by a hair worm, determined at the instance of Mr. A. L. Quaintance, of the Bureau of Entomology, by Dr. B. H. Ransom, of the Bureau of Animal Industry, as belonging to the family Mermithidz. These worms, of which there was one in each host, lay coiled up, occupying the entire int-rior of the larva and exceeding 3 inches in length when uncoiled. None was found in the larvee of the first or in those of the second broods taken in 1911 from banded trees. Predaceous insects—In February, 1911, the larve, pups, and adults of Melachius auritus Lec. were found in considerable numbers, apparently preying upon the larvee of the codlimg moth. The speci- mens, on request of Prof. Quaintance, were later determined by Mr. KE. A. Schwarz, of the Bureau of Entomology, who said in reference to them: ‘‘* * * This and other species of the same genus have repeatedly been reported to the Bureau of Entomology as enemies of the codlmg moth. The genus (excepting the imported Malachius zneus L.) does not occur in the Atlantic slope of North America.” BAND RECORDS OF 1909. Through the kindness of Mr. E. Northern, of San Jose, Cal., 20 trees of his orchard were banded to obtain records. The apples are of the Newtown Pippin variety, and the whole orchard, with the exception of the banded trees, is annually treated with several appli- cations of arsenate of lead. The bands were of burlap and were placed at an average of 30 inches from the ground after the loose bark had been scraped off. Asummary of all of the work performed, including the total number of larve and pupe (each collection), the weekly emergence of adults following, and the total number of larvee which transformed in 1909 and which hibernated until 1911, is shown in Table LIL. 162 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLE LII.—Band record for 1909. | J 3 \o x Sete Number of adults emerging from respective collections by—|o | Total eee | edit No. of | Date of |~—-—— larvee SAT: as ae record. \collecting. & plus jos | a o is a | o Oo ee | esc co [con aco pata eos | Ce |ieee | pEpsenl es eas dl) ae Fel ees pceeesibecs : y | oe fee le ad he Balls ||| bai teon Mena) rene Reo ne eee aa as GS ee | a |5 SI/SBISISISI/El/E/S S/o] so] eo \e [s A Te | PIR |/RAlTas /s}/ Ss | Ss [alaianijnioane & | 1, 602 |215 | 1,817 |264 | 378 | 388 | 399 | 402 403 2,276 | 79 | 2.355 | 0 | 249 | 607 | 646 | 666 678 946 |159 | 1,105 | 0 0 | 166 | 628 | 690 7 804 | 93 | 897 1 8 | 27} 387 | 411 761 | 59 820] 0 3 8 | 159 | 270 885 | 68 | 953] O 1 2 9 | 431 919 | 48; 967; 0 1 2 6| 84 536 | 37 573 | 0 0 0 1 3 505 | 30; 535] 0 0 0 1 2) 37 350 | 22 372} 0 0 0 0 1 1} 66] 73 | 76} 78} 79 79 | 133 297 | 22 319 | 0 0 0 0 0 Ze | boul MOT ee aes ae el eee 48 | 115 180)), 16), 196, 0) 0 0 0 0 0 UIE PR G22 FPP FP le eee 4) 42 PS55|| dg 2h 0 0 0 0 0 0 QO} 4) °22) 25 | 26 |...-| 26°) 47 115} 10] 125) 0 0 0 0 0 0 Lal | bah Silly CUE 2 al Oe aes DN La al aya 0 0; O 0 0 O01 OF) ee 71s) 184) sist es 262} 2] 264} 0} O 0 0 0 0 0} O| O {103 |105 |..../105 | 129 383 | 0 383 | 0 0 0 0 0 0 0 | OF SOF S| aLSh iF 18 | 193 403 | 3 406 | 0 ae ed) 0 0 O20") .2 Oi) SOU Zale Alles oa eon ieee 477) 4 481; 0 0 0 0 0 OF 0 1 PO! e0n eal ty oy) So 26% Sit | alae ieee Seale | [e Nemew Stae ine co Wee. Piste 0 0 | 210 DSO ON GOs laren os ieee isle era | (oars ore aioe ee etl Gea Be | 0 | 257 Fig Rays eee eh, a eS VN ET CER SI NES af 0 | 258 253)! 