Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices 1 03. Bureau of Entomology, U. S. Dept. of Agriculture Plate I. Stages and Work of the Plum Curculio. LHOCNaCO .BAL.TI M O RE w,-„ i Tho artnlt or beetle lateral aspect; fig. 2, beetle, dorsal aspect; fig. 3, larva, or grub, llterkl aspect fig 4, pupa,' ventral aspect fi| 5 larva, 'and its work in cberry ; fig 6 injury to ripe pPeacb; fg 7,PfePeding punctures and scars from egg punctures on apple. Figs. 1-4, enlarged about 8 times; Figs. 5-7, natural size. (Original.) U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY-BULLETIN No. 103. L. O. HOWARD, Entomologist and Chief of Bureau. THE PLUM CURCULIO A. L. QUAIXTAXCE, In Charge of Deciduous Fruit Insect Investigations, AND E. L. JENNE, Agent and Expert, Deciduous Fruit Insect Investigations, Issued July 13, 1912. WASHINGTON: GOVERNMENT PRINTING OFFICE. 1912. BUREAU OF ENTOMOLOGY. L. 0. How ard, Entomologist and Chief of Bureau. C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief. R. S. Clifton, Executive Assistant. W. F. Tastet, Chief Clerk. F. H. Chittenden, 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. Webster, in charge of cereal and forage insect investigations. A. L. Quaintance, in charge of deciduous fruit insect investigations. E. F. Phillips, in charge of bee culture. D. M. Rogers, in charge of preventing spread of moths, field work. Rolla P. Currie, in charge of editorial work. Mabel Colcord, in charge of library. Deciduous Fruit Insect Investigations. A. L. Quaintance, in charge. Fred Johnson, E. L. Jenne, S. W. Foster, P. R. Jones, F. E. Brooks, A. G. Hammar, E. W. Scott, R. L. Nougaret, R. A. Cushman, L. L. Scott, J. B. Gill, A. C. Baker, W. M. Davidson, E. B. Blakeslee, W. B. Wood, E. H. Siegler, F. L. Sim anton, entomological assistants. J. F. Zimmer, N. S. Abbott, W. H. Sill, entomological assistants, employed in enforce- ment of insecticide act, 1910. 2 LETTER OF TRANSMITTAL. U. S. Department of Agriculture, Bureau of Entomology, Washington, D. C, October 24, 1911. Sir: I have the honor to transmit herewith for publication a full account of the plum curculio. This is a native insect, and from the earliest times has ravaged the plums, peaches, and other deciduous fruits grown around the home and in large commercial orchards. The total annual loss occasioned by this pest by reason of its attacks upon its several food plants amounts to several million dollars, and until recently there has been no very practical method of controlling it. The plum curculio has been under careful investigation by this bureau during the past several years, and, although it has been the subject of many papers by entomologists and others, it has not here- tofore received the painstaking investigation which its importance demands. The present paper is an important contribution to our knowledge of the insect, and points out the remedial measures to be employed in its control. I recommend the publication of this manuscript as Bulletin Xo. 103 of this bureau. Respectfully, L. O. Howard, Entomologist a nd CMef ofBu re a u . Hon. James Wilson, Secretary of Agriculture. 3 PREFACE. The present bulletin gives results of studies of the plum curculio that, with considerable interruption, have been in progress since the spring of 1905. The work has been done for the most part in con- junction with other investigations at the field laboratories in Decid- uous Fruit Insect Investigations, Bureau of Entomology, located in important fruit-growing sections and representing a considerable range of climatic and other conditions. Data have thus been ob- tained on the biology of the insect in northern, central, and southern localities in its range of distribution, as in western New York and northwestern Pennsylvania, in the environs of Washington, D. C, and in Georgia. Studies for one season were made in the Ozark region of Arkansas, well toward its limit of occurrence to the southwest. The observations presented, therefore, fairly well cover the distribution of the species, though for the respective localities the results are not entirely comparable, as for one reason or another it was found imprac- tical for the several workers Jto carry out uniformly the outline of studies originally prepared. In the case of but few native American insects are there earlier or more complete records of depredations than is true of the plum cur- culio. From the time of its first noted injuries, about 175 years ago, until the present day this insect has been execrated by commercial and amateur fruit growers alike. If we are to judge from the writings in the earlier horticultural and agricultural papers, it was especially despised by the early settlers for its destruction of choice varieties of plums and other stone fruits grown around their homes, and the number of remedies proposed was legion. Many workers have con- tributed to our present knowledge of the plum curculio, and their writings have been freely used in the present paper. Among these may be mentioned Fitch, Walsh, Riley, Trimble, Forbes, Howard, Weed, Stedman, Crandall, and others. Several members of the force engaged in Deciduous Fruit Insect Investigations have made important contributions to this report, as later credited in the text. Mr. James II. Beattie spent a part of the season of 1905 in Georgia, and Mr. A. A. Girault during the same year was engaged in life-history observations in the insect ary at Washing- ton. During 1906 Mr. Girault, with ^Ir. A. II. Rosenfeld, spent the season in Georgia working on the curculio and other peach insects, and the year following the former gentleman made observations on this insect in southern Ohio. Mr. Girault's careful studies have been of the greatest value. During 1905 Mr. Fred Johnson gave considerable 5 6 THE PLUM CURCULIO. attention to life-history studies of the curculio in western New York, as also the year following in northwestern Pennsylvania, in addition to numerous field experiments in spraying during these and subse- quent years. During 1908 Mr. S. W. Foster and the junior author car- ried out extensive life-history investigations and field experiments in northwestern Arkansas, and similar work was accomplished the same season in the environs of Washington, D. C, by Mr. P. R. Jones. Dur- ing 1909 work on the curculio was limited largely to experiments with sprays in orchards, made in conjunction with experiments against the codling moth, and carried out in Arkansas and Missouri by the junior author and Mr. F. W. Faurot, in Virginia by Messrs. J. F. Zimmer and E. W. Scott, and in Michigan by Mr. R. W. Braucher. In 1910 impor- tant life-history observations were made in Michigan by Mr. A. G. Hammar, and many additional data on the curculio in the South were obtained during the same year by the junior author and Mr. E. W. Scott, with headquarters at Barnesville, Ga. In much of the orchard- spraying experiments on both peach and apple the work has been done in cooperation with Mr. W. M. Scott, of the Bureau of Plant Industry of this department. Several publications on the plum curculio have been issued during the course of the work. An article on this insect was published in the Yearbook of the department for 1905 in a paper entitled "The principal insect enemies of the peach." Circular 73 of the Bureau of Entomology, on the plum curculio, by Messrs. Fred Johnson and A. A. Girault, was published in 1906; and the results of a comparison of the demonstration and one-spray methods in the control of the codling moth and plum curculio were published in November, 1910, as Part VII of Bulletin No. 80 of the Bureau of Entomology, a revised edition of which was issued March 30, 1911. Circular 120 of the Bureau of Entomology, entitled " Control of the Brown-rot and Plum Curculio on Peaches," by W. M. Scott, of the Bureau of Plant Indus- try, and the senior author, was issued in March, 1910. This gave instructions for the preparation and use of a combined spray for the curculio and fungous diseases of the fruit of the peach. The results of further experiments in peach spraying for the curculio, brown-rot, and scab were given in Farmers' Bulletin 440, by W. M. Scott and the senior author, published in March, 1911. In the present paper are brought together the more detailed results of the studies of this insect which have been in progress, including some of the data which have been already published. Especial attention has been given to presenting the data as far as possible in tabular form, with necessary discussion of the tables to bring out the more important points. A. L. QUAINTANCE, In Charge of Deciduous Fruit Insect Investigations. CONTEXTS. Page. Classification and synonymy 13 Common names 14 History 15 Distribution 19 Western limit of occurrence 21 Northern limit of occurrence 24 Southern limit of occurrence 25 Distribution of the curculio according to life zones 25 Reported introductions of the curculio 26 Losses due to the plum curculio 27 Insects likely to be mistaken for the plum curculio 28 Description 30 The egg 30 The larva 30 The pupa 32 The adult 33 Food plants 33 Fruits in which the larvae fail to mature 38 Life history and habits 39 The egg 39 Number of eggs deposited 39 Length of egg stage 48 The larva 54 Habits of larvae just hatched and course taken in fruit 54 Larval instars 55 Death of larvae in fruit 56 Desertion of fruit by undersized larvae 59 Normal emergence of larvae from fruit during the season 60 Manner of leaving the fruit and entering soil 64 Time spent in the fruit (egg and larval stages combined) 65 The pupa= 73 Length of time spent in the soil 73 Length oi pupal stage, and time spent in soil before and after pupation . 83 Depth or pupal cell 87 Soil conditions affecting transformations of the curculio in the ground . . 88 The adult 92 Period of emergence of beetles 92 Proportion of sexes 95 Choice of food by curculio 96 Extent of feeding of the respective sexes 98 Operation of egg laying 99 Egg and feeding punctures: Position on fruit and variation in form . . . 103 Relative number of feeding and egg punctures 106 Activity of the beetles in egg laying and feeding, by day and by night . . 107 Time required for transformation from egg to adult 110 7 8 THE PLUM CURCULIO. Page. Seasonal history 112 Time of appearance of beetles in spring 1 12 Relation of temperature to appearance of beetles 118 Occurrence of beetles in orchards 120 Number of generations annually 125 Beetles from emergence to hibernation 127 Hibernation 129 Mortality of the curculio during hibernation 132 Percentage of fruit punctured or infested by the plum curculio 134 Natural enemies 139 Parasitic insects 140 (Anaphes) Anaphoidea conotracheli Girault 140 (Sigalphus) Triaspis curculionis Fitch 142 (Sigalphus) Triaspis curculionis var. rufus Riley 146 (Porizon) Thersilochus conotracheli Riley 147 (Bracon) Microbracon mellitor Say 148 Bracon dorsata Say 148 Other hymenopterous parasites 148 Myiophasia senea Wiedemann 149 Cholomyia insequipes Bigot 150 Pegomija fusciceps Zett 151 Predaceous insects 152 Fowls and birds as curculio destroyers 154 Remedial measures 155 Historical 155 Premiums for remedies for the curculio 167 The Ransom chip process 168 Jarring for the curculio 168 Present status of jarring 172 Cultivation for destruction of pupae 176 Spraying with arsenicals 178 Feeding experiments with poisons 185 Spraying for the curculio on apple 189 Early experiments 189 Experiments by the Bureau of Entomology 193 Experiments at Anderson, Mo 193 Experiments in western New York and northwestern Pennsylvania . 1 95 Experiments at Siloam Springs, Ark 196 Experiments in Virginia 197 Experiments at St. Joseph, Mo 198 Conclusions 200 Scheme for spraying apple orchards 201 Spraying peaches with arsenicals 202 Some results of spraying peaches for the curculio 208 Directions for the preparation of self -boiled lime-sulphur wash 212 Directions for using arsenate of lead 213 Schedule of applications 214 Midseason varieties 214 Late varieties 214 Early varieties 214 Spraying plums and cherries 215 Some results of spraying plums 216 Results of spraying cherries 218 Economic bibliography 219 Index 243 ILLUSTRATION'S. PLATES. Page. Plate I. Stages and work of the plum curculio. Fig. 1. — The adult or beetle, lateral aspect. Fig. 2. — Beetle, dorsal aspect. Fig. 3. — Larva. Fig. 4. — Pupa. Fig. 5. — Larva, or grub, and its work in cherry. Fig. 6. — Injury to ripe peach. Fig. 7. — Feeding punctures and scars from egg punctures on apple Frontispiece. II. Work of plum curculio on plum. Fig. 1. — Egg and feeding punctures on young wild-goose plum. Fig. 2. — Nearly ripe wild plums, showing egg scars and gum exudation from feeding punctures 32 III. Work of plum curculio on plum. Fig. 1. — Effect of egg and feeding punctures, with gum exudations, on ripe Japanese plums. Fig. 2. — Fall feeding punctures on ripe prunes 32 IV. Work of plum curculio on peach. Fig. 1. — The adult curculio on newly set peach. Fig. 2. — Curculio larva, or grub, and its work in ripe peach 36 V. Work of plum curculio on peach. Fig. 1. — Wormy windfall peaches. Fig. 2. — Peaches deformed by egg and feeding punctures 36 VI. Work of plum curculio on peach. Fig. 1. — Deformed ripe peaches. Fig. 2. — Gum exudation from curculio punctures 36 VII. Work of plum curculio on apple. Fig. 1. — Egg and feeding punctures on young apples. Fig. 2. — Egg punctures on apple some days old.. 40 VIII. Work of plum curculio on apple. Fig. 1. — Young apples, showing scars from egg punctures. Fig. 2. — Ripe apples deformed and knotty from egg and feeding punctures of the curculio 40 IX. Work of plum curculio on apple. Fig. 1. — Imperfectly developed apple from tree in which curculio grubs matured. Fig. 2. — Small drop apples in which curculio grubs matured. Fig. 3. — Nearly ripe summer apple from ground, showing extent of feeding by two curculio larva? 40 X. Injury by plum curculio to pears. Knotty and deformed ripe pears resulting from egg and feeding punctures 44 XI. Plum curculio injury to cherries. Cherries cut open, showing the grub and its work 44 XII. Methods of study in plum-curculio investigation, Barnesville, (la. Fig. 1. — Out-of-door house used in Life-history work. Fig. 2. — Soil cages used in obtaining data on life of insect in ground 48 XIII. The fall feeding punctures of the plum curculio on apple. Fig. 1. — Characteristic holes eaten into apple by the beetles in the fall. Fig. 2. — Feeding punctures of beetles on summer apples 12S XIV. Jarring apparatus in use or recently in use against the plum curculio. Fig. 1. — A wheelbarrow curculio catcher used in New York State. Fig. 2. — Curculio catcher made by sheets on frames, in use a few years ago in Georgia 172 9 10 THE PLUM CUECULIO. Page. Plate XV. Benefits of spraying apples for the plum curculio. Fig. 1. — Duchess apples from trees in unsprayed plat. Fig. 2. — Duchess apples from trees in plat sprayed against the plum curculio with arsenate of lead 196 XVI. Conditions favoring the plum curculio. Fig. 1. — Native plum thicket in the south, adjacent to peach orchard. Fig. 2. — Woods and thicket adjacent to plum orchard, furnishing the beetles with excellent hibernation quarters 200 XVII. Effect of arsenical sprays on peach foilage, Arlington Farm, Va. Fig. 1. — Unsprayed or check tree. Fig. 2. — Tree sprayed once with commercial arsenate of lead. Fig. 3. — Tree sprayed once with homemade arsenate of lead. Fig. 4. — Tree sprayed once with Paris green. Fig. 5. — Tree sprayed once with green arse- noid. Fig. 6. — Tree sprayed once with arsenic sulphid 208 XVI II. Arsenical injury to fruit. Fig. 1. — Elberta peach sprayed three times with arsenate of lead, showing burning and cracking effect of the poison. Fig. 2.— Japanese plums, showing burning from one application of arsenate of lead 208 XIX. Field experiments in Georgia for control of plum curculio and peach diseases. Fig. 1. — Gasoline power outfit in operation. Fig. 2. — Determining results of spraying, each peach being cut open 212 XX. Size of peaches at time of first spraying with arsenate of lead, show- ing on the left the earliest and on the right the latest stages in development when this treatment should be given 214 TEXT FIGURES. Fig. 1. Herbst's figure of plum curculio, accompanying the original descrip- tion in 1797 16 2. An early illustration of the plum curculio, frequently used between about 1830 and 1850 17 3. Peck's figure of the plum curculio, published with his description (Rhynchsenus cerasi) in 1819 ' 17 4. Map showing by the shaded area the distribution of the plum curculio. . 25 5. The apple curculio (Anthonomus quadrigibbus) 28 6. The plum gouger (Anthonomus scutellaris) 28 7. The acorn weevil (Balaninus victoriensis) 29 8. Fuller's rose beetle (Pantomorus fulleri) 29 9. Imbricated snout beetle (Epicxrus imbricatus) 29 10. The plum curculio ( Conotrachelus nenuphar) : Egg 30 11. The plum curculio: Larva, showing structural details 30 12. The plum curculio: Head of larva, with parts named 31 13. The plum curculio: Head of larva, lateral aspect, with parts named.. 31 14. The plum curculio: Head of larva, ventral aspect, with parts named. . 31 15. The plum curculio: Lateral, dorsal, and ventral aspects of right man- dible of larva, with muscles 31 16. The plum curculio: Dorsal aspect of maxilla and labium of larva, with parts named 32 17. The plum curculio: Pupa, showing structural details 32 18. The plum curculio: Mouth parts of the adult 33 19. Black-knot of plum, showing, on the left, infestation by plum- curculio larvae 37 ILLUSTRATIONS. 11 Page. Fig. 20. Diagram showing normal emergence from fruit of larvae of plum cur- culio during season at Siloam Springs, Ark., Barnesville, Ga., Wash- ington, D. C, and Douglas, Mich 61 21. Diagram showing normal emergence from soil of beetles of the plum curculio for the season at Barnesville, Ga 94 22. Diagram showing normal emergence from soil of beetles of the plum curculio for the season at Siloam Springs, Ark 94 23. The normal plum-curculio egg puncture and egg 105 24. Diagram of portion of peach orchard used in jarring experiments against the plum curculio, Barnesville, Ga. , 1910 122 25. (Anaphes) Anaphoidea conotracheli, an egg parasite of the plum cur- culio 140 26. (Sigalphus) Triaspis curculionis , an important parasite of the plum curculio 142 27. (Porizori) Thersilochus conotracheli, parasitic upon the plum curculio . 147 28. (Bracon) Microbracon mellitor, an occasional parasite of the plum cur- culio. . . . 148 29. Myiophasia senea, a dipterous plum-curculio parasite: Male and head of female 149 30. Cholomyia insequipes, a fly reared abundantly from the plum cur- culio at Barnesville, Ga. : Adult, puparium in curculio larval skin. 151 31. Chrysopa oculata 153 32. Harpalus pennsylvanicus, a ground beetle predatory upon the plum curculio 153 33. Chauliognathus pennsylvanicus 154 34. A simple form of curculio catcher for use by one person 170 35. A cumbersome wheelbarrow type of curculio catcher developed and patented about 1869 171 36. A light wheelbarrow curoulio catcher for sale as iate as 1905 171 THE PLUM CURCULIO CLASSIFICATION AND SYNONYMY. The Rhynchophora, or snout beetles, to which suborder the plum curculio belongs, constitute a very large and important group of coleopterous insects, comprising some of our worst insect pests, as the cotton-boll weevil, grain and rice weevils, nut weevils, plum gouger, strawberry weevil, etc. The genus Conotrachelus is distinctly American. Le Conte and Horn, in the Rhynchophora of North America, published in 1876, list for this genus 26 species from America north of Mexico. There are, however, many representatives of the genus, the species being especially abundant in the Tropics. Champion, in Volume IV, part 4, of the Coleoptera of the Biologia Centrali Americana, has listed 188 species, and states that about 200 have been described (1906). The plum curculio was first characterized and named in 1797 by Hcrbst in his "Natursystem aller bekannten in- und auslandischen Insekten-Kafer " and figured under the name Curculio nenuphar, the original description being as follows:1 587. Curculio Nenuphar. Zleun unb neun3ta,fte (lafcf. £ig« 8. H. Mus. Herschel. Cure, longirostris fusco griseoque variegatus, inaequalis, thorace punctis duobus elevatis nigris, elytris lineis elevatis interruptis, dorso gibber cari- natus. Per Kdfer ift obna.efaf)r britteijafb £inicn [ana, braun unb gteiSfdjecftg, bio (Dberjttidp fctjr uneben. Per Rfiffel ift faft fanner, aI3 bet oruftfdjifb, ^iemftdj bttf, nmb, a.efriimmt braun unb gretefdjecfig, am at§er puntt, unb ein f feinerer naif) fnnten ju, bie ffeineren ftet)en etu>a3 bitter an ber ITiittelltnie. Da§ SdjilMein liegt tief. Die Decffdnfbe ftnb braun unb greiSfdjetfig, unb Jjabeit erfyorjete ftets abgebrodjene £inien,einige erfyofyen fid) nteljr, anbre roeniger, eine auf ber ITtitte neben ber ZZatt) erfyorjet fid) meit ftarfer, al§> bie iibrigen, unb toirb ein grower fchruarjer, Idngfictjer, fdjarf, !ie(= formig ert)6r)eter fjocfer; merjr nacf) ber Sptrje gu and) neben ber Hail) ftcfyt toiebcr eine ftar! erf)of)ete abgebrodjene £inie, bie jroerjte am Hang, abcr nidjt ber auf bem Hiicfen gteid). Die ^itfte ftnb and) braun unb greigfchecf tg, bie fyiiften gme^mat gebornt. I)a3 Daterlanb tft ZTorbamerifa. In 1802 the insect was redescribed by Fabricius in Systema Eleu- theratorum under the name Rhynclisenus argula; in his catalogue of the Insects of Pennsylvania, published in 1806, Rev. F. V. Mel- sheimer used for the plum curculio the name Curculio persicse; and in 1819 Peck in the Massachusetts Agricultural Repository and Journal named the species Rhynchsenus cerasi. Dejean lists the cur- culio in his Catalogue des Coleopteres, published in 1833, as Cono- trachelus variegatus, and in Sturm's Catalogue (1843) it is given as ConotracJielus gibbosus Melsheimer. The generic position of the insect has been changed from time to time according to the ideas of different writers. Our species appears first to have been referred to Cono tracheitis in 1837 by Schoenherr in his Genera et Species Curculionidum under Fabricius's name argula. This genus, accredited by some writers to Latreille, was fully characterized by Schoenherr, who is cited by Le Conte and Horn and by other systematists as author of the genus. In Say's Ento- mology of North America, published in 1831, the name Crypto- rhyncus argula is used. The present synonymy of the species is therefore as follows: 1797. Curculio nenuphar Herbst, Kafer, Natursystem aller Insekten, VII, p. 29, Tafeln, 99, f. 8, H. 1801. Rhynchxnus argula Fabricius, Systema Eleutheratorum, II, p. 467. 1806. Curculio persicx Melsheimer, Catalogue of the Insects of Pennsylvania (No. 589), p. 28. 1819. Rhynchxnus cerasi Peck, Mass. Agric. Repos. and Journ., V, p. 312. 1831. Chryptorhynchus argula Say (Descr. N. Am. Curculionides), Ent. North America, I, p. 285 (1859). 1833. Conotrachelus variegatus Dejean, Cat. des Coleopteres, 2d ed., p. 297; 3d ed., p. 321; lists as variegatus. 1843. Conotrachelus gibbosus Melsheimer, Sturm's Catalogue, p. 222. COMMON NAMES. The plum curculio has been referred to in literature under many common names, as the fruit curculio, curculio, cherry weevil, peach weevil, peach curculio, peach worm, plum curculio, nenuphar, little Turk, Turk, kerkelo, little joker, etc. Simply " curculio" or " fruit curculio" was employed in many of the earlier articles, though "plum weevil" is also frequently to be noted, The word curculio is of HISTORY. 15 Latin origin. It was used by Cato in De Re Rustica (p. 92), 201 B. C, and other writings; also by Palladius, A. D. 210; by Pliny; and by other Roman authors. It is the name of a well-known comedy of Plautus. In its Latin signification the curculio means a cornworm or weevil, and probably for this reason the name was adopted by Linnaeus in his Systema Naturae, as the genus for a large and di- verse assemblage of species of snout beetles. While the Linnaean genus Curculio has long since fallen into disuse by entomologists, the various species having been distributed into other genera, the word is retained in the English vocabulary and applied with qualifying adjectives as the common names of several species of snout beetles, e. g., the plum curculio, rhubarb curculio, poplar curculio, willow curculio, etc. As between the numerous common names applied to the insect under consideration, plum curculio has perhaps become most firmly established from frequent use in the economic literature of the past 20 or 25 years, and the name has recently been adopted by the American Association of Economic Entomologists. It is nevertheless misleading since, while partial to plums, the curculio also injures numerous other fruits. In fact its omnivorous habits as regards stone and pome fruits make it unique among a group of weevils which as a rule confine themselves to one or but few food plants. HISTORY. Few American insects have been more written about than the plum curculio. The earliest statement referring to this insect which we have seen is in a letter from Peter Collinson to John Bartram, evidently in response to a complaint by 'Bartram in an earlier com- munication. Under date of February 3, 1736, Collinson wrote: "I never heard it was insects that annoyed your plums, apricots, and nec- tarines. If they are, water that has tobacco leaves soaked in it will kill them by making a basin around the trees, watering them fre- quently with the water." This reference considered alone might appear to refer to the peach-tree borer. Subsequent correspond- ence, however, between Bartram and Collinson, cited under history of remedies (p. 156), indicates that probably the curculio was the insect referred to. There are, later, undoubted references to this insect in the correspondence between these two gentlemen, which are quoted on page 156. It would appear that the curculio had become quite troublesome, at least in the environs of Philadelphia, before 1750. A note by the Swedish naturalist, Peter Kalm, under date of May 18, 1749, and quoted in the bibliography, leaves no doubt of the prevalence of the species in the territory about which he was writing namely, New Jersey. The original description of this species by Herbst in 1797 indicates that by that time the insect had found it- 16 THE PLUM CUECULIO. way into European collections. Benjamin Smith Barton, writing in 1802, states: "The unripe fruit of the peach is greatly injured by the curculio, but the insects most pernicious to the trees are two lepidopterous insects of the genus Zygsena of Fabricius. These, while in the larval state, destroy the bark of the root." An extended account of the curculio by Dr. James Tilton was published in Willisch's Domestic Encyclopaedia in 1804. A con- siderable knowledge of the insect is shown at this early period and the article was much quoted by subsequent writers for several years. With the increase in the number of journals and papers devoted to horticulture and agriculture, references to the curculio were much more frequent. During the first 30 years of the nineteenth centur}' numerous short articles and notes appeared, the following being among the more important contributors: Dr. James Tilton, J. E. Muse, James Thacher, S. L. Mitchell, William Prince, William Fig. 1. — Herbst's figure of the plum curculio; accompanying the original description in 1797. Wilson, and W. D. Peck. (See figs. 1 and 2 for early illustrations of the plum curculio.) Beginning about 1830 there was a noticeable increase in the number of references and articles relating to this pest from practical fruit growers and others, giving their experience in the use of remedies and suggesting plans for circumventing its injuries. Some of the more important writers between 1830 and 1850 were David Thomas, S. Reynolds, R. P. Hildreth, William Wilson, B. Manley, Dr. Joel Burnett, John Parsons, A. J. Downing, James Matthews, C. E. Goodrich, and there were many others. Excepting Melsheimer (see bibliography), the plum curculio ap- pears to have been first treated by an American entomologist in 1819, when it was described as Rhynchsenus cerasi and figured (fig. 3) by W. D. Peck, who considered it the cause of black-knot of cherries and plums, from the fact that the insect was reared from these HISTORY. 17 Fig. 2. An early illustration of the plum curculio, frequently used between about 1830 and 1850. excrescences. In his Entomology of North America, published in 1831, Thomas Say refers to the curculio as Cryptorfojn'lius argula, and gives the opin- ion of his kinsman, Bartram, as to its destructiveness. A fairly extended ac- count of the insect is given by Harris in his Insects In j ur- ious to Vegetation, published in 1841, and it was con- sidered at length by Dr. Asa Fitch in his address on the curculio and black-knot of plum trees, delivered be- fore the New York State Agricultural Society in 1860 (p. 839). The most complete account of the insect up to this time, however, was that by Dr. Isaac P. Trimble in his Treatise on the Insect Enemies of Fruits and Fruit Trees, published in 1865. In this work 99 quarto pages are devoted to the curculio, accompanied by 8 colored plates. Many observations are presented as a result of personal investigation. Important contributions to a knowledge of the insect are given in the articles by Walsh in the Prac- tical Entomologist for 1867 (pp. 75-79), and in the First An- nual Report od the Noxious Insects of Illinois (pp. 85-96). In the First Missouri Report, published in L869, Dr. C.V.Riley gives an extended account of the cur- culio, summarizing the knowledge con- cerning it up to that time, and in the Third Missouri Report (1871, pp. 11-29) gives further information on its life history, with an ex- 17262°— Bull. 103—12 2 Fig. 3.— Peck"s figure of the plum curculio, published with his descrip- tion (Rhynchxnus ccrasi) in 1819. 18 THE PLUM CUECULIO. tended discussion of apparatus for jarring. Also during the same year there was published in the American Entomologist (vol. 1, pp. 130- 136) a popular account of the curculio, this being a lecture given by Dr. Riley before the Illinois State Horticultural Society. Numerous references, or more or less extended articles, concerning this insect are to be found in the writings of the earlier entomologists, as William Saunders, William Le Baron, Townend Glover, A. J. Cook, J. A. Lintner, and others, but the writings of Walsh and Riley were per- haps of most importance. References to the plum curculio notably increased with the estab- lishment of the agricultural experiment stations. Dr. S. A. Forbes, in Illinois, had already given some attention to this insect, publish- ing interesting observations on the use of poisons in its control as early as 1885. Experiments in spraying with arsenicals had been undertaken by W. B. Alwood, working under the direction of the entomologist of the United States Department of Agriculture, begin- ning with the season of 1887, and an extended summary account of the insect, by C. V. Riley and L. O. Howard, was published in the Report of the Commissioner of Agriculture for 1888. During this latter year Prof. C. M. Weed, of the Ohio Agricultural Experiment Station, began experiments in the use of arsenicals in its control, which were continued during the two or three subsequent seasons. Similar tests were reported by Prof. A. J. Cook in 1887 from Michigan, and in 1890 Prof. C. P. Gillette, in Bulletin 9 of the Iowa Agricul- tural Experiment Station, gave results of experiments and observa- tions on the curculio and plum gouger carried out during the season of 1889. A specific investigation of the curculio as an apple pest was begun b}^ Prof. J. M. Stedman in Missouri in 1900 and continued during 1901 and 1902. Results of his investigations were given in Bulletin 64 of the Missouri Agricultural Experiment Station, published in July, 1904. Prof. C. S. Crandall, in Illinois, began in 1903 a thorough investigation of the insect as an apple pest, continuing the work during the folio whig year. Results of his investigations and studies on the plum and apple curculios are published in Bulletin 98 of the Illinois Agricultural Experiment Station (1905) and comprise per- haps the most comprehensive account of the life histories of these two insects thus far given, as well as results of experiments with arsenical sprays on a commercial scale. The year following Prof. Forbes, in Bulletin 108 of the Illinois Agricultural Experiment Sta- tion (1906), reported results of experiments with arsenical sprays on a commercial scale, showing in connection with the work of Prof. Crandall that notably less injury to apples resulted following the thorough use of arsenate of lead. During the same year Prof. M. V. Slingerland reported results of cooperative spraying against the DISTRIBUTION. 19 curculio carried out during 1904 between the Agricultural Experi- ment Station of Cornell University (Bulletin 235) and certain fruit growers in western New York. Mr. E. P. Taylor, in Bulletin 21 of the Missouri State Fruit Experiment Station, reports results in spraying for the control of the curculio on apple as obtained by him in the Ozark regions of Missouri. Observations on the curculio and results of experiments are given by W. W. Chase in Bulletin 32 of the Georgia State Board of Entomology, published in 1910. Beginning in 1905, investigations of the curculio were undertaken by the Bureau of Entomology of this department, and more or less attention has been given to this insect up to the present time. The investigation has included an inquiry into the life history and habits of the insect in various parts of fhe country and the carrying out of experiments in spraying on a commercial scale in its control on peaches, plums, and apples. As a result of the work in 1905, recom- mendations concerning the use of an arsenate-of-lead spray on peaches were given in the Yearbook of the Department of Agriculture for that year (p. 329) and in Circular 73 of the Bureau of Entomology. In the course of experiments to determine the comparative value of the one-spray method in the control of the codling moth much infor- mation was obtained on the value of spraying for the curculio, the results of which were published in Bulletin 80, Part YII, of the Bureau of Entomology. A decided advance in spraying stone fruits, especially peaches, was made with the establishment of the practicability of the control of brown-rot, scab, and curculio on peaches by the use of a combined spray of lime-sulphur and arsenate of lead. Recommendations for the preparation and use of this spray were given in Circular 120 of the Bureau of Entomology, and in Farmers' Bulletin 440 results of further experiments and demonstrations were given. In the foregoing historical sketch it has been attempted to indicate only the principal contributions or landmarks in the progress of knowledge concerning this insect and the remedies against it. By turning to the bibliography (p. 219) the reader will find reference to most of the contributors, although the list of titles could still be considerably lengthened. DISTRIBUTION. The curculio is indigenous to the eastern United States, and has probably always occupied about its present range of distribution. In some of the earlier accounts of the insect the inference is given that it had gradually spread westward from more eastern regions. As shown elsewhere (p. 156), its injuries were first noted in the neighborhood of Philadelphia about 1736. 20 THE PLUM CURCULIO. Under the caption, "The curculio in Michigan," a Mr. Adrian, writing in The Cultivator in 1852, says: I propose in this communication to speak of the progress of the curculio in southern Michigan. I have been a resident of Lenowee County for the last 18 years. The first depredations of this insect commenced about six years ago, the first season attack- ing only a few of our choicest plums; the succeeding year they were more numerous, and since continue to increase from year to year, puncturing every variety of plum and also cherries to a considerable extent and in some instances often, apples. Dr. Asa Fitch in his Essay, published in I860, says: As an evidence of its steady progress and increase [in New York State] during the past 40 years, I may state that in my boyhood the wild plum trees in my own vicinity were often well filled with fruit. But, though thrifty trees are still growing on several of the same places, I have never since that time seen a ripened plum upon any of them. A more recent statement relative to the invasion by the curculio of new territory (in Wisconsin) within its range of distribution is that by Prof. E. S. Goff in Insect Life (vol. 6, p. 37) : Until recently the peninsula lying between Green Bay and Lake Michigan has been free from invasion by the curculio (Conotrachelus nenuphar), and until the present summer (1893) it has never been found in any part of this peninsula lying north of Sturgeon Bay so far as can be learned from fruit growers in that region. In consequence of this, plum growing is becoming an industry of some importance in that district. Prof. Goff further states as a result of personal examination that he found the curculio south of the bay, but that north of the bay no infested plums could be found, though a few wormy cherries were noted for the first time in the experience of the fruit growers. The invasion apparently proceeded from the southwest. Dr. B. D. Walsh, writing from Illinois in 1867, observes: Although the curculio now infests the cultivated species of plums (Prunus domestica Linn.) to fully as great extent as our common wild species (Prunus americana), yet it is only at a comparatively recent date that it attacks our cultivated plums, and since that epoch it has been occurring every year worse and worse and making onslaughts on other fruits, such as peach and cherry, and even the apple. "The curculio," said the Hon. D. B. Baker in 1855, "were unknown and never made their incursions into tins region [Illinois] until some years after the organization of our State government, A. D. 1818. There can be little doubt, however, that the curculios have existed from time immemorial in our State, breeding in wild plums." Numerous opinions of a similar nature might be cited to indicate the belief that the curculio was not indigenous to certain regions, and that it put in appearance only after cultivated food plants had been grown for some years. It seems more probable to the writers, however, as stated by Walsh, that the insect has always been generally distributed over its range, subsisting on wild food plants. The introduction of cultivated fruits undoubtedly resulted, WESTERN LIMIT OF OCCURRENCE. 21 within a longer or shorter time, in these being attacked by the insect. and as it became abundant its injuries were sufficient to attract the attention of observant growers. From records in literature and those obtained by the Bureau of Entomology the curculio is found to occur very generally at the present time throughout the Mississippi Valley and the territory to the eastward. Records of the insect are at hand from hundreds of localities, covering practically all of tins territory. Interest attaches, however, to the western and northern limits of the occur- rence of the curculio, and especially to the consideration of factors which may have operated to prevent its further spread. WESTERN LIMIT OF OCCURRENCE. During the summer of 1910 it was possible to collect some data on the western limit of occurrence of the curculio. In early June Mr. John B. Gill, of the Bureau of Entomology, was instructed to proceed to Sherman, Tex., and from thence in a northwesterly direction (along the Fort Worth & Denver City Railway) to a point where the curculio could not be found. Next, to proceed in a north- easterly direction (along the Atchison, Topeka & Santa Fe Railway) into territory where the species was abundant. Mr. Gill proceeded in this zigzag manner to the west and east of the one hundredth meridian, as far north as Xorth Dakota, making collections at many points of wild and cultivated fruit winch might be infested. Tins fruit was sent to the insect ary at Washington where rearings were made. Owing to injury by late frosts, the fruit crop in some sections was very light or absent, and on tins' account the collections were not so representative as was desirable. At Sherman, Tex., the insect was found on peaches and cultivated plums, though no injury was observed on apples. Four curculios were reared from sendings of fruit from this locality. The insert was also found present at Denison, Tex., an adjacent town on the Red River, five beetles being secured from fruit sent in. At Arlington, Tex., curculio larvae were found in peaches and plums, but the attack in no case was severe. Three curculios were secured from fruit from tliis locality. At Wichita Falls, Tex., the curculio was found on Japan and wild goose plums and peaches, and evidence of its injury to wild plums was noted. From several collections of fruit sent in no curculios were obtained. At Quanah, Tex., no curculio attack was found, although the wild plums were slightly infested with the plum gouger (Anthonomus sejttdlaris). Plums collected from wild trees along a creek were sent in to the insectary and several plum gougers obtained, but no adults of the plum curculio. 22 THE PLUM CURCULIO. At Amarillo, Tex., also, no indication of the presence of the curculio was noted in the wild plums growing along the Canadian River, and including several small peach, plum, and apple orchards in the region. No curculios were reared from the fruit sent from Amarillo. At Canadian, Tex., an abundance of wild plums was found along the Canadian River, but no curculio attack was observed. No beetles were obtained from the fruit sent in from this locality, although 8 plum gougers were obtained. Both wild and cultivated plums at Alva, Okla., showed injury from the curculio. Two beetles were obtained from fruit collected in that region and sent in to the insectary. The curculio was very much in evidence in the environs of Wichita, Kans., the next point visited, occurring in cultivated plums, and injury to apple was also noted. A total of 51 beetles was reared from three sendings of fruit from this locality. At Hutchinson, Kans., the insect was also abundant, infesting both wild and cultivated plums, apricots, and apples. Thirty-two beetles were secured from fruit sent in. At Salina, Kans., the insect was also in evidence, injury being noted in several orchards of cultivated plums as well as in this fruit growing wild. A total of 68 beetles was reared from fruit from this section, indicating its considerable abundance. At Colby, Kans., no signs of curculio injury were found, nor were any beetles reared from the small amount of fruit sent in to the insectary from this locality. At Norton, Kans., the point next investigated, conditions were very similar to those obtaining at Colby, fruit being very scarce. No signs of curculio injury were noted nor were beetles reared from fruit received from this place. At Grand Island, Nebr., the curculio was very much in evidence on wild and cultivated plums, a total of 74 beetles being reared from the fruit there collected. The insect was also present in numbers in wild and cultivated plums at North Platte, Nebr., a total of 57 adults being obtained from several collections of fruit. At Northport, Nebr., the complete absence of both native and cultivated fruit prevented any observations whatever. However, at Sterling, Colo., in about the same latitude, curculio egg punctures were observed in wild plums, although they were nowhere abundant. No punctures were noted on apples during a careful search of several orchards. The fruit, however, was not abundant. From collections of wild plums sent in to the insectary two adults were reared. This appears to be the first record for the curculio from that State. At Rapid City, S. Dak., cultivated and wild plums were found infested by the curculio to a slight extent. A total of 18 adults was reared from material from this place. At Pierre, S. Dak., the work WESTERN LIMIT OF OCCURRENCE. 23 of the curculio was not much in evidence, although both wild and cultivated plums showed some injury. Fourteen beetles were reared from fruit from Pierre. At Aberdeen, S. Dak., practically all fruit had been destroyed and no observations on the curculio could be made. Conditions were very similar at James town, N. Dak., the point next visited. Xo fruit whatever was in evidence and no observa- tions were possible. Also at Bismarck, N. Dak., the fruit had been completely destroyed. At Fargo, N. Dak, and Moorehead, Minn., an adjacent town, there was but little in the way of fruit, although wild plum trees were in abundance in the Red River Valley. Four curculios, however, were reared from plums sent in. In this connection should be mentioned the record of the curculio at Aweme, Manitoba, collected by Mr. N. diddle, and published in the Annual Report of the Entomological Society of Ontario for 1904, page 76. While the observations made during 1910 by Mr. Gill are far from as complete as desirable, yet it appears clear that the insect has not established itself to any extent west of about the one hundredth meridian. Sterling, Colo, (longitude 103°), is the most western point from which the species has been recorded. Observations are most complete for Texas, and according to the data at hand the insect is present as far west as Victoria on the south and Wichita Falls on the north. Although fruit was present at Quanah, Canadian, and Amarillo, Tex., no beetles could be found. The general conclusion would appear warranted that the insect is not able to extend its range much out of the humid area as defined in Merriam's Life-Zone Map. In Table I the localities above mentioned, with a few additional ones, are shown, with approximate longitude and with indications of the source of the record. Table I. — Western distribution of the plum curculio. Localities. TEXAS. Victoria Garrison Morrill Arlington Sherman Denison Wichita Falls Quanah Canadian Amarillo OKLAHOMA El Reno Alva Longitude (approxi- Occurrence. mate). 97 00 Present. . . 94 30 do 95 30 do 97 00 do 96 35 do 96 30 do '.is 25 do Absent KH) 20 ...do 101 45 ...do 98 Oil Presenl . . . 