10)" “253 ee eee a. ees tae dt sel |B ere 0 | 328 309 1 5101s ba eee | eeere) eee eel Pelee ey PS or Seen tee 2 | O| 157 290°] 0'| © 290 [--2-[eeee-]-e222)eeeeefe eee Petit leon alors] once catches eee 0} 116 ) i | | 1 Records annulled through larve being arowned in winter. Figure 36 shows graphically the 1909 band record. BAND RECORDS OF 1910. Through the kindness of Mr. W. J. Farrington 12 trees of his orchard at San Jose, Cal., were banded to obtain records of the second-brood larve. The apples were of the Skinner Seedling variety; and as this HH spaee 8 Qa =) Oo mo) £ w S 12008 tf =! % x v se) E 4° = = ~ 2) 26 6 4 12 15 + 22 26 29 2 °=«5 4 12 tb 1% 23 26 29 2 6 9 13 16 20 | | June July August September Fic. 36.—Diagram showing band record of 1909. (Original. ) apple ripens early, no records could be taken after August 22, there- fore showing practically no second brood of larve. CODLING MOTH IN SANTA CLARA VALLEY. 163 A summary of all the work performed in 1910, including the date of collection, weekly emergence in 1910, and the totals for both 1910 and 1911, is shown in Table LIII. Tasite LIII.—Band record for 1910 at San Jose, Cal. 7) area (re eas = Number of adults emerging from respective collections by— cS Ne = 8 R = F 2 = No. of | Date of Pe i Saas record. |collecting. dé |g SB SS ea OO. ase Sct OCR NST |r? 2 Sees tS 7s “3 > 3 Bsil'bs. |) Bs | 8p sb bb ab + + es] sis 3 Fl ese eal ee) Se eons ee al see eye eyolieley |i earls s iliss Ste eee Wale | ¢ i) =J S x 1g S Pe 2 z 7 IASC TSTANT at Dea tr SRE September October Fia. 38.—Diagram showing band record, Northern orchard, 1911. (Original.) August 10 only two pupe were collected, so that it can be safely assumed that all the individuals taken after this date belonged to the second or overwintering brood. FIRST-BROOD EMERGENCE v. OVERWINTERING EMERGENCE, 1911. From band records collected in 1911 (see Table LIV) 774 larvee and pupe were taken. Some of these, from the first collections, were placed in vials for individual pupal records, while the remainder were placed in jars for adult emergence records. Those placed in the vials were all of the first-brood larve and only a very small percentage overwintered. The latter collections—both consisting of first-brood and second-brood larvee—resulted in an emergence of first-brood moths of about 18 per cent. Only 157 moths emerged from these collections, although a considerable number of pup died in their CODLING MOTH IN SANTA CLARA VALLEY. 165 vials. Compared with seasons 1909-10 and 1910-11 this was a very small proportion of moths for the first brood as against those hiber- nating as larve, for in both these seasons the advantage lay easily with the first brood. According to these data there appears to be an excellent reason to look for a large overwintering emergence in 1912. REVIEW OF LIFE-HISTORY WORK OF 1911. Similar records on the life history of the codling moth to those kept in 1910 were obtained in 1911. The results of these observations are shown in the diagram, figure 39. Spring pup were present about February 20 and continued until June 20, reaching the maximum about April 12. Moths began to emerge about March 24 and con- tinued until June 8, with the maximum emergence occurring about May 8. Eggs of the first brood were deposited from March 24 until July 11, with the maximum deposition taking place about May 12, while the first-brood larve hatched from April 23 until July 26, with the maximum hatching period occurring about May 30. First- brood larve cocooned from May 25 until August 26, with the maxi- mum cocooning period about June 28. The first-brood pupz were present from June 30 until September 29, with a maximum period about July 28. First-brood moths began emerging July 17 and