99 30 ...do Remarks. Reared from fruit in 1905. Do. Specimens received from correspondent Reared from fruit in 1910. Do. Do. Do. Specimens received from correspondent 24 THE PLUM CUECULIO. Table I. — Western distribution of the plum curculio — Continued. Localities. Long'tude (approxi- Occurrence. mate). Remarks. KANSAS. Wichita Salina Hutchinson Norton Colby COLORADO. Sterling NEBRASKA. Lincoln Grand Island North Platte SOUTH DAKOTA Aberdeen Pierre Rapid City NORTH DAKOTA Fargo Jamestown Bismarck MANITOBA. Aweme 97 20 Present . 97 35 ...do. 98 00 ...do. 99 50 101 00 103 15 96 45 98 25 100 50 100 25 103 15 9G 50 98 45 Absent (?) ..do Present... Present . . . ..do ..do (?) Present . . . ..do Reared from fruit in 1910. Do. Do. Reared from fruit in 1910. Specimens received from correspondent. Reared from fruit in 1910. Do. Destruction of fruit crop by cold pre- vented observations. Reared from fruit in 1910. Do. Present. . .; Reared from fruit in 1910. (?) Destruction of fruit crop by cold pre- vented observations. (?) Do. Present . . . Collected by N. Criddle (Ent. Soc. Ont., 1904, p. 76). NORTHERN LIMIT OF OCCURRENCE. The data bearing on the distribution of the curculio to the north depend almost entirely upon records in the Reports of the Entomo- logical Society of Ontario and in Dr. James Fletcher's reports as entomologist of the Canadian Experimental Farms. The most northerly point is Aweme, Manitoba, previously mentioned in con- sidering the western occurrence of the insect. This is in north lati- tude about 49°. The insect is also recorded from Gore Bay, Mani- toulin Island, Ontario, north latitude about 46°, and at Ottawa and Owen Sound, Ontario. According to Prof. William Lochhead, the insect was quite prevalent in Quebec Province during 1909. There are three records from Nova Scotia, namely, Berwick, Wolf- ville, and Port William, all in the immediate vicinity of one another in north latitude 45° 30'. So far as we have been able to determine, the localities mentioned above mark the northern occurrence of the curculio. The insect apparently is quite prevalent throughout Ontario and the lower St. Lawrence region of Quebec Province. Table II gives these localities with the approximate north latitude and the bibliograpliical references. DISTRIBUTION ACCORDING TO LIFE ZONES. Table II. — Northern distribution of the plum curculio. 25 Localities. Latitude. Remarks. Aweme, Manitoba o , | 49 00 Collected bv N. Criddle CReDt. Ent. Soc. Ont.. 1904. Gore Bay, Manitoulin Island, Ontario. . 46 00 45 30 44 35 46 35 45 30 p. 76). Wm. Saunders (Rept. Ent. Soc. Ont., 1880, p. 8). W. Hague Harrington (Rept. Ent. Soc. Ont., 1880, Owen Sound, Ontario p. 53). Fletcher (Rept. Ent. Exp. Farms Canada, 1885). Quebec, Quebec Wm. Lochhead (Rept. Ent. Soc. Ont., 1909, p. 08). Berwick, Nova Scotia Fletcher (Rept. Ent. Exp. Farms, Canada, 1896, p. 255). SOUTHERN LIMIT OF OCCURRENCE. The most southerly location in the United States from which we have records of this species is Victoria, Tex., in the southwest, and around Hampton, Fla., in the southeast. At the latter place the insect has been found very abundantly and it constitutes a very serious pest to peach growers. At Deland, Fla., to which is adjacent a considerable peach-growing industry, no trace of the insect could be discovered, although it should undoubtedly thrive in that locality. These observations, however, were made in 1905 and the insect in the meantime may have become established there. DISTRIBUTION OF THE CURCULIO ACCORDING TO LIFE ZONES. From the foregoing discussion it will be noted that the plum curculio is present in the humid area in all of the life zones except the Tropical. It is most abundant and destructive, however, in the Fig. 4.— Map showing by the shaded area the distribution of the plum curculio. (Original. ) Upper and Lower Austral Zones. While generally present through- out the Transition Zone it would appear to be much less of a pest than to the southward. Sufficient data are not at hand to indicate its relative importance in the Canadian Zone, though it is probably occasionally quite destructive, as indicated by the observations of Dr. Fletcher, Prof. Lochhead, and others. In figure 4 the shaded area indicates the present distribution of the curculio in so far as we have been able to determine it. 26 THE PLUM CURCULIO. REPORTED INTRODUCTIONS OF THE CURCULIO. There have been reports at different times of the introduction of the plum curculio into new localities in the United States and into foreign countries. Thus in 1889 it was reported by local news- papers as present in Los Angeles County, Cal., but the insect in question proved to be Fuller's rose-beetle (Pantomorus fulleri) (see fig. 8), a common insect in the West, feeding upon leaves of ever- greens, oaks, camellias, palms, cannas, etc. In Bulletin 51 of the Montana Agricultural Experiment Station the insect is stated to be present in the Bitter Root Valley, but this reported introduction was later found to be without foundation. The curculio was reported in British Columbia on plums, but upon investigation in the territory reported to be infested, none of the insects could be found. The curculio is the subject of a chapter in the Handbook of the Destructive Insects of Victoria, Part II, by Mr. Chas. French, in which he alludes to the discovery by a Mr. Parson, of Kent, of an insect injuring plums very similar to if not identical with the plum curculio. The correctness of this record, however, is plainly doubted by Mr. French, and his reason for a detailed consideration of the insect in the work mentioned results from his expressed fear that the species may before long find its way into Australia. Thus far, however, the insect appears not to have been introduced there. In Tasmania, during 1889, considerable excitement was aroused by the discovery in cherries around Hobart of grubs which were thought to belong to our North American plum curculio. Subse- quent records as to the correctness of this belief are wanting, but it is probable that the insect in question was some one of the native species. More recently, in 1900, the insect .was reported in New Zealand, near Auckland, but careful search for it in the supposedly infested territory did not reveal any trace of its presence. So far as recorded, therefore, the plum curculio is limited to the territory previously indicated in North America. It appears remarkable that in the case of an insect infesting fruits in the larval stage it should not have become much more widely distributed in the United States and to foreign countries. In fact it is entirely reasonable to suppose that at one time or another the insect has been shipped along with fruit to various parts of the world, but that owing to certain con- ditions essential for its proper development it has not been able to establish itself. In any country with climatic conditions similar to those obtaining in the humid area of the United States it would doubtless thrive, however, and become as destructive as it is at the present time in North America. LOSSES DUE THERETO. 27 LOSSES DUE TO THE PLUM CURCULIO. It is difficult to make even an approximate estimate of the shrink- age in value resulting from the attack of tin- plum curculio on its several food plants. While adequate statistics are not available on which to make accurate calculations of the value of these several crops in the territory occupied by the insect, an attempt has been made to indicate as closely as possible the approximate annual money loss from the curculio. These data were published, as a part of an article on the losses from deciduous-fruit insects, in the Report of the National Conservation Commission, Volume III, page 309. In this article the figures for the apple crop were obtained from the American Agriculturist and other figures from the Twelfth Census. That portion relating to the curculio is quoted below. Average apple crop in the infested territory, 1897 to 1907. Barrels 34. 292. 700 Estimated shrinkage of first-class fruit. 10 per cent 3. 429. 270 Value, at |1.25 per barrel >4. 286, 587 Value of fruit as culls, at 30 cents per barrel 1. 02^. 781 Total losses to apples 3.2" On apples this insect receives but little if any treatment aside from that given in codling-moth treatment. There are no available figures on the yield of peaches. It was thus necessary to determine this as accurately as possible on the basis of the number of trees, and a conservative yield which each should give. Trees in infested territory 90. 931. 542 Assuming that one-fourth bear every year, producing an average of 1 crate per tree, valued at 50 cents, net value $11, 366. 443 Estimated annual loss of 33 per cent Cost of spraying, jarring, etc 300, 000 Total 38,814 There are likewise no figures on the yield of the plum, prune, etc., and the yields of these fruits were determined in a similar manner. Trees in infested territory 15. in N Assuming that one-fourth bear fruit every year at the rate of 1 crate per tree, at 50 cents value > 188 Estimated annual loss of 50 per cent 994. 149 < lost of treatment, spraying, jarring, etc 250, 000 Total i. 244. 149 I' MAI S. Apple peach 58,814 Plum, prune, etc .149 Total 8,040 Cost of treatments ,. ooo Grand total 28 THE PLUM CURCULIO. Fig. 5.— The apple curculio (Anthonomu quadrigibbus). (From Riley.) The foregoing shows a grand total of loss each year, including cost of remedial operations resulting from the attack of the curculio, of about $8,500,000. This amount, while by no means large as meas- ured by the destruction caused by certain other insect pests, as the cotton-boll weevil, Hessian fly, etc., is nevertheless a heavy drain upon the fruit-growing industry of the country. Unquestionably this injury will be reduced more and more in the future following a more general adop- tion of spraying, especially of peaches and plums — now entirely feasible, as elsewhere shown (p. 214). The sum total of losses due to the ravages of the curculio during the past 175 years would amount to an exceed- ingly large sum, though its injuries have become especially noticeable within comparatively recent years along with the enormous development of the fruit-growing industry. During the past 25 or 30 years the total losses caused by this insect, to the various fruits which it attacks, would on a conservative estimate probably be not less than $100,000,000. INSECTS LIKELY TO BE MISTAKEN FOR THE PLUM CURCULIO. The work of the plum curculio is well known to most fruit growers within its area of distribution, and many have seen the adult or beetle. Others, however, know the insect only from its work, or as the grub or worm in the peach, plum, or cherry. Not infrequently specimens of beetles are received by the Bureau of Entomology from correspondents who believe them to be the plum curculio, and which, while mostly true snout beetles, are quite different from this insect. Among those thus likely to be mistaken for the curculio are the following: The apple curculio, Anthonomus quadrigibbus Say (fig. 5). The plum gouger, Anthonomus scutellaris Lee. (fig. 6). Fig. 6.— The plum gouger (Anthonomus scutellaris). (From Insert Life.) INSECTS LIKELY TO BE MISTAKEN FOR IT. 29 The acorn weevil, Balaninus victoriensis Chitt. (fig. 7). Fuller's rose-beetle, (Aramigus) Pantomorus fulleri Lee. and Horn (fig. 8). Fig. 7. — The acorn weevil (Balaninus victoriensis). (From Chittenden.) Fig. 8.— Fuller's rose beetle {Paniomorm fulleri). (From Chittenden.) The imbricated snout-beetle, Epicserus imbricatus Say (fig. 9), Tig. 9.— Imbricated snout beetle (Epiaerus imbricatus,. (From Chittenden.) Comparison of the illustrations of these several species with figures of the plum curculio will show important differences. 30 THE PLUM CURCULIO. DESCRIPTION. THE EGG. The egg of the plum curculio (see fig. 10) is rather broadly elliptical, dilute milky- white in color, the surface smooth and shiny; the micropyle is inconspicuous, and the ends indistinguishable. The length is variable; measurements of many specimens show a variation of from 0.43 to 0.72 mm., with a range in width of from 0.35 to 0.45 mm. The average size of 30 eggs was found to be 0.643 by 0.411 mm. THE LARVA. W "When full grown — length 6 to 9 mm., breadth 1.75 to 2.5 mm.; a yellowish-white, footless grub; nearly cylindrical, slightly flattened on ventral side ; body curved toward ventral side, bow-shaped; sides of each segment from second thoracic to eighth abdominal expanded into a fleshy lobe above and below a depressed lateral line. (See figs. 11 and 12 and PI. I, fig. 3.) Headsi8 broad as long, about 1 mm. each way; color nut-brown; epistoma, clypeus, labrum, and mandibles darker; epicranial suture and its continuation as a median line Fig. 10. -The plum curculio ( Conotrachclus nenuphar): Egg. (Original.) Fig. 11.— The plum curculio: Larva, showing structural details.— a, lateral aspect; b, ventral aspect; c , dorsal aspec t . ( O riginal . ) DESCRIPTION OF LARVA. 31 extending beyond the middle of the front also darker; frontal suture light yellow, sub- mentum yellowish white; antennae minute, one-jointed, situated at base of mandibles at ends of frontal suture; minute eye-spots usually present directly laterad and caudad of antennae; mandibles with two blunt teeth; palpi two-jointed; seven hairs on each side of the epicranium, two on the front, two on epistoma, two large and many small hairs on labrum, two on each mandible, two on submentum, two on mentum, one Submcnmm Slipa Mentum Palpifer Fig. 12.— The plum curculio: Head of larva, with Fig. 13. — The plum curculio: Head oflarva, lateral parts named. Much enlarged. (Original.) aspect, with parts named. (Original.) on stipes, two on palpifer, and eight on lacinia; hairs arranged as shown in figures 13 to 15. Thorax. — Prothcrax with a light brown chitinized shield on the dorsum and a slightly chitinized area on each side of the venter; a conspicuous oblong spiracle situated above the middle of the side, its long axis extending dorso-ventrally; three pairs of large hairs on the dorsum, two pairs of large and five pairs of minute hairs below the lateral line, arranged as shown in figures. C3= 43? : K Timor muxli Rrtrarlor miucU Eitenxrr "Melt Fig. 14.— The plum curculio: Head of larva, ven- tral aspect, with parts named. Much enlarged. (Original.) Fig. 15.— The plum curculio: Lateral, dorsal, and ven- tral aspects of right man- dible of larva, with mus- cles. Much enlarged. (Original.) Mesothorax and metathorax without spiracles; each with one pair of largo and lour pairs of minute hairs on the dorsum, a large hair on the upper and one on the lower lateral lobe, one pair of large and four pairs of minute hairs on the venter, arranged as shown in figure 11. Abdomen. — Segments I to 7 each with an oblong spiracle above the middle of the side, its long axis extending longitudinally; two pairs of largo and three pairs of minute hairs on the dorsum, one largo and one minute hair on each lateral lobe, and throe pairs of minute hairs on the venter, arranged as in the figures. The eighth abdominal segment is smaller than the preceding and tacks the outer pair of large dorsal hairs. 32 THE PLUM CURCULIO. The niDth abdominal segment is considerably smaller than the preceding, truncate posteriorly, has no spiracles, and bears two pairs of large and one pair of minute hairs on the posterior dorsal margin and two pairs of minute hairs on the venter. The anus, surrounded by three anal lobes, is situated on the ventral posterior part of the ninth abdominal segment. „ ... , THE PUPA. . Uaxtllnrij palpus / -Lnvhrin , , , , Length 4.5 to 7 mm.; breadth 2.3 to 3.75 mm.; . Labial palpus ° color white, in older specimens the eyes becoming reddish brown and then black and the mandibles -Siibmrnium an(j the tarsal claws becoming chitinized and visible Sh ^ through the pupal skin. A round spiracle is visible on the side of the second to fifth abdominal seg- ments, that on the firet segment being covered by Fig. 16.— The plum curculio: Dorsal the pad of the elytron. aspect of maxilla and labium of The hairs of the pupa, except those on the head, enllrged'^^Odgtoal T^' ^^ ^ ^ S°me °n ^ Pr0thoraX' arise from tuber" cles and are easily broken off. On the head there is a pair of large hairs near the vertex, a pair just above the eyes, a pair between the eyes, a pair on the front of the beak just above the insertion of the antennae, a pair of smaller hair3 lower down the beak, and a more widely separated pair of minute hairs still lower down the beak. There are eight pairs of hairs on the pro thorax, two pairs on the mesoscutum, two on the metascutum, and two pairs on the distal end of each femur. The pads of the elytra are elevated into ridges, from which arise groups of hairs on tubercles, there being about seventeen hairs on each elytron. Abdominal segments 1 to 6 each bear two pairs of dorsal and one pair of lateral hairs. The seventh segment has an additional pair of lateral hairs, while the eighth segment has only one pair of Fig. 17.— The plum curculio: Pupa, showing structural details— a, ventral; b, lateral; and c, dorsal aspects. (Original.) dorsal and one pair of lateral hairs. The ninth segment has a stout spine and a hair rising from a tubercle on each apical angle, and a pair of hairs on the venter. (See fig. 17 and PI. I, fig. 4.) Bui. 103, Bureau of Entomolo gy. u. s Dept. of Agriculture. Plate II. ^r r ** ?* I! A I » • wi % i * j^^^ ^^^k Fig. 1.— Egg and Feeding Punctures on Young Wild-Goose Plum. Enlarged. (Original.) Fig. 2.— Nearly Ripe Wild Plums, Showing Egg Scars and Gum Exudation from Feeding Punctures. 'Original.* WORK OF PLUM CURCULIO ON PLUM. Bui. 103, Bureau of Entomology, U S. Dept. of Agriculture. Plate III. Fig. 1.— Effect of Egg and Feeding Punctures, with Gum Exudations, on Ripe Japanese Plums. (Original.) Fig. 2.— Fall Feeding Punctures on Ripe Prunes. ^Original.) WORK OF PLUM CURCULIO ON PLUM. FOOD PLANTS. 33 THE ADULT. Length 3.5 to 5.75 mm.; breadth 1.75 to 2.75 mm. This stage is too well known to require particular description. The original description by Herbst is given on pages 13 and 14. (See PI. I, figs. 1 and 2; PL IV, fig. 1; text fig. 18.) Mandible Mcaalfa Mandibles ! ^Labial palpi Labium Maxillary palpus Fig. 18.— The plum curcuno: Mouth parts of the adult— a, and a', mandibles, lateral aspect; b, dorsal aspect; c, ventral aspect; d, maxillary palpus. Much enlarged. (Original.) FOOD PLANTS. The plum curculio feeds upon and oviposits in practically all pome and stone fruits, as the apple, pear, quince, plum, peach, cherry, nectarine, and apricot. Certain wild fruits are also more or less used, especially when those above mentioned are scarce, as Cratasgus, crab apple, etc. There are records of oviposition in huckleberry, grape, strawberry, gooseberry, currant, and wild per- simmon (Diospyros virginiana). There are also numerous records in literature of the breeding of tins insect in black knot (Plowrightia morbosa), which we were able to verify during 1910. Not all fruits used by the female for egg-laying purposes, however, furnish suit- able food for the growth and maturation of the larva, and from tins standpoint the instinct of the parent beetle is often faulty. Never- theless, there is evident choice of fruits for oviposition and, as stated by Trimble many years ago, in about the following order: Nectar- ine, plum, apricot, apple, pear, and quince. Tins order of preference nearly agrees with that indicated \yy our own observations, but Trimble does not include the cherry and peach, which we would place after plum, with the position of nectarine doubtful, as we have made but few observations on this fruit. It must not be understood, however, that in the presence of all of these fruits the curculio will choose certain kinds to the neglect of others. As a matter of fact, in orchards of mixed fruits, as phi in. peach, apple, and pear, all of these sorts will be freely punctured; but plums more so, as a rule, than the others. The insect undoubt- edly prefers smooth-skinned fruits, and in the case of plum, nectar- ine, and apricot, winch are usually first to attain sufficient size to receive the eggs, these are always much used. Nectarines and 17262°— Bull. 103—12 3 34 THE PLUM CURCULIO. apricots are very uncertain croppers throughout the range of distri- bution of the insect on account of early blooming and consequent injury by frost. During fruiting years, however, in the absence of treatment, practically none of the fruit of these varieties escapes puncturing. During June, 1910, one of the writers examined several hundred apricots from trees in a neglected home orchard near Blue- mont, Va., without finding a single specimen free from infestation. As a group, plums constitute the favorite food of the curculio, and the various species of wild plums were without doubt the original native food of this species, and are freely used at the present day. The early literature of the curculio abounds with references to its especial injury to cultivated plums, and growers of this fruit have complained bitterly of its ravages. With the extension of culture of other fruits, as peaches, apples, cherries, etc., its injuries to these fruits have likewise become more and more important. However, until in comparatively recent years the curculio was regarded as preeminently an enemy of plums. (See Pis. II and III, showing curculio injury to plums.) Cultivated varieties of plums appear to show variation as to sus- ceptibility to attack. There are frequent references in literature to the subject, but adequate data for conclusions are wanting. In an extended article Mr. D. B. Wier (Bulletin 14, old series, Division of Entomology, p. 39, 1887) presents under the caption "The native plums: How to fruit them — they are practically curculio proof," results of observations which led him to believe that native plums are especially sought for by the curculio for oviposition purposes. Thus— The first and most important is that of evidence showing that this insect seeks native plums in preference to all other fruits in which to deposit her eggs. This is a queer fact in biology which naturalists will be inclined to dispute, namely, that an insect should seek and use seemingly by preference a fruit in which to lay her eggs wherein but very few of them will hatch and in which but one of such larvae as do hatch can be nourished on its substance to maturity. Further on he states: I found that for every egg that hatched, and the larvae had fed noticeably, that there were from 1,500 to 1,900 ovipositing marks of the curculio and that only one living curculio maggot was found in 3,100 to 2,500 plums examined, and in which her eggs had been laid. These percentages are from the June observations of these two years and coincide with previous observations. Mr. Wier also observes: The reason why the plum curculio does seek the native plums to oviposit in seems to be because of their very early and fragrant bloom. His observations that native plums are much sought for as places for egg laying and that the larvae are not able to develop therein, led FOOD PLANTS. 35 him to recommend the planting of native plums among other sorts more subject to attack for the protection of the latter. In this way he believed that the cureulio could be largely exterminated. To the conclusions and premises expressed by Mr. Wier, Riley and Howard have indicated their dissent in a footnote to the article in question and also in their article on the cureulio in the Report of the Entomologist for 1887. Riley states in the First Missouri Report, page 53— That they prefer smooth-skinned to rough-skinned fruit. That up to the present time the Miner and other varieties of the Chickasaw plum have been almost entirely exempt from their attacks and that in the Columbia plum the young larvae are usually drowned out before maturing. Under the caption "Plums for the million/' Riley, in the American Entomologist, volume 1, page 92, further calls attention to the Miner and Columbia plums on account of their freedom from cureulio injury. Observations by Prof. Gillette in Iowa in 1889 include results of studies of varieties of plums as to their attractiveness to the cureulio. The following plums were examined and the percentages of injury by the cureulio were found to be as stated: Ter cent. Miner 2. 50 Wolf 17. 30 Chickasaw 15. 70 Forest Rose 13. 60 Native Seedling No. 1 8. 30 Native Seedling No. 2 25. 80 Native Seedling No. 3 5. 20 Yellow Mira Bell '. 66. CO Black Prune 14. 00 Bier 31.50 Early Red 19. 00 The four varieties last mentioned are of the Domestica, or Euro- pean type, the others being native. Mr. Gillette, in discussing the data, says: That of the European varieties an average of 46.8 per cent of all plums were injured, the maximum being in the case of the Yellow Mira Bell, the minimum of injury being to the Black Prune, namely, 14 per cent. The average injury to native plums and varieties was only 6.6 per cent, with maximum in the case of a native seedling. The several small trees of Prunus simonii carried their fruit to maturity without any signs of cureulio injury. Mr. Gillette concludes that this insect has a decided preference for the domestica varieties. From our own observations we would place Japanese varieties (Prunus triflora) and their hybrids atid crosses at the head of the plum list, as most susceptible to cureulio injury, and the varieties o( 36 THE PLUM CURCULIO. Prunus americana last, as least susceptible. Between these would come such native species and their varieties as Prunus angustifolia (Chickasaw) and P. vmbellata, the P. hortulana group, and varieties of the European plums (P. domestica) . Practically all sorts of plums throughout the range of the insect are freely attacked, but the earlier and more tender-skinned kinds will evidently be most sought out for egg-laying and feeding purposes. With peaches, there appears to be little if any difference as to the amount of injury to the different varieties. (See Pis. IV to VI for illustrations of injury to peaches.) While the fuzzy skin of this fruit renders it less attractive to the insect than plums, peaches are, as a rule, generally used where the insects are at all abundant. In the South, where early and midseason varieties are almost exclusively grown, wormy fruit is always in evidence at picking time. In the Middle States, but especially in the Northern States, wormy ripe peaches are less frequently seen, although the injury to the young fruit may have been severe. Late-maturing varieties, as Salway, Smock, Bilyeu, etc., as stated by numerous observers, are more free from attack than midsummer and early varieties, growing under identical conditions. As these varieties ripen after most of the beetles have ceased egg laying, wormy peaches at picking time are corre- spondingly scarce. It is probably true, however, that during the active oviposition period of the beetles there will be no discrimina- tion in choice of fruit of the early, midseason, and later maturing varieties. In the case of the apple, the curculio appears to oviposit indiffer- ently in all varieties early in the season, but later, on account of the changing texture of the skin and flesh, uses preferably the more tender varieties and those which mature during the summer or early fall. Such varieties as grow and mature quickly are very generally badly deformed from the egg and feeding punctures where the insect is abundant, whereas on later-maturing varieties the injury will be more nearly outgrown. (See Pis. VII to IX for illustrations of cur- culio injury to apple.) Late-fall and winter sorts are, however, often badly injured. Trimble says: "The early apples, as the Sweet Bough and Early Harvest, will suffer more than later kinds," evi- dently referring to the knotty condition of the fruit when ripe. In regard to pears, all varieties appear to be about equally subject to attack. Larvae, however, are probably never able to develop in the fruit on the trees, and comparatively few do so in drop fruit, espe- cially such varieties as the Kieffer and LeConte. The injury to pears consists largely in deformity of fruit from the egg and feeding punc- tures. (See PI. X.) Sweet cherries are perhaps preferred to sour cherries, although varieties of both classes are freely punctured. Larvae are able to Bui. 103, Bureau of Entomology, U. S. Dept. of Agriculture. Plate IV. Fig. 1.— The Adult Curculio on Newly Set Peach. Enlarged. (Original. Fig. 2.— Curculio Larva, or Grub, and its Work in Ripe Peach (Original.) WORK OF PLUM CURCULIO ON PEACH. Bui. 103, Bureau of Entomoiogy, U. S. Dept. of Agriculti Plate V. Fig. 1.— Wormy Windfall Peaches. (Original.) Fig 2.— Peaches Deformed by Egg and Feeding Punctures. ^Original.' WORK OF PLUM CURCULIO ON PEACH. Bui. 103, Bureau of Entomology, U. S. Dept. of Agriculture. Plate VI. hiG. 1.— Deformed Ripe Peaches. (Original.) Fig. 2.— Gum Exudation from Curculio Punctures. ^Original. WORK OF PLUM CURCULIO ON PEACH. FOOD PLANTS. 37 develop in the fruit on the trees, and wormy ripe cherries are vers' generally present on the trees, and on the market. (See PL XI.) There remains to be mentioned more particularly the recorded use, for egg-laying purposes and as food for larvae, of the so-called black- knot of cherries and plums. (See fig. 19.) Prof. W. D. Peck, in the Massachusetts Agricultural Repository (vol. 5, p. 312, 1819), records rearing of the beetles from grubs found in the warty excrescences of a cherry tree, for which reason he gave it the name of RhjncJisenus cerasi, or the cherry weevil. Grubs apparently the same as those found in the plums are stated to have been frequently observed in Fig. 19.— Black-knot of plum, showing, on the left, infestation by plum-curculio larva1. (Original.) the warts, which it was then thought were caused by this insect. The larvse observed by Prof. Peck went into the ground July 6 and on the 30th of the month the beetles began to appear. A resume of Prof. Peck's observations on the curculio are given by Harris, who recommends that the excrescences of plum and cherry trees be cut out each year after the last of June. He adds that the moose plum (Prunus americana) seems to escape the attack of the insect, for no warts are found upon it even when growing in the immediate vicinity of diseased foreign trees. In his Essay Dr. Fitch, in commenting 38 THE PLUM CURCULIO. on the nature of black-knot, states that the larvae of the curculio are almost always found in these growths, and the grubs consume nearly all the spongy matter of the warts. Later he adds: We think the fact well established that this insect breeds in these black-knot excres- cences with about the same avidity that it does in young fruit, notwithstanding these substances are unlike each other. Dr. Fitch expresses the belief that the curculio also resorts to the bark of different fruit trees in which to deposit its eggs when it can find no young fruits to meet its wants, and cites Melsheimer's (A Catalogue of the Insects of Pennsylvania, 1806, p. 28, No. 589) state- ment 50 years earlier that the curculio bred in the bark of peach trees as well as in the fruit. Dr. Fitch also records finding numerous curved incisions in the bark of pear resembling those made by the curculio, causing little blister-like elevations, containing from 4 to 6 minute footless maggots which he thought belonged to the curculio, the insect wintering in the larval condition in the bark. In the First Missouri Keport Riley states that the curculio deposits and the larvae mature in the black-knot of plum, and quotes Dr. Hull to the effect that it oviposits in vigorous shoots of peach, but that the larva does not mature in these shoots. Dr. Trimble says that black-knot, so often found on plum and cherry trees, is used freely by the curculio. These knots are often several days in advance of the young fruit, and the female curculio has been known to exhaust her supply of eggs in them before the young cherries or plums on the same trees were full formed. These positive statements as to the breeding of the insect in black-knot are scarcely to be questioned. During the season of 1910 we were able to verify these records. From a quantity of fresh black-knot material cut from a European variety of plum in full fruit at Bluemont, Va., one beetle was reared. Mr. A. G. Hammar, however, at Douglas, Mich., found the curculio breeding very abundantly in black-knot on plums and cherries and succeeded in rearing many hundreds of adults. (See fig. 19.) The comparative scarcity of suitable fruit in the neighborhood was doubt- less responsible for the great extent to which black-knot was used by the insect. Fruits in which the larvse fail to mature. — As already indicated, oviposition may occur in numerous fruits which are hardly fitted for the future development of the larvae. As will be shown under another caption (p. 56), there is a considerable mortality of eggs and larvae in all classes of fruit which do not fall to the ground; but in the case of pears, and doubtless the grape, huckleberry, persimmon, and similar fruits recorded as used for egg laying, the larvae would in most cases be unable to mature. This has been shown to be true in the case of LIFE HISTORY AND HABITS: THE EGG. 39 the pear, the young fruit of which upon falling dries, becoming more or less flinty. Many hundreds of Kieffer, LeConte, Duchess and other varieties of pears have been collected, but in only a few cases were adults reared therefrom. LIFE HISTORY AND HABITS. THE EGG. NUMBER OF EGGS DEPOSITED. The number of eggs deposited by the curculio was long a matter of conjecture. Riley's estimate (First Missouri Report, p. 54) of from 50 to 100 has been generally quoted in the absence of definite observations. He further states that eggs are deposited at the rate of from 5 to 10 a day, the activity of beetles varying with the tem- perature. Prof. A. J. Cook, by dissection, found that a single female may contain 30 eggs. Dissections during early May, 1887, by Mr. W. B. Alwood showed the presence of only 1 or 2 fully developed eggs, although many immature ova were found. Late in May, how- ever, 4 to 10 eggs were found in each female. Riley and Howard1 in 1888 expressed belief in Riley's earlier estimate, as based on the rate of development, dissections, and observations. The first attempt to obtain more exact information on this point was apparently in 1902, during the spring of which year Messrs. Quaintance and Smith2 made observations in Maryland on 9 females confined separately during their lives and supplied daily with fresh plums. Careful examinations of the fruit were made and the number of eggs deposited by each female daily recorded. The record is shown in abstract in the table below, from date of capture, May 14, to time of death of each individual. Table III. — Egg-laying records from 10 plum curculios, College Park, Md., 1902. Eggs laid each week by each individual. No. of individual. May 14-20. May 21-27. Mav 28- June 3. June 4-10. June 11-17. June 18-24. June 25- Julv 1. July 2 8. July 9-15. July L6-22. July 23-29. July 30^ Aug. 5. Total. 1 37 05 75 91 43 40 20 20 24 11 14 2 14 6 3 10 21 9 276 2 235 3 4 62 70 04 17 45 65 71 102 104 07 45 83 114 71) 59 04 50 51 45 51 28 36 27 2 25 5 304 14 9 0 20 30 13 4 SO (i 270 7 62 8 14 01 77 142 9 60 30 39 27 25 25 10 8 8 ..... 5 13 10 10 397 10.... ;ui> Total 490 700 414 289 192 98 40 23 12 48 71 22 2. 471 i Kepi. Km. Cr.S.Comm. Agr., 1888, p 59. * U. S. Dept. Agr., Div. Ent. Bui. 37, n. s., pp. 105-107, 1902. 40 THE PLUM CURCULIO. Table III. — Egg-laying records from 10 plum curculios, College Park, Md., 1902 — Con. ZTo. of individual. Date last egg laid. Date of death of beetles. Days un- der obser- vation. Days on which eggs were laid. Maximum number of eggs in one day. Average number of eggs laid per day. 1 Aug. 1 June 19 Aug. 2 June 20 May 22 June 19 Aug. 2 July 10 Mav 28 Mav 31 1 Julv 31 July 26 8 38 9 37 8 58 15 19 79 74 70 ' 32 15 15 3 94 2 7 34 3 4 June 18 Aug. 1 June 19 May 26 May 30 Julv 28 July 25 36 74 37 10 17 63 57 17 18 15 12 14 19 15 8 44 5... 5.89 7.30 6 7. . 6.20 8.35 8 9 6 30 10 6. 12 Escaped. In. Illinois, in 1904, Prof. C. S. Crandall1 made many interesting observations on 17 female curculios relative to their feeding and egg- laying habits. Some of these are shown in Table IV. Table IV. — Egg-laying records from 17 plum curculios on apples, Griggsville, III., 1904. No. of individual. Eggs laid. Date of first egg. Date of last egg. Date of death of female. Days un- der ob- servation. Days on which eggs were laid. Maxi- mum number of eggs in 1 day. Average number of eggs laid per day. 1 84 235 119 31 12 18 44 May 25 May 26 ...do ...do.... May 30 May 25 May 26 Julv 10 Sept. 3 July 8 July 17 June 13 Aug. 5 June 22 July 24 Sept. 15 July 20 Sept. 10 June 16 Sept, 26 June 23 63 115 59 111 25 127 32 32 84 37 14 9 12 22 9 8 9 5 2 3 4 2.64 2 2. 80 3 3.21 4 2.21 5 1.33 6 1.50 7 2.00 8 9 19 263 98 May 25 May 26 June 3 Julv 1 Aug. 10 June 25 Julv 26 Aug. 30 June 26 65 100 35 15 69 22 2 9 8 1.26 10 3.81 11 4.45 12 13 197 May 26 Aug. 30 Sept. 6 106 78 6 2.52 14 15 160 34 252 249 125 • 14 Mav 26 Mav 27 ...do May 25 June 2 June 10 Aug. 1 Aug. 17 Sept. 9 Aug. 4 Julv 17 July 18 Aug. 9 Sept. 1 Sept. 23 Aug. 10 July 23 Aug. 20 79 102 123 80 62 87 59 25 87 62 42 11 8 3 9 9 8 2.71 16 17 1.37 2.90 18 4.01 19 2.98 20 1.27 Total 1,954 The beetles were captured May 23 (one pair May 26) in the act of mating and separately confined in jelly glasses, and were kept indoors on a laboratory table. Fresh apples were supplied at regular inter- vals. Observations were continued until death of female, as shown. During the last four or five years numerous egg-laying records have been obtained by the Bureau of Entomology in different parts of the country. These and other life-history studies for the most part have been made under out-of-doors conditions, approaching as closely as possible those which obtained in orchards at the time. (See PI. XII.) i 111. Agr. Exp. Sta., Bui. 98, p. 508. Bui. 1 03, Bureau of Entomology, U. S. Dept. of Agriculture. Plate VII. Fig. 1.— Egg and Feeding Punctures on Young Apples. (Original.) Fig. 2.— Egg Punctures on Apple, Some Days Old. vOriginalJ WORK OF PLUM CURCULIO ON APPLE. Bui. 103. Breaj of Entomology, U. S Dept. of Agriculture. Plate VIM. Fig. 1.— Young Apples. Showing Scars from Egg Punctures. Original.; ^^^^^^ ^^^H . HP \ w - ■ A BW' j Il**: j Fig. 2.— Ripe Apples Deformed and Knotty from Egg and Feeding Punctl- the curculio. vorigina^. WORK OF PLUM CURCULIO ON APPLE. Bui. 1 03, Bureau of Entomology, U. S. Dept. of Agriculture. Plate IX. Work of Plum Curculio on Apple. Fig. 1.— Imperfectly developed apple from tree in which curculio grubs matured. Fig. 2 —small drop apples m which curculio grubs matured. Fig. 8.— Nearly ripe summer apple from ground, showing extent of feeding by two curculio larvae. (Original.) LIFE HISTORY AND HABITS : THE EGG. 41 Table V gives by weeks the number of eggs deposited by 8 female curculios, as observed by Mr. Fred Johnson, at Youngstown, N. Y., in 1905. The beetles were taken while mating, June 6, and each pair separately confined in a jelly glass. Observations were made morning and evening, at which times also fresh food was supplied. At date of capture, June 6, no egg punctures were in evidence on fruit in orchards, and the records are doubtless complete. Table V. — Egg-laying records from 8 plum curculios, Youngstown, X. Y., 1905. Eggs laid each week by each beetle. Z'.o. of individual. June 7-13. June 14-20. June 21-27. June 28- July 4. Julv 5-11. July Julv July 1 26- 12-15. 19-25. Aug. Aug. Aug. 2->. 9-15. Total. 1 13 20 33 22 9 17 32 46 12 21 30 28 28 20 31 16 18 25 30 20 31 22 37 18 18 27 37 28 31 33 47 13 8 28 48 20 34 27 34 5 3 30 7? 2 12 6 12 1 182 3 13 16 26 16 32 4 191 4 15 7 13 4 8 6 19 14 1 3 4 1 11 159 180 6 150 257 8 103 Total 192 186 201 234 204 i 140 6R 1 37 31 1.294 I No. of individual. Date last Date of Da5"s under Days on ppo-Iqih ■ death of observa- which eggs ^ l u" beetles. tion. were laid. Maximum number of eggs in one dav. Average number of eggs laid per day. July 12 Aug. 10 July 14 Aug. 6 Aug. 4 ..do..... Aug. 8 /Julv 16 \..do /Sept. 1 \Sept. 10 /July 15 \July 20 /Aug. 22 iSept. 3 /Oct. 3 \Oct. 12 i/Sept. 28 ilOct. 4 /Aug. 20 \Aug. 26 39 \ 39 / 85 \ 94 / 38 \ 43 f 76 \ 88 J 118 \ 127 / 113 \ 119 / 80 / 108 \ 114 / 2.. B7 3.37 5.16 3.12 3. 67 3.33 4.43 3.55 In Table VI are given records of observations by Mr. Johnson in 1906 at North East, Pa. Beetles were obtained by jarring, and the pairs in copula placed in individual jelly glasses on May 22. The food was Japan plums. 42 THE PLUM CTTRCTJLIO. Table VI. — Egg-laying records from 10 plum curculios. North East, Pa., 1906. Eggs laid each week by each, beetle. No. of individual. May 23-29. May 30- June 5. June 6-12. June 13-19. June 20-26. June 27- July 3. July 4-10. July 11-17. July 18-24. July 25-31. Aug. 1-7. Total. 1 9 33 33 2 2 2 12 16 13 30 35 56 6 1 3 11 14 16 20 17 30 25 16 24 28 7 8 7 8 5 11 22 8 12 12 1 7 1 1 7 4 7 8 7 4 5 3 4 4 54 2 6 6 1 90 3 8 2 7 9 7 6 7 1 93 4 2 3 62 5 2 3 2 102 6 122 7 2 3 17 16 13 9 8 71 8 66 9 7 12 3 3 1 79 10 4 48 Total 81 183 1 197 94 54 48 18 66 36 8 2 787 1 No. of individual. Date last egg laid. Date of death, of beetles. Days under observa- tion. Days on which eggs were laid. Maximum number of eggs in one day. Average number of eggs laid per day. 1 July 10 Aug. 4 July 7 July 14 July 26 July 2 July 22 July 15 Aug. 1 Julv 26 /July 21 \..do /June 5 ! \Aug. 282 /July 28 \..do /July 13 \July 14 /Aug. 16 \..do /Aug. 13 \Aug. 16 /June 14i \July 262 /July 18i \Julv 262 /Aug. 27 \..do (July 28 60 60 114 2 98 67 67 52 53 86 86 83 86 123 2 65 127 2 65 97 97 67 } 30 \ 32 } 32 } 26 } *> } 32 } - } 28 | 35 } 22 6 16 15 6 11 16 4 7 6 5 1.80 2 2.81 3 2.91 4 2.40 5 6 .. 2.76 3.81 7 2.09 8 2.36 9 2.26 10 2.18 I July / Male. 2 Female. In Table VII are records of eggs laid and of egg punctures by four pairs of beetles kept in the insectary at Washington in 1905. Table VII. — Egg-laying records from 4 pairs of the plum curculio, Washington, D. C, 1905. EGGS LAID EACH WEEK BY EACH BEETLE. No. of pair. May 11-17. May 18-24 May 25-31. June 1-7. June 8-14. June 15-21. June 22-28. June 29- July 5. July 6-12. July 13-19. July 20-26. Total. 1 104 40 48 40 84 56 57 16 109 60 65 8 40 44 37 32 53 29 16 30 50 35 23 50 14 17 21 17 28 1 557 2 . 278 3 263 4.. 126 Total 232 213 242 153 128 108 81 21 17 28 1 1,224 LIFE HISTORY AXD HABITS : THE EGG. 43 Table VII. — Egg-laying records from. 4 pairs of the plum CurcuKo, Washington. 1). <'.. 190o — Continued. EGG PUNCTURES MADE EACH WEEK BY EACH BEETLE. No. of pair. May n-i. Mav »-24. Mav 25-3*1. June June June June 1-7. S-14. 15-21. 22-28. June 29- July 5. Julv Julv Julv 6-12. 13-19. - - Total. 1... 9 .... 112 :: 51 88 54 S 11 110 70 01 13 52 39 51 41 16 44 12 25 22 26 19 34 2 i S B 4... 28 28 131 Total. 301 218 254 136 12-5 101 •54 Xo. of pair. Date last egg laid. Date of death PEES" *umb2Pof of beetles. | °tfl: eggs laid per day. 1 Julv 21 Aug. 2S«. • '-^r'S: 3 "— * §SKSS::: * »-«»teS: » 110 1 .".7 139 »39 4.95 0.19 4.60 3.23 Male. 1 Female. The beetles were captured at Arundel. Md.. on the 9th of May by jarring plum trees. All caught were inclosed together under a bell jar until May 11, when the pairs were separated and placed in indi- vidual jars. From three to five fresh plums were added at intervals of one to four days, and those taken out were carefully examined. After about June 10 apples and plums were used as most convenient. The insects were kept under a temperature considerably higher than out of doors, namely, in the insect ary building. The prolificacy of these individuals is not greater on the whole than in the case of those observed at College Park (Table III), but the death of pairs 2, 3, and 4 was evidently hastened beyond what would occur under normal conditions. In every case more egg punctures were made than oviposited in. though the difference in the case of pairs 3 and 4 is less than with pairs 1 and 2. In the curculio egg record on peach. Myrtle. Ga.. 1906 (Table VIII), the beetles were captured by jarring. April 5, and taken in copulation some hours later. Each pair was separately confined in a jar and supplied with peaches until July 25. As all peaches had been gath- ered from the trees by this date, foliage was supplied subsequently, which fact no doubt hastened their death, as most individuals died within a few days. 44 THE PLUM CURCULIO. Table VIII. — Egg-laying records from 9 plum curculios, Myrtle, Ga., 1906. . Eggs laid each week by each beetle. No. of individual. ft < CO 2 P. < CO 1 i ft © >> e3 1 3 >> 2 a 3 CO a> a 3 © a> C 3 Ha a 3 3 00 -» 3 >> 3 00 >> 3 >> 3 "3 O 1 4 3 11 4 4 3 13 3 1 6 8 13 11 62 3 2 10 4 25 6 38 17 6 3 20 5 1 6 17 4 1 14 10 ion 2 17 3 24 13 13 9 11 4 2 6 2 2 8 154 4 60 1 6 18 4 12 2 58 4 7 5 6 41 22 13 25 30 176 8 4 3 6 50 11 5 5 4 5 3 3 2 8 97 7 43 8 7 23 83 65 9 20 48 10 40 33 9 18 5 10 10 40 3 13 1 1 0 15 15 151 Total 688 No. of individual. Date last egg laid. Date of death of beetles. Days under observa- tion. Average number of eggs laid per day. 1 July 4 May 7 June 22 June 6 /May 18 « 143 } 3.57 } 1.55 } 5.31 | 3.53 } 1.00 J- 4.04 } 2.26 | 3.82 } 5.81 o \July 30 2 « 110 1 July 29 i i 115 \June 5 2 2 61 /Aug. 1 i I 118 \ June 26 2 2 82 /July 24 i i 110 \July 26 2 ! 2 H2 /July 20 i » 106 \ (2) ; (2) /Julv 18 i i 104 \Aug. 9 2 2 126 /June 2i 1 58 \ June 26 2 2 g2 /June 18i 174 \..do»....l 274 f Aug. 101 U27 3 4 5 G June 22 June 1 May 16 July 25 7 8 9 \Aug.ll 2 ' 1ZS 1 Male. 2 Female. Comprehensive records were obtained at Siloam Springs, Ark., during the season of 1908 (see Table IX) . Curculios were jarred from plum trees April 17 and the same day 30 pairs were selected and sepa- rately confined in jars. The beetles were given fresh plums daily as long as plums were available, after which apples were used. Obser- vations were made daily. Bui. 103, Bureau of Entomology, U. S. Dept. of Agriculture. Plate X. en a C - < •= UJ ~ a. c o - 3 V o - o - 2 = 13 — a: c z - Bui. 103, Bureau of Entomoiogy, U. S. Dept. of Agriculture. Plate XI. Plum Curculio Injury to Cherries. Cherries Cut Open, Showing the Grub and its Work. iOriginalJ LIFE HISTORY AND HABITS : THE EGG. 45 Table IX. — Egg-laying records from SO plum curcuKoi , Siloam Springs, Ark , 1908. Number of ?ggs laid each week by each beetle. No. of individual. < >> J * a a. < 2 >> S3 3 >> 83 s S M >> 03 a > 03 a OS CO 0J 1 2 c 3 1 - = 3 © | 3 >> 3 3 ex 3 «< 3 3 i si si 3 3 3 1 12 15 15 15 18 12 12 ".2 15 5 12 4 7 16 2 8 10 1 16 18 19 i 7 15 6 9 20 8 18 4 5 9 5 18 2 16 31 17 38 13 44 7 1 22 40 18 37 16 27 44 13 25 16 33 6 29 1? 