continuéd until September 29, the maximum emergence taking place August 16. Second-brood eggs were deposited from July 18 until October 4, with the maximum period about August 28, while the larve hatched between July 30 and October 18, with a maximum hatching about September 4. The second-brood larvee began to cocoon August 14 and on throughout the winter, reaching their maximum about September 18. The overwintering part of the first-brood larve commenced to cocoon about June 12, but the majority of the over- wintering larve came from the second brood. The life cycle from the time the spring pupx appeared until the last first-brood larvee cocooned occupied a period of six months. COMPARISON OF LIFE HISTORY IN 1910 AND 1911. From a comparison of figures 31 and 39 it is apparent that the main difference exists in the fact that the 1911 season was about two weeks later all through. This is quite to be expected from the colder and later season of 1911. Table LV shows a comparison of the life histories and various stages of the codling moth in 1910 and 1911. 166 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. TaBLE LV.—Comparison of life history and stages of the codling moth for 1910 and 1911. First-brood larvee Spring pupz. | First-brood eggs. in fruit. First-brood pup. Year. RS Gel 5 Poems ne A | '‘Maxi-| Mini- Aver- Maxi-'Mini- |Aver-| Maxi- Mini-| A ver-/Maxi-| Mini-| A ver- eas ae age. Mum.|/mum.) age. Mum.mum.| age. |mum./mum.} age. nest | ie Days. Days. | Days. ‘Days. Days. |Days. Days. |Days.|Days.| Days. Days. |Days. AOLO Ss oso 3 S54 Ake sen Rees 61 29 | 40.7 17 8 12.4 103 31 |48.8 55 11 | 19.04 NOU oe oe ons es See mil 30 | 42.4 15 10 |12.77 42 26 |34. 67 37 18 | 23.12 | Life cycle egg to egg. Second-brood eggs. ages righ Jarve in Year. | Maxi- | Mini- | Aver- | Maxi- | Mini- | Aver- | Maxi- | Mini- | Aver- | mum. mum. age. mum. mum. age. mum. mum, age. es Se es eS ee | Days. | Days. | Days. | Days. | Days. | Days. | Days. | Days. | Days. VONVO Hs oS. eas et eeds Seesse 2 | 101.4 58.4 | 78.62 17 7 10. 92 59 30 40 TOUS: > Sers2 6 Se hor ate nen 77 Of | agers 15 il 12.5 79 43 58.15 1 This is the sum of the length of life in the fruit and the post-larval stage. Consequently the sum of the two maxima, or 103 days, is theoretical, as the maximum life cycle was only 101.4 days. Similarly the sum of the two minima, or 26 days, is also theoretical. WEATHER RECORDS FOR 1909, 1910, AND 1911. During the three years that the codling moth has been studied at San Jose, Cal., a comparison of the weather conditions influencing the life-history records has been made. These records have been Pest [perrenaes | BcrameR 5 1 152025] 5 16152025] 5 10 15 2025 ae 10 1§ 2025 510 oe 5 10 ae Pest 10 15 2025 5 peter 5 10 | BcrameR li ii sl ‘i atin “ona tins TTS HHT Not FUNNLUNUUUUTUUNUAL inte ll ia vi i llth. < at Ha TUR HHT NS AEP LULA Fia. 39.—Diagram showing seasonal history of the codling moth during the season of 1911. (Original.) obtained through the United States Weather Bureau Station at San Jose, which is about 3 miles from the laboratory used for study- ing the codling moth. Table LVI presents the daily mean tempera- CODLING MOTH IN SANTA CLARA VALLEY. 