6 13 21 11 8 5 14 2 2 29' 3 213 2 31 23 29 ; 21 14 8 1 11 281 3 4 41 35 12 4 9 7 3 388 113 5 16 12 16 ,5 17 11 21 11 5 5 9 14 6 30 40 26 6 9 34 15 31 19 18 19 21 31 25 3 77 6 45 27 10 9 24 13 24 14 12 19 18 18 45 42 20 17 7 22 6 19 19 11 19 13 28 23 37 27 14 11 26 7 13 16 12 16 13 26 23 22 6 25 20 23 14 14 16 18 11 7 4 6 8 1 4 309 7 245 8 66 9 59 10 26 35 1 4 21 4 14 268 11 2 7 11 12 6 8 11 1 6 8 2 13 8 2 3 83 12 155 13 . 9 1 3 132 14... 26 9 * 108 15... ? 120 16... 7 4 30 10 3 6 2 12 4 3 109 17 18 2 5 ... 224 111 19 4 20 0 21 22.. . 10 9 11 7 6 4 io' 10 6 13 n 23 24 20 34 18 30 13 11 13 19 11 3 5 2 261 9 23... 19 2 17 12 .20 20 6 15 19 19 29 38 7 9 23 14 38 1 48 41 37 7 9 24 1 19 30 28 43 2 13 48 25 6 16 32 46 22 12 8 10 7 1 2 268 24 33 25 12 38 36 13 31 24 7 17 29 1 10 121 2G 27 6 14 13 9 1 8 8 2 1 2 10 .... 10 306 273 28 34 29 12 6 17 20 19 33 ...J 117 30 28 24 10 9 9 2 237 Total 254 300 343 673 619 545 536 350 399 195 Il77 133 83 49 39 14 15 4.724 No. of individual. Date last Date of i?„ioiH death of egg laid. beetles Days under Days on observa- which eggs tion. were laid. Maximum number of eggs in one day. Average number of eggs per day. 1 July 18 i£* J 170 \ a, 11 10 12 10 3.13 2 July 23 Aug. 16 July 17 May 18 July 30 Aug. 4 June 12 June 8 July 13 July 31 June 24 July 18 June 23 June 26 Aug. 4 Aug. 6 June 2 May 17 lUCl. Zi. 183 72 99 3.90 3 3.92 4 57 21 78 83 30 31 75 45 } » 60 48 53 50 28 2 0 92 } 3 } » 21 46 78 ig a :;? I.M 5 10 3.66 6 12 3.96 7 8 2.95 8 July 172 Sept. Hi July 14* »86 1 142 2 83 5 2.20 9 5 1.90 10 8 3. 57 11 5 1 M 12 /June 28i " 67 Uune 29 « *68 7 2.92 13 8 2 20 14 June 28 » June 29 2 2 67 »68 5 - 15 5 16 5 17 7 3 25 18 10 19 ::::;:::::r 3 2.00 20 0 21 Aug. 13 Apr. 26 July 27 Mav 28 S 2. S4 22 /Aug. 31 \Sept. 1 /Sept 7 \Oct. 6 131 132 138 168 4 3 00 23 24 10 3. 52 3 1. 57 25 July 17 5 2. 63 26 1 Aug. 19 27 Aug. 4 Aug. 30 130 U 3.92 12 3. M 28 July 14 6 1.79 29 June 8 6 30 July 21 9 3. 24 Male. * Female. 46 THE PLUM CURCULIO. In Table X is presented the egg-laying record of 18 beetles, as obtained by Mr. Hammar, at Douglas, Mich., during 1910. The beetles were confined June 7, and the last egg was obtained on July 24. The period of oviposition is noticeably shorter than in several other records presented. Table X. — Egg-laying record of 18 plum curculios, Douglas, Mich., 1910. No. of individual. Eggs laid each week by each beetle. June 7-13. June 14-20. June 21-27. June 28-July 4. July 5-11. July 12-18. July 19-26. Total. 47 81 201 57 74 85 64 112 110 83 57 25 25 31 83 26 148 Total . 32!) 229 1,414 No. of individual. Date last egg laid. Date of death of beetles. Days un- der obser- vation. Days on which eggs were laid. Maximum number of eggs in one day. Average number of eggs per day. 1. 2. 3. 4. 5. 6 7. 8. 9. Id 11. 12 13 14 15 16 17 IS June July June July 13 July July July July July July July July June July July July July July /July 11 \Aug. 15 | July 18 I /Aug. 22 j\Sept. 5 I/July 13 |\July 30 July 29 July 5 Aug. 1' ...do July 6 July 3 July 31 July IS' July 6 July 13 fJuly 12 [July 14 5.06 5.91 4.07 4.13 3.03 3.05 5 09 3.79 5.19 4.38 5.00 2.78 3.44 6.92 2.60 7.79 Escaped. LIFK HISTORY AND HABITS: THE EGG. 47 All of the above records, with the exception of those from Illinois, are brought together in Table XI. A total of 12,602 eggs is Bhown from the 7 localities. At College Park. Md., the maximum number of eggs deposited was 426 and the minimum 62, with an average of 274.55 eggs per individual. At Youngstown, X. Y., the range is from 257 for the maximum to 72 for the minimum, with an average of 161.75. At North East, Pa,, 122 was the greatest number of eggs deposited by an individual and 48 the lowest, with the average only 78.70. At Washington. D. C under laboratory conditions the maximum number of eggs laid by a single curculio was 557. the highest of all records for this insect, and the lowest 126. averaging for the 4 individuals under observation 306. At Myrtle. Ga.. the maximum was 154 and the minimum 1. although this latter record should perhaps be disregarded: the average was 76.44 eggs per female. The records at Siloam Springs. Ark., include a large number of eggs, namely 4.724, from 29 pairs, one of the beetles confined fail- ing entirely to oviposit. The maximum number of eggs by 1 female was 388 and the minimum 4, giving an average for all pairs of 162.76 eggs. At Douglas, Mich., the greatest number deposited by a single female was 201, and the lowest 25. with an average for the 18 indi- viduals of 78.56 eggs. In comparing the number of eggs deposited by the different indi- viduals for the respective localities and the averages of all beetles for a given locality, great variation is to be seen. Certain females, perhaps sickly or otherwise abnormal, deposited very few eggs, although feeding freeh . Others oviposited assiduously throughout their existence. The final average number of eggs per female for all localities is 144.85, ranging from 1 to 557 eggs. Although the ovipo- sition period is greatly extended, yet the bulk of the eggs is deposited rather early in the season. As shown under the heading of percent- ages of eggs deposited by the second, fourth, sixth, and eighth weeks, the proportion deposited by a given time varies much in the different localities. There is, however, a general agreement that the great majority of the eggs have been placed by the end of eight week-. The averages of all localities, shown at close of Table XI. in view of the considerable number of observations doubtless indicate about the rate of oviposition which may be expected in orchards. Approxi- mately one-fourth of the total eggs are laid during the first two weeks, one-half during the first month, three-fourths within six weeks, and 88 per cent of the total within eight weeks after fruit is of size to be usable for oviposition purpose-. 48 THE PLUM CUECULIO. Table XI. — Combined weekly egg-laying records of all beetles of the plum curculiofor each locality and percentage of eggs deposited within two, four, six, and eight weeks from confinement. Localities. ft 9 a fc5 Total number of eggs laid each week by all beetles of the respective localities. 3 5 o i 02 gcoo S St3 ft College Park, Md Youngstown, N. Y. . North East, Pa Washington, D. C . . . Myrtle, Ga Siloam Springs, Ark Douglas, Mich Total 192 81 232 58 254 72 760 186 183 213 62 300 2.59 414 201 197 242 41 343 329 '234 94 153 176 673 423 192 204 54 128 50 619 229 140 48 108 83 545 536 13 23 37 6(5 21 40 350 153 32 46 46 130 1,104 2,471 1,294 787 1,224 688 4,724 1,414 1,963 1,767 810 537 Localities. College Park, Md Youngstown, N. Y North East, Pa Washington, D. C Myrtle, Ga Siloam Springs, Ark Douglas, Mich Maximum number of eggs per individ- ual. Averages for all locali- ties combined 257 122 557 154 3SS 201 Minimum Average number of number of eggs per indi- eggs per individ- ual. 126 1 4 25 vidual. 274. 55 161. 75 78.70 306.00 76.44 162. 76 78.56 144.85 Percentages of total eggs deposited by end of— Second week. 50.82 29.21 33.54 36.35 17.44 11.71 23.40 26.56 Fourth week. 79.27 62.82 70.52 33.21 76.59 Sixth week. 91.01 89.41 83.48 87.90 68.31 57.83 99.08 Eighth week. 93.40 97.52 94.15 96.24 81.10 76.58 100.00 LENGTH OF EGG STAGE. Little exact information as to the period of incubation of eggs of the plum curculio is to be found in the earlier accounts of this insect. Trimble (Insect Enemies of Fruits, p. 29) states that if the weather be cloudy and cool, a week or 10 days is required for the eggs to hatch, but that in very hot weather the young grubs will escape in 4 or 5 days. Riley and Howard state that from 3 to 10 days are required for the egg stage, depending upon the weather. Other writers have given about the same periods. In 1904, in Illinois, Crandall determined the length of time required for hatching of 6 eggs as approximately 4^ days for 4 and 4 days 9 hours for the other two. His observations were made on eggs kept under laboratory conditions. Bui. 103, Bureau of Entomology, U. S. Dept. of Agriculture. Plate XII. Fig. 1.— Out-of-Door House Used in Life-History Work. (Original. Fig. 2.— Soil Cages Used in Obtaining Data on Life of Insect in Ground. ^Original.) METHODS OF STUDY IN PLUM CURCULIO INVESTIGATION, BARNESVILLE, GA. LIFE HISTORY AND HABITS: THE EGG. 49 During the past 3 or 4 years we have been able to secure records on the incubation period for many eggs in different parts of the country. Observations on the length of the egg stage under out-of-doors con- ditions were made at Youngstown, N. Y., in 1905, but are not as extended as could be desired. Nevertheless, the following data by Mr. Johnson are of interest: 7 eggs deposited from June 8, a. m., to June 9, a. m., had by June 15 developed as follows: 2 larvae hatched, but still in egg cavity. 1 larva escaped from eggshell. 1 larva feeding at pit of fruit. 1 larva in short burrow near egg. 2 eggs unhatched. These figures in a general way would indicate a period for the egg stage of 6 to 7 days. Forty-six eggs deposited June 15 from 1 to 7 p. m., on June 20 at 2 p. m. were found to have developed as follows: 20 unhatched. 15 larvae hatched, but still in egg cavity. 11 larvae in burrows, one-fourth to one-half inch from egg cavity. This indicates an egg stage of approximately 4^ to 5 days. Forty-three eggs deposited June 24 were found on June 30, at 6 p. m., to be in the following condition: 6 eggs unhatched. 16 larvae in burrows, about one-eighth inch from egg cavity. 11 larvae in egg cavity. 6 larvae just burrowing out of egg cavity. 4 larvae feeding at pit. The egg stage with this lot is from 5 to 7 days. At Washington, D. C, in 1905, Mr. A. A. Girault made many observations on the length of the egg stage, as shown in Table XII. The eggs were kept in the inseetary, and the temperature on the whole averaged considerably higher than at the same time out of doors. The longest period of incubation was 5 days, in the case of 30 eggs deposited on May 18, and the shortest period was 2 days and 15 hours, for a lot of 22 eggs deposited on June 14. The average incubation period, as based on the total number of egg days, is 3.77 days. (See also Table XIII.) 17262°— Bull. 103—12 4 50 THE PLUM CTJRCULIO. Table XII. — Length of egg stage of the plum curculio, Washington, D. C, 1905. Eggs under observa- tion. Date of deposition. Approxi- mate length of egg stage. Total egg days. Average length of egg stage, by months. 1 40 1 60 40 30 10 May 8 May 9-10. . May 9 May 10-11. May 15.... May 18. . . . May 19. . . . Days. 3.75 3.75 4.25 4.00 3.75 5.00 4.75 3.75 150.00 4.25 240. 00 150.00 150.00 47.50 Days. 4.10 2.88 2.75 182 745. 50 June 7 June 14 ...do June 28.... ...do 4.00 2.50 2.75 3.50 3.00 10 22 25 1 1 40.00 55.00 68.75 3.50 3.00 59 170. 25 July 1 JulvH.... ...do July 17.... 2.75 2.75 2.75 2.75 2 2 1 1 5.50 5.50 2.75 2.75 6 16.50 Total number of eggs 247 Total egg days 932. 25 Average length of egg stage, days 3. 77 Records of 140 eggs, covering the period from April 9 to June 16, 1906, at Myrtle, Ga., are given in Table XIII. Although material under observation was kept in the laboratory, yet temperature con- ditions in this instance were not essentially different from those obtaining out of doors. Table XIII. — Length of egg stage of the plum curculio, Myrtle, Ga., 1906. Eggs under observa- tion. Date of deposition. Approxi- mate length of egg stage. Total egg days. Average length of egg stage, by months. Days. Days. 1 Apr. 9 2.75 2.75 1 ...do 3.00 3.00 1 Apr. 11.... 4.75 4.75 4 Apr. 12.... 4.25 17.00 8 Apr. 15.... 5.50 44.00 2 ...do 6.75 13. 50 29 Apr. 20.... 5.25 152. 25 10 ...do 5.25 52.50 38 Apr. 27.... 4.00 152. 00 11 Apr. 30.... 3.00 33.00 4.52 105 474. 75 May 5 5.75 9 51.75 6 May 20 4.50 29.00 10 May 31.... .3.25 32.50 4.53 25 113.25 June 7 3.00 3 9.00 7 June 16 3.50 24.50 3.35 10 33.50 Total number of eggs 140 Total egg days 621. 50 Average 1 ength of egg stage, days 4. 44 LIFE HISTORY AND HABITS: TIIK EGG. 51 The shortest period, 2 days 18.5 hours, April 9 to 12, was closely approximated later in the season, June 7. The longest period, 6 days 21.5 hours, occurred April 15 to 22. The average egg period for the entire series is 4.44 days. In Table XIV are given records of 113 eggs, observed in 1907 at Xew Kichmond, Ohio, on different dates during May and June. The longest egg period was about 6| days, on May 18, and the shortest 3 days and 5 hours, on June 20. The average egg period for all lots is 4.92 days. Table XIV. — Length of egg stage of the plum curculio. New Richmond, Ohio, 1907. Eggs under observa- tion. \nnrnvi Average Date of mitPePlength Total egg length of deposition. Seeeltai days" e?gsta?e- oi egg stage. by months 39 31 Days. Mavl8.... 6.25 Mav23.... 5.00 Days. 243. 75 155. 00 70 398.75 5.69 23 June 17.... 4.00 June 22.... 3.25 92.00 65.00 43 157. 00 3. 65 Total number of eggs 113 Total egg days 555. 75 Average length of egg stage, days 4. 92 Data were secured on the egg period at Siloam Springs, Ark., during late summer from August 15 to 25, the time varying from 3^ to 6 days, the average of the 18 eggs for the period being 4.66 days. Some egg records made under out-of-doors conditions in the insectary yard, at Washington, 1908, are given in Table XV. The period included from May 7 to 22 was marked by abnormally low temperature, and its effect upon egg development is clearly shown. Table XV. — Length of egg stage of the plum curculio. Washington, D. C, 1908. Eggs under observa- tion. Date of deposition. Approxi- mate length of egg stage. Total egg day-. 3 1 4 5 3 1 2 1 5 3 7 1 1 3 3 1 May 7 8 ...do May 8-9... ...db ...do ...do Ma v 9-10.. ...db May lo-ll. ...do May 11.... May 13.... May 13-14. May 14.... ...do Dai/". 11.00 10.75 9.75 10.00 9.50 9.75 10. 50 10.75 9.50 8 ' 8.00 8.00 7. 75 33.00 10. 7.'. 39.00 50. ixi a ;i. ::, 21.00 10. 7:. 28 a - 34.00 24.00 * 415.25 Total number of eggs Total egg days Average length of egg stage. . 52 THE PLUM CUKCULIO. The longest egg period was 11 days 2 hours, the shortest 7 days 18 hours, the average length of all lots being 9.23 days. These figures are in wide contrast to those, obtained at Washington in 1905, and indeed at all other localities, except for April, at Barnesville, Ga., and the early part of June at Douglas, Mich., in 1910. Comprehensive data were obtained by Mr. Hammar during 1910, at Douglas, Mich., for June and July, these months averaging some- what cooler than normal. A total of 944 eggs was observed under out-of-doors conditions, as detailed in Table XVI. Table XVI. — Length of egg stage of the plum curculio, Douglas, Mich., 1910. Eggs under obser- vation. Date of deposi- tion. Eggs hatching in specified days from deposition. Total egg days. 4 5 6 7 8 9 10 11 12 11 8 40 22 52 46 54 28 27 36 11 50 31 33 18 14 92 36 38 33 37 June 9 June 10 June 11 June 12 June 13 June 14 June 15 June 16 June 17 June 18 June 19 June 21 June 22 June 23 June 24 June 25 June 26 June 27 June 28 June 29 June 30 To July 1 July 3 July 4 July 5 July 6 July 7 July 8 July 9 July 10 July 11 July 12 July 14 July 15 Julv 17 July 18 July 19 July 21 July 22 July 23 July 26 July 28 To 1 2 33 19 2 4 6 4 2 117 78 353 195 408 332 362 152 137 180 52 246 156 180 110 80 129 189 198 175 185 7 3 40 10 4 10 36 30 20 12 2 3' 12 6 10 1 "3' 11 16 25 36 8 32 18 2 5 4 28 24 1 37 4 7 17 3 10 13 7 11 21 2 4 9 .... 2 647 al 4,014 13 22 12 21 10 18 16 30 40 10 18 16 14 3 6 8 8 8 10 5 9 297 19 12 14 10 2 4 25 20 io' 15 6 84 129 123 60 78 84 175 220 60 92 95 83 18 42 40 25 25 61 39 63 3 Li "~8" "6" 5 "2 12 5 20 5 .... 2 5 5 3 3 6 8 5 5 5 I6 3 9 1 1 | tql 1,668 Average length of egg stage for June Average length of egg stage for July Average length of egg stage for June and July. .days.. 6.20 .do.... 5.61 .do.... 6.02 LIFE HISTOEY AND HABITS: THE EGG. 53 At Barnes ville, Ga., during 1910 the length of the egg stage under out-of-doors conditions was determined for different lots of eggs; during April, May, June, and July, including a total of 445 eggs, all as shown in Table XVII. Table XVII. — Length of egg stage of the plum curculio, Barnesville, Ga., 1910. Eggs under obser- vation Date of deposition. Eggs hatching in specified days from deposition. Total egg days. 3 8J 4 4i 5 5* 6 6i 7 7J 8 8i 9 H 10 10! 11 in 12 m 13 W. 33 43 93 169 Apr. 8 Apr. 9 Apr. 11 Tota May 9 May 10 May 12 May 17 May 18 May 19 May 21 May 23 May 25 May 26 May 27 Tota June 16 June 17 June 18 June 20 June 22 June 23 June 24 June 25 June 27 June 28 June 29 June 30 5 7 9 12 8 7 18 1 1 i" 1 262.5 381.0 1,018.5 3 3 3 32 44 14 .' _ __'__._ .'..... ..'... 1,662.0 , 10 14 19 2 3 14 32 2 13 45 11 1 5 1(1 Y 3 7 2 2 85.0 110.5 140.5 10.0 13.5 62.0 134. 5 10. 5 61.0 198.0 49.5 1 5 2 3 8 3 4 24 2 5 1 5 1 8 24 11 17 4 165 . ... 875. 0 1 1 3 2 1 1 o 3 6 2 5 1 "i" 1 3.5 3.0 11.5 8.0 3.5 4.0 6.0 11.0 21.5 7.0 22.0 3.5 1 1 1 2 1 1 2 \ 1 2 3 i" l 1 2 1 3 1 28 Total July 1 July 3 July 4 July 6 July 7 July 12 July 14 July 15 Julv IS July 20 Total i i i i 104.5 1 2 17 18 9 6 10 10 8 1 — I— 4.0 9.0 8.0 54.0 64.5 27.0 19.0 40.0 47.0 33.5 2 ii" i 9 4 6 13 2 4 2 5 2 1 6 2 2 4 1 1 4 83 i i 306. 0 Average length of egg stage for April da vs. . 9.83 Average length of egg stage for May do. . . . 5. 30 Average length of egg stage for June do 3.73 A verage length of egg stage for July do 3.68 Average length of egg stage for season do 6. 63 The gradual decrease in the length of the egg stage following the rising temperature is well shown, dropping from the average, 9.83 days, for April to 3.68 days for July. The average for the four months is 6.62 days. Table XVTTT gives a summary of the preceding data. There is seen to be a range of from 2\ days to 13$ days for the different localities, the averages varying from 3.77 to 9.23 days. 54 THE PLUM CURCULIO. Table XVIII. — Length of egg stage of the plum curculio, various localities. [From preceding tables.] Localities and years. Eggs ob- served. Minimum period. Maximum period. Average period. Remarks. Washington, D. C, 1905 Myrtle, Ga., 1906 247 140 113 45 18 944 445 Days. 2.50 2.75 3.25 7.75 3.50 3.00 3.00 Days. 5.00 6.75 6.25 11.00 6.00 12.00 13.50 Days. 3.77 4.44 4.92 9.23 4.66 6.02 6.62 Eggs kept in insectary. New Richmond, Ohio, 1907.. Washington, D. C, 1908 Siloam Springs, Ark,, 1908. . . Douglas, Mich., 1910 Do. Eggs kept out of doors. Eggs kept indoors. Barnesville, Ga., 1910 Do. THE LARVA. HABITS OF LARVAE JUST HATCHED AND COURSE TAKEN IN FRUIT. After making its escape from the egg, the little curculio larva usually remains for a short period in the egg cavity before boring into the fruit. In a comparatively short time after hatching, how- ever, it has usually buried itself out of sight. Thus a larva hatching at 9.50 a. m. on wild plum remained in the egg cavity until 10.45 a. m., but had disappeared in the flesh by 11a. m. A larva hatching at 10.46 a. m. was found partly entered at 11.07 a. m. Three larvae found in their egg cavities at 9.40 a. m. entered the tissues at 10.20, 10.26, and 10.40 a. m., respectively. A larva hatching on apple at 9.30 a. m. did not succeed in getting out of sight in the flesh until 1 p. m., though upon hatcliing it at once began to burrow. Frequent dissections from fruit of larvae of known age indicate that within 2 or 3 hours after hat clung the fruit has been penetrated. The course which the larvae may take in the fruit is somewhat variable, though in general the pit or core is soon reached. Some detailed observations were made on this point by Messrs. Girault and Rosenfekl (Table XIX). Table XIX.— Course in fruit taken by newly -hatched plum-cur culio larvse. Dates of observa- tion. Kind of fruit. Location of puncture. Fruits exam- ined. Course taken by larvse in fruit. Apr. 20 May 1 1 5 o Straight into pit. Red June plum do Apex Basal £ Base end of pit. Into side of pit. then around to apical end. Do. do do 1 2 Straight into pit. do Basal § Apex Straight in about ■£% inch, then around to 2 do apical i of pit. Straight into pit. do Basal § Center side do Do. Do. do do do Do. 3 do Do. Do. 5 then in toward pit; then out toward side of fruit, and in an irregular manner down to about center of side and finally to pit,' LIFE HISTORY AND HABITS: THE LARVA. 55 Table XIX. — Course in fruit taken by newly-hatched plum-curculio larvx — Contd. Dates of observa- tion. Kind of fruit. Location of puncture. Fruits exam- ined. Course taken by larvae in fruit. May IG 20 2G Red June plum Early Belle peach Wild plum 1 1 1 1 1 1 1 1 1 1 1 In to base of pit. Center side BasalJ Apical § Basal § Apical % do In to pit. Under skin about TV inch, and around to 27 center of side, then into pit. Into pit. 28 do Straight in and into pit. 30 do Straight into pit. 30.. do In straight to apex of pit, and then around do Apical % to center of other side of fruit. Into apical J of pit, then along pit to center 3 ... do of side. Into pit; around to center side and into pit. 6 ...do Center side do Into about center of fruit, then to basal J, 9 do and down toward pit. Straight into pit, then along pit to apical J; then down side of pit. Prof. Oandall has recorded observations on the course taken by larvae hatching in apples, as follows: The course taken by the larvae on emerging from the egg has been traced in a number of apples, and is found to be variable. In one apple examined the bore proceeded straight from an egg cavity near the basin to a point just beneath the skin on the border of the cavity. Another bore was traced in a spiral 2\ times around the fruit. Other bores were found to be tortuous, but in no apple examined did the early bore extend to the core. LARVAL INSTARS. The number of molts made by the curculio larva in the course of its growth has not heretofore been determined, probably on account of the difficulty of following the growth of the insect in the fruit. Mr. Hammar, during 1910, in Michigan,. determined the number of molts and length of the respective instars for 10 individuals, as shown in the following table: Table XX. — Larval instars of the plum curculio. Dates of molting. Individual No. Hatched. First molt. Second molt. Third molt. Left fruit. Adult. l June 2S June 30 .. do June 30 July 2 July 2 July 4 .. do July 5 Julv 8 July 7 July 10 Julv 9 July 8 July 9 July 11 July 12 July 8 ...do ...do Julv 15 Julv 14 Julv 11 Julv 12 Julv 16 Julv 18 Julv 17 Aug. 4 Aug. 10 Lug 14 2 3 4 July 1 do July 3 July 7 July 6 ...do Julv 7 July 8 July 9 5 Aug. 16 Aug. 12 Aug. 15 Aug. 89 \U" li 6 July 2 do July 4 do 7 8 July 4 July 5 ...do July 6 July 7 ...do 9 10 Aug. 16 56 THE PLUM CUECULIO. Table XX.- — Larval instars of the plum curculio — Continued. Duration of larva linstars. Individual No. First instar. Second instar. Third instar. Fourth instar in fruit. Total days to adult. 1 Days. 2 2 2 2 2 2 2 2 2 2 Days. 2 2 2 4 3 2 3 2 2 2 Days. 3 2 3 3 3 2 2 3 3 3 Days. 4 3 2 5 5 3 3 5 6 5 37 2 41 3 45 4. 5 46 6 41 7 44 8 56 9 41 10 42 Totals 20 2.0 24 2.4 27 2.7 41 4.1 393 39.3 Measurements were made of the width of head-casts of the respective larval molts in the case of one larva, as follows: 0.306 mm., 0.425 mm., 0.595 mm., 1.02 mm. Head measurements of 19 larvae at time of leaving the fruit showed a range in width of from 0.935 to 1.071 mm., the average of all being 0.998 mm. DEATH OF LARV.E IN FRUIT. There is much evidence to show that many larvae die within the fruit, though the cause, or causes, of this mortality is not easy of positive determination. In general, if the fruit falls at the time or shortly after the egg is deposited, this insures favorable conditions for growth of the larvae. If, however, the fruit remains on the tree, the chances are much more against their successful development, and in the case of some fruits, as the apple and pear, almost entirely so. Prof. Crandall has made interesting observations on the mortal- ity among larvae in apples. In a lot of 716 fallen apples, 169 curculio larvae were found, 103 of which, or about 61 per cent, were dead, from causes not established. Most of the larvae found dead were less than half grown, and many were not more than 2 or 3 days from the egg. Although it is not so stated, it is probably true that these larvae were killed while the fruit was yet on the trees. The mortality of larvae in fruit for the most part results appa- rently from the crushing effect due to the rapid growth of surround- ing tissues; and in the case of stone fruits, as peach and plum, the abundant secretion of gum is perhaps an additional factor. The extent of mortality also varies with the different kinds of fruit. Thus in the case of apple many observations show that larvae are almost never able to survive if the fruit remains hanging on the trees for some time after the hatching of the eggs. The eggs for the most part hatch, and the young larvae begin to feed inward, but before they penetrate far they succumb. Such larvae show evidence of having been crushed, and often the burrow behind them is well grown over. Apples punctured while still small are most likely to fall; and LIFE HISTORY AND HABITS: THE LARVA. 57 after the apple has grown to three-fourths inch or 1 inch in diam- eter the punctures have much less effect, though the fruit may fall during the thinning process of the tree itself. The e^ and feeding punctures, however, usually result in disfigurement of the fruit, often very extensive, as will be discussed under another heading. During the 4 or 5 years that the curculio has been under investi- gation no observations have been made wherein the larvae have sur- vived to maturity in healthy apples on the trees, with the one excep- tion, as observed by Mr. Johnson at North East, Pa., on July 16, 1906, of the occurrence, in a ripening apple on the tree of the Yellow Transparent variety, of three nearly full-grown larvae. (See PI. IX, fig. 10.) As in this instance, it is possible that when eggs are depos- ited in summer varieties as they are beginning to ripen, the resulting larvae would mostly be able to survive, since the stage of rapid growth of the fruit has passed. On another occasion in this locality Mr. Johnson observed, August 1, 1906, in an orchard of the Baldwin variety, numerous small and highly colored apples on the trees about the size of walnuts, some of winch contained full-grown curculio larvae, and other fruits showed their exit holes. Unquestionably in this instance the normal development of the fruit had been checked from other causes, though it had failed to fall. The condition is not essentially different from that when the fruit drops to the ground. In interesting contrast to the practically complete death of all larvae hatching in apples which remain on the trees, and to a large extent of those which do not drop until some days after hatching, is the condition found to obtain when eggs are deposited in confine- ment in apples removed from the trees. In such cases, as has been observed frequently, a large percentage' of the deposited eggs pro- duces mature vigorous larvae. Figures obtained by Crandall. involv- ing 1,474 eggs deposited in fallen fruit, show that 1,238, or 83.92 per cent, of these resulted in mature larvae. In the case of pears, although these are oviposited in freely by the beetles, larvae appear never able to survive in fruit on the trees, and but rarely on fruit on the ground. Unlike the apple, the young pear. when it falls, tends to dry up, and on account of the stony tissue present becomes very hard. In 50 young fruits of the LeConte and Kieffer pear taken from trees at Myrtle, Ga., May 2, and bearing numerous egg-punctures, no live larvae were found, none of the punc- tures was fresh, and all were more or less outgrown. An examina- tion of the e^g cavity showed in most cases, however, borings o( the young larvae, and their dead bodies. In lots of Kieffer pears containing eggs, collected at Myrtle, Ga., April 9 and 20, the eggs were observed to hatch, but larvae failed to develop. Pears of this same variety collected from the ground April 13 and 20 and May 9 gave no results except from one lot, 4 adults 58 THE PLUM CURCULIO. being reared. Further attempts at rearing from pears in this locality gave no results. May 21 and 23, 1905, at Washington, D. C, and again May 30, 1905, young KiefTer pears from trees were confined with beetles, and eggs were deposited freely. No larvae, however, succeeded in devel- oping. During the course of the season of 1905 many fallen pears were examined by Mr. Johnson at North East, Pa., and he found only a single curculio larva, about one- third grown, feeding in the core of a pear on the ground. No larvae were found in fruit on the trees. Observations on plums, wild and cultivated, in many localities show that there is also a high mortality among larvae where the fruit remains on the tree or if its dropping be materially retarded. Plums punctured while small are more apt to drop than if the fruit is one- third grown or over. This dropping of the smaller fruit and the shedding of the fruit by the tree itself enables the species to more than maintain itself. Larvae hatching in fruit which does not fall are ordinarily able to penetrate the flesh but a short distance before succumbing, perhaps due to the combined effect of the copious gum exuded and the pressure of the growing tissues. The evidence also is that the egg may be destroyed by the gum exuding at the punc- tured point, and our notes show the examination of many punctures in which the egg could not be found, or was crushed, the cavity being completely filled with gum. The number of eggs or larvae missing has been quite too large to be accounted for otherwise. Many plums of the Japanese and Domestica types and of wild native sorts have been examined when taken from the trees and bearing egg punc- tures, and the conclusion is evident that larvae are not able to survive during the rapid growing period, and, as in the case of the apple, their successful development depends on the falling of the fruit. After the fruit has become grown, and the ripening process begins, larvae are more likely to survive, and ripe wormy plums, especially of the cultivated Japanese sorts, are not infrequently to be met with. The development of the peach, with reference to its availability as a host for the curculio, may be divided into three stages. The first stage includes the time from the beginning of oviposition to near the time when the pits begin to harden, a period of 3 or 4 weeks, during which approximately 75 per cent of the total infestation of the season occurs. The fruit in this stage, though growing rapidly, does not exude gum upon being punctured and readily drops from the tree when infested by curculio larvae. (See PI. V, fig. 1.) Prob- ably no fruit infested at this time remains long on the tree. The second stage in the growth of the peach begins when the pits show the first signs of hardening and extends up to the ripening period. LIFE HISTORY AND HABITS: THE LARVA. 59 At the beginning of this second stage there is a sudden cessation of both egg laving and feeding, and during the whole time the beetles refrain from puncturing the fruit except in occasional instances. The fruit in this stage exudes gum very copiously when punctured. (See PL VI, fig. 2.) Relatively little growth is made while the pit is hardening, but in the few cases in which eggs are laid and hatched at this time the larvae are killed at an early stage by the flooding of their burrows with gum, the fruit failing to fall from the tree. The third stage includes the ripening period, when the beetles resume oviposition and the larva? are able to mature normally. It i> at this time that all the infestation of ripe fruit occurs, though the number of individuals developing is small in comparison with those in the young fruit which falls off. Another factor in the mortality of larva3 in drop fruit, as noted by Crandall in apples, is the effect of sunshine. According to this gentleman, no living larva? could be found in fruit exposed to the sun for a few hours, whereas fruit taken from under the shade of the trees contained a fair proportion of living larva?. An interesting experiment is quoted, bearing on the matter: In one box were placed 200 apples and in another 250, the latter being placed in full exposure to the sun. Later examination of soil in the respective boxes gave for the former 42 pupae and for the latter 3 only. As suggested by Prof. Crandall, this points to the advisability of following a method of orchard management winch will insure as free access of the sun as possible. DESERTIOX OF FRUIT BY UNDERSIZED LARV.E. On many occasions it has been noted that larvae may leave the fruit before reaching maturity and burrow below the soil as for pupation. This premature abandonment of fruit is perhaps often forced by reason of the unfavorable condition of the latter, but in many cases this explanation will not suffice. Fruit in an excellent condition for feeding purposes has been often thus deserted. An unhealthy condition of the larva itself, as from parasitism, might be suspected, but roarings of such individuals indicate that this i< not the case. Larvae have at times been observed to leave fruit, as in a glass jar without soil. and. in the absence of suitable surroundings for pupation, reenter the fruit and there finally pupate. It is doubtful, however, if there is any tendency of Larvae to leave one fruit in search of another, and a faulty instinct seems most likely to account for this behavior. Larvae emerging from peaches and plums collected throughout the season (p. 62) at Washington, I>. ('.. in 1908, varied in about the following proportion: Large, 45.25 per cent; medium, 60 THE PLUM CURCULIO. 39.04 per cent; and small, 15.69 per cent. Adults were never reared from the small larvae, though the attempt was repeatedly made. At Barnesville, Ga., during 1910, observations were also made on this point. Among the first larvae of the season to leave drop fruit was a large number of undersized individuals. Many were not more than one-half normal length, and from this they varied to full size. The proportion of small larvae was greatest during the first week or ten days after larvae began leaving the fruit, the proportion becoming less and less until by two weeks after the first larvae began emerging practically all individuals were of normal size. In Table XXI is shown the proportion of undersized larvae during the period from May 2 to 21, when they were in evidence. Table XXI. — Record of undersized and normal larvse of the plum curculio from drop fruit from 31 peach trees, Barnesville, Ga., 1910. Dates. May 2 3 4 5 6 7 8 9 10 11 Larvae Distinctly leaving undersized fruit. larvse. Number. Per cent. 49 38 78 68 33 48 119 48 40 1G4 66 40 175 26 15 99 26 26 110 12 11 357 80 22 240 29 12 209 28 23 May 12 13 14 15 lti 17 18 19 20 21 Larvae leaving fruit. 272 159 S6 58 48 38 33 71 102 54 Distinctly undersized larvae. Number. 22 6 5 2 1 1 0 0 1 1 Per cent. NORMAL EMERGENCE OF LARV.E FROM FRUIT DURING THE SEASON. In order to determine over what period and in what abundance larvae left the fruit and entered the soil for pupation, as bearing on the period for cultivation for the destruction of the pupae, it was planned in 1908 regularly to collect, at frequent intervals through- out the season, all of that fruit which fell to the ground and to rear and record the larvae as they emerged from the respective lots of fruit. This work was done during 1908 at Siloam Springs, Ark., using all drop fruit for the season from 120 peach trees; and during the same year at Washington, D. C, by Mr. P. R. Jones, with both peaches and Japan plums, using all of the drop fruit on 10 peach trees, and in addition to the drop fruit from 8 Japan plum trees that from the trees at ripening time was also used. During 1910 similar data were obtained at Barnesville, Ga., and by Mr. Hammar at Douglas, Mich. In Georgia all of the drop fruit throughout the season from 31 peach trees was regularly collected and larvae recorded as they came from the respective lots. At picking time the fruit from 12 of the 31 trees was gathered and LIFE HISTORY AND HABITS: THE LARVA. 61 larvse recorded, but for uniformity the estimated number of larvse from the fruit from the 31 trees is used in the table. In Michigan the drop and picked fruit from 15 peach trees was used, collections beginning June 30 and continuing to August 27. These records, it is believed, should show the normal seasonal history of the insects in this stage under orchard conditions. Such WO /soo /250 /OOO 750 SOO %250 I 0 \ 2 9 /6 23 30 6 /5 20 27 4 tT ■ /O 2f / 3 'S --—.^ 1 , / \ V \ \ \ i X \ \ \ \ 1 A \ \ \ \ 7 i \ \ / s r ^ SSgjg !>/zz^ G*„/3 'O <§£.d!& X.t/90& S* '^v, \. \ \ ^ %0> ---""' 500 750 /OOC /250 1500 1750 \ 1 ^->. 4y y \ / \ c i \ 1 0>^ \ i - Fig. 20.— Diagram showing normal emergence from fruit of larvae of plum curculio during season at Siloam Springs, Ark., Barnesville, Ga., Washington, D. C, and Douglas, Mich. (Original.) records are evidently much more reliable than those winch do not take account of all of the fruit for the season. In Table XXII are shown the totals emerging for each of the four localities by days, as also the number and percentages of larvae emerging by months. These same data, summarized by weeks, are shown graphically in figure 20. 62 THE PLUM CURCULIO. Table XXII. — Emergence of plum curculio larvae throughout the season, from total fruit, in various localities, 1908-1910. Barnesville, Ga., 1910. Siloam Springs, Ark., 1908. Washington, D. C, 1908. Douglas, Mich., " 1910. Dates. g cj Sco CD >> l>> O o a o 03 CD <2 "3 o En a c3 af ct> g Pj '3d CD © >> "3 o "S o s ,a o a CD a n o C3 CD S-. SJ0° SB pi o o o be ti 'So cj 6,5 cS t3 "3 O Eh id Pi o S o 03 (D O Eh o 03 Q) •2.C C3 g > _£3,Q "ea o Eh PI o E o 03 CD M •2 "3 O Eh o 03 . li 0 = 0 A o 1 * t 8 c - Boo 0 ~ \ s 0 = .J z >. -3 £A ~ * a I i ~z i M || \ z - Z Z. f, 0 A a = ~ 3 3 u O Eh - | . hi - - z E ± Julv 6 i 9 5 16 36 39 29 10 11 27 43 36 41 3-5 17 14 91 56 31 19 140 55 17 15 4 15 -- 34 4 5 2 ...... 8 4 1 1 9 8 1 10 11 3 12 13 2 12 10 14 6 13 4 1 3 13 12 30 29 56 51 77 35 56 26 29 5 5 21 13 11 5 t 3 8 14 4 5 8 6 8 8 11 14 ;;:;;;; 1.5 16 17 18 10 19 20 3 45 63 38 15 17 12 12 19 21 22 23.. 24 35 46 38 24 29 21 11 24 25 20 27 15 4 4 3 4 29 30 31 458 14. 02 4' 7 - 469 7.12 99.33 Aug. 1 16 24 6 S 2 2 4 4 1 g 0 3 1 4 5 3 1 6 7 8 - 9 1 4 1 10 ;. 11 12 13 2 14 99 3. Oil 74 1.25 2 .03 \ Total.... 3.264 B,264 100.00 5,920 5,920 100.00 6,588 588 895 89E In the above table, the Georgia records show a total of 3,264 larva1 leaving the fruit between May 2 and August 9. A large majority of these, 2,665, or 81.64 per cent, issued during May: during June only 42, or 1.28 per cent, issued, while during July. 458, or 14.02 per cent, was secured. August shows a total of 99 larvse, or 3.06 per cent. At Siloam Springs, Ark., in 1908 a total of 5,920 larva1 issued, the interval covering the period from May 12 to August 13. Larvse to the number of 3,664, or 61.89, left the fruit during the period from May 12 to 31 ; while for June, 1,715, or 28.97 per cent, left the fruit, a total for the approximately 7 weeks of 5,379, or 90.86 per cent. 64 THE PLUM CURCULIO. July shows an emergence of 467 larvae (7.89 per cent) and August 1 to 4, after which no more emerged, 74, or 1.25 per cent. At Washington, D. C, during 1908, a total of 6,588 larvae was reared, 1,115 emerging during the last 7 days of May. During June 5,002 larvae left the fruit, a total for May and June of 6,117, or 92.85 per cent. Only 7.12 per cent of the total-larvae emerged during July, emergence practically ceasing with that month. The Michigan rec- ords include only 895 larvae, of which 889, or 99.33 per cent, left the fruit during July. The foregoing data, with the additional records by Crandall from Illinois, are shown in Table XXIII with the dates of blooming of peach trees for that }ear. The relation of these data to the time of making cultivations is shown on page 176. Table XXIII. — Emergence by months of plum-curculio larvx in different localities. Approx- imate May. June. July. August. September. si si H3 date of *5b Ei bo '5b be Localities. full blos- som of £ o 8 > S3 t 93 "3 c3 03 3 03 a a> 03 0) o ^ * ~ Ph h3 Ph A Ph h3 Ph H Barnesville, Ga Mar. 15 2,665 81.64 42 1.28 458 14.02 99 3.06 3,264 Siloam Springs, Ark Mar. 18 3,664 61.89 1,715 28.97 467 7.89 74 1.25 5,920 Washington, D. C Apr. 6 Apr. 20 May 10i 1,115 16.92 5,002 75.93 469 7.12 2 .03 6,588 895 662 99.33 53.47 6 272 .67 21.97 Griggsville, 111 254 20.52 50 4.04 1,238 Apple. MANNER OF LEAVING THE FRUIT AND ENTERING THE SOIL. Upon completing its growth, the larva leaves the fruit in winch it has been feeding, and soon makes its way beneath the soil. Fruit tying upon the ground will usually show, when examined, the small exit hole of the grub, mostly along the lower side where the fruit was in contact with the earth. An examination of 200 infested drop peaches showed these exit holes to be located as follows: Apex, 8; apical third, 64; center of side, 66; basal third, 46; base, 16. This shows that 88 per cent of the exit holes are along sides as against the ends, which is perhaps proportionate to the respective areas. In deserting the fruit on the trees, as peaches and cherries, the larva must fall, and this is probably not injurious to it. Once upon the ground, the instinct is immediately to get below the soil. The time occupied in accomplishing this will vary according to character of soil, whether cultivated or not, and the presence of crevices, etc. At this time especially the larvae are exposed to predaceous insects, par- LIFE HISTORY AND HABITS \ THE LARVA. 65 ticularly ants, and numerous larvae perish from their attack. Many larvae have been timed by the watch, and the interval occupied until out of sight belowthe soi] has varied from about one-half to 50 mini Table XXIV includes observations made in Georgia and in Washing- ton,D. C, both in the orchard and in small jars in the laboratory. It will be noted that more time is usually spent in .-earclnng for a suitable place to enter than in actually working below the surface. The average time on the ground and until beneath the soil, in the data given, is about 12 minutes. A larger series of observations would probably change these figures somewhat. Table XXIV. — Time occupied by larvx of the plum cure*/" Localities. Larva Xo. Time on soil. Be- Time neath occu- soil. Kind of soil. Myrtle. Ga.: Laboratory j 10.00 10.06 10.115 Hi Fr^h sandy loam soil in glass jar, gentlv packed. 2 2.07 2.15 2.21 14 Do'. 3 10.21 10.21| 10.22 1 Do. 4 9.13 9.14 9.15 2 Do. 5 4.12 4 Do. 9.-59 10.00" 10.03 4 Do. . 9.43 9.44 9.49 6 Do. 8 10. 22 10. 23 10. 24 2 Do. Q 10. 22 25 10.30 8 Do. lb - - 10 Do. In orchard ii 5.22 5.23 1 Dry sandv soil under peach tree. "Do. 12 S -- ■ - 4 13 .5. 22 .5.27 5 Do. 14 5.22 5. 31 9 Do. 15 5. 22 ' _ Do. 16 5.22 5.39 17 Do. 17 5. 22 5.49 27 Do. Washington. D. C: Insectary 18 . 1.29 1.41 14| Sandy garden soil in box. moder- - compacted. 19 1 1.59 2.19 49 Do. 20 1.48 - 3. 23 35 Do. 21 2.23 - 2.40 '17 Do. 22 . 2.37 2.42 32 Do. 25 2.44 2. 46 2 7 3 24 2.2] 2.41 2.44 21 Do. In orchard 25 2.55 2.55 3. 11 16 Clav loam, well cultivated. Larva? placed under plum tree. - - S 3.00 5 Do. 27 3. 33 3.34 3 Do. 28 3. 15 15 Do. 29 3.20 3. 22 3. 25 5 no. 30 3. 14| ■ 2 TIME SPENT IX THE FRUIT (EGO AND LARVAL >T.\ In 1904 Prof. Crandall determined, for Illinois, the time -pent in apples (combined eg^ and larval - >r 1 ,238 individual-. A few larvae left the fruit within 12 and 13 days from deposition of egg, and some -pent an unusually long time in the fruit. The great majority, however, developed and left the fruit in about the average time. Table XXV gives Ms emergence records by months, and also the average period per individual within fruit for that month. L7262°— Bull. 103—12 5 66 THE PLUM CURCULIO. Table XXV. — Length of time spent in fruit by plum curculio, Illinois, 1904. Months. Total num- ber of larvae emerging. Percentage of whole. Average time in fruit. 254 662 272 50 20.52 53.47 21.97 4.04 Davs. '18.07 July 19.15 21 55 26. 00 Total . 1,238 100. 00 The average time for egg and larva in the fruit for the whole season was about 20 days. In Table XXVI are given records of a few observations from Youngstown, N. Y. (1905), and North East, Pa. (1906). Table XXVI. — Length of time spent in fruit by the plum curculio (egg and larval stages combined), Youngstown, N. Y., 1905, and North East, Pa., 1906. Eggs depos- ited. Date of depo- sition. Larvae emerged Ap- proxi- mate time in fruit. Total num- ber of larvrr devel- oped. Total num- ber of egg and larval days. Aver- age Localities. X um- ber. Date. num- ber of days in fruit. 43 (?) June 24.1905 fJune 13.1906 June 14.1906 [June 15,1906 f 8 1 1 3 1 5 { I 6 4 July 10,1905 July 12,1905 July 13.1905 July 14.1905 July 9, 1906 July 3,1906 July 5,1906 July 3. 1906 Davs. 16700 18. 25 19.00 20.00 25. 50 21.00 20. 75 18.00 1» } ' 6 4 303. 25 169. 50 124. 50 72.00 17. S3 24.21 20.75 18.00 Total 34 669. 25 Average time spent in fruit during June for both localities days. . 19. 68 During 1905, at the insectary in Washington, data were obtained on the length of time spent in the egg and larval stages in the fruit for miscellaneous lots during May and June. As in the case of egg- hatching records, these were obtained under the same conditions in the insectary, where the temperature was higher than normal. These records are given in Table XXVII. LIFE HISTORY AND HABITS: THE LAKVA. 67 Table XXVII. — Length of time spent by the plum curculio in fruit [egg and larval stages combined . Washington, J). ('.. 1905. Larvae emerged. Total Total Eggs de- Date of ASS?" JH number of eeg and lar- val days. Average number Host pos- deposition. time in 1 1U1 \ rU devel- oped. of days fruit. ited. Number. Date. fruit. in fruit. Days. ! f 2 Mav 23 11.50 ) 2 Mav 24 12.50 (?) May 12 \ 2 3 6 2 Mav 25 Mav 26 Mav 27 Mav 30 13.50 } 14.50 15.50 J 15.00 1 1.5 211.50 14.10 Plum. 7 May 15 3 May 31 16.00 } 7 112. 00 16.00 Do. 1 2 June 1 17.00 J 1 Mav 16 1 June 2 16. 75 1 16. 75 16. 75 Do. May 16-17 3 June 3 f 1 June 1 { 14 June 2 17.50 14.75 1 3 52.50 17.50 Do. May 16-18 16.00 } 30 523. 75 17.46 (?) 15 June 3-6 19.00 | 9 May 18-19 ( 3 June 3 \ 2 June 7 15.50 l 19.50 ; 5 85.50 17.10 /Plum. \ Do. 5 May 19 5 June 6 16 June 5-6 { 7 June 7 1 5 17. 75 Do. (?) May 20-23 16. 25 25 388. 25 15. 53 Do. 2 June 8 17.25 1 6 June 6 12. 75 (?) May 23-25 21 June 7 11 June 10 f 2 June 6 14.00 13. 50 i 38 554. 75 14.60 Apple. 16 May 23-24 \ 2 June 7 6 June 9 [ 1 June 7 14. 75 16.75 13. 50 ! ! 10 157.00 15.70 Plum. 14 May 24-25 { I June 9 June 10 15.50 16.50 i 12 188.00 15.67 Do. 9 May 2.3-26 5 ...do 15. 50 5 __ . 15. 50 Apple. 9 May 25-27 Total / 5 June 7 \ 2 June 8 xnd average 13. 00 14.00 19. 2.5 } 7 93.00 13.29 Plum. 163 2.549.2.5 15. 64 f 4 June 26 1 15 June 6-7 { I June 27 June 30 20.25 23. 25 !■ 15 308.75 20.58 Apple. June 9-10 4 June 24 14. 25 4 57.00 14.25 Plum. 7 June 10 2 I • : 1 d June 21 June 25 10.50 12. 25 2 21.00 10.50 Do. 24 June 11-13 June 26 June 29 13.75 1 16.75 f 21 374. 25 17.82 Apple. July 1 18.75 13 June 10-13 { i June 27 Jun^ 2S 15. 00 15. 50 ) 11 166.00 15.09 Do. 20 June 14 : •! June 29 June 30 14.75 \ 15.75 f 18 273. 50 15.19 Do. 10 June 14-15 { i June 28 Julv 1 13. 25 16.50 ) 9 129.00 14.33 Do. 2 June 1 7 Total 2 July 4 17. CO 2 34. 00 17.00 Do. ind average =on S2 1 . 363. 50 16.62 Total for sea. 245 3,912.75 Average time spent in fruit for season, days The records show a ran":? for combined egg and larval stages of from 10J to 2.')} days, with the average for the season of 15.99 days. The total number of larva' under observation was 245 and the sum of egg and larval days was 3,912.75. Observations made at Myrtle, Ga.. during 1906, on miscellaneous lots of eggs and larva1 in peaches, during April, May, and June, are detailed in Table XXVIII. 68 THE PLUM CURCULIO. Table XXVIII. — Length of time spent in fruit by the plum curculio (egg and larval stages combined), Myrtle, Ga., 1906. Eggs de- pos- ited. Date of egg depo- sition. Mature larvse devel- oped. Larva? leaving fruit in specified days from deposition of eggs. Total egg and larval days in fruit. 11 12 13 14 15 16 17 18 19 20 21 22 23 24 '25 26 27 28 29 30 9 ■ 21 (?) (?) (?) 15 14 7 12 13 6 7 14 1G 16 14 12 11 20 11 8 5 4 7 5 10 6 13 Apr. 19 Apr. 21 Apr. 23 Apr. 26 Apr. 27 Total. 4 , 1 1 4 3 7 5 2 2 2 . 1 3 ... 1 2 1 3 1 1 23 . 3 4 2 4 4 3 1 1 1 1|- 395 May 1 May 7 Mav 8 May '.i May 10 Mr, 11 Mav 13 May 14 Mav 15 Mav 16 Mav 17 Mav IS May r> Mav 20 Mav 21 May 22 Mav 2-', Mav 24 Mav 25 May 26 10 11 ? 8 10 9 6 0 6 6 3 2 5 4 2 2 2 1 2 4 1 1 I 1 3 1 ... 4 2 1 1 ... ... 1 ... 1 1 1 2 1 2 2 1 "i" 1 ...!... i 1 3 "i" 2 ::::::: 1 2 3 ... 1 "i" 1 2 1 ... 2 9 1 2 1 1 1 ' I 2 "2" 1 1 1 i 1 1 1 1 1 i 1 1 1 1 2 1 2 1 ... 1 i i . ... 1 8 9 29 16 17 7 11 5 2 Total. 116 1 ... 5 1 2 1 1 2,112 June 2 June 8 June 17 4 ... 3 ... 1 ... 1 2 ... 2 1 ... 1 1 9 4 ... 3 ... ... Tola]. 16 ...L.| 2 4 5 ... 4 I 248 Tot A a al . for pril. May, id June.. 5 13 13 11 37 20 20 8 11 6 3 1 2 ... 2 ) 1 2,755 Average time in fruit for April days. . 17. 17 Average time in fruit for May do'. . . . 18. 21 Average time in fruit for June do 16. 13 Average time in fruit for April, May, and June do 17. SI A total of 155 larva? emerged, the time spent in the fruit varying from 11 to 30 days, with an average for the period of 17.81 days. Table XXIX gives observations on 411 larva3 reaching maturity during Ma}^, June, and July, at Siloam Springs, Ark., in 1908. The fruit used was peach. LIFE HISTORY AND HABITS: Till-; I.AKVA. 69 Table XXIX. — Length of lime spent in fruit by the plum curculio (egg and larval stages combined), Siloam Springs, Ark., 1908. Eggs de- pos- ited. Date of egg depo- sition. Mature larva) devel- oped. Larvae leaving fruit in specified days from deposition of eggs. Total and larval days in fruit. 15 16 17 is 19 20 . 22 23 24 25 26 27 28 29 30 8 6 10 38 56 39 Mav 12 Mav 13 May 14 May 15 May 16 Mav 17 6 6 8 35 52 37 28 6 5 16 6 13 6 6 8 8 1 1 ■> r 10 15 20 2 1 2 3 1 4 9 1 3 2 1 1 3 21 1 1 2 5 4 31 10 1 8 Y 2 30 Mav 18 1 3 1 10 8 16 10 16 16 May 19 Mav 20 Mav 21 Mav 22 May 23 Mav 24 T "2 3 3 1 3 ... 1 1 1 2 i" "2 1 1 1 3 1 5 '4' 2 3 1 T T 1 ... i 2 ■ --,--- - ... 7 ! Mav 25 9 Mav 28 2 2 ... 2 3 5 3 2 3 1 1 1 9 7 8 10 11 16 17 9 10 5 5 7 11 12 8 5 7 11 10 10 5 3 4 4 2 2 3 May 29 May 30 May 31 Total. June 2 June 3 June 4 June 5 June 6 June 7 June 10 June 11 June 14 June 15 June 16 June 17 June 19 June 20 June 22 June 25 June 27 Total. July 7 July 13 July 15 July 17 July 22 July 24 July 26 Total. 1 2 1 1 ... 1 1 ... 1 2 1 260 i 7 13 3 21 M 52 27 21 11 12 4 3 1 5.424 8 10 14 14 9 9 5 4 7 10 8 7 4 6 10 6 6 4 2 ... 2 1 1 4 A 1 2 7 1 2 3 2 "6' T 1 1 1 1 "z 1 3 4 T 2 2 1 1 1 1 2 2 ... 1 ... 1 . 1 . 2 2 1 ... 2 2 4 3 ... ... 1 ... 2 1 9 2 2 1 1 2 1 1 2 1 1 1 - 2 3 "2 2 1 2 1 ... 1 137 3 14 22 2g 16 19 9 7 5 ... 3.057 3 2 3 2 1 2 1 1 1 1 i 1 . 1 : 2 1 1 1 1 1 1 1 ' 14 : 1 1 i 1 To J J tal for May, imc, and uly 411 i 7 13 6 "7 39 33 24 12 9 1 1 ; Average time ill fruit for May days. Average time in fruit for June • ^\o 22.31 Average 1 Lme in trail for July do. . Average time in fruit for May, June, and July do 21.43 70 THE PLUM CURCULIO. A total of 411 larvae was under observation, the time spent in the fruit varying from 15 to 30 days. The average of all individuals was 21.43 days. Observations were also made at Douglas, Mich., during 1910 by Mr. Hammar, on the complete life-cycle period of 121 individuals. For purposes of comparison the egg and larval stages combined are shown in Table XXX. The fruit used was peach. The average time for all individuals for June and July was 20.8 days. Table XXX. — Length of time spent in fruit by the plum curculio (egg and larval stages combined), Douglas, Mich., 1910. ^ggs depos- ited. Date of egg deposi- tion. Larvae leaving fruit in specified days from deposi- tion of eggs. Total egg and larval days in fruit. 16 17 IS 19 1 i 20 i 21 22 23 24 25 26 27 6 10 4 June 24 June 29 June 30 i i ! i 3 3 2 1 3 2 2 i 1 Total 3 3 5 4 1 1 3 392 38 20 19 16 6 1 1 1 July 1 July 2 July 3 July 4 July 6 July 20 July 21 'otal 1 3 22 "4" 0 ...J 5 6 7 8 3 2 1 8 10 7 6 1 1 1 4 10 15 32 24 1 19 11 2 1 1 2,122 3 T 'otal for June and July 36 ! 25 20 11 5 1 1 2,. 514 Average time in fruit for June days. . 19. 6 Average time in fruit for July do 21 Average time in fruit for June and July do 20. 8 In Table XXXI are shown the results of observations on the length of time spent in the fruit by the curculio at Barnesville, Ga., during 1910. The fruit used was peach. LIFE HISTORY AND TIABTTS : THE LAEVA. 71 Table XXXI. — Length of time spent in fruit by the -plum curculio (egg and larval stages combined), Barnesville, Ga.. 1910. Ma- ture larvae devel- oped. Larvae leaving fruit in specified days from deposition of eggs. Total larval days in fruit. Dale of egg deposition. 12 ;; ., 14 14 1 2 1 1 1 1 •2 4 1 5 2 I 1 2 5 2 13 31 1 1 61 „ 1 2 3 1 2 •"> 2 ; 2 1 2 1 1 1 6 1 19 1 3 i '7 "i 8 1 "i 3 '5 '4 i i 5 9 25 4 3 7 B 17 1 1 10 1 3 1 2 2 1 1 6 3 16 2 6 1 9 38 is 1 i 2 1 1 i 1 1 12 3 L8 3 2 2 1 S 29 19 *;:; 3 2 1 i 7 1 13 1 3 5 21 2 6 2 i 1 1 " 1 1 2 15 21 4 4 1 9 1 2 1 "2 3 10 1 2 5 8 27 1 22 23 24 25 1 2 2 4 s 4 '■'■ 2 2 3 • 11 "8 1 10 9 26 7 1 1 1 30 3132 _LL ..8 5 15 12 3 20 23 9 33 34 1 2 35 i 2 36 1 1 2 " 2 :: :: :: :: . 1 Apr. 8 9 11 29 68 4 2 -> 7 7 1 2 3 6 5 10 15 = 1 1 1 4 6 2 8 12 11 3 1 j 12 i Total. 112 i ■_ 4 7 7 4 2.. 3.465 May 9 10 12 13 17 18 19 21 23 25 26 5 8 13 1 1 1 1 15 2 1 16 1 21 23 9 ( 2 ;; ■■ Total. 64 •■ 1 1 2 4 .5 7 6 1 32 1.135 June 16 17 18 20 22 24 25 27 28 29 30 1 1 3 2 2 3 3 5 3 5 3 i i 2 2 4 7 1 1 1 1 1 1 4 4 2 7 ,2 i i — 2 1 3 3 7 9 Total. 31 463 Inly l 3 4 5 (i 7 8 9 12 14 IS 20 21 26 30 1 3 4 14 11 25 8 11 7 I 3 4 48 45 Total. 198 3.309 Aug. 7 9 10 17 15 43 31 2 91 « Total. , 1.910 Total for sea- son . 491) 10,283 Average time in fruit for April... Average time in fruit for May Average time in fruit for June.... Average time in fruil for July Average time in fruit for August. Average for the season days. . 30.94 do .. . 17.74 . 14.94 . 16.76 20. 96 Tho Barnesville records include observations on 496 larvae, the period in fruit varying from 12 to 42 days. Tho aver season was 20.73 days. ago for the 72 THE PLUM CURCULIO. In Table XXXII are brought together from the preceding tables the totals showing the time spent in the fruit at the several localities. The horizontal bars mark weekly periods from time of deposition of eggs, beginning with the second week. The percentage of the total number of larvae emerging weekly is also shown. From the Illinois, District of Columbia, and Georgia records it will be noted that there was a considerable emergence of larvae in the localities in question during the second week. This was highest in the District of Columbia, where almost 30 per cent of the total larvae emerged during the second week. In Georgia, 18.7 per cent of the larvae came out during the second week in 1906, and during 1910 the pro- portion was 20.77 per cent. In all localities a notable majority of the larvae emerged during the third week, and with the exception of the Georgia material during 1910, emergence from the fruit was practically over by the close of the fourth week from deposition of eggs. Table XXXII. — Length of time spent in fruit by the plum curculio (egg and larval stages combined), all localities. Griggsville, 111., 1904. Washington, D. O, 1905. Youngstown.N.Y., 1905, and North East, Pa., 1906. Myrtle, C.a., 1906. Days. Larvae emerg- ing. Percent- age of larvae emerg- ing by weeks. Larvae emerg- ing. Percent- age of larvae emerg- ing by weeks. Larvae emerg- ing. Percent- age of larvae emerg- ing by weeks. Larvfe emerg- ing. Percent- age of larvae emerg- ing by weeks. 10 ... 2" 2 17 42 73 137 210 219 179 89 77 4.") 38 27 22 23 8 J / 9 3 1 1 ! 1 2 1 1 1.70 - 76. 66 • 19. 38 1.94 .32 f 2 2 \ 9 17 I 43 f 58 53 14 15 21 8 1 29. 79 6S. 98 1.23 11 12 1 \ 1 13 [ 14 f 6 22 36 16 14 8 11 5 2 1 1 18. 70 13... 79. 41 20.59 14... j 15 16 17 18 21 \ 72. 95 19 .. 20 21 . I 6 22 , 23 3 24 7 25.. 1 6.45 26 . 2 27 28 29 f 2 1 30 31 32 \ 1.90 33... 34... 35 36 37... 38... 39 1 40 41... 1 1 42 Total 1,238 100. 00 245 100. 00 34 100.00 155 100.00 LIFE HISTORY AND HABITS: THE PUPA. Table XXXII. ■Length of time spent in fruit bytfu plum curculio egg and larval stages combined), all localities — Continued. Siloam Springs, Ark., Douglas, Mich., 1910. Barnesville, Ga.,1910. Days. Larvfe emerging. Percentage of larvae emerging by w< Percentage Larvae 1 of larva? emerging, emer. by v Larvae Pcrc : Of 1 :' emer. by w< 10 | .„ 11 12 9 13 33 r a 43 38 29 21 15 27 f 2v 12 12 5 11 10 27 21 23 9 4 2 o 4 I 14 15 1 13 39 97 53 39 33 24 12 9 1 1 57. 91 41.60 .49 31.40 10 17 4 18 19 20 3 15 36 25 20 11 5 41.13 21 22 23 24 25 I 17.54 26 1 1 27 2s 29 30 31 32 1 33 34 35 36 37 38 39 *• L81 40 41 42 1 ' Total 411 100.00 121 100.00 THE PUPA. LENGTH OF TIME SPENT IN SOIL. Considerable information has been obtained on the length of time spent by the curculio after entering the soil for pupation until the emergence of the beetle. As in the ease of the statistics showing the length of time occupied in the egg and larval stages in the fruit, the present data have been obtained, often from miscellaneous collections of infested fruit, and at irregular intervals. Records are also given from collections where the complementary data were not obtained, or during another season. U THE PLUM CTJECTJLIO. Table XXXIII gives data on time spent in the ground by the cur- culio at Youngstown, N. Y., during 1906. A total of 826 larvse were under observation, and the average time hi soil for all beetles emerg- ing was 31.04 days, varying from 19 to 54 days. Table XXXIII. — Length of time spent in soil by the plum curculio, Youngstown, N. Y, 1905. Lar- va'. Adults emerging in specified days from time of entering soil by larvae. Date larva1 entered soil. 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 1 34 June 27 40 55 1 "9' 2 2 13 1 9 2 5 5 3 5 11 5 1 19 1 2 11 q 2s 2 .... 2 5 1 29 250 2 3 Total 345 2 2 1 .7 10 17 10 12 19 25 14 13 July 1 150 126 135 70 3 1 7 3 9 13" 5 10 4 3 2 11 2 6 3 16 3 2 3 "8" 3 7 6 8 Z 2 4 3 9 2 2 2 5 Total. 481 2 2 6 15 27 19 22 24 11 21 13 82(5 2 2 4 7 7 25 44 29 34 43 36 35 % Date larvae en- Adults emerging in specified days from time of entering soil by larvse. Total adults Total davs tered soil. 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 54 spent in soil. 3 3 1 1 1 1 1 34 21 96 28.... 29 1 4 1 1 1 Total. 4 » 1 1 2 1 1 1 151 4,711 2 1 July 1 . ....1 5 ....: 2 i|.... 78 38 39 25 2 2 1 .... 1 1 3 Total... 2 1 ' 2 1 1 180 5,565 Total for sea- 4 5 J, 3 8 4 1 1 1 1 331 10, 276 Average time spent in the ground during Tune days.. 31.20 Average time spent in the ground during July do 30. 92 Average time spent in the ground during season do 31. 04 Table XXXIY shows similarly the time spent in the soil by curcu- lios from miscellaneous collections at Myrtle, Ga.; in 1906. A total of 459 larva? entered the soil, yielding 376 adults. The average time in the soil of all beetles was 25.95 days, the range being from 16 to 46 days. 1.1 KK HISTORY AND HABITS: THE PI'I'A. 75 Table XXXIV. — Length of lime spent in the soil by the plum curculio, Myrtle, Ga.y 1906. Date larv;c entered soil. Larrae. A.dults emerging in specified days from time of entering soil by larvae. in 17 18 19 20 21 22 23 24 25 26 27 May 17 63 30 36 40 71 4 1 8 5 10 8 19 1 20 2 VI 25 3 5 13 18 12 4 1 13 27 2 6 3 8 .... 31. Total 244 2 9 15 34 14 4 21 2 20 | 20 43 32 6 2 Ill 2 3 8 7 9 Total 75 2 3 8 7 9 4 1(5 " 6 ?, Total for Way and June Miscellaneous laboratory records 319 140 2 1 3 1 8 4 9 4 9 11 15 19 19 is 17 30 16 22 7 8 3 (i 2 459 3 4 3 G 12 13 20 34 62 35 46 29 31 >4 Date larvae entered soil. Adults emerging in specified days from time of entering soil by larvae. Total adults. Total days spent 30 31 32 33 34 35 36 37 38 39 40 42 45 4G in soil. May 17 2 4 2 .... 1 1 41 2 27 19 20 4 5 4 25 23 27 2 1 2 (17 31.... 1 5 Total 6 9 6 2 | 3 2 1 165 | 4,405 ........ ........ June 9 1 I 40 31 10 Total 1 i 71 1 726 Total for May and June G 1 7 9 1 10 6 2 8 2 3 3 2 o 1 4 23G 110 6 131 Miscellaneous laboratory records from May 1 to July 7 2 1 1 l 1 2 1 3 621 Total for season 5 5 2 1 1 2 5 l 1 2 1 370 9. 7S2 Average time spent in Ihe ground during May days. . 26.67 Average time spent in the ground during June do". ... 21. 30 Average time spent in Ihe ground during May and June do 25.98 Average time spent in the ground for season." do 25. 95 A few records were obtained by Mr. Girault at New Richmond, Ohio, during 1907. The 75 beetles emerging requiring an average of 22.21 days. Data for the month of June only were obtained, and the variation in time occupied by individuals is comparatively small. from 18 to 26 days. (See Table XXXV.) 76 THE PLUM CURCULIO. Table XXXV. — Length of time spent in the soil by the plum curculio, New Richmond, Ohio, 1907. Date larva? entered soil. Larvae. Adults emerging in specified days from time of entering soil by larvae. Total adults. Total days spent IS 19 20 21 22 23 24 25 26 m soil. June 12 30 20 20 23 1 "a 2 2 1 5 4 6 3 3 3 9 2 1 8 2 4 1 4 1 29 17 11 IS 15 17 IS 2 4 Total 93 2 5 7 16 11 14 10 5 5 75 1 666 Average time spent in the soil days.. 22.21 The records from Siloam Springs, Ark., are fairly extensive and cover the three months, May, June, and July. (See Table XXXV.) A total of 5,860 larvae was used, yielding 1,774 adults. The range for the various beetles is from 19 to 47 days, with an average for all of 29 days. In this and other tables on the length of time spent in the ground, and also on the time spent in the fruit, the monthly totals and averages shown are largely arbitrary, in that the month is based upon the time of larva? emerging from the fruit. Larvae leaving the fruit in. late May, for instance, would be in the ground during much of June. Table XXXYI. — Length of time &peni in the soil by the plum curculio, Siloam Springs, Ark.. JUGS. Date larva? entered soil. Larva1. Adults emerging in specified days from time of entering soil by larva'. 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 May 14 328 574 9(15 550 62 1 719 1 12 8 12 54 11 3 11 11 2 62 54 "l(V 17 37 14 30 1 13 14 17 2 9 5 23 2 21 32 4 18. 2 1 3 4 10 47 23 14 21 16 24 1 5 21 3 3i' 2 2 1 16 30 7 Total 3.765 1 2 1 29 35 87 98 143 108 56 83 r,Q June 2 532 449 270 124 107 81 61 42 39 8 2 23 10 2 1 1 9 9 18 12 ~ 6 3 Mi 38 23 38 2 1 25 2 3 6 4 21 12 23 36 2 25 4 I 1 5 1 14 10 9 5 9 3 6 1 29 6 1 6 3 19 6 2 2 8 . 2 1 11 1 5 2 13 1 2 11 1 1 1 "i 4 5 4 1 17.... 14 2 1 20 23 3 26 1 1 Total 1,705 2 2 17 40 64 143 no 104 63 48 56 11 5 July 22 146 119 74 51 6 1 3 33 3 3 8 17 i 4 12 3 2 3 5 3 14 6 1 7 3 4 6 1 2 2 3 1 2 "2 1 I 1 25. 1 1 1 28 1 1. 31 1 Total 390 1 | 1 10 39 33 21 11 21 10 11 5 4 4 It 1 Total for season 5.860 1 1 12 41 52 62 104 199 207 213 211 160 116 97 65 I LIFE HISTOEY A.XD HABITS: THE PUPA. 77 Table XXXVI. — Length of time spent in the soil by the plum curculio, SUoam Springs, Ark., 1908— Continued. Dale larva entered soil. Adults emerging in specified days by lurv from time of je. entering soil Total adults. Total spent 34 35 30 37 38 39 40 41 43 44 45 40 47 in soil. May 11 2 14 1 1 7 1 11 .... 2 2 4 .... 5 2 1 4 2 3 » 1 1 - 50 124 131 123 2-33 211 JS 12 6 3 14 1 17 3 1 1 1 21 . 24 27 1 .... 1 30 1 Totil : 22 18 14 in S 3 2 1 3 1 2 | 4 27.470 June 2 10 1 4 ' ' 1 X 293 124 71 31 49 50 34 29 19 4 2^ 8.... 1 1 2 •> 11... 2 14.... 17 20 23 26.... .... 1 . 1 Total 7 12 2 3 3 4 1 1 1 1 700 19. 434 July 22 1 .... 1 ■ 89 27 4 25. ..!••£•::: i 28 31 Total 1 18 1 15 1 1-2 4. .547 - Total for season 74 50 24 23 10 4 1 2 1.774 51.451 Average time spent in the ground during May days. . 30. 79 Average time spent in the ground during June do.. . Average time spent in the ground during July do Average time spent in the ground for season do 29.00 Data on time spent in ground in Washington, D. C, were obtained by Mr. Jones during 1908. A total of 1,114 adults was reared from 5,050 larva* entering the soil, the range for, individuals being from IS to 56 days, with an average of 31.09 days for the season. (See Table XXXVII.) Table XXXVII. — Length of time spent in the soil hi the plum curculio. Washington, D. C. 1908. Dates larva* entered soil. Larva . Adults emerging in specified days from time of entering soil by larvae. is 19 20 21 22 23 21 25 " 27 . 30 31 2 1 2 12 2 4 2 6 4 17 6 33 34 5 27 1 I 7 1 35 13 4 Mav27 187 283 218 297 11 28 3 4 3 30 31 1 Total 3 i 7 8 23 32 2: "1 June 1 2S1 90 17! 213 223 157 151 249 1 7 5 1 4 4 '7* 4 1 - - 1 2 i 3 1 4 1 1 1 T 5 ' 1 1 3 1 ti 7 1 : 1 1 s 1 3 2 2 9 1 ... 1 1 1 T 1 5 ".V ... 4 LO 1 ... I 11 ... 78 THE PLUM CURCULIO. Table XXXYII. — Length of time spent in the soil by the vlum curculio, Washington, D. C, 1908— Continued. Dates larvae entered soli. Larvae. Adults emerging in specified days from time of entering soil by larvae. 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 June 1? 3C9 172 190 140 296 107 60 122 106 4 8 4 1 11 10 8 1 6 4 2 6 1 1 3 1 1 1 10 2 2 3 9 2 7 8 12 3 13 3 8 4 4 13. .. ... ___ 2 9 15 14... 1 3 3 1 "4" 15 16 2 2 4 9 1 5' 2 1 4' ■i" 1 14 9 4 2 1 6 3" T 17 2 6 2 Hi 1 2 5 4 6' 13" 18... 1 Y 2 1 19... 2 3 2 "i" 12 4 4 9 1 3" 2 9 6 1 1 5 3 1 1 1 1 20 2 2 1 "'2 21 139 175 22 24... 1 1 25 .. 64 148 97 HI 24 2 1 2 26 2 2 "3* 1 1 27 2 3 5 28 3 1 29... 2 30 B 1 Total 4.6-J5 1 ... 2 i * 4 15 31 63 si) 38 S3 72 81 46 65 36 29 10 Julv 1 47 42 34 24 27 16 34 28 39 10 i 11 6 18 2 3 ', 1 2 2 5 1 1 5 3 2 3 T i i 4 1 3 2 "i" 3" 2 1 4 1 1 2 6. . 2 1 i 1 "i" i 6 4 1 1 2 1 8 1 1 9 2 10. 11 13 14... Total ,326 2 1 1 4 8 14 13 12 7 8 3 2 .... 1 1 Total for season 5.. 956 1 ii * 2 3 8 23 45 76 48 98 83 106 7S S7 .9 34 Dates larvae entered soil. Adults emerging in specified days from time of entering soil larva1. »y Total adults. in soil. Total days spent in soil. 37 38 39 40 41 42 43 44 U 46 47 48 49 50 51 52 53 M 56 May 27 3 12 11 14 15 3 3 1 3 1 2 2 1 1 2 85 103 38 25 28 30... 1 31... 1 1 1 Total 15 26 16 3 3 1 3 1 2 1 ...|... 2 1 1 2 251 8,823 1 5 2 8|... 1 1... 71 37 24 20 4 7 2 3 1 1 4 5... 1 2 1 3 1 6. 1 1 1 1 1 7 1 1 2 8 1 2 5 9... 4 2 1 2 37 10. . 1 18 11. . 1 .... 14 1 12. . 1 j 3 7 4 1 1 84 13 9 17 1 ... 8 3 1 ... 1 84 14 1 1 42 6 52 19 20 39 31 18 29 15 16 3 1 1 17 18 19 1 20 21 22 LIFE HISTORY AND EABITS : THE PUPA. 79 Table XXXVII. — Length of time spent in the .soil by the plum curculio, Washington, D. C, 1908— Continued. Dates larvae entered soil. Adults emerging in specified days from time of entering soil by larvae. Total adults. Total spent in soil. 37 38 39 40 41 42 43 44 4.5 46 47 51 52 53 54 50 insoil June 24 11 25 13 26" 27 14 28 31 29 i-i 30 21 Total 10 IS 26 21 5 0 3 10 3 4 3 3 2 777 24.354 Julv 1 I 8 9 0 3 14 4 9 5 6 6 2 8 2 ... 1 11 3 10 1 1 2 13 1 1 2 1 1 i 2 2 86 2. 300 20 45 43 26 8 9 8 |ll | 5 j i - - l 4 0 12 1,114 | 35.507 1 No beetles emerged. Average time spent in the soil during May days.. 35.15 Average time spent in the soil during June do 31.34 Average time spent in the soil during Julv do Average time spent in the soil for season .' do 31. 09 Data obtained by Mr. Hammar at Douglas. Mich., during 1910 are shown in Table XXXVIII. A decided lengthening of the period is evident, the range being from 27 to 58 days, with an average for all individuals of 36.32 days. A total of 177 adults was reared from 207 larva?. Table XXXVI 1 1. —Length of time spent in the soil by the plum curculio, Douglas, Mich., 1910. Datelarvjv en- tered soil. Larva\ Adults emerging in specified days from time of entering soil by larva-. Total adults. Total days spent in soil. 27 28 29 '2 2 30 31 32 33 3 ] 2 ! M 1 1 1 1 1 3 12 3 i i 9 36 ■_> 3 "a 10 10 37 2 2 3 3 3 4 3 1 17 38 2 3 4 3 2 1 I.", 39 1 1 1 40 41 !_' "l 1 3 2 1 43 44 15 47 2.... 2 '2 -• - 1 1 50 1 1 58 1 June 24 6 10 11 0 10 29 30 Total Julvl " 2 3 4 2 2 3 2 ■_> 27 37 24 19 18 i "i 2 2 "i i j 2 "2 2 4 i '3 •• •- 4 l i i 3 1 6 0 i "2 2 .1 6 71..1 1 2 37 19 19 13 8 4 0 9 9 42 12 10 :::: :::: 8 2 2 0 10 1 13 20 25 "i Total 180 IX 21 29 155 5,585 Total for season 207 10 22 32 » ,, Hi ■ : 9 .. 1 I 177 Average time spent in ground during June Average time spent in ground during Julv Average time spent in ground during season 80 THE PLUM CUBCULIO. Table XXXIX gives details of time spent in the ground of 1,568 individuals at Bamesville, Ga., covering the period May, June, July, and a part of August. A total of 2,917 larva? was used. The range of the different individuals is from 21 days to 02 days — the longest yet noted — the average being 34.44 days. Table XXXIX. — Length of time spent in the soil by the plum curculio, Barnesville, Ga.. 1910. Date larvae en- Adults emerging in specified days from time of entering soil by larvse. tered soil. "luv'1- 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 4 39 30 11 10 12 2 1 5 13 39 3 13 10 1 1 3 5 "l" 4 40 2 41 Ma v 3 457 566 240 272 1.59 192 142 G 9 40 22 18 31 is 64 21 29 91 5 Hi 52 13 9 35 8 9 11 5 3 51 37 14 12 13 2 11 8 5 3 5 5 3 It 19 22 in 11 1 1 7 10 10 1:. 27 1:, 25 14 11 12 4 8 1 ; 11 2 10 3 1 3 11 2 12 1 2 8 1 •5 14 0 9 15 N 9 3 3 2 13 20 •».) 1 15 1 2 2 6 2 1 4 2 1 9 4 2 17 13 9 3 10 10 4 1 2 is 1 1 2 1 8 q 21.. 190 66 33 28 1 1 2 ! \ 7 IT, 9 9 fi 25 1 1 1 28 T 31 ... 3 4 1 Total 2. Col 1 | 1 | 4 | 3 - L6 L5 22 2 " "7 91 1.1 I; -. 151 127 41 37 21 ■ I 1 in 14 2 2 | 1 L. 1 i Told 42 | ... . 1 1 1 ........ July 4 4 4 3 9 13 1 2 L5. 2 2 1 5 1 -' 3 3 2 1 18.. 23 25 ;,l 27 12 17 8 1 2 3 23 1 1 1 1 4 ! 1 1 1 "3" 1 1 6 2 2 1 1 1 1 .... 1 1 1 1 i 26 1 1 1 ! 1 1 1 29 1 1 30 2 '•> 1 Y 2 1 1 1 I 31 1 1 Total 210 ... 1 3 8 13 10 7 14 5 7 3 l| 3 2 »l » 1 ... 4 10 11 13 1 1 2 1 1 1 1 3 .. 1 1 1 , 1 1 1 1 4 1 1 Total 34 I 2 • 5 2 1 3 3 1 ... 1 1 Total for season 2,917 12 | 16 29 32 2 1 42 43 63 61 96 139 1S9 201) 165 152 L28 42 37 25 Date larv;r en- Adults emerging in specified days from time of entering soil by larvae. Total adults. Total days tered soil. 42 43 44 4.5 46 47 48 49 50 51 52 ! 53 54 55 56 5 / 58 59 60 01 62 spent in soil. May 3 1 28 182 276 105 109 170 117 145 101 108 45 21 13 5 7 2 T 1 . ... 1 1 8 1 1 3 10 1 11... 1 1 1 "i" 1 1 1 12... 1 1 1 13... 1 1 1 ... 1 1 15. . . 1 4 1 1 18 21 1I1 2 25 . . . 28 31 .. . 12 8 TT Total 15 4l2 1 1 2 1 1 1 >l> 1,420 49,570 LIFE HISTORY AXD HABITS: THE PUPA. Table XXXIX. — Length of time spent in the soil by the plum. curatKo, BarnetviUe, Ga., 1910 — Continued. Date larva en- Adults emerging in specified days from time of entering soil by larvae. Total Total davs tered soil. 42 43 44 4.') - 4< "I" 52 ' ' - adults. spent in soil. 1, 10 Total. 22 July 4 0 0 ii 13 .. 1 IS 15 Is 3 23 1 1 ... 1 1 1 20 1 . 1 i 1 . S :::::::: 12 - 28... i 29 -. 30 ....... 1 31 1 ... . . Total 2 1 ... 1 1 ... 1 ... 3 ... 1 ... 3 10H 3.317 Aug. 1 4 8 3.. ' : :::::; . . . . ... Total. 543 Total for season.. 14 9 ... 3 6 1 6 4 5 1 1 ! i 1 ... 1 1 1 1,568 54,002 Average time spent in the ground during May days . . 56 time spent in the ground during June do Average time spent in The ground during July do 31. 25 Average time spent in the ground during August do 27. 15 Average time spent in the ground during season do 34. 44 In Table XL the totals from the foregoing tables on length of time spent in the soil are given for more ready comparison. The hori- zontal bars divide the period into weeks, beginning with the third week. The percentages of total adults emerging each week are also shown. Except in the Ohio records, which are perhaps abnormal, and the Georgia record for 1906,, comparatively few beetles were out within three weeks from the time of entering the soil by the larvae. During the fourth and fifth weeks, however, the great majority of beetles appear and by the close of the sixth week emergence has practically ceased. 17262°— Bull. 103—12 6 82 THE PLUM CURCULIO. Table XL. — Length of time spent in the soil by the plum curculio; totals for all localities. Locality and date. Youngstown, N. Y., 1905. New Richmond, Ohio, 1907. Douglas, Mich., 1910. Washington, D. C, 1908. Days in soil. Beetles emerg- ing. Percent- age of beetles emerging, by weeks. Beetles emerg- ing. Percent- age of beetles emerging, weeks. Beetles emerg- ing. Percent- age of beetles emerging, by weeks. Beetles emerg- ing. Percent- age of beetles emerging, by weeks. 16 0.60 26. 89 62. 54 9.07 .60 .30 40.00 • 00. 00 17 18 2 5 16 f 11 14 10 5 5 1 19 2 0.63 20 2.26 50.85 • 37. 29 8.48 .56 .56 4 2 f 3 8 23 45 76 92 48 f 98 83 106 78 87 69 53 f 3i 26 45 43 26 8 9 f 8 11 5 5 3 3 2 f 2 1 4 21 22 2 23 24 4 7 7 25 44 29 34 43 36 35 26 4 5 5 4 25 26. 48 26 27 2 2 f 4 4 6 6 16 22 32 f io 19 15 1 10 4 7 9 28 29 30 31 32 I 51.53 33 34 35 36 37 38 39 3 I 17. 14 40 8 4 1 41 42 43 44 45 1 46 1 I 3.32 47 2 2 1 48 49 1 50 51 52 53 \ .90 54 1 1 55 1 56 2 57 58 1 59 60 61 62 * Total « 100. 00 75 100.00 177 100. 00 1,114 100.00 LIFE HISTORY AND HABITS: THE PUPA. 83 Table XL. — Length of time spent in the soil by the plum curculio; totals for all localities — Continued. Locality and date. Days in soil. Siloara Springs, Ark., 1908. Myrtle, (In., 1906, Barnesville, (la., 1010. Beetles emerging. Percentage of beetles emerging, by weeks. Beetles emerging. Percentage of beetles emerging, by weeks. Beetles emerging. Percentage of beetles emerging, by weeks. 16 0.79 49. 49 43. 58 5.47 .67 f 4 3 6 12 13 f 20 34 62 45 46 29 3i f 24 7 10 8 5 5 2 ( 1 1 2 5 1 10. 62 69. 95 15. 80 2.85 .78 17 18. . 19... 1 1 12 41 52 62 104 199 207 213 211 160 116 97 65 74 50 24 23 18 15 10 4 3 2 3 1 2 4 0.06 20 21. 1 f 2 12 16 29 32 24 42 f 43 63 61 96 139 189 209 f 165 152 . 128 42 37 25 14 9 22 23 24 25 1 10. 01 26.. 27... 28 29 30. 31... 32 51. 02 33 34. 35.... 36 37. 38. 39 I 35. 91 40 41. 42.. 1 43 44 45 2 1 3 6 6 4 f 5 1 1 46 \ 1.85 47. 48 49. . . 50 51 52 53 .89 51 3 56... 4 57 58 1 59 1 1 . 28 6] 62 Total 1,774 100.00 3S6 100. 00 i 5i a i oa.no LENUTH OF PI PAL STACK AND TIME S ! • E N T IN SOU. PUPATION. BEFORE AND AFTER The data on the length of time spent in the soil do not show the length of the pupal instar, since a few days arc spent by t ho larva in its eel! before transforming to the pupa, and after the pupa has trans- formed to the adult, ov beetle, a variable time is spout before the insect makes its escape from the ground. Tins latter period will vary 84 THE PLUM CUECULIO. much, depending upon the character of the weather, whether dry or rainy. During periods of drought beetles appear to remain in their cells much longer than if the earth be moist or wet, as from rains. In fact, in orchards it has often been observed that shortly after a good soaking rain beetles were soon in evidence in large numbers, whereas previously they had been quite scarce. Some data have been collected on the exact time spent in these three conditions in the soil and are brought together in the following tables. Writers appear not to have investigated this point hereto- fore. The data from a practical standpoint are important, since dur- ing the pupal stage the insect would be likely to suffer most from cultivations. Table XLI. — Length of -pupal instar of the plum curculio and days spent in soil as larva, pupa, and adult, Washington, D. C, 1908. Individual No. Date larva Left fruit. Date of pupation. Date of transfor- mation to adult. Date beetle left soil. Days in larval stage before pupa- lion. Days in pupal stage. Days as beetle in soil. Total days in soil. 1 June 6 ...do June 19 June 18 June 22 June 18 June 19 June 18 ...do June 27 ...do.... ...do.... ...do.... June 29 ...do.... June 27 June 29 June 27 June 29 ...do.... July 3 June 30 ...do.... ...do.... July 1 June 29 ...do.... June 30 July 1 June 29 June 30 July 5 July G Died. July 5 July 6 July 8 July 6 July 8 July C July 5 July 6 Julv 11 ...do.... July 7 ...do July (i July 5 Julv 8 Died. July 7 ...do.... do 13 12 10 12 13 12 12 16 12 13 12 15 13 13 13 13 10 14 14 14 14 14 8 9 5 9 10 11 9 7 9 10 11 9 8 8 8 9 10 6 7 8 6 7 8 9 29 2 30 3 ...do 4 ...do 8 7 9 9 9 9 6 8 11 7 5 6 9 29 5 ...do 30 6 ...do.... 32 7 ...do 30 8 ...do June 22 June 18 June 19 June 18 June 24 June 22 ...do.... ...do.... ...do.... June 19 June 23 ...do.... ...do ...do 32 9 ...do 30 10... ..do 29 11 ...do 30 12 June 9. ...do 32 13 32 14 ...do 28 15 16 17 . ...do.... ...do.... ...do 28 27 26 18 ...do 29 19 ...do.... ...do 20 (> 8 7 28 21 ...do 28 22 .do... ...do... 28 Total 290 184 155 587 13. 18 8. 30 7.75 29. 35 From the table it will be noted that the average time spent in the soil before pupation for the 22 individuals is 13.18 days; the length of the pupal instar, 8.36 days; and the period occupied in the soil as a beetle before emergence, 7.75 days. The average time spent in the ground from entrance of larvse to emergence of adult is 29.35 days. These larvaB were kept in large glass vials, the soil being a sandy loam. Specimens were kept in an out-of-doors breeding cage in the insectary yard, at Washington, D. C, where the temperature would be somewhat higher than in the soil. Mr. Hammar made observations during 1910, at Douglas, Mich., on a large series of individuals, as detailed in Table XLII, LIFE HISTORY AND HABITS: THE PUPA. 85 Table XLII. — Length of pupal instar of the plum curculio and time spent in the soil as larva and as adult, Douglas, Mich., 1910. Individual No. 23 24 25 2G 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 88 Totnl . Date larva left the fruit. June ..do. July ..do. July ..do. ..do. July ..do. July ..do. ..do. ..do. ..do. ..do. ...do. ...do. Julv ..do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. ...do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. ..do. ..do. July .do. ..do. ..do. 20 ..do. ..do. ..do. ..do. .do. Julv ..do. ..do. ..do. 25 Date of pupation. July July July July ...do. July ...do. July July July July July July ..do. July ...do. ..do. July July ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. ..do. July ..do. 25 .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. .do. ..do. ..do. Julv July ..do. Aug. July ..do. ..do. ..do. .do. Aug. ..do. ..do. Aug. Aug. .do. Aug. Aug. Date of transfor- mation to beetle. July 26 July 25 July 27 Aug. 2 ..do... Aug. 1 Aug. 2 July 30 ..do... Aug. Aug. Aug. Aug. Aug. Aug. Aug. ..do... Aug. 8 Aug. 9 Aug. 7 Aug. 8 ..do... ..do... Aug. 9 Aug. 7 ..do... ..do... Aus[. 8 ..do... Aug. 9 Aug. 8 ..do... Aug. 4 Aug. 8 ..do... Aug. 9 ..do ..do... ..do... ..do... Aug. 8 ..do... ..do.... ..do... Aug. 9 ..do... Aug. 10 ..do... Aug. 9 ..do... Aug. 8 Aug. 9 Aug. 10 .do... Aug. 16 Aug. 15 ..do.... Aug. II Aug. 15 ..do.... ..do.... ..do... . ..do... . Aug. II Aug. 17 ..do... . Aug. 18 .do... . Date beetle left the soil. Aug. 1 July 29 Aug. 2 Aug. 7 Aug. 8 Aug. 5 Aug. 8 Aug. 3 ..do Aug. 10 ...do... Aug. 8 Aug. 10 Aug. 12 Aug. 10 Aug. 14 Aug. 16 Aug. 13 Aug. 15 Aug. 16 Aug. 17 Aug. 15 Aug. 16 ..do... ..do... ..do... ..do... Aug. 15 Aug. 16 Aug. 17 ..do.... ..do.... Aug. 15 Aug. 16 Aug. 17 Aug. IS ..do.... Aug. 17 ..do.... Aug. 16 Aug. 12 Aug. 13 Aug. 18 Aug. 14 Aug. 16 Aug. 14 Aug. 15 Aug. 18 Aug. 12 Aug. 17 Aug. 18 Aug. 12 Aug. is Aug. 13 Aug. 23 Aug. 22 Aug. 23 Aug. 22 Aug. 23 Vug. 21 Aug. 23 .do... ..do... . Aug. 20 Aug. 23 Aug. 22 Aug. 23 .do.... Average for all individuals. Days in larval stage before pupa- tion. 818 12.03 Days in pupal stage. 960 11.12 Days as beetle in soil. |v.-. 7.10 Total days in soil. 32 29 31 36 35 32 28 28 33 33 31 33 35 33 37 39 31 33 34 35 33 34 34 34 34 34 33 34 35 35 35 33 34 35 36 36 35 35 34 30 31 36 32 34 32 33 36 30 35 36 30 36 31 41 33 ::t 33 34 33 34 34 31 31 29 29 29 2.203 S 86 THE PLUM CTJRCULIO. These individuals were also kept in vials under out-of-doors conditions. The average of the 68 examples for the time spent in soil previous to pupation is seen to be 12.03 days; for the pupal stage, 14.12 days; and an average of 7.10 days was spent in the soil before exit of adult, after transformation. The average of the total days in the soil for all stages is 33.28 days. The range in time in soil before pupation is from 7 to 19 days. The range for the pupal stage is from 9 to 19 days; and for the beetle in the earth, 3 to 13 days. The entire time spent in the ground varies from 28 to 39 days. Similar data from Barnesville, Ga., obtained during 1910, are shown in Table XLIII. Records for 38 individuals were obtained from May 20 to July 11, when the last beetle left the soil. The insects were placed in glass-bottomed boxes containing a shallow layer of sand and kept in a dark box under shade out of doors. Table XLIII. — Length of pupal instar of the plum curculio and time spent in the soil as larva and as adult, Barnesville. Ga.. 1910. Individual No. Date larva left fruit. Date of pupa- tion. Dale of transfor- mation to beetle. Date beetle left the soil. Days in larval stage previous to pupa- tion. Days in piipal stage. Days as beetle in soil. Total days in soil. x May 20 .. .do June 5 Jime 7 May 31 June 3 ...do.... ...do.... June 4 June 5 ...do June 14 June 17 June 8 June 13 June 12 June 13 June 14 June 15 June 14 June 15 June 14 June 16 ...do June 11 June 18 June 19 June 21 June 25 June 26 June 25 July 3 July 6 ...do Julv 7 ...do Julv 4 July 1 July 2 ...do Julv 4 ...do ...do.... July 7 July 6 ...do ...do.... ...do.... June 20 June 22 June 14 June 19 June 20 ...do.... June 21 ...do June 20 ...do June 23 June 24 June 21 June 20 June 24 June 25 June 27 Julv 1 Julv 2 June 29 Julv 6 Julv 11 July 12 Julv 9 July 14 July 9 Julv 7 ...do ...do.... Julv 10 ...do Julv S July 11 Julv 10 ...do ...do.... July 11 16 18 11 14 14 14 15 16 16 16 16 16 17 13 18 19 22 26 27 13 18 19 19 20 20 15 12 12 12 13 13 1J 16 14 14 14 14 9 10 6 5 31 2 33 3 ...do... 8 10 9 10 10 10 9 10 9 11 ro 8 10 10 9 9 9 8 8 10 9 9 9 9 8 9 9 9 6 6 8 7 7 6 6 5 9 8 5 9 6 6 6 6 6 4 3 5 6 2 7 5 6 5 5 6 25 30 4 ..do... 5 6 ...do.... ...do.... 31 31 7 ...do.... 32 8 ...do.... 32 9 ...do 31 10 ...do.... ...do 31 11 12 . ...do.... ..do ...do.... ...do 34 35 13 .do June 6 June 3 June 8 June 9 June 12 June 16 June 17 ...do June 25 June 26 June 27 June 28 ...do June 25 June 23 ...do.... ...do.... June 25 ...do.... .. .do June 28 June 27 ...do.... ...do.... ...do.... 32 14 May 21 ...do ...do.... ...do.... ...do.... ...do 30 15 16 17 18 19 34 35 37 41 42 20... June 4 June 7 ...do.... June 8 ...do.... ...do.... June 10 June 11 ...do.... ...do.... June 12 ...do.... ...do.... ...do.... June 13 ...do.... ...do ...do 25 21 22 23 24 25 26 27 28 29 30 29 34 34 31 36 29 26 26 26 28 31 32 33 34 y 6 9 4 9 ; 4 9 4 9 4 9 1 4 9 5 28 26 29 27 35 36 37 27 27 28 Total 595 340 208 1.143 Averages for all indi- viduals 16.08 1 9.18 5.62 30.89 LIFE HISTORY AND HABITS: THE PUPA. 87 These figures show interesting differences from the Michigan records. Thus, the average number of days for all larvae in soil before pupation is 16.08, as against 12.03 in the Michigan records. The average length of the pupal stage at Barnesville, 9.18 days, is notably less than shown for Michigan, namely, 14.12 days. However, adding together the average larval and pupal stages for each locality shows these sums to differ by only 1 day, the lengthening of the larval stage in the ground in Georgia being offset by a shorter period in the pupal condition. In the Georgia records the average time spent by the adults in the ground before emerging is 5.62 days. The average time of the 37 individuals spent in the soil is 30.89 days. DEPTH OF PUPAL CELL. Great diversity of opinion was expressed by the earlier writers as to the depth to winch curculio larvae entered the soil for pupation, and no very accurate observations on this point seem to have been made. Riley states that they go below the surface from 4 to 6 inches, and remarks that he never found them deeper than 6 inches. Riley and Howard, writing in 1888, state that the larvae seldom burrow to a greater depth than 4 or 5 inches. Other wTiters say "a few inches," 11 2 to 3 inches," "a short distance," and one states "15 to 36 inches." Prof. Crandall was perhaps the first to secure exact data on tliis point. In 1903 observations were made on the depth of pupae in ground, including 78 individuals secured under natural conditions under trees in orchards, 79 from bottomless soil boxes, and 22 from breeding cages in the laboratory — a total of 179. In 1904 data were obtained on 645 individuals, 24 by digging' earth under trees. 298 from soil boxes, and the remaining 323 from larvae pupating in the labora- tory. Using the records for both seasons obtained under out-of-doors conditions — that is, under trees or in soil boxes, sod and cultivated — we find that of the total 482, 336, or 69.70 per cent, pupated within 1 inch of the surface, and 475, or 98.54 per cent, within 2 inches of the top of the soil. Prof. CrandalTs laboratory records do not show important differ- ences from those obtained out-of-doors. Some individuals pupated at a greater depth, as 8 at 3 inches, 1 at 3J inches, and 2 at 3J inches, as against 1 at 2^ inches, 3 at 2V inches, and 3 at 2j inches, under out-of-doors conditions, due perhaps to a greater dryness of the soil in the laboratory. Messrs. Girault and Rosenfeld, in Georgia, in 1906, obtained records on the depth of pupation of 121 larvae under natural out-of- doors conditions, the soil being a sandy loam. One hundred, or 82.64 percent, pupated within 1 inch of the surface, and all. or !00 per cent, within 2 inches. Other records on depth of pupation in the 88 THE PLUM CURCTJLIO. same soil in the laboratory do not differ essentially, though 5 larva) went to a depth of 2\ inches, one to 2\ inches, and two to 3 inches. The above figures are better shown in Table XLIV, which includes also records on 40 larvae at the insect ary in Washington, obtained by use of a soil box, under natural conditions, the soil being a sandy garden loam. Table XLIV. — Showing depth to which larvse of the plum curculio enter soil for pupation, various localities. W m to A A rZ A A I o fj A cj f> A _• a a a S a a a H a a a H a a Eh HM rfs nW 1-1 rH 1-1 *-* 20 1 1 } 20 3 21 5 21 •> 21 1 2 1 3 1 3 22 9 22 7 22 23 2 1 -, 23 23 3 Total 3 20 m; »r 56 A total of 3 egg and 20 feeding punctures is shown on the normal fuzzy fruit as compared with 116 egg punctures and 56 feeding punctures on fruit from which the hairs had been removed. 17262°— Bull. 103—12 7 98 THE PLUM CURCULIO. EXTENT OF FEEDING OF THE RESPECTIVE SEXES. The extent to which feeding is done by the respective sexes of the curculio during their lives is shown in Table LI. Individuals of each sex were separately confined and each beetle supplied daily with 4 wild plums, examinations of the fruit being made daily. Table LI. — Extent of feeding of each sex of the plum curculio during the season, Myrtle, Ga., 1906. Feeding punctures by males. Feeding punctures by females. Dates. Bee- tle No. 1. Bee- tle No. 2. Bee- tle No. 3. Bee- tle No. 4. Bee- tle No. 5. Bee- tle No. 6. Bee- tle No. 7. Bee- tle No. 8. Bee- tle No. 1. Bee- tle No. 2. Bee- tle No. 3. Bee- tle No. 4. \pr 16 3 3 2 3 2 8 1 2 1 4 4 5 2 1 4 4 4 2 1 7 2 1 1 4 5 1 2 2 1 3 5 2 3 3 1 5 1 3 1 1 4 3 4 7 2 2 3 2 2 3 1 1 1 4 3 4 7 5 2 1 4 8 6 5 3 2 4 ...... ...... 2 2 ...„. 3 2 ...„. 11 4 5 5 3 4 6 10 5 1 5 2 3 2 2 1 1 1 2 1 4 3 5 3 4 1 3 2 4 2 2 3 2 6 5 1 3 3 4 3 2 4 2 5 3 w 1 1 2 1 1 1 1 1 1 1 3 2 3 1 2 ...... 1 1 2 ...... 3 2 2 2 ...... 1 2 ...... 1 1 ...... 3 ..... 2 1 ...... 2 2 13 3 5 8 1 2 8 2 1 5 4 5 3 12 2 1 7 8 3 2 2 3 4 8 1 5 6 5 6 6 4 4 6 9 4 4 5 ...„. 4 6 7 5 4 7 5 2 2 5 4 4 5 3 5 4 4 4 5 4 12 5 4 2 4 5 2 2 5 ...... 3 5 4 3 2 6 8 5 4 5 5 5 5 5 6 7 4 4 8 4 4 12 6 6 7 4 5 12 14 7 6 8 2 1 4 4 6 3 1 1 1 3 4 4 8 8 8 4 5 5 3 3 3 3 4 4 5 8 8 3 8 2 8 19 9 2 3 1 8 6 1 2 2 3 10 3 4 5 8 4 13 10 5 2 11 9 2 6 3 3 1 1 ""2 3 4 2 3 2 7 7 4 18 5 19 3 20 1 2 1 1 ""2" 2 1 1 1 1 1 1 1 1 ...... 2 1 1 1 2 1 1 2 1 3 3 2 1 1 1 2 2 1 4 1 3 3 ...... 2 3 2 6 21 13 22 8 23 3 24 1 25 6 26 4 27 11 28 3 29 8 30 4 May 1 2 4 1 3 2 2 2 1 3 2 3 1 1 3 7 3 3 5 • 2 2 1 5 2 1 1 4 3 1 5 1 5 4 1 1 1 4 4 5 3 2 6 5 2 3 3 11 4 1 5 3 6 1 7 2 3 7 1 8 9 3 10 3 2 1 1 1 1 4 5 6 4 1 2 5 5 2 11 1 2 3 2 2 12 2 13 3 14 2 1 2 ...... 2 ...„. 1 ""2 1 3 15 1 16 1 ....... 4 2 1 3 2 7 17 4 18 1 19 6 20 14 21 1 2 ...... 1 ...... '1 2 6 3 3 4 1 1 3 2 ...„. 2 1 3 22 2 23 2 24 2 25 2 4 8 1 5 5 7 6 2 10 3 1 7 26 2 5 | 3 I 1 1 1 1 5 ! 2 1 5 2 3 1 2 3 2 4 1 2 1 3 2 2 3 2 2 1 ...„. 3 ...... 3 2 3 (2) 6 27 13 28 3 29 2 30 4 31 3 2 2 2 3 2 4 8 5 3 6 6 2 6 2 4 4 7 7 8 6 1 2 1 2 1 5 1 1 4 9 2 10 4 2 3 11 . 16 12 14 13 I... 13 1 Died. 2 Escaped. LIFE HISTORY AND HABITS: THE ADULT. 99 Table LI. — Extent of feeding of each sex of the plum curculio during the season, Myrtle, Ga., 1906— Continued. Feeding punctures by males. Feeding punctures by females. Dates. Bee- tle No. 1. Bee- tle No. 2. Bee- Bee- Bee- Bee- Bee- tle 1 tie 1 tie tie tie No. 3. No. 4. No. 5. No. 6. No. 7. Bee- tle No. 8. Bee- Bee- tle tie No. l. No. 2. Bee- Bee- tle I tie No. 3. No. 4. 22 2 22 7 4 2 7 19 10 15 4 3 1 8 3 5 8 2 1 1 2 8 15 6 16 5 17 3 18 4 3 1 "6 3 8 2 19 ...... 1 4 2 5 20 9 21 9 22 3 5 l l 5 23 8 24 5 3 3 2 10 25 3 26. . . 2 2 (2) 27 5 (2) 2 28 0) 29 30 Julv 1 6 7 1 1 3 « 4 3 6 1 5 4 6 rt ....* 5. :::::: 3 9 3 1 12 17 0) 18 0) 19 <'> 20 0) :::::::::::: 30 8 31 (») Aug. 4 0) (') 369 Total 157 186 . 210 54 , 127 81 102 1 86 1 ! 1 1 1 1 404 361 288 J Died. 2 No record. The individual records show that the females feed more actively than the males. Most of the males had practically ceased feeding by June 11, although the females continued to feed freely during the rest of the month. The average number of feeding punctures per male, excluding Xo. 4, is 135.55, as compared with the average of 355.50 for each female. OPERATION OF EGG LAYING. The process of egg laying of the plum curculio has excited the interest of many observers, and it has been frequently described. There is much variation in the statements as to time occupied, se- quence, and relative time of the various acts, etc. Many writers have not distinguished at all the separate steps involved, as, for example: As soon as the plums, peaches, cherries, and apples are sot the curculio commences operations, imprinting the familiar crescent and placing an egg inside. 100 THE PLUM CTJRCULIO. Riley's account of oviposition is, however, much more complete, as follows: That the egg is deposited in the following manner, the whole process requiring about five minutes: Having taken a strong hold on the fruit, the female makes a minute cut with the jaws, which are at the end of her snout, just through the skin of the fruit, and then runs the snout under the skin to the depth of one-sixteenth of an inch, and moves it back and forth until the cavity is large enough to receive the egg it is to retain. She next changes her position, and drops an egg into the mouth of the cut; then, veering round again, she pushes it by means of her snout to the end of the passage, and afterwards cuts the crescent in front of the hole so as to undermine the egg and leave it in a sort of flap, her object apparently being to deaden this flap so as to prevent the growing skin from crushing the egg, though Dr. Hull informs me that he has repeatedly removed the insect as soon as the egg was deposited and before the flap was made, and the egg hatched and the young penetrated the fruit in every instance. Prof. J. M. Stedman also described the process: In making punctures for the purpose of depositing eggs, the females also eat the tissues of the apple, and this is probably the reason why during the egg-laying season they do not make as many purely feeding punctures as they do earlier and later in the season. The female first eats a small hole through the skin and then eats the pulp back about one-sixteenth of an inch, thus making a small cylindrical hole, usually quite parallel to the skin. She then turns around and deposits an egg in this hole, which is just large enough to receive the egg nicely. Having accomplished this, she then eats the tissue while cutting a small crescent-shaped hole through the skin and into the pulp so as to partly surround and partly undermine the egg. In Prof. CrandalTs studies many attempts were made to secure data on the entire operation, but owing to the difficulties of so doing, three instances only from start to finish were observed, as follows: In the first observation, the female moved about the apple for several seconds, keeping the end of her beak in contact with the surface, as if seeking a favorable spot. When the exact spot was decided upon, the minute jaws at the end of the snout began a rapid movement which quickly made an opening through the skin. This opening was no larger than necessary for admission of the tip of the beak. No skin was re- moved; it was simply torn and thrust aside to give access to the pulp below. Later, as the excavation proceeded, the broken skin was seen as a sort of fringe around the beak at the surface of the fruit. As soon as excavation in the pulp was commenced, the beak was deflected backward so that the work was carried on under the insect, just beneath the skin and nearly parallel with the surface. As the work advanced, the opening through the skin became slightly enlarged by lateral motions of the beak. The pulp was all eaten as excavated. During the process the beak was not once withdrawn, nor was there any cessation of motion. When the excavation of the cavity was completed the beak was withdrawn by a quick motion, the insect turned about, adjusted the tip of the abdomen to the opening and deposited an egg, which was forced to the extremity of the excavation by the ovipositor. The insect now rested without motion for two minutes; then, turning again, proceeded to cut the crescent in front of the egg. This crescent puncture was not wholly a separate punc- ture, but, starting in the original opening through the skin, was cut laterally in either direction, partly by the jaws and partly by crowding the beak first one way and then the other. The direction of the beak was but little deflected from the perpendicular and the cut was made as deep as the length of the beak would allow. The pulp torn LIFE HISTORY AND HABITS: THE ADULT. 