167 ture for the growing season from February to October, inclusive, for the years 1909, 1910, and 1911; also the mean temperature for the month and the departure from normal. Table LVII is a summary of Table LVI and shows that in 1909 one month was normal, two were above normal, while the remaining six of the growing season were below normal. The total accumulated mean temperature for the 1909 growing season was 15.9° below the normal, giving an average monthly departure from the normal of —1.76°. The 1910 season shows four months above the normal and five below, with a total accumulated mean temperature for the growing season of 7.9 below normal, with an average monthly departure from the normal of —0.87°. The 1911 season shows one month above the normal and the remaining eight below, with a total accumulated mean temperature of 23.7° below normal for the growing season, which gives an average monthly departure from normal of —2.63°. The 1910 season was much the warmest and 1911 unusually cold— so much so that most stone fruits did not sugar up well. The 1910 season, barring June, which was very cold, was practically a normal growing season. Looking at the three seasons from a meteorological point of view, one should expect to find the largest percentage of the first-brood larve transforming in 1910, with a large second brood indicated by the band record, while 1911 should give the smallest percentage of transforming first-brood larve, with a smaller second brood indi- cated by the band record. The 1909 season should have given a larger percentage of transforming first-brood larve than 1911 but less than 1910 and a larger second brood than the 1911.and a smaller one than the 1910 season. Just what did happen is given under that paragraph comparing the seasonal history of the three years. TaBLe LVI.—Daily mean temperature for the years 1909, 1910, and 1911 at San Jose, Cal. } | | Date. 1909 1910 | 1911 Date. 199 =| 1910 | 1911 oR ON, alles OU °F, are Hi Hep: 12 56 42 | 54 || Feb. 18....- 52 46 54 Pease 58 43 | 56 19s 2h 48 49 48 BS tae 50 41 50 7 ae 47 | 48 46 Aes 48 43 52 Py eee 49 48 48 Bote ay 47 44 52 Pak 48 50 48 6 47 44 46 23. 52 58 48 Tl 46 50 44 24a; te 50 56 50 Bite 46 48 | 47 25. 48 | 50 44 Oren 46 2 46 26... 50 50 43 10S 47 | 50 49 7 54 49 40 yes 54 49 48 DR ey. 52 58 42 ae 52 | 51 47 - 1 eee 51 56 44 Total av .| 50.6 | 48.7 46.9 Mee 50 46 40 || Departure 1 ee 58 46 40 — from nor- | AG S266 60 48 41 mal for | | (na 54 48 46 month...| Normal. —1.9 —3.7 168: Tasie LVI.—Daily mean temperature for the years 1909, 1910, and 1911 at San Jose, DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Cal _—Continued. Date. Mar. ico: Total av. Departure from nor- mal for month... Total av. Departure from nor- mal for month... 1909 1910 1911 Date. or oR: ORR 54 60 44 May: (lee. 54 61 47 Doss 58 60 53 Os asic 47 54 49 45 43 47 52 52 aaa 50 52 51 6: 428 50 54 52 tee 50 54 57 Secs. 52 60 50 Gee: 54 58 50 LOE = 53 60 51 fi eae 50 52 54 ID: 258 50 55 56 TS eeee 52 58 58 1. ee 50 57 58 iGEeS SS 50 62 54 16... 50 62 53 Ms 52 56 57 18385 48 54 56 19a 46 56 52 2055.12 45 52 53 21... 47 54 55 D2 50 48 56 i a 48 48 58 24reyes 52 52 55 PA = 50 50 53 265-280 48 46 58 Diener 50 52 60 28-5 ois 48 54 65 OOM A 48 58 66 cies Seb 53 60 61 Bee 50.5 55.3 54.6 Total av . Departure from nor- mal for —3.2 +1.6 +0.9 month... 56 58 56 60 53 56 55 56 52 47 58 56 32 56 60 54 56 54 58 52 51 60 56 56 64 56 54 54 56 50 54 52 49 58 56 45 58 56 48 62 58 b2 64 62 56 62 62 56 62 66 60 51 59 53 50 60 56 52 58 56 54 61 56 56 66 HY 57 72 57 59 68 57 58 58 58 62 57 50 56 54 50 56 53 53 59 53 50 64 54 50 yal 58.1 53.8 Total av . Departure from nor- mal for +0.5 +1.5 —2.8 month... 