101 away in making the crescent was eaten, just as was done in excavating the egg cavity. The crescent completed, the insect walked away, drew the legs closely under the body, and settled down, apparently to sleep. The time occupied in the process described was distributed as follows: Minutes. Excavating egg cavity 9 Deposition of egg 1 Rest 2 Cutting the crescent 3£ Total 15* The egg cavity was cylindrical, with a rounded bottom, and by measurement was found to be 0.04 inch in depth. The egg when deposited very nearly filled the cavity. The second observation of the complete process was nearly identical with the one described. The insect spent no time in choosing the exact spot, but went to work at once. It worked in a more leisurely way and did not excavate as deep an egg cavity. Eleven minutes were spent on the cavity, 2 minutes in depositing the egg, 2 minutes in rest, and 4 minutes in cutting the crescent, a total of 19 minutes. The egg cavity measured 0.035 inch in depth and was completely filled by the egg. On completion of the process the insect moved a short distance and immediately began a second cavity. Essential differences from procedure in the two preceding cases were noted in the third complete observation. Excavation of the egg cavity was the same, except that it was deeper in the pulp and of greater depth. After depositing the egg the beetle turned and with her beak worked the egg back to the bottom of the cavity. Then she began tearing off bits of skin and pulp, which were carefully packed in, above the egg, until the cavity was full. Following this, the crescent was cut in much the same manner as in the preceding cases. Then she appeared to make a final inspection, and added some further packing above the egg. Finally the work appeared to be satisfactory and she walked away and began a second puncture. The time consumed in this process was longer than in the others, and was divided as follows: Minutes. Excavating egg cavity 12 Depositing egg H Placing the egg with the beak 2 Packing the cavity 4 Cutting the crescent 4 Finishing touches 3 Total 26* Mr. Johnson observed the operation of egg laving in 1905 at Youngstown, N. Y., in a Niagara plum, from which the calyx had recently fallen. The excavating of egg cavity, placing of egg, packing of cavity, and cutting the crescent was done without a pause and occupied 10 minutes. According to the observations of Mr. J. H. Beattie at Fort Valley, Ga., in 1905, a beetle was occupied 1 minute in making the egg cavity in a plum, after which, turning around, it deposited an egg in about 5 seconds, a few seconds more being required in pushing the egg into the cavity. However, in cutting the crescent 6 minutes were occupied, a total of a little more than 7 minutes. 102 THE PLUM CURCULIO. Mr. Girault observed a beetle at Myrtle, Ga., May 7, throughout the entire operation. This individual had been previously starved and was furnished with a fresh wild plum upon which it climbed at 4.36 p. m., settling on the side. It carefully examined the surface of the fruit before beginning oviposition, as follows: Minutes. Egg cavity begun 4.43. Egg cavity finished 4.51 8 Egg deposited 4. 51-1 f § Egg pushed in cavity 4.51|-2| | Packing egg cavity 4.52|-4| 2\ Began crescent 4.55 Crescent finished 5.08 13 Total 24i During the process the body was in an extended position, legs well out grasping the fruit, and while excavating the cavity the body was at an angle of about 45°. Difficulty was evidenced in holding to the fruit. The tarsi were continually being lifted and extended, and applied to the fruit, and this was followed by a drawing motion, to engage the claws if possible. The antennae were motionless, the scape lying alongside the rostrum. At Barnesville a beetle was observed ovipositing on plum, April 11. Its time record was as follows: Minutes. Beak inserted 9.47. Beak withdrawn and ovipositor inserted 9.49 2 Ovipositor removed 9.49^ ■ J Packing cavity, until 9.52 2\ Began cutting crescent 9.52 Crescent completed 11 .07 Actual time occupied in cutting 36 Beetle rested 6 times while cutting crescent, a total of 39 Total interval 80 Also at Barnesville a beetle was observed April 20 ovipositing in young peach. At 9.30 the hole was started in fuzz, the beak being worked down full length. At 9.4 If beak was withdrawn and the ovipositor inserted. The ovipositor was withdrawn at 9.42^ and the egg pushed down with the beak. The beetle withdrew at 9.46 without rilling the hole in the fuzzy covering of the peach as usual, the total time being 16 minutes. Another beetle, ovipositing on plum, inserted the beak at 9.08, the egg cavity was finished and ovipositor inserted at 9.09^, and the ovi- positor was removed at 9.10. After packing the egg cavity the crescent was begun, which was finished by 9.28, a total of 20 minutes for the entire process. LIFE HISTORY AND HABITS: THE ADULT. 103 EGG AND FEEDING PUNCTURES: POSITION ON FRUIT AND VARIATION IN FORM. The position of the egg puncture on the young fruit, as would be surmised from observations on the process of oviposition, is deter- mined in a general way by the part affording the beetles the best anchorage for their feet during the work of excavating the puncture and crescent. This position will vary according to the age of the fruit, and also according to the kind, as whether plum, peach, apple, or other species. Some data were secured by Messrs. Girault and Rosenfeld as to the location of egg and feeding punctures, which are set forth in Tables LII to LIV. In the case of the peach, it proved to be difficult to separate positively the two forms of punctures, and these are considered under the same heading. Table LII. — Location of egg and feeding punctures of the plum curculio on wild plums Myrtle, Ga., 1906. Fruits examined. <8 3 § 3 p. Ml be W Location of egg punc- tures on fruit. g 3 O a 3 P. bfi c •3 CP Location of feeding punctures on fruit. Dates of examinations. CD From— i < <6 2 © "3 a O S "3 o "S. < 3 3 pq H O 2 3 "3 p. < 1 M 3 i Apr. 9 200 100 100 50 50 50 50 50 50 50 50 25 50 Tree ...do ...do Ground . . . Tree Ground . . . ...do Tree Ground . . . Tree ...do Ground . . . Tree 22 48 55 43 76 101 52 73 102 48 62 58 42 782 22 45 49 32 36 45 13 4 17 11 8 2 2 286 11 21 3 14 5 10 6 4 5 7 3 6 3 98 2 8 .... 3 .... 1 4 6 1 4 1 3 6 1 .... ? 13 2 3 4 14 21 8 3 5 8 1 1 2 72 1 3 3 19 17 25 51 46 18 34 .45 17 279 i 20 22 l 2 8 2 2 14 8 14 7 18 76 3 5 10 4 13 20 '3 5 3 3 69 8 30 1 30.... q May 8 6 8... 1 2 2 1 1 1 1 1 1 *2 13 9 31 9 31 4 June 6 1 6 5 11 1 14 8 21 • Total. 875 42 Table LIII. — Location of egg and feeding punctures of the plum curculio, Myrtle, Ga., 1906. KIEFFER PEAR. Fruits examined. CO a. 3 u C 3 £. bfi to a Location of egg punc- tures on fruit. c/5 3 0 a 3 C bfi a 1 Location of feeding punctures on fruit. Dates of examinations. s i 3 From— i < PQ 2 'co O S g ■d 1 2 "3 eS P3 a - (9 ■a 0 5 c 5 1 2 "3 "5. < "3 a Apr. 9 200 100 100 100 50 50 50 50 50 Tree Ground... Tree Ground... Tree Ground... Tree Ground. .. Tree 16 3 20 7 40 9 26 •J_> Id 159 s 2 13 7 21 3 11 12 8 88 2 '3' 6 1 4 9 5 15 8 3 1 8 12 16 77 1 5 2 11 6 3 1 6 S 6 45 3 9 1 13 2 13 2 20 4 "% 7 a 24 12 3 3 2 4 35 20 "3" 3 3 3 1 •j 9 May 2 a 4 l 2 6 •j 3 3 31 1 5 Total 810 11 1 is 104 THE PLUM CURCULIO. Table LIII. — Location of egg and feeding punctures of the plum curculio, Myrtle, Ga., 1906— Continued. APPLE. Fruits examined. Location of egg punc- Location of feeding to tures on fruit. a punctures on fruit. o > C3 P >> ca P 1 >> 03 P i >> P | a P P 1 03 P 03 P 2 03 P 1 2 a P Apr 10 11 4 4 5 "2 4 1 2 4 2 2 1 10 6 2 2 5 5 7 17 8 6 7 2 5 3 5 3 4 4 2 1 "3" 7 2 1 12 7 8 3 2 2 3 2 2 1 1 6 1 4 1 5 5 2 1 1 1 2 3 4 6 5 8 6 4 3 2 6 7 3 1 2 1 5 "5" 6 5 7 1 2 "3 2 6 4 3 2 0 3 5 6 5 4 3 2 1 1 3 1 4 1 5 4 7 8 3 3 1 5 2 4 5 2 1 5 2 2 2 3 7 6 4 2 1 3 11 13 . 1 1 1 1 1 2 "4" 3 1 4 2 5 4 1 1 2 "3* .... 2 2 1 1 "2 27 10 7 6 8 5 3 2 10 1 3 2 4 6 n 14 "4 4 2 1 7 1 •5 4 3 4 3 2 1 2 3 ? 15 .... 2 "2" 1 2 3 2 .... 3 5 2 3 4 3 2 1 2 4 3 1 4 .... 4 2 s 16 17 18 . 3 3 1 2 4 2 9 ? 19 2 20 3 5 3 "e 4 4 6 .... 1 3 3 2 4 3 7 2 i 2 3 21 2 22 1 3 1 3 6 4 2 9 23 24 3 2 1 1 2 i .... 1 4 1 3 25.... 1 4 2 3 26 "2 3 2 "2" '3' 2 2 3 27 5 28 2 Rept. Comm. Agr. for 1888, p. 61. 2 Bui. 64, Missouri Station, p. 16. LIFE HISTORY AND HABITS : THE ADULT. 109 Table LVI. — Comparative activity during day and night of five pairs of the plum curculio in feeding and oviposition, Myrtle, Ga., 1906 — Continued. Pair No. 1. Pair No. 2. Pair No. 3. Pair No. 4. Pair No. 5. Date of exami- nation. Feeding Eggs. I punc- tures. Eggs. Feeding punc. tures. I Feeding Feeding Eggs. punc- Eggs. punc- l tures. tures. Eggs. Feeding punc- tures. 1 2 >> 2 - i >> - 2 ^ if a 2 03 -s. 2 0 g 0? I >> i & I >> - Apr. 29 1 8 2 4 3 4 2 3 5 3 4 1 3 4 3 3 2 5 5 7 4 5 5 3 4 .... 5 2 6 12 5 3 6 2 4 1 3 4 9 4 1 3 3 10 9 7 12 7 4 2 3 "3' 6 1 2 3 5 7 7 8 8 6 1 1 9 5 8 6 S "3" "'8' 4 5 G 6 6 5 8 8 3 5 2 5 3 3 3 1 5 .... 3 3 3 9 4 9 6 4 2 5 3 6 3 1 5 6 6 8 .... 2 1 1 G 2 3 7 7 3 5 4 3 4 3 1 3 2 "2 1 2 1 .... 1 '2' 1 "3 3 1 .... 2 6 4 4 3 2 2 1 3 1 2 1 3 1 2 2 3 2 5 3 "3 3 2 "2 1 3 3 2 2 1 5 2 3 4 2 4 1 2 1 2 2 1 .... 3 2 1 1 1 1- 1 6 1 4 3 5 2 4 1 4 2 2 .... 2 J S .... l 1 1 1 3 2 3 4 6 2 3 2 G 1 5 5 3 5 3 4 3 5 9 3 G 4 3 3 2 2 3 4 2 3 2 2 3 1 2 5 3 4 5 6 1 3 1 4 2 4 4 1 2 4 6 4 30 May 1 2 1 i "5 4 5 1 4 5 1 2 2 1 3 3 4 4 2 3 2 6 6 4 1 2 10 3 4 2 1 2 6 1 1 1 1 2 1 3 "3" 6 2 10 5 4 1 3 2 3 2 9 1 3 5 1 5 3 4 9 8 8 7 7 G 3 2 7 2 1 2 1 4 2 5 3' 1 G 1 3 4 5 4 3 12 10 1 7 4 1 4 10 5 G 5 4 6 4 6 8 9 7 1 6 .... 2 1 1 "2 2 1 2 2 3 1 1 1 .... .... "6~ 3 2 3 3 3 2 3 "i 2 1 2 4 1 1 1 2 5 2 6 5 3 5 2 2 2 3 2 1 "3" 1 1 1 2 2 1 4 1 1 2 1 3 5 3 1 5 6 2 3 5 5 3 3 2 1 3 2 2 3 2 2 1 1 3 2 4 2 2 .... 3 1 4 2 1 2 "3' 2 2 2 5 5 4 3 1 4 3 5 2 6 3 7 1 1 S 1 1 3 1 9 1 10.... 2 3 3 4 5 4 2 5 1 5 .... 1 4 0 5 3 13 11 3 8 2 7 5 4 3 8 ■ ? 11 4 12.... 2 3 5 3 6 6 4 10 7 s 1 1 7 3 5 4 6 3 5 7 2 8 6 7 4 0 3 7 3 1 1 2 1 1 1 .... 3 2 "4" 3 3 4 1 3 2 4 1 2 1 2 5 2 2 3 5 20 "2 1 2 1 3 4 4 6 3 1 4 3 4 3 2 4 3 "'.V 3 6 2 3 4 3 4 3 2 13 a 14 15 8 8 Hi ■ 1 17 18 1 19 1 20 1 1 7 1 5 2 1 G 1 1 3 3 1 3 5 3 2 2 3 3 2 4 3 ?, oi 5 2 22 1 23 2 1 24 1 4 1 8 5 4 3 4 4 5 2 2 1 5 1 0 25 3 2 26 1 27 1 .... 2 .... 1 1 4 28 .... 3 3 29 1 30 3 31 2 3' 2 1 2 3 1 :: "2 3 .... 1 "2 1 1 1 "2 3 "l" 2 3 June 1 3 3 " 2" 1 1 2 1 1 1 3 6 6 8 3 11 9 4 3 6 5 3 .... 1 5 4 5 4 6 7 4 2 2 3 1 3 1 1 2 2 2 1 1 1 .... 1 .... 3 3 4 4 1 1 1 G 6 .}.. 9 7 1 2 _' 7 5 8 1 2 2 1 4 9 ■> 10 2 "*6 .... "2 2 11 1 .... 1 1 R 12 _\ "2" 4 2 4 5 4 2 2 5 5 3 4 3 3 13 1 14 0 7 2 G 1 7 2 5 2 2 "l 1 4 3 5 2 15 4 4 6 2 6 5 3 2 1 1 5 2 2 "3" "2 3 1 2 3 2 16 17 18 4 1 1 1 1 19 20.... 21 4 2 4 4 3 "2 4 "9" 7 6 .... 2 2 6 1 5 oo 3 5 3 2 2 4 5 1 23 9 6 4 3 3 7 3 1 5 2 2 1 3 9 24 25 1 1 7 2 1 4 1 5 4 "5 4 l 1 2 .... .... 26 27 1 3 2 "3 .... 7 28 ""8" 3 2 29 30 July 1 3 58 3 3 3 9 2 5 5 4 3 9 7 13 6 6 2 5 1 1 7 3 3 4 14 9 12 1 1 30 143 total 204 197 M 299 92 124 298 271 101 94 219 170 97 115 210 110 THE PLUM CURCULIO. It will be noted that in the case of each of the five pairs, the num- ber of eggs deposited during the day is greater than the number laid at night. Of the total of eggs laid (1,291), 654 were laid from 9 a. m. to 9 p. m., while 637 were deposited during the balance of the 24 hours, a difference, however, of only 17. A total of 2,800 feeding punctures is recorded, 1,607 being made at night and 1,193 during the day, a difference of 414 in favor of night feeding. The data suggest, therefore, that the curculio feeds rather more at night than in the day and that egg laying goes on at about an equal rate during night and day. TIME REQUIRED FOR TRANSFORMATION FROM EGG TO ADULT. The length of time spent in the fruit and in the soil has been shown separately in Tables XXV to XL. While these data are not entirely comparable, as representing different parts of the season and a variable number of individuals, nevertheless the final averages, when brought together, should give an approximate idea of the time required for the complete life cycle of the curculio. The final averages of time occupied in the fruit and in the soil as detailed are given in Table LVII with time for all stages shown, as determined by adding together these two periods. Table LVII. — Time required for the complete transformations of the plum curculio {combined data from preceding tables). Localities. Season. Time spent in fruit (egg and larval stages com- bined). Time spent in ground. Time re- quired for complete transfor- mation. Grigesville, 111 Youngstown, N. Y., and North East, Pa. Washington, D. C Myrtle, Ga Siioam Springs, Ark Douglas, Mich Barnesville, Ga 1904 1905-C) 1905-190 1900 1908 1910 1910 Days. 20.00 19. 68 15.52 17.90 21.74 20.80 20.73 Days. 28.24 31.04 32. 04 25.15 29.00 36. 41 34.38 Average. 19. 30.89 Days. 48.24 50.72 47.56 43.05 50.74 57.21 54.38 50.27 Considerable variation is shown between the averages of time spent in the fruit, and also between the averages of time spent in the ground, for the several localities. The shortest average time in fruit is shown by the 1905 Washington records, 15.52 days, and this is most closely approximated by the Georgia records a year later, namely, 17.90 days. The longest average is from Arkansas, in 1908, with 21.74 days. As regards the average time spent in the ground, the Georgia record for 1906 is lowest, 25.15 days, and the 1910 Michigan records highest, 36.41 days, though closely approximated by the Barnesville records for 1910 of 34.38 days. TIME FROM EGG TO ADULT. Ill The average time required for complete transformation and emergence of beetles, as shown in Table LVII, also varies considerably, but in view of the variations in season and in the localities from which records were obtained are more uniform than had been expected. Thus, between the shortest time, 43.05 days (Georgia, 1906), and the longest, 57.21 days (Michigan, 1910), there is a variation of only 14.16 days. The average time for the complete life cycle from egg to emergence of adult for all localities is 50.27 days. Complete records were obtained, in the case of a few individuals, of time occupied from deposition of egg to appearance of adult, as shown in Table LVIII. The averages for each locality are based on the total number of life-cycle days. The Barnesville, Ga., records include individuals from eggs laid each month from April to August, inclusive. These are separated in the table so as to show the marked lengthening of the life cycle in the earliest individuals, from eggs laid April 8-14. Table LVIII. — Showing time required for transformations of the plum curculiofrom egg to adult. Individual records. Localities. Barnesville, Ga. Do Do Do Do Total. Youngstown, N. Y North East, Pa.... Washington, D. C. Myrtle, Ga Douglas, Mich Grand total. Dates of oviposit ion. Indi- viduals. J Beetles emerging in specified days from oviposition. I ) 40 41 42 43 44 45 46 47 4S 49 50 36 37 Apr. 8-14, 1910.. Ma v 9-26, 1910.. June 16-30, 1910. Julv 1-30, 1910.. Aug. 7-17, 1910.. 27.. 1 2 1 177 71 3382846942 21 4| 3321.. 21.. 3 3 1115 13 12 1.5 17 13 16 9 9 15 6 1 1 2 1 7 3 5 6 16 7 415 .. 5 5 12 IS 17 20 June 21-24, 1905 June 13-14, 1906 Mav 10-June 10, 1905. May 7-16, 1906 June 24-Julv 6, 1910.. , .10 17 33 17 11 4 . . 24 1 4 8 1 28 23 30 24 20 26 36 15 1 2 2 2 2 597 17 16 9 13 22 25 21 30 23 30 29 25 33 40 I Localities. Dates of oviposition. Indi- Beetles emerging in specified days from opposition. 5152 53 54 55 56 2 11 12 65 Barnesville, < ia Do. . Apr. 8-14, 1910 Mav 9-26, 1910 91 49 '.'. 1 1 - » Do... June 16-30, 1910. l 1 .. fa .. Do... Julv 1-30, 1910 177 Aug. 7-17, 1910 3 5 4 3.. 2 1 1 .. 4 3 2 5 3 1 8 9 7 8 3 3 4 1.. Do 3 3 Total 415 11 12 Youngstown, X. Y • North East , Pa June 21-24, 1905 June 13-14, 1906... 3 3.... i .. i 1 ;; 3 .. 1 "i " " Washington, D. C Myrtle, Ga -.luii- 10, 1905.. 33 Mav 7-16, 1906 24 June 24-Julv 6, 1910... Douglas, Mich 1 1 1 3 19 9 7 4 11 " N 7 4 Grand total 14 14 ^ 1223 12 11 5 14241 12 1 Is 14 U) 112 THE PLUM CURCULIO. Table LVIII. — Showing time required for transformations of the plum cur culio from egg to adult. Individual records — Continued. Localities. Dates of ovipo'i- tion. Indi- vid- uals. Beetles emerging in specified days from oviposition. Total life cycle. Aver- age length of life cycle. 66 17 17 67 8 11 8 "i 68 7 3 70 71 72 2 " 73 74 75 76 77 1 78 1 Apr. 8-14, 1910 May 9-26, 1910 June 16-30, 1910... July 1-30, 1910 Aug. 7-17, 1910.... 91 49 27 177 71 415 10 17 33 24 98 Days. 5,984 2,327 Days. 67.23 Do... 4K. f>4 Do... 1,204 44.59 Do... 7,979 4.VOR Do... 3,511 49.53 Total 7 "i 3 1 2 1 1 20,995 498 832 1,220 1,086 5,728 50.35 June 21-24, 1905... June 13-14, 1906... Ma vlO-June 10,1905 Ma v 7-16, 1906 June 24-July 6,1910 49.80 43.06 Washington, D. C Myrtle, Ga 36.97 45. 25 58.45 Grand total 597 17 9 8 3 1 2 1 1 30,359 49.85 The several averages of time for complete transformations in the individual records show a range of from 36.97 to 67.23 days, the former from the insect ary records of 1905 at Washington and the latter from Barnesville, Ga., in 1910. There is here a difference of 30.26 days, but it should be borne in mind that the insect ary records show a much shorter life-cycle period than normal, by reason of the high temperature under which the insects were reared. The average of all localities is 49.85 days, differing by only a fraction of a day from the average of 50.27 days already shown in Table LVII. SEASONAL HISTORY. TIME OF APPEARANCE OF BEETLES IN SPRING. The curculio is roused from hibernation in spring by about the same temperature conditions required to bring into blossom the various deciduous fruits upon which it subsists. It is a matter of importance, however, to know just when the beetles first appear in orchards with reference to the condition of the trees ; as whether before blossoming, during this period, or after the fruit has set. This question has a bearing on the time of making spray applications and of beginning other remedial work, as jarring. Little exact information on this point is to be found in literature. Dr. Tilton (loc. cit., p. 116), writing in 1804, remarks that — Early in the spring, about the time when the fruit trees are in blossom, the cur- culiones ascend in swarms from the earth, crawl up the trees, and as the several fruits advance they puncture the rind or skin with their pointed rostra, and deposit their embryos in the wounds thus inflicted. Mr. William Bartram, in a paper read in 1789, expressed the belief that the insects appeared when the fruit was half grown or younger, TIME OF APPEARANCE OF BEETLES IN SPRING. 113 and Dr. Harris (loc. cit., p. 67) remarks that they begin to sting plums as soon as the fruit is set. Dr. Fitch (Essay, p. 16), writing in 1860, states that the insects make their appearance on plum trees when the young fruit is about one-third or one-half grown. The question was well investigated by Dr. Trimble (loc. cit., p. 72) in Xew Jersey in 1864, and frequent jarrings were made beginning May 12, at which time quince trees were in full bloom and green gage plums were just forming. Three beetles were caught from plum on May 13, 1 on May 18, and 10 on May 20 on knots of cherry and plum. Curculio punctures were in evidence on pears and cherries on May 18 and on plum on May 19. Walsh (Prac. Ent., vol. 2, p. 75) states that the female curculio makes her appearance early in the season, and as soon as the young plums are a little larger than a hazelnut. According to Dr. Riley (loc. cit., p. 53) the beetles in central Missouri begin to enter orchards during the first days of May, and commence to penetrate the fruit about the middle of the same month, varying with the season, peaches at this time being about the size of a small marble. Riley (Amer. Ent., vol. 2, p. 131) further states that the curculio commences to puncture peaches when they are the size of small marbles or hazelnuts, though she may be found in the trees as soon as they are in blossom. This point is not touched upon in the excellent account of this insect by Riley and Howard in the Annual Report of the Commis- sioner of Agriculture for 1888, though in the colored plate accompany- ing the article the weevils are shown on 'a plum twig, the buds of which are not }^et expanded. Lintner (11th X. Y. Rept., p. 122), writing in 1895, says that the plum curculio enters upon the scene at least two weeks before its first crescentic cuts are made in the fruit. More exact data are presented by Prof. Crandall (loc. cit., p. 495) in his studies of the curculio in Illinois, in 1903 and in 1904. Thus, during the spring of 1903 apple trees were carefully searched at fre- quent intervals, but no beetles were found until May 10. when they were abundant, appearing to come all at once. Apple buds were opening by April 16, the trees were in full bloom April 22, and the petals had practically all fallen by May 4. The beetles, therefore, were not in evidence on the trees until a week after the blossoming period, coining suddenly in large numbers. In the spring of 1904, systematic jarring of two trees was begun April 28. One beetle was taken from tree No. 1 on May 4, 1 on May 5, 5 on May 7. and subse- quently, a total of 15 by May 19. On tree No. 2 the first beetle was taken on May 17, and 1 the day following. On other trees beetles wero taken May 7, and a few subsequently during the month. Apple 17262°— Bull. 103—12 8 114 THE PLUM CURCULIO. buds in 1904 were expending about May 3, trees were in full bloom May 10, and the blossoms had fallen by May 15. As compared with the condition of the trees, in 1904 the beetles were in evidence about two weeks earlier than in 1903. Some data have been obtained on this point by the Bureau of Entomology. In 1905 records were made by Mr. Johnson, at Youngstown, N. Y., (see Table LIX) and though jarrings were a little late, the results are of interest as showing the occurrence of insects with reference to the condition of the trees. Table LIX. — Time of appearance of plum curculio on trees in spring. Jarring records, Youngstown, N. Y., 1905. Dates trees Japan plum. Domestica plum. Peach. Pear. Condition of trees. jarred. Trees. Cur- culios. Trees. Cur- culios. Trees. Cur- culios. Trees. Cur- culios. May 11 12 50 25 25 25 50 25 25 25 15 25 25 1 9 34 1 39 9 8 6 30 26 32 25 50 2 6 25 25 25 25 25 25 25 25 15 25 25 1 1 1 »' 4 2 15 Japan and Domestica plums in full bloom. 16 17. 25 50 25 25 25 15 25 4 23 12 7 2 11 15 25 19 22 24 27. . 25 25 25 2 1 Pears in full bloom. Plum blossoms fallen. 30 Peach and pear blossoms fallen. 2 2 First egg punctures seen on apple and plum. Total 195 82 15 3 Also, similar data were secured by Mr. Johnson at North East, Pa., in 1906, as shown in Table LX. Table LX. — Time of appearance of plum curculio on trees in spring. Jarring records, North East, Pa., 1906. Dates trees Sweet cherry. Sour cherry. Apple. Domestica plum. Condition of trees. jarred. Trees. Cur- culios. Trees. Cur- culios. Trees. Cur- culios. Trees. Cur- culios. Apr. 30 25 Cluster buds of apple just opening. May 2 50 25 50 8 25 50 50 50 1 1 6 25 8 Sweet cherry and plum 14. . 25 25 25 25 trees in full bloom. 16 25 1 17 1 25 25 25 17 7 7 Sour cherry in full 20 25 25 bloom. 28 First egg punctures on plums, pears, apples, and cherries seen May 24. Total 1 39 58 1 TIME OF APPEARANCE OF BEETLES IN SPRING. 115 The same year (1906) Messrs. Girault and Rosenfeld investigated this point in Georgia. In addition to the trees jarred, as shown in Table LXI, various trees in the woods, as Crataegus, wild plum, etc., were also jarred, but without results. Table LXI. — Time of appearance of plum curculio on trees in spring. Jarring records, Myrtle. Ga., 1906. Wild plums in thickets. Peach. Japan plum. Pear. Apple. Dates trees jarred. 0) — 2 3 1 ■a 2 i a> i o 3 ■A i 3 r- g 3 o Condition of trees. Feb 28 Many Many Many Many Many Many. Many. A few peach and wild plum blossoms open. Many. Many. Many. Many. Manv. 9 Wild plum trees in full bloom. 12 14 Many. Many. Many. Many. 16. . Elberta peaches in full bloom. 18... Many Many. Many Many. Many. Many. 21.. Blossoms fallmg from peach, pear, and plum. Peaches, pears, and plums well set. • Apples in full bloom. 23.. 24.... Manv. 2 Many. 25 ... Many Manv. 5 Many. 4 Many. Many. 26.... Manv 28 . .... Many. Many. Many. 1 3 4 29.... Manv 30.... Many. 1 Apr. 4 A few. 2 11... 1.000 1.000 1.000 227 422 88 • 13.... 16.... 2 » 4 Total. 750 2 ' At Siloam Springs, Ark., in 1908, jarring records were made in a peach orchard as shown in Table LXII. Table LXII. — Time of appearance of beetles on trees in spring. Jarring records. Siloam Springs, Ark., 1908. Dates trees jarred. Trees. Curculios. Condition of trees. Mar. 18 26 28 30 31 Apr. 2 4 6 8 11 13 14 15 17 20 22 950 950 950 6 950 950 2 950 950 1 950 1 950 42 950 17 950 13 950 8 950 13 950 M 050 146 950 ieo Tears, cultivated plums, and peaches in full bloom; cluster buds on apple showing. Petals mostly down from peaches, pears, and cultivated plums. Ben Davis apples nearly In full bloom. First feeding punctures" by caged beetles on peach. Petals mostly down from apples, cherries, and wild plums; calyces beginning to shed from peaches. First feeding punctures on peaches in orchard. First egg punctures in plums. First egg punctures in peaches. Calyces entirely shed from peaches. 116 THE PLUM CURCULTO. At Olden, Mo., in the spring of 1907, beetles were out unusually early owing to a protracted warm spell. On March 26, a few feeding punctures were found on Kieffer pear and on newly set cherries. On the same date, egg and feeding punctures were noted on recently set plums. An examination of 200 young plums from an isolated tree gave sound fruit 186, 2 with egg punctures, and 12 with feeding punctures, the fruit being from 3 to 4 mm. in diameter, and the calyces just dropping off. Jarrings made on March 27, of wild plum, cherry, peach, and pear, gave only 3 adults, all from cherry, with fruit barely set. April 4, 30 adults were captured by hand from seedling pear located near peach trees, and about as many beetles escaped. None was found feeding on adjacent apple and peach trees. The condition of the fruit trees at this place is shown by the following: March 24, cherries were in bloom; wild plums well set; petals of Elberta peach and Kieffer pears mostly fallen. March 26, Gano apples were in about one-third full bloom and Ben Davis trees were showing first bloom. In the vicinity of Washington, D. C, in 1905, a single beetle was taken April 27, and 4 specimens were jarred from peach on the day following. First punctured fruit (plums) was observed May 4, at which time it was about the size of a small bean. Punctures in fruit were increasingly in evidence after this date. Peach and pear trees were in full bloom that year by April 14 and apple trees by April 21. Native and Japanese plums were in full bloom by April 10, and earlier. On May 2, 1906, a single beetle was captured in the insectary yard, at Washington, on plum. A jarring of 7 peach trees, May 4, gave 14 curculios, and from 8 plum trees 122 beetles were taken. The peaches at this date were just shedding the calyx shucks, and plums were f of an inch in diameter. On May 16 curculios were very abundant on peach and plum, a thousand being caught in jarrings from 6 a. m. to 10 a. m. Peach, plum, and pear were in full bloom by April 14 and apple by May 1. In 1908, pear trees were in full bloom by April 9, while peaches and plums had dropped most of their petals by this date. Apple trees were mostly in full bloom April 24. The first signs of the curculio were noted April 24, when beetles were found feeding upon plum foliage, and additional specimens were found on plums April 27. Jarring records were made in the spring of 1910 at Barnes ville, Ga., North East, Pa., and Douglas, Mich., all in peach orchards. The relation of the appearance of beetles to the condition of the trees at these places is shown in Tables LXIII, LXIV, and LXV. TIME OF APPEARANCE OF BEETLES IN SPRING. 117 Table LXIII. — Time of appearance of beetles on trees in spring. Jarring records, Barnesville, Ga.. 1910. Dates trees jarred. Trees. Curculios. Condition of trees. Mar. 1) 336 19 Scattering blossoms open on Elberta peaches. 14 336 9 Elberta peaches in full bloom. 10 336 1 Red June and Abundance plums in full bloom. 18 336 0 Carmen peaches in full bloom. 21 336 20 23 336 483 25 336 840 Petals fallen from Elberta peaches; first egg punctures in plums. 28 336 1,071 30 336 563 Petals fallen from Carmen peaches. Apr. 1 336 534 4 336 427 Peaches bursting through calyces. 6 336 243 8 336 166 Table LXIV. — Time of appearance of beetles on trees in spring. Jarring records, Xorth East. Pa.. 1910. Dates trees jarred. Trees. Curculios. Condition of trees. Apr. 15.... 20.... 22.... 26.... 28.... May 2.... 4 6.... 9.... 11.... 13.... 16.... 19.... 21.... 23.... Less than 5 per cent of peach blossoms open. About 75 per cent of peach blossoms open. Peaches 90 per cent in full bloom. Peaches shedding some petals. . Nearly all petals fallen from peaches. All petals fallen from peaches. 19 Peaches beginning to burst calyces. 22 A few calyces falling. 22 Many calyces fall ine. Table LXV. — Time of appearance of beetles in spring. Jarring records. Dough 1910. 'as, Mich Dates trees jarred. Trees. Curculios. Condition of trees. Mav 4 Many. . - Apr. 25, Elberta peaches, pears, and sweet cherries shedding petals. . ..do 2 3 2 3 15 115 58 67 57 74 82 97 94 315 ISO 114 103 10... .do 13 16... ..do.... ..do... Apr. 30, sour cherries in blossom; also apples. 19.... . . .do . . . 2 1 ...do... 2 ...do.... ...do.... May 3, Bartlett pears in blossom; also some peaches. June 1 .do May 4, Baldwin apples in full bloom. 3 ..do.. ...do.. May 10, Spitzenberg apples in full bloom. '.i. do 12 ...do... 1.".. . .do 18 ..do 21 ...do 24 ...do... From the foregoing data it appears that the curculios usually first appear on the trees each season at nearly the same time relative to the advancement of fruit trees, namely, during or a little before the 118 THE PLUM CURCULIO. blooming period of apples or shortly after the petals of peaches, pears, and plums have fallen. In some seasons, however, the curculios may appear as early as the blooming period of the plum or be retarded until after apples have shed the petals. Thus it appears that the beetles are affected by temperature to a different degree than are the plants on which they live. Probably the curculios are more sensi- tive to short periods of warmth and less so to longer periods at a somewhat lower temperature. RELATION OF TEMPERATURE TO APPEARANCE OF BEETLES. A comparison of the numbers of beetles caught in jarrings with the average daily mean temperature immediately preceding each jarring furnishes information on the temperature necessary to bring the beetles out of hibernation. Such data are available from Youngs- town, N. Y., for 1905; Siloam Springs, Ark., for 1908; and from Barnesville, Ga., North East, Pa., and Douglas, Mich., for 1910. These are given in Table LXVI. Table LXVI. — Jarring records showing relation of temperature to appearance of beetles of the plum curculiofrom hibernation. Barnesville, Ga. Siloam Springs, Ark. North East, Pa. Douglas, Mich. Youngst own.N. Y. IB Q 38 3 ® 1.9 2 S i.9 5 w >>M >>w >»ai >.„ >>„ Dates. fcjO Dates. '3 u • 2Bc I Dates. 38 • 2-3 a be 3 Dates. 1U bO 3 Dates. £ 3 tx 2 « c to 3 a X o5 3 c o2'E cu _ -* c3 5 «'P V c ~ c3 M H ej ■+3 c5v % £S? 5j P£^ 53 £2* (0 $S£ g S S£ 0) 0 >£* § >££ 8 < pq < n < pq •> 49 27 16 0 0 4 9 3 3 3 2 B 51 29 6 4 t 3 3 2 1 1 3 1 1 1 9 1 July 2 2 17 5 13 3 9 2 1 1 •) 24 8 6 4 4 3 1 3' 1 1 4 5 1(> 11 1 4 2 a 26 13 L2 10 5 6 2 3 5 3 3 1 2 1 3 5 4 1 a 34 29 29 Aug. 2 1 1 M 5 1 5 5 3 13 6 2 65 3 2 1 2 2 4 3 3 10 2 2 1 ..... 5 5 1 •> 8 1 V 8 10 12 1 1 1 6 15 10 L9 1 s ! 26 29 7 Sept. 2 4 8 1 1 3 119 5 36 13 8 3 1 9 2 5 B :>n 10 7 32 1 3 3 4 4 ..... 2 1 4 9 m 12 1 1 - 57 16 14 4 2 1 1 1 M 124 THE PLUM CTJRCULIO. Table LXXI. — Jarring record for the plum curculio on peach, Barnesville, Ga., 1910— Continued. Dates of Number of curculios caught, by rows. Total. jarring. Rowl. Row 2. Row 3. Row 4. Row 5. Row 6. Row 7. Row 8. Row 9. Row 10. Sept. 23 27 1G 3 8 1 3 13 5 3 2 1 2 4 1 1 1 2 1 3 2 1 ..... 2 32 9 30... 1 11 Oct. 4... 1 4 7... 5 11... 1 2 1 21 15 18 22 Total. 3,197 975 641 393 269 229 275 227 503 788 7,497 A study of this table shows the beetles to have first become active March 10, when 16 were taken on row No. 1. During the interim March 18 to 23 they began to appear in numbers, and were out in full force during the last week of March. Considering the results of jarrings from the individual rows, the influence of the woods as hibernation quarters is very plainly shown. Thus, up to March 23 rows Nos. 1 and 2 gave a total of 476 beetles, as against 61 from the other eight rows. By March 25, 15 da}^s after emergence began, diffusion of the beetles had become quite general over the block, though the number taken from the first row on a given date was in most cases in excess of that taken from any other single row. For the season, row No. 1 yielded 3,197 beetles, 42.64 per cent of the whole number captured. From the first three rows adjacent to the woods a total of 4,813 individuals was taken during the season, or 64.19 per cent of the total. The influence of the grass-covered terrace between rows Nos. 9 and 10 is also evident, more insects being captured from each of these than from any one of the rows Nos. 4 to 8. The beetles were in maximum abundance in the orchard from about March 25 to April 13, during which period 4,108 individuals were taken, or 54.79 per cent of the total. The appearance of the new generation of beetles is marked by a sudden increase in the jarrings for June 7 and several days subse- quently. Beginning with the third week in August an increase in the number of beetles taken is again noted, reaching its maximum about September 2. This may doubtless be attributed to the issuing of the beetles that developed from ripening fruit, the ripening period being approximately July 7-20. No beetles were captured in this orchard after October 11, though the jarrings were continued to October 26. But during late fall jarrings were made in other orchards, both sprayed and unsprayed, and also in woods adjoining peach orchards. After beetles ceased to appear on the regular jarred plats, many were taken in some of these MMBER OF GENERATIONS ANNUALLY. 125 other places. On October 12, 3 beetles were jarred from 60 trees in a sprayed orchard, and 1 beetle from 50 oak and hickory trees in adjoining woods. On October 14, 133 beetles were jarred from 104 trees in a badly infested unsprayed orchard consisting of Late varieties. The trees in this orchard had been bare of foliage for more than two weeks. On the same morning 144 beetles were jarred from 28 small oak trees in woods adjoining this orchard, showing a heavy migration to the woods. The same 104 peach trees were again jarred October _'■';. Only 30 beetles were taken, and only 7 beetles from 20 oak trees in the adjoining woods. On October 26 as many trees as possible were jarred in the woods adjacent to the regular jarred block of peach tr Only 3 beetles were secured The last beetles of the season were jarred November 1, when 2 beetles were taken from the 104 trees in the unsprayed orchard previously mentioned. No beetles were secured in jarring 18 oak trees in the adjoining woods on the same date. This probably marks the complete entrance of the insect into hiber- nation. NUMBER OF GENERATIONS ANNUALLY. It has been accepted for years that there is but one generation of the curculio annually, though this was a much-disputed question among the earlier writers. Thus, the writer of an article in the National Gazette, which was reprinted in the American Farmer of November 15, 1830, states: "There are three generations of them during the five months of their existence above ground, and they are all very tenacious of life." Dr. Fitch ■ believed the insect to be two-brooded each year, the second broodpassing the winter in the larval condition under the bark of pear trees. He was led to this erroneous belief by the resemblance to the curculio crescent of a curved incision in the bark which he supposed was the egg puncture of the insect in question. The absence of fruit he thought necessitated this change in e^g laying by this brood, and agreed with the earlier observations of Melsheimer that the curculio bred in the bark of peach tree-. Dr. Trimble, as the result of observations, believed the curculio to be single-brooded, and this opinion was, in the main, accepted by subse- quent writers. Dr. Riley, however, in an anonymous communication under the signature of " Y" in the Prairie Farmer for July, 1867, gave it as his conclusions that the insect was occasionally two-brooded. In his first Illinois report (1867), Walsh states his belief in the double- broodedness of the curculio, as follows: "I find there are two distinct broods of the plum curculio every year, the iirst of which comes out in the beetle state, in the latitude of Kock Island, 111., from about July 19 to August 4, and the second from about August 23 to Septem- »3d Bept Ens. N. v.. p. 351. 126 THE PLUM CURCULIO. ber 28." He cites in detail rearing experiments to support his con- clusion, and cites Riley's note in corroboration. Riley * fully corroborates the conclusions of Dr. Trimble by rearing the curculio in a large cage over a tree, and states emphatically that the curculio is single-brooded, but further goes on to say: But as there seem to be exceptions to all rules, so there are to this; yet the exceptions are only just about sufficient to prove the rule, for as far south as St. Louis not more than 1 per cent of the beetles lay any eggs at all until they have lived through one winter; or, in other words, where one female will pair and deposit a few eggs the same summer she was bred, ninety-nine will live on for nearly 10 months and not deposit till the following spring. In more northern latitudes I doubt if any exception to the rule will be found. During the present study of the curculio but little information on the tendency of the insect to produce a second brood under field conditions has been secured. Late records of larvae in fruit could readily be accounted for as from eggs deposited by the longest-lived individuals of the overwintering beetles. During 1905, however, at Washington, D. C, a second brood of larvae was obtained, though no individuals reached the adult condi- tion. Infested peaches were received May 1 from Fort Valley, Ga., and confined over moist soil in a large covered glass jar kept in the insect ary, where temperature conditions were abnormally high. By June 8 many adults were emerging from the soil, and on June 12 several apples were added. On July 13 eggs were found in four apples, and subsequently fertile eggs were laid on the 17th, 20th, 21st, 22d, and 24th of July, and by August 2 several larvae had developed to full size,* some remaining in the fruit and others entering the soil. Several larvae were separated for particular observation, but all of these died without transforming to the pupal stage, and no adults were secured from larvae "entering soil in the breeding jar. During the summer of 1910 a second generation was again reared under laboratory conditions, at Barnesville, Ga., this time a large number of individuals being reared to the adult stage. Adults of the first generation were reared out of doors from infested peaches gath- ered in an orchard, the beetles beginning to emerge June 6. On emerging, the beetles were put in large muslin-covered battery jars, 100 to 175 beetles to each jar, and kept in the laboratory. They were fed on peach foliage and fruit, but were often neglected, allowing the jars to become very humid and sometimes moldy. On July 11 several eggs were found in peaches taken from these jars. The beetles, 480 in number, were then supplied with ripe Elberta peaches from which all curculio eggs had been removed. On examining this fruit two days later 113 eggs were found. Eggs were subsequently obtained in abundance, a typical record of eggs laid in fruit left in the jars overnight being shown in Table LXXII. 1 Third Missouri Rept., p. 11. BEETLES FROM EMERGENCE TO HIBERNATION. 127 Table LXXII. — Record of eggs laid by 864 new-generation beetle* during om night. Barnesvilk. On.. 1910. Dates of observation. infant I Dates beetles emerged from soil. Eggs laid. : Night of Julv 26 120 6 Do... 113 1 156 185 109 101 80 June IS— 19 11 Do Do... June 20-22 June 23-2.5 16 49 Do. June 26-29 20 Do Do June 30- Julv 4 July 5-16 - 13 Total 964 142 The beetles continued to oviposit freely until August 10. By this time peaches were scarce and no further observations were made until August 17, the beetles being fed on foliage alone during the intervening week. On August 17 some late seedling peaches, both green and ripe, were put in the jars and on the next day were exam- ined for eggs, only two being found. Xo more eggs could be obtained from these beetles or from beetles recently captured by jarring, although eggs were being laid in the field, where fruit was available, for a month longer. All eggs laid by the new-generation beetles appeared to be fertile and hatched in from three and one-half to four and one-half days unless injured by handling. One hundred and eighty-live individuals were reared through to the adult state under the same outdoor conditions used in the other rearings. The larva? developed in ripe peaches, remaining in the fruit from 9 to 24 days. The life in the soil ranged from 18 to 45 days and the entire life cycle from 36 to 61 days. The adults from this material emerged from the soil August 22 to October 10. Adults from infested peaches collected in the field emerged as late as November 9, at which date there were yet many pupa? and even larvae in the soil, though there is no evidence that these late individuals from the field were of the second generation. BEETLES FROM EMERGENCE TO HIBERNATION. In general, after emergence the adult insects pass the time in hiding and feeding, their activities growing le -•> 38 3 14 13 134 2. June 13-22 Oct. 1-Nov. 3 A.ug.6-Sept6... June 30-July 16... Sept. 7-9 ;: 3 99 4 Teach foliage only Peach foliage, peaches, and apples. Teach foliage only Teach foliage, peaches, and apples. Peach foliage and apples g Is 1 g i u 230 6 125 6 206 7 June 23-29 Sept. 10-15 . M7 8 119 9 Oct. 11 22' 302 10 Peach foliage only after inc. 30. 95 Total. 2,378 112 1 . 779 Jarred. 134 THE PLUM CURCULIO. Table LXXIII. — Mortality of hibernating beetles of the plum curculio, Barnesville, Ga., 1910-11— Continued. Lot No. Date put in winter cage. Hibernation material used and exposure. Date final exami- tion. Alive. Dead. Miss- ing. Per- centag alive. 10 Total. 1910. Nov. 4 ..do... ..do... ..do... ..do... ..do... ..do... ..do... ..do... ..do... Chips; exposed to rain Sod; exposed to rain Dry leaves; exposed to rain Dry leaves; sheltered 1 1 ay; exposed to rain Dry leaves; exposed to rain Bare dirt; exposed to rain Chips; sheltered Dry leaves; exposed to rain Dry oak leaves; exposed to rain 1911. Mar. 8 ..do.... ..do.... ..do.... .do.... .do.... .do.... .do.... .do.... .do... 1 1 )-l 64 53 113 111 SG 1 2 35 V\ 60 24 133 3 94 100 127 3 58. 95 46.84 64.64 23.04 90.40 53.88 34.81 .84 .66 36. 84 648 i 36. 42 1 Based on totals. Observations on the hibernation of beetles were also made by Mr. Hammar during 1910 at Douglas, Mich. To determine if any indi- viduals lived over two seasons, a lot of beetles, 1,591 in number, were placed in rearing jars as collected from the trees between May 7 and June 30, and before any beetles of the new generation had appeared. These were supplied with food during the summer and fall until hibernation. On May 10, 1911, the contents of the cages were examined and the sand sifted, and 1,400 individuals recovered. No live beetles, however, were found, though some were alive in the fall. This indicates that the beetles do not live over a second winter. A lot of beetles, 610, reared from fruit in the laboratory during the summer of 1910 was placed in a rearing cage in a protected place out of doors and fed until hibernation. At the final examination, May 10, 1911, 416 dead beetles were found and the remains of a few dis- integrated individuals. The live beetles unfortunately had escaped through an imperfection which developed over winter in the cage. These figures, however, give a winter mortality of about 70 per cent. PERCENTAGE OF FRUIT PUNCTURED OR INFESTED BY THE PLUM CURCULIO. In a general way it has long been known that the curculio, through- out its area of distribution, injures or destroys a large amount of" fruit each year. The amount of injury will vary from season to season, and will depend more particularly upon local conditions in the orchard. Injury will be notably worse in uncultivated orchards and where good hibernation quarters are afforded the beetles. Cultivated and sprayed orchards suffer least, though in well-cultivated, southern peach orchards the pest is often quite destructive. In connection with spraying experiments during the past several years, the per- centage of fruit injured by the curculio on untreated trees has been FRUTT PUXCTrRFJ) OR [NFESTED. 