1909 1910 1911 PF: °F. oF. 67 51 53 60 56 59 60 52 54 59 52 58 58 | 58 54 62 59 54 60 63 51 56 60 54 54 65 56 53 60 56 53 60 57 56 60 56 58 58 52 58 64 56 53 | 7 54 52 71 54 53 64 56 52 62 56 56 62 59 53 62 67 50 58 68 52 63 63 52 63 56 58 62 52 60 64 54 60 65 53 56 62 58 55 64 58 60 7 56 64 78 58 70 72 62 57.2 62.3 56.5 =ae5 SING al eee 63 65 60 63 62 62 60 58 62 58 58 60 56 54 61 64 54 60 62 57 60 58 64 58 66 7 62 63 62 64 60 62 67 57 61 60 52 54 60 56 57 61 66 58 64 60 58 64 56 56 * 65 57 55 68 60 58 64 62 56 62 63 56 55 70 56 54 78 62 58 68 65 58 65 70 61 64 64 70 59 60 62 58 58 60 56 59 58 62 62 64 61.4 59.8 61.5 366 i), < Boo. | aoe ° CODLING MOTH IN SANTA CLARA VALLEY. Date. Total av . Departure from nor- mal for month... Avg. to. Total av . Departure from nor- mal for month... Neen ne ee Cal.—Continued. 1911 Date. Sept. 1-.-... Totalav . Departure from nor- Total ay . Departure from nor- mal for month... —1.3 169 Taste LVI.—Daily mean temperature for the years 1909, 1910, and 1911 at San Jose, 170 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. Taste LVII.—A summary of Table LVI, showing the departures from normal of the average mean temperature for the growing season 1909, 1910, 1911, at San Jose, Cal. Departure from normal in— Month. 1909 1910 1911 At Bis Boe Lei 0) qa: 12h) See Renee See te 2e Copemrct ake pemene aos case nee ee s+ Normal. —1.9 — 3.7 IN Ita] ee een Fmt A se Seales je emeeeetas «Ss cHeaeecee se | — 3.2 +1.6 TEC) Arpril: eee nats o ase Sexes sce ciceaeene = Shae ne alee! ofall ctor ote | + .5 41.5 258 (MG ie Pete Seetene aol ee AMER aaa oo -o6 tb eeeesaaa = Wasaga maa = | — 3.5 +1.6 = 49 TREES spe eerie ee aes Bene ed Neat Sohn a ee eS... Sees - == SG => a= gar Hi hie ee erin benercoroe: Haan see Agee aaeas os ac aoe ag Ss | — 3.1 —1.4 —1.1 PANT UIS Gite oe carci iste ara c= eo aaa ea ee einer | — 2.1 ay — ae “Sj 8] fe) 8710121 Cle Se OR ErE Se aRn asa. See cbbac Se BeaPaagoecas. ccs agesoeseree | Bs Lobes Ly ey = B07 O70) 077) Ree Sate eae Se Soe eae s SUE eos ona ooo nase | =O] + .9 Sars Bee sa SE eRe eee 5 ena 250 35S ans cose Se |} —15.9 | —7.9 —23.7 Average monthly departure from normal. ...:.-.-.---------.------- | = 1s ay — 2.63 | COMPARATIVE LIFE-HISTORY STUDIES FOR THE SEASON OF 1909, 1910, AND 1911. The temperature conditions (see Table LVI) indicated that 1910 was a very warm season favorable for the development of the codling moth, while the 1911 season was very cold and unfavorable to this insect, with 1909 an intermediate season. The 1910 season, while apparently very warm, was a more normal season than the other two. On account of many lacking life-history records in 1909 but with a good band record, and a poor band record in 1910 but with com- plete life-history records, it is impossible to make perfect comparisons of the three seasons. An examination of both band records and rearing experiments shows the following data, however. (See Table LVIIL) Taste LVIII.—Summary of the band records for 1909, 1910, and 1911 along with rear- ing results, showing the comparative size of the broods and relative number of trans- forming and wintering larve. Percentages for— Larval collections. 1909 1910 1911 Transforming larvee—total band collection.......-..--..-.--------------- 27.6 (1) 18.0 Wintering larvee—total band collection. .....-.-.- 72.4 Q) 82.0 Relative proportion of first-brood larve......---- 95.0 | 2+50.0 50. 0 Relative proportion of second-brood larvee. -- ----- 5.0 | 2+50.0 50. 0 Transforming larve of first brood........------------ 33.5 33. 4 40.0 Winterine:larvssiotairsh blOO Cts. n= eee cldee ane = eee eee ere eat 66.5 66. 6 60.0 1 Band record from summer apples. 2 Approximately (from rearing records). The results as indicated by Table LVIII are not entirely in con- formity with expectations. The relative proportions for the broods for 1909 and 1910 appear correct in comparison with the weather conditions, but the relative proportions for 1911 seem incorrect after examining the weather condi- CODLING MOTH IN SANTA CLARA VALLEY. cag | tions for that year. Theoretically, on account of the very cold season there should have been a large first brood and a small second brood, which is further borne out by the small percentage of transforming larve of the total band collection. One fact is evident, however, there were more codling-moth larve present in the field in 1909 and 1910, which gave a larger series in the band records for these years in comparison with 1911. The 1911 season was apparently so cold early that moths did not Oviposit properly and the temperature conditions probably exerted such an influence that the infestation was light, therefore cutting down both broods and making them nearly equal. CONTROL OF THE CODLING MOTH ON PEARS AND APPLES IN THE SANTA CLARA VALLEY. While prunes, apricots, and cherries are the chief fruits raised in this valley, there are about 500 acres set to apples and 1,400 acres to pears. These orchards on the whole have probably paid better financially the past five years than many orchards of the first three varieties of fruits. Situated as they are, on the lower and wet but rich soils near Alviso, they have escaped the attacks of the chief insect pest to deciduous fruits in central California, the pear thrips (Euthrips pyri Daniel). The codling moth, aside from several species of plant-lice, has been practically the only insect worthy of the atten- tion of apple and pear growers in the Santa Clara Valley. It is needless to say that spraying, both good and bad, has been practiced for the codling moth, but the majority of the fruit growers have either sprayed at the wrong time or in an indifferent manner or have used ineffective poisons. The writers have seen apple orchards that had been sprayed three times during the season and these had from 75 to 80 per cent wormy fruit. Until the past two or three years there was a tendency to do slipshod work at low pressure, and even now many growers try to use too many leads of hose and to cover more trees with too little material. The practice of using four lines of hose on one spray outfit should be discouraged since it is difficult to maintain a suffi- ciently high pressure and the nozzle men frequently interfere with one another. It would be much better business to use more spray outfits, and even to spray from a tower. Data are presented here from one apple orchard and one pear orchard where the spraying was done after the directions of this bureau. On both orchards the work was in the nature of a commer- cial demonstration and it is in a way unfortunate that no checks could be obtained on the pear orchard, which was sprayed two sue- cessive years, although the early history of the place is known. 56602°—Bull. 115, pt. 3—183——5 172 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. THE O'TOOLE PEAR ORCHARD AT ALVISO, CAL. This orchard lies on a road intersecting the Alviso and Milpitas Roads about 6 miles north of San Jose and is, strictly speaking, in the Alviso section of the Santa Clara Valley. The soil is entirely ‘‘made soil,” the orchard itself being surrounded by a high levee. The type of soil is a very rich sandy loam styled ‘‘Fresno sandy loam”’ on the map by the United States Geological Survey. This orchard, 30 acres in extent, is composed of six varieties of pears and the trees are some of the finest in the State