135 determined for various fruits and localities by actual founts of fruit. Typical data of this kind are furnished in the tables following. Not all fruit punctured is worthless, though its market value is reduced. In Table LXXIV are given data on amount of fruit infested by larvae from specified trees in several localities in Georgia and in Penn- sylvania, including both drop and picked fruit. On account of the difficulty of determining punctures in the peach, only actual infesta- tion was noted, mostly of fallen fruit. Table LXXIV. — Percentage of infested peaches for the season, various localities. Season. Variety. Trees used. Fruit from ground. Localities. Tested. Sound. Total. Mavfield. Oa 1937 1908 1906 1906 1906 1906 Elberta Red River 5 4 12 5 8 4 328 167 231 2,522 831 467 . a 1,485 941 171 Mar^hallville, Ga 634 Belle of Georgia Miscellaneous 469 2 58 North East. Pa Do . . Sneed Hills Chili 3,463 1.002 Total and average per 4,672 3.541 - Variety. Trees Used. Fruit from trees. Total Per- centage Localities. Season. In- fested. Sound. Total. • iuiai fested. so,m,L infested for season. Mavfield, Ga 1907 1908 1906 1906 1906 1906 Elberta 518 100 264 35 0 0 113 2,264 895 489 2.200 Ms 631 846 342 71.21 Marshallville, Ga... Mvrtle, Ga Arlington, Va North East, Pa Red River Belle of Georgia. Miscellaneous... Sneed 4 12 8 4 2.3'-4 1.159 524 2.200 A A 267 495 28 2,522 831 2.731 1.133 1,984 3.141 1.019 8.91 30. 40 24.04 44.53 Do Hills Chili 44.91 Total and av- erage per cent of in- 917 7,726 10. 350 35.06 As shown in Table LXXIV, the percentage o( infestation to peaches in the several localities varies from 8.91 to 71.21 per cent of the total crop produced, with an average of 35.06. These figures represent the actual proportion of the crop destroyed, since it includes only infested fruit. The total number of infested fruits from the ground, 4,672, exceeds notably that infested on the trees, i. e., 017. The percentage of drop fruit infested is 56.87, as compared with 11.86 per cent from the trees at picking time. During seasons (^ light crops practically all of the fruit may become infested when small and drop, though during years of full crops the thinning out by the beetles is not especially important. In Table LXXV is shown the condition of the drop fruit for the season from 120 Elberta peach trees at Siloam Springs. Ark., during 100S. The fruit at picking time was by mistake of orehardist 136 THE PLUM CURCULIO. removed before records could be made of condition of same. The percentage of infestation, 11.25, is notably less for drop fruit than shown in the preceding table, 56.87, due to the greater scarcity of the beetles. Table LXXV. — Percentage of injury to drop peaches, Siloam Springs, Ark., 1908. Dates fruit was collected. Fruits. Fruits infested. Apr. 30 2,500 6,500 30, 840 7,200 2,400 498 198 135 251 68 101 21 16 41 90 104 689 648 328 1,481 674 1,658 958 301 89 80 56 16-19 21 25 30 8 13 67 17 19 22 25 27 7 July 1 2 5 15 11 50 15 30 20 300 25 87 29 21 Total 52,628 5,920 Average per cent of infestation, 11.25. The degree of infestation by the curculio of all fallen fruit for the season from 10 peach trees in the District of Columbia is shown in Table LXXVI. The percentage of infestation, 44.73, closely approximates the averages of the figures in Table LXXIV. Table LXXVI. — Percentage of injury to drop peaches, Washington, D. C, 1908. - Dates fruit was collected. Number of fruits. Number of fruits infested. May 24 676 2,500 902 247 79 342 1,202 10 . 290 16 . 124 July 3 - 12 Total 4,404 1,970 Average per cent of infestation, 44.73. JJl FRUTT PrxriiCKD OR TXFKSTED. 137 Extent of injury to miscellaneous sorts of plums is indicated in Table LXXVIT. Records were made by gathering the specified number of fruits here and there from the trees or from the ground. It is regretted that similar data are not available from more northern localities. Table LXXVII. — Percentage of injury to plums by egg and feeding punctures, various localities. Localities. Varieties. Date col- lected. Fruits with egg punc- tures. Fruits with feeding punc- tures. Unin- jured fruit. Total num- ber of fruit. Average percent- age of fruit injured. Remarks. Myrtle, Oa Wild plum.. do 1908. Apr. 9 13 20 22 30 30 May 8 31 . 31 June f> 6 n Apr. 9 14 Mav 7 7 190o. Mav 9 9 20 20 22 22 22 37 43 36 36 43 36 32 22 34 27 40 28 4 C.I 3 32 33 63 117 122 30 35 14 14 6 10 5 4 4 5 5 4 3 8 2 6 13 5 3 12 25 4 104 49 51 4 9 3 10 13 23 12 20 2 20 90 20 17 55 112 18 2 01 5 200 100 100 50 50 50 50 50 50 50 50 50 50 100 100 25 35 100 200 139 124 100 50 From trees. Do Do. Do do do do do do do do do do do do Red June. . . do Do. Do From ground. Do From trees Do Do From ground. From tree. Do From ground. Do From tree. Do Do From ground. From tree. Do From ground. Do From tree. Do Do. Do... Do. Do do do Do. Do From ground. From tree. Arundel, Md. . . Burbank do Do Do. Riverdale, Md.. (?) (?) (?) (?) Do. Do From ground. Bennjngs, D. C. Do. 9 10 From trep. From ground. Total for all 930 171 700 ,873 59.10 localities. In the above table the figures for injury show merely the number of punctures. While most of the fruit punctured would fall, not all of it would do so, the fruit more or less outgrowing the injury. The average percentage of injury, i. e., 59.10, is therefore perhaps a little high. The extent to which pears may be punctured is shown for two localities in Table LXXYITT. As elsewhere explained, the real injury to such pears as Le Conte and Kieffer is small, as the thinning of the young fruit is in most cases desirable and the punctures are mostly outgrown bv the finit on the trees. 138 THE PLUM CURCULIO. Table LXXVIII. — Percentage of injury to pears by egg and feeding punctures, Georgia and Maryland. Localities. Varieties. Date col- lected. Fruits with egg punc- tures. Fruits with feeding punc- tures. Unin- jured fruit. Total num- ber of fruit. Average percent- age of fruit injured. Remarks. Myrtle. Ga Do LeConte do 1906 Apr. 9 9 14 14 20 20 May 2 4 31 Apr. 4 0 9 13 13 20 20 May 2 4 31 12 12 11 12 182 188 93 86 35 44 28 37 35 160 173 152 59 84 23 34 29 25 28 25 42 200 200 100 100 50 50 50 50 50 200 200 1G0 100 100 51 50 50 50 50 45 127 Do... do 4 11 4 19 10 18 18 3 29 9 25 13 16 18 10 Do... do 10 4 2 3 3 8 22 9 5 12 2 3 5 7 12 From ground. Do... do Do... ...do From ground. Do. . ...do... Do . .do... From ground. From tree. Do do Do KeifCer .do Do. Do Do. Do.* do Do do Do ...do From ground. Do .. .. do Do... ....do Do... ...do Do... ...do From ground. Do... .do... Bartlett Keiffcr Do. Do... Do. 232 133 1.562 2.032 23.12 averageper cent of in- j nry for botliloc li- ties. The extent of injury to apples in several localities during 1908 and 1909 is shown in Table LXXIX. These records are from unsprayed or control trees used in spraying experiments and demonstrations against the codling moth and plum curculio, and are further referred to under the heading of spraying apples (p. 193). Table LXXIX. — Number of egg and feeding punctures and percentage of injury to apples, including drop fruit and fruit from tree, various localities , for seasons 1908 and 1909. Localities. Variety. Date. Tree No. Egg punc- tures. Feed- ing punc- tures. Injured fruit. Total num- ber of fruit. Aver- age per- centage of fruit injured. Anderson, Mo Do Lansingburg do Season 1908. Season 1908. Season 1908. Season 1908. Season 1908. Season 1908. Season 1908. Season 1908. Season 1908. 1 2 3 4 5 6 8 9 1,486 1.5(2 1.492 1,615 1,910 1,882 2,547 2.142 2,021 438 542 381 448 539 573 907 599 752 166 298 219 284 389 344 544 484 566 169 308 235 298 400 308 585 516 626 Do do Do. . . do Do... ...do... Do Do... do ...do... Do... do.. Do... do Total and aver- 16,657 5. 179 3,294 3,505 93.98 age per cent of injury. Ben Davis ...do ... Season 1908. Season 1908. Season 1908. Season 1908. Season 190S. Season 1908. Season 1908. 1 2 3 4 5 6 7 ' Douglas, Mich Do 538 916 1,241 1,778 2,343 9,482 4,627 301 282 740 780 1,121 891 493 274 316 528 458 1,012 1,079 1,285 751 592 944 933 3,003 1,132 1,632 Do ...do . Do Hubbard stown do... Do Do Olden berg Do 20, 925 4, 011 4 952 8 9K7 55.10 age per cent of injury. XATfliAL ENEMIES. 139 Table LXXIX. -Number of egg and feeding punctures and percentage of injury to apples, including drop fruit and fruit from tree, various localities, for seasons 1908 and 1909 Continued. Localities. West field, X. Do Do Do Do Variety. Baldwin. ....do... ....do... ....do... ....do... Date. Season 1908. Season 1938. Season 1908. Season 1908. Season 1908. Total and aver- age per cenl of injury. Crozef,Ya Yellow Newtown. Season 1909. Do do Season 1909. Do do Season 1909. Do do Season 1909. Do do I Season 1909. Do ' do Season 1909. Do do Season 1909. Do do Season 1909. Total and aver- age per cent of injury. Fisherville, Va Do Do Do Do Do Winesap . do. . . do... do... do... do... Total and aver- age per cent of injur}-. Mount Jackson, Va... Do Do Do Do Do Do Do Total and aver- age per cent of injury. Ben Davis. ....do ....do ....do ....do ....do ....do ....do Season 1909. Season 1909. Season 1909. Season 1909. Season 1909. Season 1909. Season 1909. Season 1909. Season 1909. n 1909. Season 1909. Season 1909. Season 1909. Season 1909 Tree. No. Egg punc- tures. 139 169 119 117 191 Feed- ing Injured punc- fruit. tures. 52 181 110 298 62 283 212 121 286 ""'of SE£ 1 of fruit injured. fruit. 748 1,518 881 1.100 4-40 1.210 5,085 24.77 1.070 1,627 479 631 1.419 1,068 1.433 1,170 1,076 1.2.55 3. 423 944 1.571 - 220 437 816 331 531 1,016 1,071 1.415 3.111 871 1,193 865 1,285 2.091 G95 1,098 1,980 9.497 6.079 8,785 19.107 45. 97 1.326 536 1.350 4,463 7_'7 3*9 799 3.134 1,718 518 1.378 3.537 1.573 37s 1.420 4,055 2. 793 795 2.307 5,892 1.019 206 803 2.244 9.156 2,822 8,057 23.325 34. 53 5.119 2.217 3. 186 3.926 3.545 952 2,226 3.109 1.703 509 1.079 1,840 2.179 709 1.226 1 . 508 3.723 1.307 2.399 3,189 4,113 2.009 2. 823 4. 153 5.541 3,238 3.611 5. 121 3,785 1.199 2.107 2 795 29. 708 12, 140 18,657 25.(,41 12. 72 The injury indicated for apples ranges from 93.88 to 24.77 per cent of the total crop, both dropped and picked fruit. Tt is not to be inferred that the figures indicate1 the actual amount of fruit lost from curculio attack, since1 in many instances in the case1 of fruit from trees there would be but a single feeding puncture1, or an old egg scar, largely outgrown. Such specimens, while unfit for fancy market fruit, would possess considerable value. NATURAL ENEMIES. There are many factors which taken collectively exert an important influence on the numbers of the curculio, as unfavorable conditions during the winter, drought during pupal period and time of emergence of beetles from the1 soil, scarcity e>f fruit for oviposition due te> frosts e>r other causes, and the1 influence of parasitic and predaceous enemies and disease. Notwithstanding all of these, the insect is able to main- 140 THE PLUM CUBCULIO. tain itself most successfully, and puts in its appearance in the spring in numbers with much regularity. Under favorable conditions for development, as in neglected orchards, they often become excessively abundant, but for any locality do not show as a rule any great varia- tion in numbers from season to season. Although the curculio in its egg, larval, and pupal stages lives well protected — as in the fruit and below the soil — yet it is subject to the attack of several species of parasites. PABASITIC INSECTS. (Anaphes) Anaphoidea conotracheli Girault. Only one parasite of the egg of the curculio is known, namely, (Anaphes) Anaphoidea conotracheli Girault, first reared by the senior author in 1902 at College Park, Md., and next from ma- terial collected in 1905 at Fort Valley, Ga. (See fig. 25.) The description of this species by Gir- ault will be found in Entomological News.1 These mi- nute insects, barely visible to the naked eye, are quite active, jumping readily when disturbed. This parasite ap- pears to be widely distributed, and has been reared from eggs of the plum curculio in the fruits indicated, from the following localities: Table LXXX. — Records of rearings of (Anaphes) Anaphoidea conotracheli, various localities. Fig. 25.— (Anaphes) Anaphoidea conotracheli, an egg parasite of the plum curculio. (Original.) Localities. Date. Fruit. July 3-18, 1905 Plum. Washington, D. C May 9-3 1 , 1905 Plum, apricot. College Park, Md July 22-29, 1905 Riverdale, Md May 3-July 24, 1905 Apple, plum. Peach, pear, plum. Arundel, Md May 16-June 15, 1905 Arlington, Va... June 13-July 13, 1905 June 15-10, 1905 Apple, cherry. Apple. East Falls Church, Va Aug. 12, 1905 . . . Victoria, Tex June 15, 1905 . . Tryon, N. C May 20, 1905 Do. Lexington, Ky June 18, 1905 Do. Ardmore, Okla May 30, 1905 . Wild plum. Wild plum, Japan plum. Fort Valley, Ga May 9-June 2S, 1005 Apr. 26-Mav 13, 1901 i Myrtle, Ga Wild plum. Apple. Wild plum. Charlottesville, Va May 18, 1905 Barnesville, Ga May 17-20, 1910 i Ent. News, vol. 10, p. 220 (1905). NATUBAL E2STEMIES: PARASITIC INSECTS. 141 From the records from localities in the environs of Washington, (College Park, Riverdale, Arundel, Md., and Arlington, Alexandria, and East Falls Church, Va.) it would appear that the insect is out ovipositing nearly coincident with the period of oviposition of its host, namely, May 3 (Riverdale, Md.) to August 12 (East Falls Church, Va.). Hearings have been made from eggs in various fruits, including wild and cultivated plum, and it is probable that the parasite will search out eggs in any fruit used by the curculio for e^g laying. In its distribution the Anaphoidea is seen to range pretty well over the Eastern States, and rearings from Ardmore, Okla., indicate its occurrence in the Southwestern States. The insect probably follows its host, though no data of note are at hand as to its distribution in the Mississippi Valley and Middle-Western States. In several instances it was possible to determine the percentage of parasitism of the eggs. Thus, in a lot of eggs from Arundel, Md., in plums collected from trees May 9, 62.8 per cent yielded adults of the Anaphoidea. In another lot from the same locality, on the same date and host, the parasitism amounted to 70.76 per cent. A lot from Berlin, Conn., in plum, gave about 85 per cent parasitism. At Myrtle, Ga., eggs in wild plum collected May 16 gave 10 per cent, and another lot taken May 1 gave 16.6 per cent parasitized. From Bemiings, D. C, a lot of eggs in plum taken May 31 gave 12.2 per cent parasitized. Of 36 eggs collected at Barnesville, Ga., May 17, 36.11 per cent gave out adult parasites. In a lot of 28 eggs collected May 19 the percentage was 46.43, and of 97 eggs collected May 26 the percentage producing adult parasites was 56.70. In these three lots, if account be taken only of the eggs which either hatched or gave out adult parasites, the proportions parasitized would be 46.43 per cent, 76.47 per cent, and 91.66 per cent. Five eggs hi these lots produced two parasites each. Certain observations on the habits and biology of the Anaphoidea parasites, made by Mr. Girault, are of interest, especially in view of the paucity of our knowledge concerning these minute creatures. Parasitized eggs were found to maintain their normal pale white color until within two days of the emergence of the parasite, at which time or a little later the large reddish eyes and the three reddish ocelli between them become evident and the general outline of the parasite becomes discernible. Gradually the parasite becomes dusky and a lew hours before emergence almost entirely black. The time required for the development of Anaphoidea from egg to adult varied from 9 to 11 days, averaging approximately 10 days. Thus during the 6 to S weeks of egg laying o{ the curcidio there would be time for six or seven generations of the parasite. Oviposition was observed several times. In a typical instance, the female carefully examined the egg puncture, which was two days old; the long flexible antennae moved alternately up and down very 142 THE PLUM CUECULIO. rapidly, tapping the plum. After an instant of greater excitement she suddenly stopped, with body raised, holding the antennae straight and rigid before her. The slender ovipositor was quickly inserted, the tip of abdomen being bent cephalad for the purpose. Oviposition occurred within 30 seconds. In removing the ovipositor the antennae were lowered partly beneath the fore-body, evidently as a help, and the abdomen quickly arched. (Sigalphus) Triaspis curculionis Fitch. The Sigalphus parasite of the curculio (fig. 26) was first discovered by Dr. Fitch, and a description with' figure of the female published in the Country Gentleman for October, 1859 (p. 221), and also in the Albany Cultivator in October of the same year. A more extended account is given in his address "On the curculio and black knot on plum trees," delivered before the New York Agricultural Society in 1860. The specimens upon which the description was based came from D. W. Beadle, St. I Catherines, Ontario, and had been reared by him from black knot on plum trees which were infested with curculio larva3, the adult curculios appearing in numbers in the rearing jars. The fact that the black knot is also infested by the larvae of other in- sects, especially that of the so-called plum moth (Enarmonia prunivora Walsh), casts doubt on the exact host relations of the Sigalphus. In fact, Walsh in his report as acting entomologist of Illinois ridiculed the idea that the Sigalphus was a parasite of the curculio, and this doubt was not removed until 1870, when Dr. Riley reared the insect in large numbers from curculio larvae placed in jars in carefully sifted earth. Little has been added to our knowledge of this insect since the observations by Riley. Prof. Gillette, in Iowa Station Bulletin 9, page 378, gives some interesting notes on the insect; he found it quite common in the vicinity of Ames during the summer of 1889. The variety rufus Riley, later mentioned, was four times as abundant as the true curculionis. The substance of the same article was also published in the Canadian Entomologist, volume 22, page 114 (1890). The Sigalphus has been reared by Fayville and Parrot, in Kansas, from larvae of the potato stalk weevil, Trichobaris trinotata Say (Kansas Station Bulletin 82, p. 12), and the parasite is recorded from the same host by Dr. Chittenden (Bui. 33, n. s., Bur. Ent., Fig. 26.— (Sigalphus) Triaspis curculionis. an important parasite of the plum curculio: a, Male; 6, female; c, antenna. (After Riley.) NATURAL ENEMIES: PARASITIC [NSECTS. 143 U. S. Dept. Agr., p. 17). The insect was reared from the cotton boll weevil (Anthonornus grandis) at Calvert. Tex., and is doubtfully recorded from Oonotrachdus juglandis Tec Specimens of curcuVu were also received from Prof. A. H. Conradi, Clemson College, S. C, in 1908, and from Prof. Fred E. Brooks, Morgantown, W. Va., Jan- uary, 1907, who had reared them from Balaninus sp. As stated by Mr. W. D. Pierce (Journ. Econ. Ent., vol. 1, p. 386), it com- monly attacks Conotrachdus elegans Boh., at Dallas and Victoria, Tex. At Four Mile Run, Va., it was reared from Trichobaris trinotata Say in eggplant. Riley records the Sigalphus from a stalk-borer in Ambrosia (Ins. Life, vol. 2, p. 353). In West Virginia it has been reared in abundance from Conotrachdus affinis Boh. and in lesser numbers from C. juglandis Lee. (W. Va. Agr. Exp. Sta., Bui. 128. p. 182). This, so far as the writers know, is the complete host list of the species, and Sigalphus is so much more common on Conotrachdus nenuphar that this is without doubt its principal host. (Sigalphus) Trias pis curculionis is of general occurrence througn- out eastern Xorth America, its range probably being coextensive with that of the plum curculio. A list of localities, with dates of rearing, is given in Table LXXXI. Table LXXXI. — Distribution of ■sigalphus* Triaspis curculionis. with dates of rearing. Localities. Dates of emergence. Localities. Dates of emergence. New Haven. Conn July 12-18, 1005. JulV 14-Aug. 18, 1905. July ^14. 1906. June 24-Julv 12, 1907. Julv 21, 1905. July is, 1905. June 21-Julv 2G, 1905. June 16-Julv 6, 1905. May 22-July 17, 1905. June 24-Julv 30. 1908. June 2-Julv 30. 1905. June 15-17, 1905. June 20, 1905. Do. Fort Vallev, Ga j Myrtle, Ga. May 22-July 3, 1905. June 10. 1906- North East, Pa New Richmond, Ohio.. Barnesville. Ga i Lake City, Fla Mav 23-June 30, 1910. May 23, 1905. East Lansing, Mich Valparaiso, Ind Arundel, Md Riverdalo. Md Washington, D. (' Do Hampton, Fla May 31, 1905. June 15, 1905. Mexia, Tex Siloam Springs, Ark. . . Bentonville, Ark June 18 June3-Julv 18, 19 8 June 24-26, 1906. June 21-Julv 8, 1905. Arlington, Va Salina. Kans Julv 22, 1910. Winchester, Va Raleigh, X. C Tryon, X. C Grand Island, Xebr Xorth Platte, Xebr Julv 18-22, 1910. Do.- Localities in literature: St. Catherines, Ontario (Fitch). St. Louis, Mo. (Riley). Ames, Iowa (Gillette). The insect has been reared from many localities during the past four or five years, exclusively from plum curculio larvae, but never in noteworthy numbers, although the degree of parasitism in a few- cases reached 25 per cent. This would vary, perhaps, depending upon when the infested fruits were collected, as larvae are parasitized principally in early spring. In three records that covered the entire season the average infestation was 2.78 per cent. In connection with the records of emergence o( larvae from fruit for the season in the insectary yard and other data ^see p. 62), ac- 144 THE PLUM CURCULIO. count was taken of the emergence of this parasite from the soil boxes, as shown below : Table LXXXII. — Record of emergence of (Sigalphus) Triaspis curculionis from plum curculio larvse for season, Washington, D. C, 1908. Lot No. Date larvae placed in soil. Larvae placed in soil. Sigalphus emerging. Percent- age of larvae parasit- ized. Beetles emerging, Percent- age of larvae trans- forming to adults. Percent- age of larvae unac- counted for. 23... 24... 25.... 26.... 27.... 28-59. May 27 28 30 31 June 1 2 3 4 9 10 11 12 13 14 15 16 17 18 19 20 21 22 24 June 25- Aug. 1 187 2s3 218 297 281 206 162 90 171 213 2D.S 203 L57 154 2-: 9 369 172 190 Ml) 296 107 60 122 106 139 177, 177 860 0.71 6. 88 1.34 5.34 4.86 2.47 11.11 1.15 6.17 1.44 .49 1.27 1.95 2 .54 4 2.33 1 .53 1 .34 1 .93 1 1.67 1 .94 3 2.16 1 . ;>( i 85 103 38 45. 45 36.40 17. 43 8.41 25.27 17.96 4.32 26. 67 11.49 1.65 2.88 2.46 23.57 11.04 5.62 22.76 48.84 22.11 4.29 17.57 17.76 33.33 31.97 29.25 12.95 16. 57 6. 21 21.51 Total. 6.027 1.113 18.47 54.55 62.89 75. 69 90.25 69. 39 77.18 93.21 62.22 87.36 92. 18 95. 68 97.05 75.16 87.01 94.38 76.70 48.83 77.36 95.71 82.09 81.31 65. 00 68. 03 69. 81 84.89 83. 43 93.23 78.49 79.85 The percentage of parasitism, it will be noted, varied widely — ■ from less than one-half of 1 per cent to 11.11 per cent on June 4. The average percentage of parasitism for the season is small, and it seems probable that the insect during 1908 was less abundant than normal. Similar records of parasites emerging from lots of larvas taken over the whole season from Elberta peaches were made at Siloam Springs, ■ Ark., during 1908, as set forth in Table LXXXIII. Table LXXXIII. — Record of emergence of (Sigalphus) Triaspis curculionis for season, Siloam Springs, Ark., 1908. Lot No. Date larvse entered soil. Larvae. Sigalphus emerging. Percent- age of larvae parasit- ized. Beetles emerging. Percent- age of larvae trans- forming to adults. Percent- age of larvae unac- counted for. 1 May 12-16 May 17-19 328 573 965 550 629 719 532 449 394 107 81 61 637 3 18 21 19 18 5 1 0.91 3 .14 2.18 3.45 2. 86 .97 .94 . 22 50 124 131 123 253 211 293 124 102 49 50 34 230 15.24 21. 6 4 13.58 22. 36 40.22 29. 35 55. 08 27. 62 25. 89 45.79 61.73 55.74 36.11 83.85 2 75.22 3 May 20-22 84 27 4 May 23-25 74.19 5 May 26-28 6 May 29-31 69 68 7 43 98 8 72 16 9-10 June 7-12 74.11 11 June 13-15 4 4 2 3.74 4.94 3.28 50.47 12 June 16-18 33 33 13 June 19-21 40.98 14-23 June 22-Aug. 13 63.89 Total. 6,025 102 1.(9 1,774 29.44 68.87 NATURAL. ENEMIES: PARASITIC INSECTS. 14 5 Here also the percentage of parasitism varies with the different lots, but is less than in case of material from Washington. The average parasitism for the season was 1.69 per cent, approximately the same as that from Washington. This would be of but little im- portance as affecting the abundance of the curculio. At Barnesville, Ga., in 1910, data of the same character were ob- tained from all the larva? infesting the fruit on a block of 31 Elbert a peach trees during the season, as shown in Table LXXXIV. These data show a considerably higher percentage of parasitism and also a larger percentage of larva? transforming to adults, with a correspond- ing decrease in the proportion of larva? failing to produce either para- sites or beetles. This was doubtless due to a more favorable condi- tion of the soil in the rearing cages. Table LXXXIV. -Record of emergence of Sigalphus curculionis for season, Barnes- ville, Ga., 1910. Lot No. Date larvae entered soil. Number of larvae. Number of Sigal- phus emerg- ing. Percent- age of larvae parasit- ized. Number of beetles emerg- ing. Percent- age of larvae trans- forming to adults. Percent- age of larvae unac- counted for. 1 May 2-3 457 566 20 96 47 25.97 21.01 8.30 4.58 3.83 4.04 2.52 2.C8 2.11 3.68 1.52 28 182 276 105 109 170 117 145 101 108 45 21 13 15 133 36.36 39.82 4S.76 43.75 52.15 62.50 73.59 75.52 71.13 56.84 68.18 63.64 46.43 57. 09 51.55 37. 67 2 May 4-6 39.17 3 May 7-9 42.94 4 May 10 240 51.67 5 May 11 209 272 159 192 142 190 66 33 28 26 258 8 11 4 4 3 i 0 0 1 0 44.02 6 May 12 33.46 7 May 13... 23. 89 8... May 14-16. . . 22.40 9... May 17-19. . . 26.76 10 May 20-23 39. 4S 11 May 24-26 30.30 12 May 27-29 36.36 13 May 30-June 1 June 2-8 53.57 14 3.85 4s. 16 15 to 29 June 9-Aug. 9 May 2-Aug. 9 48.45 Total 2,915 213 7.31 1,568 53.79 3S.90 Observations on miscellaneous lots of larva? at Youngstown, X. Y., in 1905 (see Table LXXXY) show a much higher percentage of parasitism, the average for all lots being 18.66 per cent parasitized. These records, however, are not made from proportionate numbers of larva? throughout the season. The parasites were perhaps at their greatest abundance during the period under observation. Table LXXXV. — Record of emergence of (Sigalphus) Triaspis curculionis from miscel- laneous lots of larva-, Youngstown, N. Y, 1905. Lot No. Date larvae entered soil. Number of larvae. Number of Sigalphus emerging. Percentage of larva parasitised. ! Juno 27 do 10 40 55 80 150 150 126 1 SB 1 20 8 35 20 15 20 14 10 (Hi 2 20 00 3 June 28 June 29 .. do .. 4 25 iX"1 5 40 l\l 6 do 7 July i Julv 2 Julv 3 13 33 8 9 10 Julv 7 20 00 Total lJifl B 17262°— Bull. 103—12- -10 146 THE PLUM CURCULIO. In reality, however, the percentage of parasitism, as shown in these several tables, is too low, since it is based on the total number of larvae which were placed in pots of soil or other container. In all rearing work a considerable proportion of larvae, aside from those killed by parasites, failed to develop to adults, from various causes, as immaturity, etc. Taking the total emergence of beetles and para- sites as a basis, the percentage of parasitism for the season of 1908 at Washington, D. C, was 8.32; at Siloam Springs, Ark., 5.44; and at Barnesville, Ga., in 1910 it was 11.96. Even these figures are probably too low, since the removal of the infested fruit from the orchard to the laboratory must have prevented a certain degree of parasitism that would normally have occurred in fruit lying exposep in the orchard. (Sigalphus) Triaspis curculionis var. rufus Riley. This variety was described in his Third Missouri Report, page 27, by Riley, who states that it is slightly larger and differs so remark- ably from the normal form that were it not for the absolute corre- spondence of all of the sculpturing of the thorax and body, and the venation of the wings, it might be considered distinct. The great length of the ovipositor is very characteristic. Concerning this variety in Iowa Prof. Gillette observes (Canadian Entomologist, vol. 22, p. 114): The variety rufus appeared much more abundant than curculionis in my breeding cages last summer. The two forms differ so much from one another, and in some respects, especially in the number of joints of the antennae, from Riley's description that I have made the following notes upon them. "* * * Rufus is decidedly more robust in every case than curculionis, and were it not for the fact that so eminent an authority as Dr. Riley considers them the same species, I should think that rufus ought to be raised to the rank of a species." Attempts were made by Prof. Riley to distribute both the Sigal- phus and Porizon parasites, specimens being sent to several corre- spondents from Kirkwood, Mo. In the bureau collection of Sigal- phus reared from the curculio, 725 specimens, only 40 are of the rufus variety, from the following localities: Fort Valley, Myrtle, and Barnesville, Ga.; Valparaiso, Ind.; Arlington, Va.; Riverdale, Md.; Washington, D. C, and Siloam Springs, Ark. These, with its recorded occurrence in Missouri and Iowa, indicate a distribution similar to that of curculionis. It appears from observations made at Barnesville, Ga., in 1910 that while practically all of the typical forms emerge from the earliest larvae, the variety rufus only reaches its full numbers very late in the season, after curculionis has ceased to appear. A few isolated specimens of rufus emerged in connection with the typical form from material from Elberta peaches, but most of them were NATURAL ENEMIES: PARASITIC INSECTS. 147 reared much later from other material. From 240 curculio larvae which entered the soil August 30 to October 15 there emerged 16 specimens of rufus from September 24 to October 23. This gives a percentage of parasitism of 6.66. Xo other kinds of parasites emerged from these late larvae, while the proportion and number of rufus were larger than at any previous time. (Porizon) Thersilochus conotracheH Riley. This ichneumonid parasite of the curculio (see fig. 27) was described by Riley in 1871 (Third Missouri Report, p. 28) from speci- mens reared from cocoons sent him by Dr. Trimble, of Xew Jersey. The parasite feeds upon the curculio larva, and while developing to the adult form in the fall, remains in the cocoon until the following spring. This habit of ovenvintering in the soil perhaps has con- tributed to its general oversight by persons who have reared cur- culios, for there are very few references in literature concerning it. Five specimens of adults of this species were dissected from cocoons by Mr. Johnson, at Youngstown, X. Y., August 24 and October 2, 1908, and on October 4 of the same year a total of 76 cocoons of this parasite was found in curculio rear- ing jars, in which had been placed a total of 836 curculio larvae, giv- ing a percentage of parasitism for this species of 9.09. Mr. John- son also succeeded in rearing this species from material kept over winter. On October 5, 1905, 55 cocoons were found in a jar for breeding curculios at Youngstown, X. Y. This jar was again exam- ined May 18, 1906, by which time 11 adult parasites had emerged. Forty-eight cocoons were found in a jar in which had been placed 549 curculio larvae, at Xorth East, Pa., August 24, 1906. Dr. Riley evidently reared this species, along with (Sigalphus) Triaspis curculionis, in numbers in Missouri, for he speaks of having distributed specimens of each, from Kirkwood, to several localities. The insect is recorded by Dr. Howard from Coon Island, Pa., in 1887, and Riley and Howard (Kept. Com. Agr., 1888, p. 64) refer to receipt of specimens from a correspondent who found them ovi- positing and regarded them as a new enemy of the plum. Prof. Gillette, in his curculio studies in Iowa, makes do reference to Pori- zon, which presumably was not observed. The species is probably of much less economic importance than the preceding, though, as FlG. 27.— (Porizon) Thrrsiloclius conotrachdi, parasitic upon the plum curculio: a, Fe- male; b, male. (From Riley.) 148 THE PLUM CURCULIO. stated, its habit of wintering in the cocoon may have caused it to have been overlooked. Specimens are in the U. S. National Museum from Long Island and Oswego, N. Y., Connecticut, southern Illinois, Missouri, and Onaga, Kans. (Bracon) Microbracon mellitor Say. A specimen of {Bracon) Microbracon mellitor (fig. 28) was reared from the plum curculio by Prof. F. E. Brooks at French Creek, W. Va., in 1902 (U. S. Dept. Agr., Div. Ent., Bui. 38, n. s., p. 109). In 1905 it was again reared from the plum curculio at Youngstown, N. Y., North East, Pa., Arundel, Md., and For t Valley, Ga. Observa- tions by Mr. Fred Johnson at Youngstown,N. Y., and North East, Pa., indicate that this parasite lives ex- ternally upon the curculio larva, destroying the lat- ter before it leaves the fruit. The cocoon of the parasite is then formed within the fallen fruit. Bracon dorsata Say. Several specimens of this insect were reared from curculio - infested plums from Arundel, Md., Wash- ington, D. C, and Lexington, Ky. Other insects were also present, and there is a doubt that this species is a parasite of the plum curculio. Other Hymenopterous Parasites. A chalcidid of the genus Eurytoma was reared from Conotrachelus nenuphar at French Creek, W. Va., in 1902 (U. S. Dept. Agr., Div. Ent., Bui. 38, n. s., p. 109). At North East, Pa., 4 specimens of a species of Anisocyrta (Braconidae) emerged, July 24, 1906, from the soil in a jar in which curculio larvae were transforming. An ichneu- mon fly, Pimpla (Epiurus) sp., was also reared at North East, Pa., from curculio-infested prunes, 3 specimens emerging July 9-23, 1906. What is very likely the same species was reared at Youngstown, N. Y., in 1905. The parasite destroyed a curculio larva in a small apple and formed a cocoon in the dropped fruit. At Vienna, Va., during 1911, Mr. R. A. Cushman reared the following from the curculio: Eurytoma sp., Catalaccus sp., Cerambycobius sp., and Microbracon lixi Ashm., which was next in abundance to Triaspis curculionis. Fig. 28. — (Bracon) Microbracon mellitor. an occasional parasite of the plum curculio. (From Hunter and Hinds.) NATURAL ENEMIES: PARASITIC INSECTS. 149 Myiophasia eenea Wiedemann. This tachinid fly (fig. 29) is a widely distributed parasite of the larva? of several species of weevils, including the plum curculio. It is a very variable species, having been described and recorded under many names. The species was first described from Monte- vidio, Uruguay, South America, but has since been found in Central America, Mexico, and all sections of the United States. In the col- lections of the National Museum and the Bureau of Entomology there are specimens from the following localities: Chinandega, Nicaragua; City of Mexico, Mexico; Sierra Madre, Chihuahua, Mexico; Pecos, X. Mex. ; Beulah, X. Mex.; Corvallis, Oreg. ; St. Louis, Mo.; Dallas, Tex.; Baton Rouge, La.; Inverness, Fla. ; Tifton, Ga. ; Barnesville, Ga. ; Clemson College, S. C; Arundel, Md.; White Mountains, X. H.; Douglas, Mich. Other recorded localities are: Santa Fe, X\ Mex.; Charlotte Har- bor, Fla.; Xew Jersey; Massachusetts; Gypsum, Ohio; Constantine, Mich.; Carlinville, 111. ; South Dakota. It is thus seen that the species extends greatly beyond the range of the plum curculio, subsisting on other hosts. Riley, Lugger, and Pergande reared Myiophasia senea from Balaninus uniformis Lee, at St. Louis, Mo., in 1876. In 1886 Pergande reared it at Washington, D. C, from Conotraclielus elegans Say, infesting young twigs of hickory. Parasites reared by Forbes from Sphenophorus parvulus Gyll., and a cutworm (HeliopMla unipuncta Haw.) were identified under one of the synonyms of M. senea (Psyche, FlG. »._ *,***«* ***, a dipterous plum VOl. 6, p. 467), but it is probable that curculio parasite: Male and head of female. there was an error in recording it as a parasite oiHeliopliila unipuncta, there being no other known instance of M. senea attacking anything but weevil larvae. At Gypsum, Ohio, Webster found M. senea as a parasite of Ampeloglypter scsostris Lee. (Ent. Xews, vol. 10, p. 53, pi. 3). In this case a secondary para- site (Calyptus tibiator) was reared from M. senea. More recently Pierce (Journ. Econ. Ent., vol. 1, p. 381) has reared M. senea from the boil weevil (Anihonomus grandis Boh.) ami from Conotmclulus elegans Say at Dallas and Victoria, Tex. In the National Museum are many specimens of M. senea reared from Chalcodermus seneus Boh. by G. G. Ainslee, Clemson College, S. C. It had previously been reared from a species of Chalcodermus by II. A. Morgan at Baton Rouge, La. 150 THE PLUM CURCULIO. So far as known M. senea was first obtained as a parasite of the plum curculio by Mr. A. A. Girault, who reared a single specimen from curculio-infested peaches collected at Arundel, Md., June 29, 1905. In 1908 another specimen was reared from the plum curculio in cherries by R. W. Braucher at Douglas, Mich. At Barnesville, Ga., 13 specimens were reared from 1,115 curculio larvae from peaches collected on August 5, 1910. The larvae entered the soil August 6 to 13, and the parasites emerged from August 29 to September 5. This species must be considered as only an occasional parasite of the plum curculio, the highest known percentage of parasitism being 1.16 in the case of the lot reared at Barnesville, Ga. A few speci- mens of this fly were reared from curculio larvae by R. A. Cushman during 1911, at Vienna, Va. Cholomyia inaequipes Bigot.1 Like the preceding species, Cholomyia inaequipes (fig. 30) is a very widely distributed parasite of weevil larvae. It was first described by Fabricius from South America in 1805 as Musca longipes, and later by Bigot from Mexico under the name of C. inaequipes. Speci- mens are in the National Museum and in the Bureau of Entomology collections from the following localities: Frontera, Tabasco, Mexico; Dallas, Tex.; Lawrence, Kans. ; St. Louis, Mo.; SUoam Springs, Ark.; Mound, La.; Fort Valley, Ga.; Barnesville, Ga.; Peaks of Otter, Va.; Arlington, Va.; Arundel, Md.; Lexington, Ky. ; West Virginia; North East, Pa. This insect was first reared by Riley at St. Louis, Mo., under cir- cumstances indicating that it was a parasite of the plum curculio. In 1897 it was reared at Mound, La., from Conotrachelus juglandis Lee. Metadexia basalis Giglio-Tos, which Mr. D. W. Coquillett regards as probably a synonym of C. inaequipes, has been reared from Cono- trachelus juglandis in West Virginia. Pierce has reared C. inaequipes from Conotrachelus elegans Boh., at Dallas, Tex. At Siloam Springs, Ark., it has been reared from Conotrachelus affinis Boh. The Bureau of Entomology has records of the rearing of this species from the plum curculio as follows: Arundel, Md., July 13, 1905, 1 specimen (plum). Arlington, Va., August 14, 1905, 1 specimen (peach) Fort Valley, Ga., October 1, 1905, 1 specimen (Crataegus). North East, Pa., July, 1906, several specimens. Siloam Springs, Ark., July to August, 1908, 4 specimens (peach). Barnesville, Ga., June 20 to September 15, 1910, 81 specimens (peach). 1 Concerning the synonymy of this species, Mr. D. W. Coquillett has stated that longipes as a specific name for this dexidid is preoccupied by Musca longipes Fab. (1794), an entirely different insect from the present one, also described by Fabricius under the same name in 1805. The species, therefore, had no distinctive name in 1805, and must take the name given it by Bigot in 1884. The synonyms of Cholomyia insequipes Bigot (1884) are Musca longipes Fab. (1805) (not 1794), and Thelairodes basalis Giglio-Tos (1893). NATURAL ENEMIES '. PARASITIC INSECTS. 151 In the last instance, at Barnesville, Ga., 74 of these parasites were reared from 1,115 curculio larvae from peaches, entering the soil August 6 to 13. The parasites from this lot emerged August 30 to September 15, the females emerging slightly later than the males on an average. In this case the percentage of parasitism by C. in<&- quipes was 6.63. Fig. 30. Cholomyia inxquipes, a fly reared abundantly from the plum curculio at Barnesville, Ga.: Adult on left, puparium in curculio larval skin on right. (Original.) The puparium of Cholomyia (fig. 30) is formed in the soil, within the skin of the host larva, the adult parasite, on emerging, breaking through the posterior end of the old skin. Pegomya fusciceps Zett. This anthomyiid fly has appeared many times in jars and cages in which the plum curculio was being roared. But it is unlikely that this species is ever parasitic, and its presence may in moel cases be accounted for as a feeder upon the more or less decayed fruit in com- pany with the curculio larvae. 152 THE PLUM CURCULIO. PREDACEOUS INSECTS. Several species of predatory insects are recorded as attacking the curculio, especially in the larval stage, though their importance is difficult to estimate. In our own investigations ants have been found to be efficient enemies of curculio larvae as they are leaving the fruit and entering the soil. Numerous observations in peach orchards in Georgia show that these creatures are ever on the alert for an insect as food, and seek out and quickly destroy curculio larvae or other soft-bodied insects. Mr. Girault, and also Mr. Rosenfeld, record frequent observations of ants attacking larvae in the course of breeding work at Myrtle, Ga., interfering greatly with the experi- ments. Thus on June 16 a large number of larvae were placed on the soil in a box for pupal records. These, however, were soon dis- covered by the ant, Dorymyrmex pyramicus Roger, which destroyed numbers of larvae before they could be driven off. Within a quarter of an hour ants were literally swarming over the soil, in the box, and very few larvae succeeded in getting any distance into the soil before being attacked and destroyed. In the course of timing larvae in entering the soil in cultivated orchards, these were often found and attacked by one or more ants (Dorymyrmex pyramicus Roger), usually with fatal results to the larva. Thus, a larva placed on the soil at 4.23 p. m. (May 30, 1906) was attacked eight times in succession by ants, which were repelled each time, but succeeded at the ninth attack — at 4.33 p. m. This species is especially common in Georgia orchards, and in the aggre- gate must exert an important influence in destruction of the curculio. A species of thrips is recorded by Riley (2d Mo. Rept., p. 6) as very effective in destroying the eggs of the curculio. Mr. Walsh, in an interesting article in the American Entomologist for 1868, page 33, gave observations on certain insects regarded by him as predatory on the curculio. These observations are given by Riley in his Missouri Report (p. 56), and the substance appears in Riley and Howard's well-known article on the "Plum curculio." There can be no doubt whatever as to the accuracy of Mr. Walsh's observations, but practically nothing has since been added to our knowledge of the usefulness of these insects in destroying the curculio A larva of a species of lacewing (Chrysopa) was observed by Walsh in one side of a peach badly bored by a curculio. It was actually feeding upon a curculio larva, one-half of which had already been sucked dry. One of these insects is shown in figure 31. They are well known to feed upon various soft-bodied insects, especially plant-lice. A carabid beetle, Aspidoglossa subangularis Chaud., was found inside a peach completely excavated by the curculio, from which Mr. Walsh concluded that this species also was an enemy of the curculio. These two species were regarded as undoubtedly predatory on the curculio NATURAL ENEMIES! PREDACEOUS INSECTS. 153 above ground, and the larva of a ground beetle was found by a Mr. Swing in loose earth under peach trees in large numbers, which Mr. Walsh believed searched out the insects in the ground. Fig. 31.— Chrysopa oculata. Species of Chrysopa are recorded as predaceous on the plum curculio. (From Marlatt.) Four other species of ground beetles were found which were believed to attack the curculio grubs, although known to be general feeders, namely, Harpalus pennsylvanicus De Geer (fig. 32), H. f annus Say, Fig 32.— HarpoitU pt nntylvankus, B ground beetle predatory upon the plum curculio. ^From Webster.) 154 THE PLUM CURCULIO. Evarthrus orbatus Newman, and E. obsoletus Le Conte. The first mentioned (H. pennsylvanicus) was noted to be especially abundant, " absolutely swarming in all di- rections underground," and was thought to be the parent of the larva earlier alluded to. Walsh thus records 6 different species of insects, 2 of which fed upon the curculio, while the remaining 4 were strongly suspected of so doing. An additional species ( Chauliognatlius 'pennsylvanicus) (fig. 33) in the larval stage was found in curculio-injured peaches, and actually observed to feed upon the curculio grub by Mr. Swing, who forwarded the specimens to Walsh. Fig. 33. — Chauliognatlius pennsylvanicus. The larva of tliis beetle is recorded as a very effective enemy of the plum curculio. (After R iley . ) FOWLS AND BIRDS AS CURCULIO DESTROYERS. The value of chickens and other fowls in checking the curculio has been alluded to by several writers, notably the older ones. There is practically no definite observation, however, to show to what extent fowls feed upon these insects. Without doubt, in orchards fre- quented by chickens many of the beetles and possibly the larvae as they are leaving the fruit are found and eaten, but the good influence of fowls in this way is at most small, and confined prin- cipally to the vicinity of the house. On the importance of birds as curculio destroyers, there are but few data. Dr. Isaac Trimble was probably first to record that the Baltimore oriole will feed upon this insect, which fact has been con- firmed by subsequent observations. The Bureau of Biological Survey of the United States Department of Agriculture has found plum curculio beetles in the stomachs of 7 species of birds, namely: Baltimore oriole (Icterus galbula), Windsor, Ont.; orchard oriole (Icterus spurius), Atlanticville, N. Y., Chester County, Pa., Marshall Hall, Md.; rose-breasted grosbeak (Zamelodia ludoviciana) , Portland, Conn.; bank swallow (Riparia riparia), Sing Sing, N. Y.; yellow-throated vireo (Lanivireo flavifrons) , Sing Sing, N. Y.; veery (Hylocichla fuscescens) , Syracuse, N. Y.; hermit thrush (Hylocichla g. pallasi), Washington, D. C. Dr. Trimble states also that he found this insect in the stomach of a toad. THE PLUM CURCULIO. 