of California, many of them reaching a diameter of 8 to 10 inches at the base. During the years 1910 and 1911 the writers have, through the courtesy of Mr. George Reed, manager of this orchard for the Ander- son Fruit Co., been able to obtain figures on the wormy and non- wormy fruit. Mr. Reed, in talking with the authors, stated that the orchard usually contained from 15 te 60 per cent wormy fruit before it was placed in his hands, even when sprayed for the codling moth. The early Bartlett pears were seldom extremely wormy, but late varieties, such as the Winter Nelis and Easter Beurré, frequently had more wormy pears than clean ones. One peculiar fact relating to this orchard should be mentioned here. The west and north sides are closed in by a levee of the Coyote Creek, which is about 10 feet high. This has caused the orchard to blossom and mature its fruit about 10 days earlier than other orchards in the vicinity and has therefore made earlier spraying necessary also. Spraying operations—A power outfit was used both years at a high pressure and arsenate of lead as a poison at the rate of 2 pounds to 50 gallons of water. An old spraying outfit was used in 1910 and a new one in 1911; consequently much better work was done in the latter year. In all of the spraying large-chamber nozzles were used, one to each spray rod. All of the work was done from the ground, the men using 12-foot rods and 50-foot lengths of hose. Since no check on the spraying was left, no figures are presented here on the cost of spraying and the benefit derived, but a summary is given of the wormy and sound fruit of the trees examined under each variety. Season of 1910.—The fallen fruit was collected under five trees weekly throughout the season and examined for the entrance place of the worms on each of the six varieties. (See Table LIX.) 173 CODLING MOTH IN SANTA CLARA VALLEY. 88°F 18° e122 | SI6‘T | #8 Tes‘T | 669‘T | 0 6 g ial eset | 918 z or | 9% OL OFZ 8¢°% (fag 00°€% | 200‘T | 92 186 106 0 0 g € £06 O0T 0 Or €I & LL 9F'9 69'T €s°ST | 9ce &% eee 9&% 0 h 0 F (add OZ 0 CT f 61 101 Fe°9 €¢'T 16% | ZS cE LTS 9cF 0 c z Live 6hF 96 z LT 6 8% | $9 | nn a | et ——— + | 29'S LF 'T So°LT | SIF‘9 | 89T cr‘9 | 896°¢ | ¢ oF If 88 018‘G | Scr € rE «| «GF 08 cle €8°T 18° FOE | FSO'T | FI OFO‘T | 296, 0 € 0 € £96 18 10 L F II 92 £0°S E'S =| €0°6a | Zc‘ | 29 OLT‘T | SOIT | 0 rat FI 9% Z80‘T | PZT z €I 1Z 9¢ 88 09°% yO'l | FL 1% | 196, cZ 986. S16. z ¢ OL CT 006, oF 0 r 9 OT 9¢ 08 "1 6E°T £L'8 | GIL'T | 8 8g9iT | 9T9'T | Z Or OL a F6S‘T | SOT I f F 6 6 Sh '% £9°T CLL | 2FP‘T | 98° | TIPT | cee | T | FI L (a ogs‘T | 6 0 9 8 iat 18 $63 Roue €8'% «| 922'F | G6 SLAP MMIC Lame |G Il LP 09 1992 | Sos'tT | T 7 OT cg OLE ‘T 89 °% 08° F's =| c80‘T | 62 eco‘T | €TZ 0 1¢ at 02 £69 698 0 L 6 6 098 86'% 61% | 90°F 16 8% $16 c6S 0 if €1 FI T8¢ OPE I 6 F ial (469 628 29'F | 00°T OFS SI 82S OFS I | Il 9 ogg 00 0 I T jz S61 ore 0L° GL: Tso, F LYS #82 2 | «0 10 z Z 8S 19% 0) I if z C9z PT Z0'T 1e% =| 9OL‘T | OT 060‘T | €8Z I le F 8 CLL £2E 0 9 z 8 cle 86°% 92°T 16°ZI | LOL‘9 | Z8T Gz6‘S | e1z‘G | T ce | og 99 L¥1‘S | ¥68 I 16. lupe OIL sll (6a Clap 91°6 e9e‘T | 8 ose‘T | sct‘T | 0 Or g &I CFI ‘T | 90z 0 61 I 0% CST 9c" 19°T zo"Ts | 0L8, Tg 6E8 LES, 0 Il ¢ ial £28 ge 0 LI 0 I 91 8¢°% c6° 96°L TIS‘ | 68 Gly | 6StiT | T z 8 Il SPIT | G8 0 02 =| 8 8% POE 60°F FLT 000g | 99¢‘T | #9 zos‘t | 9gF‘T 10 6 OL & TIF ‘T | O&T I 9% | 2 68 16 6L°T SFO | 26°9 16L cT Z8L £29 0 € 0 € 029 PLT 0 6 € ral | ZOT “We}S | Opis} “xATep “ule}s | opis] “xA[eD ‘ o "901} *punoi3 . | “fk “AULIOM) . “f 4, | AULIOA Be el katy “ymay |+Sur0m | SUHOM ae PABOAN | gong a[s bora BHO | yo “10d ee suion {B10 q [ei0J, 40u *podlo}Ue SULIOM O1OU[ AA *polo}Ue SULIOM a10Y AA 9381199 | 938} 000 Te10O.L TROL -1dg -19g ‘901} U0 JIN *punois UO JIN y * poulquiod g-]T seedy, oe . 