155 REMEDIAL MEASURES. HISTORICAL. Measures for the control of the plum curculio have occupied the attention of fruit growers from the earliest times, and the total writ- ings on this subject in various horticultural, farm, and other journals would comprise a very large volume. The curculio, being native, soon attacked the choice fruits planted by the pioneer settlers, and accounts of its depredations soon found their way to print. The insect was especially complained of by reason of its injuries to plums, and the culture of this fruit seems to have been attended with the greatest difficulty. Many persons, if we are to judge from the earlier accounts, gave up the fight in despair, cutting down the trees. Dur- ing practically all of the last century a succession of remedies was proposed, and much discussion resulted as to their merits. Most of them were of but little if any value, and some of those proposed were actually absurd. The plan of jarring, or "shaking," as it was gen- erally designated, is practically the only one which survived of the innumerable ones proposed. The employment of arsenicals against the curculio marked a distinct advance, though until recently their use on stone fruits had not become very general on account of injury to foliage and fruit. As indicating the feelings of the early fruit growers toward the curculio, and their efforts to circumvent its injuries, several of the earlier accounts of the insect are inserted. These articles possess distinct historical interest, for in but few instances is it possible to follow from so early a date the gradual increase of an insect in importance as a pest, along with the increase in plantings of its host plants. The remedies proposed were legion, and about as varied as the nostrums proposed for some human ailment, as rheumatism. While no special effort has been made to list all the early remedial sug- gestions, the following have been noted: Seaweed under the trees; stable manure spread under trees; thor- ough whitewashing of trees; air-slaked lime dusted on trees in early morning while wet with dew, after setting of fruit; fumigation with sulphur fumes; wood ashes thrown over trees during blossoming when wet with dew; sulphur and powder fired from a gun into the top of trees for a few successive mornings; sulphur, lard, and Scotch snuff mixed and rubbed on trunk and larger brandies; drenching the tree with putrid soapsuds, followed by dusting with lime; flowers of sulphur sprinkled over trees after setting of fruit; sulphureted hy- drogen generated from calcium sulphid; packing the earth under the trees; tobacco smudge; hanging in trees putrid flesh, as dead mice, etc., to be used by the beetles for ovipositing; burning leather 156 THE PLUM CUECULIO. under trees on pans of charcoal; soft soap placed in crotches of limbs; burning soot under trees; paving the earth under trees with brick, slate, mortar, etc.; branches of tansy hung in trees; burning under trees woollen rags saturated with brimstone; destroying the eggs in the fruit by means of a needle-like instrument; passing around the trees a blazing straw torch, into which the beetles would fly; protecting the fruit with mosquito netting; confining in the orchard pigs, geese, poultry, etc.; fencing out the curculio with a high, 9-foot fence; fall plowing; liberal use of salt around the trees; removal of surface of soil and contained insects from around base of trees; covering soil with salt during midsummer to kill worms escaping from the fruit; picking up and destroying stung fruit; dilute sulphuric acid thrown on the soil to destroy insects in ground ; bruising the tree to cause exudation of gum to prevent its development on the fruit upon which the larvae feed; removal and destruction of black-knot disease; flooding the soil to drown insects; placing quicksilver in holes bored in trunk of trees; corrosive subli- mate thrown into the soil to destroy the insects in the ground; jarring insects onto sheets held or placed under trees; asafoetida spray; whale-oil soap, sulphur, lime-and-tobacco spray; coal-tar and water spray; piles of small stones around trees; trapping curculio under chips, small boards, etc., placed on the ground under the trees; planting of nectarines as a trap crop; light traps; belts of cotton batting around the trees; lead-pipe troughs around the trees filled with oil; hanging in trees bottles of sweetened water as a bait. The first remedial suggestions which we have seen are those in Darlington's Memorial, giving the correspondence between the early American botanist, John Bartram, and his patron, Peter Collinson. Under date of March 14, 1736-37, Peter Collinson, writing to John Bartram, refers 1 to the — very particular account how your plums are destroyed by an insect. Pray change the stock, and graft plums and nectarines on peach stocks, which being a vigorous, free stock, and not liable to these insects, may succeed better. Pray try; I have a great opinion of its succeeding. That the above referred to the plum curculio is evident from a later communication. John Bartram, writing under date of April 16, 1746, and speaking of the strawberry and sloe, the last of "which we have had in the country these 50 years. I plant them about my hedges, where it grows to a large size. The blossoms are prodigious full, but never one ripe fruit. They were bit by the insect, as all our stone fruit is ; but the peaches, and some kinds of cherries, overgrow them." 2 In a letter under date of April 24, 1746, Peter Collinson, in writing to John Bartram, adds: To prevent the destruction of the beetle, I confess, is not so easy as some other bad effects; yet as we know the duration of this insect is but short, if while he is so noxious, i Darlington's Memorial, p. 93. 2 Darlington's Memorial, p. 175. REMEDIAL MEASURES! HISTORICAL. 157 some contrivance could be found out to disturb or destroy him, you might then hope to taste a nectarine — one of the most delicious fruits in the universe, and much exceeds a peach, in a rich vinous-flavored juice. And an apricot is also one of the fine fruits. Last year our standards were overloaded, which were allowed to excel the wall fruit. Suppose as soon as this beetle is discovered if the trees were to be smoked, with burning straw under them or at some distance, so as to fumigate their branches at a time the beetles are most liable to attack the fruit, or if the trees were to be squirted on with a hand engine with water in which tobacco leaves were soaked; either of these two methods, I should think, if they did not totally prevent, yet at least would secure so much of these fine fruits as would be worth the labor of people of circum- stances who are curious to taste these delicious fruits in perfection. I take it the reason the plum succeeds so well is the frequent shaking of the trees by being planted in a frequented place. The beetles are tumbled off, or else are disturbed and frightened from settling on the trees. The earliest extended account of the insect is that by Dr. James Tilton, of Wilmington, Del., in Willich's Domestic Encyclopaedia (vol. 3, p. 116), published in 1804. This original article shows a considerable familiarity with the curculio, and was much quoted by subsequent writers. Some of the methods suggested for control later came into much notoriety and use. This comparatively inac- cessible article is here reproduced: Curculio, a genus of insects belonging to the Coleoptera, or beetle order. The species are said to be very numerous. The immense damage done, by an insect of this tribe, to the fruits of this country, of which there is no similar account in Europe, has given rise to a conjecture with some naturalists, that we have a peculiar and very destructive species in America. The manner in which the insect injures and destroys our fruits, is, by its mode of propagation * * *. Early in the spring, about the time when the fruit trees are in blossom, the Curculiones ascend in swarms from {he earth, crawl up the trees, and as the several fruits advance they puncture the rind or skin, with their pointed rostra, and deposit their embryos in the wounds thus inflicted. The maggot thus imbedded in the fruit preys upon its pulp and juices, until in most instances, the fruit perishes, falls to the ground and the insect escaping from so unsafe a residence, makes a sure retreat into the earth: where, like other beetles, it remains in the form of a grub or worm, during the winter, ready to be metamorphosed into a bug or beetle, as the spring advances. Thus every tree furnishes its own enemy; for although these bugs have manifestly the capacity of flying, they appear very reluctant in the use of their wings; and perhaps never employ them but when necessity compels them to migrate. It is a fact that two trees of the same kind may stand in the nearest possible neighbor- hood, not to touch each other, the one have its fruit destroyed by the curculio, and the other be uninjured, merely from contingent circumstances, which prevent the insects from crawling up the one, while they are uninterrupted from climbing the other. The curculio delights most in the smooth skinned stone fruits, such as nectarines, plums, apricots, etc., when they abound on a farm; they nevertheless attack the rough-skinned peach, the apple, pear, and quince. The instinctive sagacity of these creatures directs them especially to the fruits most adapted to their purpose. The stone fruits more certainly perish by the wounds made by these insects, so as to fall in due time to the ground, and afford an opportunity to the young maggot to hide itself in the earth. Although multitudes of seed fruits fall, yet many recover from 158 THE PLUM CUECULIO. their wound, which heal up with deeply inflicted wounds * * * This probably disconcerts the curculio, in its intended course to the earth. Be this as it may, certain it is, that pears are less liable to fall, and are less injured by this insect than apples. Nectarines, plums, etc., in most districts of our country, where the curculio has gained an establishment, are utterly destroyed, unless special means are employed for their preservation * * * Cherries escape better, on account of their rapid progress to maturity and their abundant crops: the curculio can only puncture a small part of them, during the short time they hang upon the tree. These destructive insects continue their depredations from the first of May until autumn. Our fruits collec- tively estimated must thereby be depreciated more than half then value. It is supposed the curculio is not only injurious above ground, but also in its retreat, below the surface of the earth, by preying on the roots of our fruit trees. We know that beetles have, in some instances, abounded in such a manner as to endanger whole forests. Our fruit trees often die from manifest injuries done to the roots by insects, and by no effect more probably than the curculio. In districts wherein the insect abounds, cherry trees and apple trees, which disconcert it most above, appear to be the special objects of its vengeance below the surface of the earth. These are serious evils; to combat which, every scientific enquirer is loudly called upon to exert his talents; every industrious farmer to double his diligence, and all benevolent characters to contribute their mite. Naturalists have been accustomed to destroy vicious insects, by employing their natural enemies to devour them * * *. (See Blight.) We are unacquainted with any tribe of insects able to destroy the curculio. All the domestic animals, however, if well directed, contribute to this purpose. Hogs in a special manner are qualified for the work of extermination. This voracious animal, if suffered to go at large in orchards, and among fruit trees, devours all the fruit that falls, and among others the curculiones, in the maggot state, which may be contained in them. Being thus generally destroyed in the embryo state, there will be few or no bugs to ascend from the earth in the spring, to injure the fruit. Many experienced farmers have noted the advantage of hogs running in their orchards. Mr. Bordley, in his excellent "Essays on Husbandry" takes particular notice of the great advantage of hogs in orchards; and although he attributes the advantage derived from these animals to the excellence of their manure, and their occasional rooting about the trees, his mistake in this trivial circumstance does by no means invalidate the general remarks of this acute observer. The fact is, hogs render fruits of all kinds fair and unblemished, by destroying the curculio. The ordinary fowls of a farm yard are great devourers of beetles. Poultry in gen- eral are regarded as carnivorous in summer, and therefore cooped sometime before they are eaten. Everybody knows with what avidity ducks seize on the tumble bug (Scarabseus carnifex), and it is probable the curculio is regarded by all the fowls as an equally delicious morsel. Therefore, it is, that the smooth stone fruits particularly succeed much better in lanes and yards, where the poultry run without restraint than in gardens and other enclosures, where the fowls are excluded. Even horned cattle and all sorts of stock may be made to contribute to the preserva- tion of our valuable fruits. By running among the trees they not only trample to death multitudes of these insects; but by hardening the ground, as in lanes, it becomes very unfit to receive or admit such tender maggots as crawl from the fallen fruits. Besides, the curculio is very timid, and when frightened by the cattle rubbing against the tree or otherwise, their manner is to fold themselves up in a little ball and fall to the ground; where they may be trampled and devoured by the stock, poultry, etc. Col. T. Forest, of Germantown, having a fine plum tree near his pump, tied a rope from the tree to his pump handle, so that the tree was gently agitated every time there was occasion to pump water. The consequence was that the fruit on this tree was preserved in the greatest perfection. REMEDIAL MEASURES : HISTORICAL. 159 All the terebinthinate substances, with camphor and some others, are said to be very offensive to insects generally. Upon this principle, General T. Robinson, of Naaman's Creek, suspends annually little bits of board, about the size of a case knife, dipped in tar, on each of his plum trees * * *. From three to five of these stripe are deemed enough, according to the size of the tree. The General commences his operations about the time or sooner after the trees are in full bloom, and renews the application of the tar frequently, while the fruit hangs on the tree. To this expedient, he attributes his never failing success. Other gentlemen allege, that common turpen- tine would be still better; being equally pungent and more permanent in its effects. Some have sown offensive articles, such as buckwheat, celery, etc., at the root of the tree, and have thought that great advantage followed. Ablaqueation, or digging round the trees, and making bare their roots in winter is an old expedient of gardeners for killing insects, and may answer well enough for a solitary tree, a year or two; but the curculio will. soon recover from a disturbance of this sort, and stock the tree again. There is no surer protection against the curculio than a pavement. This, however, is only applicable to a few trees. It may serve in town; but will not answer in the country * * *. (Flat stones, however, may be placed around the tree, and where lime is at hand, they may be cemented.) Many other expedients, such as smoking, brushing, watering, etc., may be suc- cessfully employed, for the protection of a favourite tree or two; but it is manifest from the preceding history, that a right disposition of stock, especially hogs, among the fruit trees, can only be relied on by a farmer, with orchards of considerable exter . And that the stock, poultry, etc., may perform the task assigned them, it is evident, that a proper disposition of fruit trees is essentially necessary. As the smooth stone fruits are the grand nurseries of the curculio, special care should be taken to have these effectually protected. Unless this can be done, a farmer should not suffer them to grow on his plantation. He will derive no benefit from them; and they will furnish a destructive vermin that will ruin his other fruit.-. Cherry trees, nectarines, plums, apricots, etc., should therefore be planted in lanes and hard beaten yards (or paved yards), the common highways of all the stock of the farm, and not beyond the range of the ordinary domestic fowls. Orchards of apple trees, pear trees, peach trees, etc., should be in one enclosure. The pear trees and peach trees may occupy corners of the whole design, so as occasionally to be fenced off. In large orchards, care should be taken that the stock of hogs is sufficient to eat up all the early fruit which fall from May until August. This precaution will be more especially necessary in large peach orchards: for, otherwise, when the hogs become cloyed with the pulp of the peach, they will let it fall out of their mouths and content themselves with the kernel, which they like better; and thus the curculio escaping from their jaws may hide under ground, until next spring. Solitary trees of one fruit or another, remote from the orchard, should be regarded as nurseries of the curculio, and ought to be cut down or removed to the common enclosure. A young orchard should not be planted in the place of, or adjacent to an old one; that it may not be immediately infested with the curculio. It is also apparent, from what has been said, that great advantages might result from an association or combination of whole neighbourhoods against this common enemy. Although an intelligent farmer may accomplish much, by due attention, within his own territory, the total extermination of the curculio can hardly be expected, but by the concurrent efforts of whole districts. (On this subject it may be added, that a gardener near Baltimore, who has been successful in raising plums, finds that the insect does most mischief in the night; and hence he shakes the tree every evening, and catches the insect in a sheet around it. He always burns them instantly. Wrapping each plum in a muslin bag, or in thin paper perforated with a pin, is a certain, though troublesome, mode of guarding against the attacks of these insects.) 160 THE PLUM CURCULIO. William Bartram, an eminent naturalist of Philadelphia, in a communication to the Philadelphia Society for Promoting Agricul- ture, for 1807, after a description of the curculio, goes on to say: During my travels from Pennsylvania to Florida I had sufficient opportunity to observe that the fruit trees on the sea coast and brackish water were free from the ravages of this destructive insect; this suggested to me an idea, that the saline vapors were pernicious to them, and thus I imagine that if we were to go to the trifling ex- pense of showering our choicest fruit trees with a weak solution of common sea salt, once or twice a week, it might answer the same end of preserving the fruit; and by per- severing further in a little more expense, in extending the same care to our orchards, we might in a few years expel them. But this is only a conjecture, having never made the experiment. In the beginning of the year 1808, he added the following note: The spring following I put the experiment on showering a plum tree on trial, with a weak solution of sea salt dissolved in water; but being too strong of salt, most of the leaves and fruit fell off on consequence of it, otherwise the experiment might have produced the desired effect, as what fruit remained was not touched by the insect, though small and disfigured by the strength of the brine; yet a few arrived to their natural size and ripened, so that I am induced to believe, that with care in tempering the solution, it will be found to be the best and cheapest remedy against the ravages and increase of those pernicious insects, yet discovered. It should be so weak as just to taste of salt. Joseph E. Muse, writing in the American Farmer, volume 1, No. 16, page 124, under date of July 16, 1819, under the caption "Ento- mology/' treats among other insects, the curculio, as follows: Another insect, the curculio, of which there are nearly one hundred species, belong- ing also to the Coleopterous order, commands, from its universal ravages both upon the farmer and the fruiterer, the attention of every member of the community, who has it in his power to contribute, in the smallest measure, to the destruction of this ruthless foe to the wealth and luxury of man; which frustrates, by its concealed and wily move- ments, the most rational and well founded plans, executed by the most ardent and efficient energies of the human mind and body. Are we not inclined to exclaim, with the moral and philosophical Seneca, " Natura quam te colimus inviti quoque." How repugnant to the proud feelings of man to stoop to combat with this insignificant animalcule! How resistless are the ordinances of nature, which compel us, by acts so humiliating, to admire and adore that complex creation whereby the great architect has 6een fit to enforce them! I have made experiments on the larvae of several species of curculiones, and have found the parents so nearly similar in habitat, metamorphoses, and most other circum- stances, that one description will suffice for their whole history; at least of those which I have examined; and the only mark of idiocrasy in the tribes which I have observed, consists in their choice of a nidus; selecting, from their peculiarities in this respect alone, the cherry, the plum, or the grain of corn, as their instinctive or innate propensities might incline them. In a transparent bottle containing some earth, I deposited several cherries, in which were the larvae of the curculio, that infests that fruit; in a few weeks, or rather as soon as the pulp of the fruit was consumed, which was at different periods, they retreated into the earth where upon examination some time after, I found they had assumed the state of chrysalis, which shortly resulted in that of the imago or parent; the wings of the insect were not sufficient to accomplish the flight of the insect, but merely to assist REMEDIAL MEASURES: BISTOBICAI* 161 its ascent of the body of a tree; from which circumstances, I was led to the following reflections and experiments to test their correctness: That the remedy must be such as would act, physically, to wit: To interrupt the metamorphoses, by preventing the descent of the larvae into the earth; to exp< the weather, the pupa, after its descent; or to intercept in its ascent of the body of the tree, the parent insect; or, chemically, by substances known to be generally deleterious to that class of animals. The fruit being the nidus of the ovum, and the earth the habitat, in which it is brought to maturity and makes its abode, and the larva, from its soft and delicate structure, incapable of traveling, or sustaining the exposure; when the fruit contain- ing the larva has fallen and is rotted and consumed by the inject, the larva must descend, by the most direct route, from its original depository, the fruit, into the earth, its permanent abode, there to undergo the metamorphoses, which will bring it to maturity, and fit it for a new series of depredations, which is so secretly performed, that though myriads are employed, they are never detected in executing their work of destruction, the deposit of their ova. Hence, I concluded, that one of the most effectual preventives, would be paving with brick, stone, shells, or some other hard substance, impervious to the soft larva, a circular space round the fruit tree, as exten-ive as the fall of the fruit, by which it would be interrupted in its descent into the earth, and consequently perish; or that it might be accomplished, by turning up the earth under the tree to the same extent, and thereby exposing to the inclemency of the weather, the tender pupa, of which two methods, the former is to be preferred; because thereby you arrest the passage of the larva to maturity, and necessarily destroy it. The latter method, if not performed in time, may allow the perfection of the imago, and in this state it is unquestionably more hardy and capable of providing another habitation, as secure and comfortable as that of its first election. And by the experi- ments which I have made, its descent and maturity are at uncertain and unequal periods, which would make an insuperable difficulty, in point of time, for performing the operation; if below the descent, it would necessarily be useless; if after the maturity, equally so, for reason^ given. This view of the subject has led me repeatedly to both experiments, which I have fairly and impartially made, without the influence'of any prejudice, which it might be presumed, my reasoning had connected with or in favor oi the former; the result was, the fruit with which I made the experiment that had been destroyed by curculi- ones, for many years, were in all cases, when I paved or shelled, entirely exempt; in two cases only, when the earth under the tree was turned up, at different seasons, the fruit escaped injury, but from the number that failed, I was inclined to ascribe these two to causes accidental and extrinsic. The third method proposed, viz: to intercept the parent in its ascent of the body of the tree, by various obstacles which the mind will readily suggest, and thereby prevent its deposit of ova, though I have made no experiments upon it. I conceive to be rational, and easily accomplished; and with those species of curculiones, of which there are many, whose wings do Dot admit of flight, but assist them only in climbing, it would undoubtedly be effectual. The fourth remedy which I propose, of a chemical nature, I have made but partial experiments to establish, such as are not yet satisfactory or conclusive; when finished, it will give me pleasure to report them, if the result be successful, by a fair and candid detail of facts. The above seems to be the first definite recommendation for paving and the use of various obstacles to prevent the ascent of the trees by the supposedly wingless adults. 17262°— Bull. 103—12 11 162 THE PLUM CUKCULIO. Also during this year (1819) the curculio was first given a scien- tific name by an American entomologist, Mr. W. D. Peck, from beetles reared from black-knot on cherry; the original account of 'which is given below: This insect belongs to the same genus with the Ehjnchsenus slrobi or white pine weevil, described in the Massachusetts Agricultural Journal for January, 1817, to a plate in which I would refer for a representation of the parts of the mouth. In that, the rostrum or snout is nearly straight; in the present species it is curved, so as to form the segment of a circle. All the thighs have two small obtuse points on the under side. In colour it is variegated with white and red hairs; the ground colour of the shelly coat on which they are placed is dark brown; The thorax is contracted behind the head; its surface is irregular, much pitted, and has a raised longitudinal line in the middle, with three small tubercles on each side of it, placed in a triangular form. The elytra are marked with longitudinal ridges and on these are placed oblong tubercles of which there are ten or twelve; four of these in the middle of the elytra are largest, smooth, and of a brown black colour. On the under side the body is pitted, or marked, with large impressed points, like the top of a thimble. The first pair of feet is rather the largest; the second the smallest, and all sprinkled with white and bright rust- coloured hairs. Figure 5 shows the natural size of the insect, and figure 6 magnified. Mr. Pomroy was so obliging as to bring me three tumours cut from his plum-trees, later in the season, but the larvae had left them. Being, therefore, uncertain whether the disease of the plum-trees is to be attributed to this insect or to another species of the same genus, I would call it the cherry weevil. It maybe distinguished by the specific name of rhychaenus (cerasi) femoribus dentatis; fulvo alboque variegatus, elytris tuberculis pluribus carinatis, quatuor in medio manoribus nigris. Among the 272 species of this genus, mentioned by Fabricius, there were several found in Cayenne and Carolina, which are nearly allied to this; but it differs from them all, and appears to be undescribed. The evil produced by this insect cannot be wholly remedied; but something may be done to diminish the mischief by cutting off the diseased branches. This, how- ever, must be done at the right season, and must be the joint care of a whole neighbor- hood at the same time. Those which furnished the data above set down, ceased to feed on the 6th of July, rose from the earth on the 30th, and were soon ready to deposit their eggs in healthy branches; but if the diseased branches be cut off in the last half of June, a great number may be destroyed, and most effectually, by burning the amputated parts. It is possible, that in some situations they may be disclosed earlier; it will therefore be surest to prune away the diseased parts as soon as they appear, cleaning the trees now of the old tumours, that new ones may be more readily perceived. A treatment out of the usual was that followed by a correspondent of David Landreth: When the fruit is perfectly set or half grown, I take a small hammer and bruise the trunk of the tree in 12 or 15 places, from near the root to the branches; the sap or gum will run out which I am satisfied will prevent the fruit from falling off. My neighbor, Mr. L., has practiced the same with success. I viewed his trees a few hours ago; he is well satisfied with the utility of it. I will not undertake to give exact reasons why it should prevent the fruit falling off at a premature age; it may be that the insects feed on the sap or gum that also there may be a superfluous quantity of sap in such trees, I will entirely leave it to those of superior judgment. REMEDIAL MEASURES: HISTORICAL. 163 Also, the following in The Farmers' Guide (1824), page 208: It is recommended to put a ring round the tree, of a mixture of grease, or blubber, mixed with salt. Perhaps some of the other ingiedients for destroying worm.-, would answer a better purpose. Again, in the New England Fanner, volume 9 (1830). is the follow- ing: In the month of July, I visited the beautiful settlement of Mr. Rapp, at Economy, on the bank of the Ohio, 14 miles below Pittsburg, and was highly gratified to w e his numerous plum and prune trees loaded with fruit, uninjured by the insect. The senior Mr. Rapp informed me that while his trees were in bloom, his gardener placed around the body of them, a few inches above the ground, two pieces of boards, of suit- able size, say six inches by twelve, out of which a semi-circular portion had been cut, so that when fitted together, around the tree, they would completely invest the body. These were confined together by two narrow battens, secured with screws, on the under surface. On the upper surface, a circular channel was cut, half an inch deep, and one inch wide, so as to surround the tree. The joints between the two boards, where crossed by this channel, were closed with putty, and any vacancies between the boards and the tree carefully stopped with clay mortar. The circular channel is then fitted with tar, and presents an effectual barrier to the progress of the insects. Some atten- tion is required, to see that the tar does not leak out or become hardened. An article by James Thatcher, in the New England Farmer for March, 1840, is illustrative of a series of recommendations based on the believed efficacy of repellent substances, a portion of which La given : There is another process to be recommended, in which I have great confidence, as a part of our warfare against the curculio. It is to make a direct attack upon the female beetle while she is about to puncture the fruit to engender her young brood. This may be done by throwing from a garden engine or Willis' excellent syringe, a liquid substance that will create a sort of deleterious atmosphere which will compel her to quit the tree, and will destroy the vitality of her eggs, should they have been deposited. I will name the following artieles for this purpose: the composition of sulfur and lime recommended for grapes in Mr. Kendrick's Orchardist, p. 328; a strong decoction of tobacco or snuff; chloride of lime; a weak solution of potash or even Boapsuds. These material-, if showered over the trees and fruit, would prove so offen- sive as to force the female visitor from her generating process. The most proper time for this operation is in the evening, in order to meet the enemy, whose attack is sup- posed to be during the course of the night. This operation should be repeated sev- eral times during the week, from May to August, and the tree should frequently receive a thorough shaking, by which the insects will be greatly disturbed and made to fall to the ground. Should my plan be deemed too onerous, the cultivator who may adopt it in full or even partially, may be assured that (in my opinion) he will have no cause to regret his labor. Belief in the efficacy of paving is shown by the following article which appeared in the New Genesee Farmer, volume 3, page l-,s (1S33): D. Longstreet says that a gage plum tree which stood over a pavement, ripened its fruit in perfection last year, while all the fruit oi his other trees o\ that kind, which were not over pavements, was destroyed by the curculio. In order to show that the result was caused by the pavement, he says that a plum tree, standing near the path to the barn, not paved but which was frequented almost hourly, lost all its fruit. Such facts ought to be recorded and generally known, 164 THE PLUM CUECULIO. The codling moth and curculio were for a long time confused in the minds of many fruit growers and more or less the subject of debate in the journals of the day. The following, by N. Darling, from the Cultivator, December, 1840, page 190, is illustrative of this fact: In the September number of the Cultivator (p. 136) you say in answer to a corre- spondent that "the worm in the apple as well as in the plum and cherry is a species of curculio." Also, that "the worm with the fruit, falls upon the ground, in which the worm takes up its abode in the chrysalis state, until revivified and changed by the spring, it issues a perfect insect. I am well convinced there is a mistake here, in two particulars: 1st, as to the worm in apples being a curculio; 2nd, as to the curculio continuing in the ground till spring. In 1831, seeing it stated in all the books that the curculio, in its chrysalis state, remained in the ground during winter, I undertook to verify the fact by actual experi- ment. The result was communicated to the "New York Farmer" (Vol. IV, p. 178- 179). But as many of your readers have probably not seen that book, you may do a service by publishing an extract from it. I put some moist earth into a tumbler, about the first of June and placed about 20 small peaches, containing worms, upon the earth, and covered the tumbler with a piece of glass. June 30th, the worms had all left the peaches and had all crawled into the earth below. July the 7th, the worms had divested themselves of their skin, without having formed a shell or cocoon, and were nearly changed to bugs. At this time they were white, and showed upon the breast the soft rudiments of the proboscis, legs, and wings. These parts had not attained their full size, and appeared immovable- One insect, however, had completed his metamorphosis and was a perfect bug, of a mahogany color. All have since left the earth of their own accord, having finished their change, and are now (July 19th) creeping about the tumbler and feeding on a plum leaf. On the 10th of July I opened the ground under a peach tree and found the insects in great numbers from two to four inches beneath the surface, in all stages of their metamorphosis. July 19th, I found one in the earth under an apple tree, but could find none under peach trees. It appears then that this insect retreats into the earth about the.first of June, where it divests itself of its skin, and changes into a bug before the 19th of July, by which time it leaves the earth. What becomes of the bug from July to May following, remains to be discovered. The curculio is not the only insect that produces the worm in our fruits. I stated above that about twenty peaches were placed in the tumbler. In the earth under them were six small, oval cocoons, thick strong and smoothly spun, which contain worms that manifest no approach toward a change. The same cocoons are also found under peach trees. The worms in these envelopes are different from those of the cur- culio; they are smaller; they are white throughout;1 while the larvae of the curculio have orange colored heads. There is reason for the belief that the larvae of the curcu- lio, all or most of them, leave the various fruits in which they are deposited as early as the beginning of July, and that the worms found in fruits after that time, have a different parent. Some years ago, I preserved a worm from a Vergalieu pear, which produced a gray miller. La^t November a worm from a Newton Pippin placed itself in a cavity on a board, covered itself with a web, and remained till April when it pro- duced a gray miller like that produced from the pear. I continued my observations during that summer, and sent another communication to the New York Farmer (Vol. IV, p. 248), from which the following is an extract: I have said there is reason for the belief that the larva? of the curculio, all or most of them, leave the various fruits in which they are deposited as early as the beginning of i Probably (Porizon) Thersilochus conotracheli Riley, a parasite of the curculio. REMEDIAL MEASURES: HISTORIC AT,. 165 July, and that the worms found in fruits after that time have a different parent . ( fog reason for this belief is, that after that time very little frail is left in which their eggs can be deposited, and what little is left is, for the most part, untouched by the cur- culio. Let me present a hasty estimate of cherries, apricots, plums, and peaches, in my orchard; on the first of May last, there were probably 200,000; on the first of July, the number remaining on the trees did not, I am confident, exceed 500. Of that 500 perhaps 20, before the middle of August contained a curculio, the rest continued fair. I think it would puzzle Dr. Tilton to say where that vast multitude of curculios that deposited 199,500 eggs before tjie first of July, have deposited them since that time, if they continue their ravages, and equally puzzling it must be to devise a reason why any fruit has escaped — why only 20 eggs should be deposited, and 4S0 peaches left undisturbed if this vast swarm of insects have continued its operations ever since the first of July. It may be said that they resort to apples and pears. But before the first of July the greater part of the apples had also disappeared from the trees; most of those remaining have continued since untouched by the curculio. The worms found in them are not the larvte of that insect. I have not succeeded in finding a curculio in a pear at any time. The only worms that I have found in pears, (and I have taken pains to collect a considerable number this summer), are the larvae (I believe) of the gray miller mentioned in my former communication. They resemble the larvae of the curculio in having orange colored heads, but differ from them by being larger, and having a slight tinge of scarlet or brick color upon portions of the body. Instead of popping into the ground, they crawl under the rough bark of the trees, inclose themselves in a web, and are transformed into a chestnut colored chrysalis. Placed in a tumbler with moist earth, they form a web upon the cover of the tumbler, and there undergo their change. As none have yet left the chrysalis state, I suppose (as was the case with those which I have before preserved) that they do not complete their metamorphosis till spring. All the worms found by me in apples, since the first of July, have been similar to those in the pear. An excellent observer, David Thomas of Cayuga, maintained the prevailing opinion in regard to the worms in our fruits, and with a view to show that I was incorrect, he took "a worm with an orange colored head, from a Bell pear and put it in a tumbler, with moist earth, " on the fifth of August. On the eighth of August he took from apples "three more worms with orange colored heads, and which appear to be the full grown larva? of the curculio — another similar, but only half as long— and two others resembling the former with brown heads, but 100 (10?) times less in bulk than the first kind. Viewing these last under the microscope, I am satisfied that they also are larvae of the common curculio, thus far confirming Dr. Tilton's remark that this inseel continues its ravage- from May until autumn. " (New York Fanner, Vol. IV, p. - In a subsequent communication, in October, with his accustomed candor, he says, " N. Darling may be interested to learn that the worms which I confined 'with orange colored heads,' left the moist earth, and encased themselves in a web under the cover of the tumbler. Soon after one of them came forth a dark gray miller; and I conclude there was no curculio among them. We are therefore indebted to him for the interest- ing discovery that the larvae of several insects feed on our fruits: and it is now rendered at least probable that Dr. Tilton ascribed too much of this mischief to the curculio.'' (New York Farmer, Vol. IV, p. 281.) With these facts before us I think we may safely conclude that the worm in apples is a larva of a gray miller, and not of the curculio, which is a bug. Also that the curculio leaves the ground in a short time after entering it. Its winter retreat has not, within my knowledge, yet been discovered. If your correspondent will look under the rough bark of his apple trees in October. he will find a great many of the worms from this fruit, which have shut themselves in with a web, and are transformed into a chestnut colored chrysalis. If he will care- 166 THE PLUM CURCULIO. fully preserve them, he will find them coming out a gray miller. By simply scratch- ing off, or rather picking off this rough bark (the scales or flakes, I mean) a vast multi- tude of these insects may be destroyed — not all, however, for they resort to other places of concealment, such as crevices in boards, posts and rails. That the curculio could be fenced out was the belief of some; note the experience of W. Manice from the Cultivator, of 1854, p. 157: W. Manice, of Long Island, constructed many years ago a tight board fence around his plum orchard, about nine feet high, with tight board gates. The curculio did not fly high enough to enter, many striking the sides of the fence and falling outside. An acquaintance when in full fruit informed us that all the trees within the enclosure were heavily loaded with plums at the same time he observed a tree outside that had lost every specimen. The following is interesting as indicating the prevalent opinions of fruit growers as to remedies by the middle of the last century: At the regular monthly meeting of the St. Louis Horticultural Society, held on the 7th of May, 1849, the curculio was the subject of some interesting remarks; an abstract oi which we publish from the minutes. We hope the worthy president will perse- vere in his experiments until he shall have discovered a specific for this most serious hinderance to the cultivation of fruit. The president stated that his attention had been called to the various recommenda- tions of remedies or preventives of the ravages of the curculio, one of the most nefari- ous pests of the orchard in that part of the country. This insect invariably takes our entire crop of apricots, nectarines, and plums, and injures the cherries, and even peaches. He has determined to try every practicable proposed remedy of which he could avail himself the present season. The following were among those suggested: 1. Horse stable manure. This was believed to be ineffectual. 2. Spreading sheets under the trees, and tapping the body and branches with a mallet, the insects will fall into the sheets, and may be caught and killed. This is believed to be perfectly effectual, though laborious practice: it must be pursued every morning for two or three weeks from the time the trees cast their flowers. He presented a vial containing sixty-one of these insects, which he caught from three apricot trees on the morning of the 5th of April, the young apricots being nearly the size of peas. 3. Placing a lighted candle under the tree, for two or three hours in the evening in a tub or box whitewashed inside, and having at the bottom an inch or two of wafer. 4. Placing old iron hoops, or pieces of iron, in the branches of the tree. He had seen at his mother's residence, last fall, a green gage tree having an iron hoop entwined amone; its branches, and from which a crop of fruit was always obtained whilst the fruit of other plum trees near by, without the iron, was destroyed. Dr. S had mentioned to him facts in connection with the subject, which led him to infer that some potent effect was attributable to the iron; it may be worthy of a trial. 5. The insects may be fenced out by a tight board fence eight to ten feet high. A gentleman on Long Island succeeds perfectly with his, but he also paves the ground and plants his trees in dwarf, six feet apart. 6. Placing a coat of salt under the trees. This is believed to be ineffectual, as he had partly tried it, but without success. 7. Covering the ground under the trees with clay. This he had tried, and it did no good. 8. Hanging bottles of sweetened water in the trees. 9. Smoking the trees with the fumes of burnt sulfur. 10. Washing the trees, and even the fruit with the strongest decoction of tobacco and whale oil soap suds will have no effect. j PREMIUMS FOR REMEDIES. 107 11. Swine and poultry, running daily among the trees, during the fin . a~ a permanent annual practice, will ultimately drive away or destroy the insect. The poultry, however, are not alone sufficient. Swine are the best exterminators, by destroying the larvae of the insect in the fruit as it falls. The insect will avoid places unfavorable to the entrance of its young into the ground. Captain Bissell said he had tried horse manure and salt without any effect. He was inclined to try the swine. General Milburn said that a Mr. Price, of ihi< county, kept off the insects by tying a band of sheep's wool around his plum trees. Mr. Turner said that a withe around the tree, kept moist with tar, had proved ineffectual with him. Mr. Clark said that the insect would not attack the fruit upon a tree standing in a frequented walk. The foregoing will indicate the general trend of the early remedial suggestions. In the literature on the subject there is much testimony in favor of pasturing orchards with hogs and sheep, and allowing fowls to run in them, and of paving under the trees. Jarring, although recommended and practiced to a certain extent by 1S30, apparently did not come into general use until considerably later. The develop- ment of this method forms an interesting chapter in the evolution of remedies for the curculio, but may be considered only briefly (p. 1( PREMIUMS FOR REMEDIES FOR THE CTJRCULIO. Premiums have often been offered for the discovery of a suit able method of control of an injurious insect, and the plum curculio is no exception. The amounts of the awards, however, actually offered were small as compared with the amounts offered for other specie-, notably the cotton boll weevil, for which, a premium of .