2. 2... Soa. pa eee eee 134-135, 155 natural enemies; . .2\2'.5.antes EU a A Pes ee ee 160-161 review of life-history work of 1910.32 20....2. J ogbieestl oats eee 142-143 INDEX, 185 Codling moth in Santa Clara Valley of: California—Continued. Page. fouow. OF lite-tistory wOrkoL 1911.2... 2222 seas es does eae 165 Peasant -histary phudion on 1909)... 050) Ger 2 2 oe as ble et a a 114-118 Gera -HISGOLy/SuddOs OF TONO.. sc: Ske ek o's en oc on ae ele ag = Soe 119-143 REAROHD = MIStOLvySbUCIeS Olpb Ole -- 25a lap ae teers 6, ie thy ne erreee 143-160 DPMS OTUOCIEP ON. «= 25 SR ar ielye hon cone «2 Padi SeheES Me nic in} arte ae eee ae 118 second-brood eggs, incubation period...............-...--.--- 135-140, 156-159 second-brood larvee, feeding period.......2......-.-.<----.-- 140-141, 159-160 pecone-prood Jarves, time onhatchine. 2.2. ob as ee oko outa cee eee 159 second-brood larvze, time of leaving fruit for wintering.......... 141-142, 160 RECOM ME OMOTA TOM =.= 2h ge a Sei OS wc her eee Phy ae 118, 135-142, 156-160 BECON GORETION OL TAT VES: (505205 cai OA sisi s Satae eines toss eee Sey pie oe 143-146 pean POC TENT kinier =: hi. hoe eit ot ee Sean ater ig SS coat ot ee 115 parine-praad: moths. Jonpevity-\AB... 26 << beife na o~ erect suas sh < aon ce 149-150 spring-brood moths, period of oviposition. .................--.-.-- 125-126, 149 spring-brood moths, relative percentage of larve wintering from band material and percentage emerging as first-brood moths the year larve WErerCOMPaLede meer ets oi 4a. 2 oi hah cepa a eee ok bo Son eee ee Lee 124-125 spring-brood moths, time of day moths emerged..........-.-.------ 125, 148-149 spring-brood moths, time of emergence..............-------------- 122-123, 147 spring-brood moths, time of emergence versus time wintering larvz leave IRN ERE CRON NPE eI cise 22 sole. SR ks oe are the igen 123-124, 148 isuee Aree GIHee ee Sac 2. oS ok a. 2 c's Hae Eada. sis a ae ee 114 spring-brood pup, comparative length of pupal periods of male and female Peer Peer Sees 2k. Jatin | RNS om 3 ede ade 4 a au saya 122 spring-brood pupe, length of spring pupal stage...............-.-..--- 120-122 Eprine-prood pupa, time of pupation. .:. 2.2.20... ---i-2..2 cesses eeu 119, 143 See A PEM ree eS 10 wo Jee tink gals ee Sega Se ee 180-181 temperature conditions for spring brood of pups, 1911..........-...-.-. 146-147 Paweumnenrecordsor 190961910. and: 1910) 208.2. ek ease ee 166-170 Codling moth, one-spray ‘method in control— PSH IRTOR No See e et Ae atte OL ee. CSR aoe Sa Loy le Pes eee Be 110-112 SepevIMen ta lit UMN WARG. 1. 250. ete a hei 55 nn Suilsa- o's) iad ok ee ae 98-102 BEN GNGS ll MOMMPANS scion 2 foul eanee Sieg inlem mosis «nie ea Say aerate 102-107 SRP PLUMeT see MAC MIO AIA tek ae oars Loe See els Genk = Sie 2 sees See ee 92-98 Pei erUINOTiiy Ae VAI SS ei a se BEL Sow tn 42 Stee ee eeeeee 87-91 ROMPRES .O TORMIEN Sek et. fo his aye ae Sea oes see ace POR eee ee 107-109 Davipson, W. M., Jones, P. R., and, paper, ‘‘ Life History of the Codling Riothiin the Sean th Clar aValley of Califomia.” 222... .2<5- kv nce et owe Distillate-oil emulsion, tobacco extract, and arsenate of lead acadhiat pear thrips See BROR ENE MIOUN: eo hoe Pane de go c.~ eh ok ose ee see etd eee OR eee 179-180 Puma -cnenty of codling Moth... .. ...