$50,000 was offered by the State of Texas. The first suggestion for an award for a remedy for the control of the curculio seems to have been made about 1830. At this time a lady of New Jersey started a movement to raise $2,000 by subscription, and the matter was considered by the Penn- sylvania, the Xew York, and the Massachusetts Horticultural Socie- ties, the last organization at least recommending that $200 be appro- priated by the society for this purpose.1 The same society, in 1842, offered a premium of $100 lor a successful remedy for the curculio, which amount was raised to $200 by additional subscriptions. There were several contestants for this latter premium, though no method of control presented particularly warranted the giving of the award. A paper highly commended and published in the proceedings of the society for 1S43 was prepared in this connection by Dr. Joel Burnett. As stated in the Genesee Farmer for L856 (p. 192) a reward of $500 was offered by the Kentucky Horticultural Society for an effectual remedy which would not be so costly and troublesome as to prevent its general employment. » History Massachusetts Horticultural Society. | 168 THE PLUM CURCULIO. Ten years later (1865) a gentleman from Philadelphia, writing in the Country Gentleman (p. 270), suggested a reward of $50,000 for a method of curculio control, though no action appears to have resulted from his suggestion, A somewhat different plan of securing the subjugation of the cur- culio was adopted by the Fruit Growers' Association of Ontario. In their list of prizes for 1870 (p. 72) is the following: To any person sending to William Saunders, esq., London, transportation prepaid, 2,000 plum curculio (Conotrachelus nenuphar), the sum of $25, or sending 1,000 the sum of $10, or sending 500 the sum of $5. As a result of this offer numerous fruit growers made sendings of plum curculio during the year, the total reaching 13,653, the largest number being sent in by any one person being 2,280, jarred from 20 plum trees, 10 English cherry, and 30 peach trees, obtained for the most part from the plum trees. The year following a reward was again offered, but the amount to be paid reduced. Thus, for 5,000 curculio, $20; for 3,000, $10; and for 2,000, $5. As stated in Mr. Saunders's report to the association for 1871, the number of beetles received was notably less than during the year previous, supposedly on account of the reduction in price, no award being made for a less number than 2,000 beetles. THE RANSOM CHIP PROCESS. Considerable interest was aroused in the so-called Ransom chip process proposed by W. B. Ransom, of St. Joseph, Mich., in 1870, the discovery of which was announced in an extra of the St. Joseph Herald. The proposed method is reviewed at length in the American Entomologist for June, 1870 (p. 225), by Dr. Riley, who points out that the process had been previously proposed by Mrs. H. Wier, of Johnsonville, N. Y., in the Rural New Yorker of January 28, 1865. The plan consisted in first taking from under the trees all trash, clear- ing and packing the soil for a couple of feet around the collar of the tree and, second, in placing pieces of bark, chips, small stones, etc., close to the trunk of the tree, for hiding places for the beetles, from which they were to be regularly collected and destroyed. The method was compared with jarring by Dr. E. S. Hull 1 during the period May 29 to June 2, with the result that by the chip process 13 beetles were taken (including 7 apple curculio), whereas by jarring 309 were captured. JARRING FOR THE CURCULIO. Jarring, or shaking, as the practice is very generally designated in the earlier literature, was recommended at a very early date. Its value rests upon the habit which the beetles have of folding their legs and falling to the ground when disturbed. i Trans. 111. Hort. Soc, 1870, p. 228. JARRING FOR Till. CUBCULIO. 169 A suggestion as to 1 he worth of the practice is found in the Bartram- Collinson correspondence in 1740 (p. 157). Jarring was more or in vogue at the beginning of the lasi century. In Dr. Tilton's article, published in 1804 (p. 157), lie refers to the successful experience in jarring of a gentleman living near Baltimore. He also records results obtained by Col. T. Forest, of Germantown, who, having a fine plum tree near his pump, tied a rope from the tree to the pump handle so that the tree was gently agitated every time there was occasion to pump water. The consequence was that the fruit on this tree was preserved in the greatest perfection. The habit of the curculio to fall to the ground or to play possum when disturbed is commented on in the American Farmer for July 1 ?} 1829, namely: When the branch on which it is at work is shaken with some little violence, it drop- to the earth but makes no attempt to hide. It immediately contracts itself into a small lump very much resembling a grain of small black gravel, and thus it evades generally the closest inspection. Mr. David Thomas was perhaps one of the first fruit growers to exploit the method of jarring, and he occasionally published accounts of his success, which doubtless greatly hastened its more general use. Writing in the Xew England Farmer for 183] (p. 413), he says: We have lately discovered that much fruit has been punctured by the curculio, and we have found it necessary to resort to the method which I proposed in the Xew York Farmer, Vol. Ill, Xo. 3. By spreading sheets and jarring the trees we have destroyed more than 300 of these insects within the last 24 hours, and have only to regret that this work has been so long delayed. Further along in the article he adds: Before closing this comment I wish to express my entire confidence in the method which we now employ for destroying this insect; and again recommend it to those whose fruit trees stand in inclosures from which (:ce tree violently, we caught within less than one hour more than 200 of these insects 170 THE PLUM CUECULIO. The following spring Mr. Thomas again refers to his method of catching the curculio (Genesee Farmer, 1832, pp. 155-156), and describes shaking the trees and catching the beetles on sheets kept exclusively for the purpose, as commonly practiced. It would thus seem, that jarring was rather generally employed in his neighborhood at that time. In 1833 the discovery was made that it was advantageous to strike the sawed-off butt of a limb as follows : This spring I sawed off one or more lateral branches of about an inch in diameter from each tree, leaving a stump to project, from which I removed the bark that the wood might harden and also made the head convex with a knife to prevent it from battering under the mallet. There are frequent accounts in subsequent literature dealing with the methods of jarring and giving instructions for the preparation of sheets (see fig. 34), but the practice seems to have become notably general by about 1850. The um- brella type of catcher came into use apparently somewhat before 1848. In The Cultivator for that year (p. 182) is grven a short account of an umbrella catcher which, it was stated, had been employed for some years. Num- erous forms of catchers were described and some of them illus- trated, but all were essentially of the sheet type, to be held or placed on the ground under the tree, or in the form of an inverted umbrella. An interesting resume of Mr. Thomas's experience after more than 20 years was given by him in The Cultivator for August, 1851 (p. 269), in which he expressed fullest confidence in the method and stated that whenever the work had been thoroughly done he had never been disappointed in results. Mr. James Mathews, writing in the Country Gentleman, February 17, 1853 (p. 102), speaks of having employed the jarring system for many years. He employed the umbrella type of catcher. A much more pretentious curculio catcher was devised by Dr. E. S. Hull, of Alton, 111., a description of which was given in the Practical Entomologist for April, 1867, and also in the Iowa Homestead, a reduced illustration of which is shown in figure 35. A patent was later taken on this catcher by Dr. Hull, but as it proved cumbersome several modifications were quickly developed, and some of them by Dr. Hull himself. A machine which Dr. Riley considered an im- Fig. 34.— A simple form of curculio catcher for use by one person. (After Popular Gardening.) JARRING FOR THE CtJRCTTLlO. 171 provement over that of Dr. Hull was described in lus Third Missouri Report, page 20. Dr. Riley stated thai this machine, whichhad been devised by Mr. L. M. Ward, was in quite general use around St. Joseph and Benton Harbor, Mich. Fig. 3c A cumbersome wheelbarrow type of curculio catcher, developed and patented about 1^69. (After American Entomologist.) Another curculio catcher, devised and patented by Dr. M. M. ITol- ton, of Centralia. 111., is also described by Riley. All of these devices indicate an increase in the practice of jarring and the general demand for apparatus for this purpose. J Fig. 36.- -A light wheelbarrow curculio catcher, for sale as late as L905. At the present time there are perhaps few if any individuals or firms offering curculio catchers for stile, although unquestionably a consid- erable number are still in use. A form o( catcher which was on the market in 1905 is shown in figure 36, and has been much used in 172 THE PLUM CURCULIO. western New York. According to the manufacturer, the umbrella was made in sizes of 8, 10, and 12 feet, costing from $15 to $16.50, according to size. Many growers who have jarred for this insect, and especially where labor has been abundant, have preferred to use sheets on frames. Extensive work has until recently been in progress in the orchards of the Hale Georgia Orchard Co. and elsewhere in the South. The sheets and mode of use are shown in Plate XIV, figure 2. PRESENT STATUS OF JARRING. The last few years have witnessed a notable increase in spraying for the curculio, with a corresponding decrease in jarring. This old remedy will doubtless more and more fall into disuse with the increase in spraying operations. One of the largest jarring operations recorded is that by Messrs. W. M. Scott and W. F. Fiske.1 During 1900 a Georgia orchardist jarred 200,000 bearing peach and 50,000 bearing plum trees about six times during the period from April 18 to June 1. Eleven gangs, or 55 hands, were engaged in the work, at a total cost of about $1,000. It was estimated that about 137,000 curculios were caught during the season. Curculio damage in tins orchard was placed at about 4 per cent of the crop, as compared with an estimate of about 40 per cent injury in an adjacent orchard of 130,000 trees. Although jarring had so long been in use, and was so generally recommended, there are practically no precise data in literature indicating just what degree of protection is afforded, nor any rela- tive to its value as compared with its cost. During 1906, at Myrtle, Ga., an attempt was made to secure data on the value of this work on peaches. A block of 1,000 6-year-old Elberta trees was selected from a larger block of 10,000 trees and jarred every other morning from April 11 to June 9. Twelve trees in the jarred block were used for making examinations of the fruit throughout the season and an identical number were used in the larger, unjarred block of the same variety. The results are shown in Table LXXXVI : i Bui. 31, n. s., Bur. Ent., U. S. Dept. Agr., pp. 24-35, 1902. Bui. 103, Bureau of Er.torro ogy U. S. Dept Plate XIV. Fig. 1.— A Wheelbarrow Curculio Catcher, Used in New York State. Fig. 2.— Curculio Catcher Made by Sheets on Frames, in Use a Few Years Ago in Georgia. JARRING APPARATUS IN USE OR RECENTLY IN USE AGAINST THE PLUM CURCULIO. _J JABRING FQB THE (URCUL10. 173 Table LXXXVI. — Results of jarring Elberta peaches for the plum curculio, Myrtle, Ga., 1906. rial No. Treatment. Tree No. Jarred. Untreated . Fruit from ground. Fruit from tree. Total number. Total number infested. Total number. 24 79 29 58 7 96 29 157 10 192 20 310 12 120 19 345 12 270 2 99 7 47 1 30 Total number infested. 625 188 35 61 71 14 21 30 36 8 32 20 27 Total number of fruits. 154 101 152 229 2:i5 423 155 441 313 118 71 36 172 1,803 109 | 2.42S 45 356 38 6 138 9 14 99 7 22 195 17 0 44 3 17 123 14 9 129 13 11 192 11 0 29 1 8 175 5 4 95 9 0 105 8 544 173 1G0 266 58 144 159 228 37 207 115 132 15.3 223 Total number of fruits infested. 281 INS Average - age sound fruit. 87. 04 As will be noted, the jarred plat gave 88.42 per cent of fruit free from infestation, as against 87.04 per cent on the untreated block, a difference in favor of the jarred plat of 1.38 per cent. Only 2,606 beetles were captured during the season, and the comparative scarcit}" of these doubtless explains why there was practically no difference between the two blocks. Table LXXXVII gives results of jarring peaches at Silo am Springs, Ark., during 1908. A block of 950 Elbert as was jarred from March 28 to June 27. Nine trees from the jarred block and a like number from an adjacent untreated part of the orchard wore used for making counts, as detailed in the following table. 174 THE PLUM CTJRCULIO. Table LXXXVII. — Results of jarring Elberta peaches for the plum curculio, Siloam Springs, Ark., 1908. Treatment. Tree No. Fruit from ground. Fruit from tree. Fruit knocked off in j arring. Total num- ber of fruits . Total number of fruits infested. Average percent- age of sound fruit. Plat No. Total num- ber. Total num- ber in- fested. Total num- ber. Total num- ber in- fested. Total num- ber. Total num- ber in- fested. Jarred Untreated . 1 2 3 4 5 6 7 8 9 r i 2 3 4 5 6 8 9 815 520 498 469 326 512 705 679 461 14 3 8 26 5 6 15 12 8 47 45 31 22 26 19 83 31 33 IS 13 10 7 7 7 25 11 8 309 165 110 92 87 1S3 267 211 182 1 1 0 0 1 0 0 1 0 1,171 730 639 583 439 714 1,055 921 676 33 17 18 33 13 13 40 24 16 I 4, 9S5 97 337 106 1,606 4 6,92S 207 97.01 324 352 341 513 458 598 243 480 414 28 29 23 39 22 35 32 22 22 32 29 25 49 34 42 37 40 41 17 13 11 24 15 19 17 12 13 356 381 366 562 492 640 280 520 455 45 42 34 63 37 54 49 34 35 II ~v 3,723 252 329 141 | !.... 4,052 393 90.30 1 i The spring of 1908 in that locality was cold and the beetles, which were not numerous, were much retarded in their movements. A total of 2,189 curculios was taken during the season. The jarred block shows a gain of only 6.71 per cent of sound fruit over the block not jarred. Also, at Barnesville, Ga., during 1910, a block of 336 trees in 10 rows was jarred from March 10 to time of picking fruit (and subse- quently for other records). A check plat of 60 trees (10 rows of 6 trees each) was laid off on one end of the jarred block. Counts of fruit for infestation were made on 20 trees of each plat, as shown in Table LXXXVIII. A total of 6,994 beetles was captured by July 30, when all fruit had been gathered. JAKRINC FOR THM ( !'l:< I/LIO. 175 Table LXXXVTII ■Results of jarring Elberta peaches for fhf plum curculio, Barnes- vilte, <'■«.. 1910. Plat No. Treatment. Jarred. Tree No. Total num- ber of fruit. 857 1,845 1,286 1,076 606 529 615 547 434 439 295 159 4^0 355 519 486 47S 202 413 112 Total num- ber of fruit in- fested. 11,793 4S 80 1 1 5 168 19 12 Aver- age per- centage of sound fruit. 2 0 3 1 3 2 9 6 3 4 95.57 Plat No. II. Treatment. Untreated. Total Tree num- Xu. ber of fruit. Total num- ber of fruit in- fested. f 1 961 2 1 . 890 3 1,123 4 1,238 5 364 491 7 410 - n 9 470 10 637 11 181 1-' 726 13 421 14 706 15 39S 16 256 17 424 18 178 19 633 i 20 - 12,553 299 137 147 46 95 4> 49 48 54 18 A ver- of sound fruit. 85.91 Comparing the amount of uninfested fruit from the two plats, there is shown a gain in favor of jarring of 9.66 per cent of the crop, an amount quite insufficient to compensate for the cost of the work. During 1909 Mr. W. W. Chase,1 of the Georgia State Board of Entomology, following a plan outlined by the Bureau of Entomology, jarred a block of 1,200 Elberta peach trees. The work of jarring, although carried out irregularly on account of scarcity of suitable labor, nevertheless gave results of interest. The block of trees used was 40 by 30 rows and paralleled a piece of woods, being separ- ated only by a farm road. Rows were numbered from 1 to 30, beginning with the one parallel to the wood... In the jarred block. 10 trees were selected for making examinations of all of the fruit and 8 trees were selected from a nearby section of the orchard, untreated. As stated in the table, a total of 4,338 peaches was examined from the 10 jarred trees, of which 1,739 were infested, giving a percentage of sound fruit of 59.91. From the unjarred block of S trees a total of 2,515 fruits was taken, 1,664 being infested, giving a percentage of sound fruit of 33.84, a difference in favor of jarring o{ 26.07 per cent.3 1 Hul. 32, Ga. State Bd. Entomology, p. 29, 1910. -In the publication cited an error in computation manifestly exists where a benefit of 8 percent is stated in text, though a loss of 0 percent is given in the table, while a correct computat ion from the numbers given of infested and uninfested fruit shows a benefit of 26 per cent. 176 THE PLUM CUKCTJLIO. Considering the several records of jarring on peach given above, it would appear that this practice, on the whole, is not warranted from the benefits derived. Notwithstanding the large total of beetles caught in the course of the Barnesville experiment, averaging 20.81 per tree, there was a lessening of infestation of only about 10 per cent, as compared with the check. In the other instances, where the insects were less abundant, the difference is inconsequential. It is, however, a firmly established belief that jarring has been of the greatest value in protecting the plum crop, though no exact data have been given, and the inference possibly follows the fact of capture of the beetles in considerable numbers. It is regretted that there has been no opportunit3r to try jarring on plums. In jarring for peachee, furthermore, quite a number of the fruit is almost unavoidably knocked off, a considerable proportion of which is sound. When there is an abundance or excess of fruit, this is beneficial; but when the crop is light, there is an important loss of fruit. In the Siloam Springs work, in 1908, a total of 1,610 peaches was knocked off during the season from the 9 trees, of which 4 only were infested. CULTIVATION FOR DESTRUCTION OF PUP2E. As has been shown elsewhere (p. 87), practically all of the larvae of the plum curculio pupate less than 3 inches below the surface of the soil. Over 92 per cent pupate within 2 inches and 63 per cent within 1 inch of the surface of the ground. The pupa? of the curculio, in com- mon with those of many other insects, are extremely tender and are readily killed or injured by disturbance of the soil. It is probable that the mere breaking of the pupal cell, leaving the earth in contact with the body of the pupa, would be fatal to many, while others are undoubtedly killed by the crushing action of the earth. Superficial tillage of orchards when the pupa? are in the ground in maximum numbers should therefore serve greatly to reduce their number for the following season, and tillage during this season is extremely desirable as a part of proper orchard management. Pupa? not actually killed are exposed to the elements and are subject to the attacks of preda- ceous enemies, as ants, bird, etc. Sunlight appears to be quickly fatal to them and, as stated by Crandall, exposure to the air on a warm day in the shade will result in then death in a few hours. Extended observations on the life history of the curculio from various localities (p. 64) indicate that the insect is in the pupal condition in the ground for any locality in from 50 to 65 days after the falling of the blossoms of such fruit as the peach and plum. Data have also been presented to show that the minimum time spent in the ground is about 20 days, though the actual period of pupation is less. CULTIVATION FOR DESTRUCTION OF PUP^. 177 Shallow cultivation should begin therefore in about 9 weeks after blossoming of peach. These cultivations should be frequent, that is, every week or oftener if practicable, and continued for 6 or 7 weeks. As most of the larvae enter the soil near the deserted fruit, the earth under the spread of the limbs of the trees will contain the great ma- jority of the pupa? and should receive special attention in the course of the cultivations. Some experiments have been made to determine the effect, on pupse, of disturbing the soil. Boxes containing soil were kept in a way to approximate out-of-doors conditions as nearly as possible. In some boxes the soil was stirred, and in others left undisturbed for com- parison. While it has been impossible exactly to duplicate the dis- turbance of the earth that would result from field cultivations, yet the results are in a way comparable, and indicate as definitely, perhaps, as may be determined what may be expected from work of this char- acter. The essential features of the results are shown in Table LXXXIX. In the work at North East, Pa., the boxes were sunk in the soil beneath peach trees so that the top would be about level with the surface, and were thus subjected to practically normal conditions. As indicated in the table, the soil in two boxes was disturbed with a rake on July 11 and 20, while two other boxes were left undisturbed. In the experiments at Siloam Springs, Ark., in 190S, boxes 2 feet square without bottoms were sunk practically level with the earth under the shade of an apple tree. One box was cultivated with a hoe June 23. In the tests in the insectary at Washington, D. C, in 190S, 4 lots were used, 2 being treated and 2 untreated. The larvae were placed in boxes 24 by 10 inches and 8 to 10 inches deep. These were sunk almost level with the surface of the earth. Lot Xo. 1 was cultivated by means of a hoe July 8 and 15, while lot Xo. 2 was cultivated only once, on July 15. The soil was disturbed to a depth of 6" inches, exposing many of the pupae. At Douglas, Mich., the boxes were placed in a bright though some- what shaded location and the soil in lot No. 1 was disturbed weekly by means of a small stick or lend pencil drawn back and forth, extend- ing to a depth of 3 or 4 inches in the soil. In the experiments at Barnesville, Ga., in 1910, 4 bottomless wooden boxes 10 by 12 by 8 inches were used and sunk in the soil on the north side of a house, thus being shaded for about one-half of the day. Lots Xos. 1 and 3 were placed in sandy loam and lots Nos, 2 and 4 in red clay. 17262°— Bull. 103—12 12 178 THE PLUM CURCULIO. Table LXXXIX. — Effect of stirring soil on destruction of pupae of the plum curculio. Locality and date. Lot No. Num- ber of larvae used. Treatment given soil. Adults emerg- ing. Per- centage of adults from larvaa. Aver- age per- centage adults from treated boxes. Aver- age per- centage adults from un- treated boxes. Per- centage gain from treat- ment. 1906. North East, Pa 1 2 3 4 1 2 1 200 200 200 200 451 451 558 51 468 137 98 173 191 173 191 Soil disturbed July 11 and 20. do 25 32 71 75 60 135 20 24 267 59 2 17 21 12 119 98 12.50 16.00- 35.50 37.50 13.30 29.93 3.58 47.06 57.05 43.07 2.04 17.35 12.14 6.28 68.79 51.31 Do 14.25 Do Soil not disturbed do Soil disturbed June 23.. . Soil not disturbed Soil disturbed July 8 and 15. Soil disturbed July 15. .. Soil not disturbed do Soil disturbed f r e - quently. Soil not disturbed Soil disturbed June 17... Soil disturbed June 8 Soil not disturbed ..do Do 13.30 36.50 22.25 1908. Siloam Springs, Ark Do 29.93 16.63 Washington, D, C Do 2 7.22 Do 3 Do. . 4 1 2 1 2 3 4 2.04 53 88 4fi fifi 1910. Do , 17.35 15 31 Barnesville, Ga Do 9.06 Do... Do. . 59.61 50.55 10.20 43.85 33.65 As will be noted, there is with one exception an important decrease in the number of adult curculios emerging from boxes in which the earth was stirred. In the case of lot No. 2, at Washington, D. C, an unusually large number of adults emerged. The larvae were placed in this box June 29 and were doubtless all in the pupal stage by July 15, when the cultivation was given. It is to be noted, how- ever, that there is a considerable variation in the percentage of insects killed by stirring the soil from the different localities. This perhaps results from differences in the methods of treatment. The total average percentage of adults emerging from the treated boxes, namely, 10.20, as compared with the total average from all untreated boxes, namely, 43.85, shows a difference in favor of stirring the soil of 33.65 per cent. Comparing the total number of beetles emerging from the untreated boxes, 841, with the total number of beetles from the treated, 196, shows a probable number killed by treatment of 645, a percentage of benefit of 76.75. SPRAYING WITH ARSENICALS. It is impossible to state with certainty who first used arsenical poisons for the control of the plum curculio. They doubtless came in along with the use of Paris green against cankerworms and the codling moth. Paris green was recommended by Mr. G. M. Smith, SFBAYIlfG WITH ARSEXTCALS. 179 of Berlin, Wis., to the St. Joseph, Mich., Horticultural Society in the fall of 1870, ' in the article which follows, which is the earliest recom- mendation we have seen: My method of destroying the little Turk is to give the trees a judicious sprinkling of Paris green. My plum trees are living witnesses of the excellence of this treatment, for they are for the first time loaded with fruit and some of them overloaded, and not a mark of the curculio can be found. This is the third season in this region that we have used the Paris green for destroying the Colorado potato beetle, and I find it effectual not only for them, but for all insects that feed on the foliage of trees or plants. Xo other preparation, as I am aware, has yet been used that is so inexpensive and easily prepared and applied as this. It is a perfect protection to the melon and squash vines against the ravages of the striped bug, to rose bushes from the slug, and the currant and raspberry from the worm. This is as far as my experience extends, but I see no reason why the cankerworm and the caterpillar could not be destroyed by this preparation. Last season I applied the Paris green to my trees, and I was satisfied that it had its effect on the curculio, but the season was so cold and wet here, and insects generally were so scarce and the fruits rotted so badly, I could not fully decide. But this season the unusual warm weather brought them out early, and on noticing their marks on the fruit I made an application of the green to my trees and repeated it every week or ten days. The fruit that was stung dropped off, but it is the last I have seen of the curculio, although in other localities where it has not been used they have been constantly at work. My manner of using this poison is to mix 30 parts of flour or fine middlings to one of the Paris green (this is the same proportion that we use on our potato vines); take a two or three quart tin pail and perforate the bottom and fasten to a pole, and while the dew is on shake it over the tree, standing on the windward side and not inhale any of the dust. A slight dusting is sufficient, and it will be found strong enough for all practical purposes. The value of Paris green for this insect was questioned by Dr. Riley in the American Entomologist and Botanist for October, 1870, and the paragraph which appeared there -also appeared in his Third Missouri Report, published the same year. Riley states: Even if the uniform application of such a poisonous drug on large trees were true, it would never succeed in killing one curculio in a hundred. Paris green kills the leaf-eating beetles by being taken internally with the larvae, but the curculio, with its snout, prefers to gouge under the skin of the fruit, and only exceptionally devours the leaves. Yet, notwithstanding the palpable absurdity of the remedy it is very generally passed from one journal to another without comment. It would seem that the suggestion by Mr. Smith in 1870 was very generally copied in the horticultural and agricultural journals of the day. The writers, however, have not been able to find references t<» the subject during the interim from 1870 to about 1880. The recom- mendation had apparently not made much impression, for in an extended article on the plum curculio, dealing especially with reme- dies, Mr. B. Gott, in the Annual Report of the Entomological Society of Ontario (1879), makes no mention whatever of Paris green or other arsenicals. 1 Moore's llural Now Yorker, vol. 22, p. 45, 1S70. 180 THE PLUM CURCULIO. By the early eighties, however, Paris green had come into some use. Thus Riley and Howard record the case of Mr. J. Luther Bowers, of Herndon, Va., who had informed these gentlemen that during the summer of 1880, while he was living in Clark County, Va., he had sprayed his trees with Paris green in the proportion of 1 tablespoonful of green to 5 gallons of water, making the applica- tion with a Whitman fountain pump. He sprayed soon after the petals fell and again in a week or ten days. The result was the most perfect crop of plums he had ever grown. In his annual address as president of the Ontario Entomological Society, delivered October 15, 1884, Mr. William Saunders, con- cerning the Paris green treatment for the eurculio, said: From the evidence thus far obtained it would appear that the remedy which has been found so efficacious in subduing the codling moth of apple, namely, Paris green and water in the proportion of a tablespoonful of the poison to a pail of water, will also protect the plum crop from the ravages of the eurculio. Under the caption " Paris green and the eurculio," Mr. William Creed, writing in Purdy's Fruit Recorder for November, 1885, states: In the October number of the Fruit Recorder of the present year, you invite the experience of those who have experimented with Paris green upon the eurculio. You will find a record of facts in this direction, from my pen, in your paper dated August, 1884, and until some tangible refutation can be produced by others to affect its value, it should not be looked upon with distrust. That Paris green will " do the buisness " for the little Turk, I think is irrefutable — certainly it is so from my own knowledge and trial for the three last seasons, and I will say positively that on very close inves- tigation upon this year's crop, I have not had one plum, prune, or damson fall from the punctures of a eurculio. But previous to the use of this remedy I looked upon plum culture with an instinctive dismay almost ungovernable, on account of its non- reliability. Of course, it is not for me to force an argument or intrude too much upon your columns concerning this eurculio remedy, but will simply crave a little space to show the sample of some plum growers' logic when told of my experiments and re- sults. The whole batch of arguments by these men do not, however, amount to a "row cf pins.-" The following "walks and talks" happened in 1884. The first was with a nurseryman, who said, so far as 1884 was concerned, he considered the apparent success as stated was no criterion to go by, as it was a great plum year in this neighbor- hood. The second talk was with a gentleman who has about 5 acre3 of plums, prunes, and damsons. He would not listen to the subject a moment. " But, " said I, "you now have coming into bearing a fine lot of nectarine trees and you may want a eurculio remedy, " and I at once suggested the intelligent use of Paris green by spray- ing, but to no avail. " Shaking, " would do for him. The third gent was from Michi- gan and editor and proprietor of a paper and a lover of good fruits, but hater of the eurculio, which was evidenced by saying that his remedy for the eurculio was to cut the tree down, which he had done, and bought his plums from distant localities where the insect is less plentiful and the plum crop more to be depended upon. You will see from the foregoing that there is but poor encouragement and little temptation to introduce a good thing, and had you not invited another year's expe- rience, I should have let the matter drop. Let it be understood that I do not claim priority of suggestion of the use of Paris green for the extinction of the eurculio, as there may have been thousands of others investigating the matter on the same basis and about which I am totally ignorant; but what I do know is that I gave you my SPRAYING WITH AHSKXTCALS. 181 method after a second year's trial, and as in this case, so also with regard to pear blight, I first put forth my theory of the latter in the Fruit Recorder, as being among the papers with the largest circulation and as most likely to meet with the largest results and atten- tion; and in November, 1877, when I classified pear blight as a zymotic disease and suggested an investigation upon this theory it was apparently at once taken up by Prof. Burrill and continued by other professors of microbotany, and to-day the bacterian theory of pear blight has become an established fact and the prevention or modification of the disease may be looked upon with a degree of certainty at no distant day. Now for some one to step forward and supplant the first stepping-stone to the proper study of pear blight as it appeared in the Recorder of 1877. In the spring of' 1885, Dr. Riley, in an address before the Missis- sippi Valley Horticultural Society, at New Orlenas, La.7 discussing the feeding habits of the beetles, urged experimentation with arseni- cals in tins direction, as promising fair results — not, however, in the very nature of the case as satisfactory as in the case of the codling moth. During the summer of the same year Dr. S. A. Forbes began ex- periments in Illinois in the control of the codling moth and apple and plum curculio, reporting the results in the Prairie Farmer of December 19, 1885, and also in the Transactions of the Illinois wState Horticultural Society for that year, which appeared from the press the following year. Paris green and London purple were tried on apple. Paris green was used at the rate of three-fourths ounce to 2 J gallons of water (equaling approximately 1 pound to 50 gallons), the metallic arsenic present being 15.4 per cent. Two trees were sprayed eight times during the season, the first applications being made on June 9 and 13, respectively. Two trees of the same variety of apple were left unsprayed for purposes of comparison. In regard to the effect of the treatment of the curculio, Prof. Forbes says: Of the 1,975 apples from these two poisoned trees which were examined for the curculio injury, 542, or 27.3 per cent, bore the brand of the insect "s beak, while of the 1,172 obtained from the check trees, G02, or 57.3 per cent, had been so injured, the ratio of apples punctured by the curculio on the poisoned trees being half as many times on the trees that had not been sprayed. A careful inspection of our tables showed that this was a fact apparent throughout the season. Considering the picked apples only the results are somewhat more favorable, and if the fallen apples are also taken into count, the percentage of those damaged by the curculios on the cheek trees being 7G.5 and upon those sprayed with Paris green 34.4 per cent. During the summer of 1886 Prof. Forbes continued his experiments with arsenicals in the control of the codling moth, particularly com- paring Paris green and white arsenic, noting also the effect of the treatments on the curculio. These experiments by Prof. Forbes seem to be the first careful ones made to determine the value of arsenicals in curculio control. In an earlier part of his article Prof. Forbes notes that Paris green had been very generally recommended. 182 THE PLUM CUKCTJLIO. In the report of the secretary of the State Board of Agriculture for Michigan for 1887, Prof. A. J. Cook reports upon Paris green for the curculio as follows: Paris green in the proportion of 1 tablespoonful to 6 gallons of water was very thor- oughly sprayed upon 4 plum trees May 18. The petals had all fallen, but the dried calyces still clung to the fruit. On August 20 the trees were visited, when it was found that the two treated trees of the wild goose variety had dropped all their fruit, as had the untreated trees of the same kind. Another treated tree of a yellow variety was loaded with plums, of which only 15 per cent were stung and those not badly. The fourth treated tree was a purple variety and had not less than 75 per cent of its fruit badly stung. During the season of 1887 experiments were begun with Paris green sprays by Prof. W. B. Alwood, at that time an agent of the Division of Entomology of this department, as detailed in the Report of the Entomologist for that year. These experiments were not begun until after the beetles had commenced work. No definite inferences in regard to the experiments may be drawn, since these were not finally concluded. Prof. Alwood thought, however, that the cur- culios ate enough to make it possible to poison some of them, but the benefit derived was in his opinion yet unsettled. In Bulletin 3 of the Ohio Agricultural Experiment Station, issued in May, 1888, Prof. C. M. Weed, under the caption "Experiments with remedies for the plum curculio," announced proposed tests of three specified methods of control of this insect, and adds: Spraying with London purple or Paris green as soon as the blossoms fall as recom- mended for the apple. I am reliably informed by many of the largest fruit-growing firms of western New York that in this way they succeeded in avoiding the curculio and raised large crops of plums. The method has been recommended at various times for several years, but as yet has certainly received little attention. The same season Prof. Weed put into effect his line of treatment, the results of which were given in Bulletin 4 of the Ohio Station, which appeared in July. A young orchard of early Richmond cher- ries was employed, and in regard to his work he concluded as follows : (1) That three-fourths of the cherries liable to injury by the plum curculio can be saved by two or three applications of London purple in a water spray (in the propor- tion of 1 ounce to 5 gallons of water) made soon after the blossoms fall. (2) That if an interval of a month occurs between the last application and the ripening of the fruit no danger to health need be apprehended from its use. As a precautionary measure, however, I would advise in all cases, and especially where there are few rains during this interval, that the fruit be thoroughly washed before it is used. Prof. Weed continued his studies of spraying for the curculio in 1889, using also the early Richmond cherry. His statement of results covering two seasons' work on cherry is as follows: This series of experiments carried on through two seasons upon two varieties of cherry trees and four varieties of plum trees, during which a total of 6,500 cherries have been individually examined, seems to me to confirm the conclusions provisionally an- nounced one year ago, which may now be put in the following form: (1) That about SPRAYING WITH ABSENICALS. 183 three-fourths of the cherries liable to injury by the curculio can be saved by two or three applications of London purple in a water spray in the proportion of 1 ounce to 10 gallons of water. (2) That a sufficiently large proportion of the plum crop can be 3aved by the same treatment to insure a good yield when a fair amount of the fruit is set. (3) That if an interval of a month or more occurs between the last application and the ripening of the fruit no danger to health need be apprehended from ii- (4) That spraying with the arsenicals is cheaper and more practical than any other known method in preventing the injuries from this insect. During the season of 1890 spraying experiments on a commercial scale were carried out by Mr. Weed in an orchard of 000 five-year-old plum trees in the fruit belt along the lake shore in northern Ohio. and a comparison was made relative to the merits of spraying versus jarring. As a result of this test several plum orchards in northern Ohio were sprayed for the curculio during 1891 and the consensus of opinion of the growers was in favor of the practice. Tests were also made the same season by the horticulturist of the Ohio Station, Prof. W. J. Green, both on the station grounds and in Ontario County, Ohio. Paris green was used in combination with Bordeaux mixture. The results on sprayed trees showed that about 20 per cent were injured by the insect, whereas unsprayed trees had about 70 per cent of injured fruit. Prof. Herbert Osborn, at that time an agent of the Division of Entomology of this department, also carried out spraying experi- ments in the use of arsenicals against the curculio during the summer of 1888. The poison used was London purple, at the rate of one-half pound to 100 gallons of water, with the addition of a small amount of soapsuds. The first treatment was given June 1. when the fruit was the size of small peas and before any indications of injury by the insect were to be found. The results of counts of all fruit from sev- eral varieties treated, sprayed and unsprayed, gave for the sprayed trees 32.48 per cent stung and 5.71 per cent containing larvae. The unsprayed trees gave 41.86 per cent stung and 10.39 per cent of the fruit infested. It was concluded that the proportion o( fruit stung in the orchard was so small as to give no benefit from spraying. London purple was also tested during the season of 1888 on plums by Mr. G. C. Brackett, at Lawrence. Ivans. Prof. Cook, in Bulletin 39 of the Michigan Agricultural Experiment Station, issued in l^sv says: It will be remembered that I have used the London purple several years with quite indifferent success to keep out principally the curculio. The tact that Borne fruit growers reported excellent success with this remedy led me to conclude that possibly I had not been persistent and thorough enough in this warfare. The curculio com- mences to work anywhere on the plum, which has a smooth surface, while the codling moth lays its egg righl in the cup or funnel-like calyx end oi the apple. Thus the wind and rain would free the plum or cherry or general surface oi the apple oi the poison much more readily and quickly than they would the rough cavity end oi the apple. Thus we can understand how. granting that the arsenites are alike effective 184 THE PLUM CUKCTJLIO. against the codling moth and curculio, more care would be required in resisting the attack of the latter. This season we arranged our experiments with this point directly in view. On June 4, the trees, both plum and cherry, were jarred and curculio were caught. The mark of the curculio was also found on both cherries and plums. The trees were sprayed June 6, June 12, and June 20. The material was the same as that used in spraying the apples, namely, 1 pound London purple to 100 gallons water. Careful examinations June 12 found no stung cherries and very few plums. June 26, 250 cherries were picked from the sprayed trees, and not one was injured. The crop cf cherries was large and no cherries from the sprayed trees were wormy. July 16 and 18 the fallen plums were all gathered under the trees and cut open. On tree No. 1 there were 16 plums, of which 10 were wormy. Tree No. 2 (wild goose), 117 plums, 23 wormy. Tree No. 3 (Washington), 33 plums, 3 wormy. Close examination found no stung plums on the trees, and the crop upon picking was very free from injury. Cherry and apple trees near by not sprayed suffered seriously. CONCLUSIONS. From these experiments and those of former years I conclude that while one appli- cation will not save our plums and cherries and prevent apples from being stung, two or three applications may be of signal advantage. Iii 1888 Prof. Forbes began a series of observations to determine some details of the food and feeding habits of the curculio and to test its susceptibility to arsenical poisons when distributed on the trees frequented. Observations were also made on a strength of poison which might be used on peach foliage without marked injury. As a result of his studies he concluded: There can certainly be no further question of the liability of the curculio to poisoning by very moderate amounts of either London purple or Paris green while feeding on the leaves and fruit of peach and plum, but much additional experimentation is needed to test the possibility of preventing serious injury to these fruits by this means. The pupal hibernation and late appearance of a considerable percentage of the cur- culios make it possible that spraying must be several times repeated and perhaps car- ried further into the season than is consistent with safety; and the limit of tolerance of these poisons by the peach under ordinarily trying circumstances had not been clearly ascertained. Further, the observations reported above on the food plants of the cur- culio make it likely that in nature a smaller proportion of the food of these beetles comes from the peach or plum than has hitherto seemed possible, and that poisons there applied would kill less certainly. It seems worth while to make the attempt to attract the adult to flowering plants in the orchard other than the peach, with the hope of poisoning it there (especially late in the season) without using these dangerous insecticides on fruits afterwards to be eaten. Prof. C. P. Gillette, in Bulletin 9 of the Iowa Agricultural Experi- ment Station, issued in May, 1890, records observations on the cur- culio and plum gouger, giving results of spraying plums with London purple for the control of both of these insects. His work led him to believe as follows regarding the efficiency of arsenic als : The two applications of London purple and water, although not made at the times best suited to destroy the curculio, apparently gave a protection of 44 per cent against the ravages of this insect. feeding experiments with Khsons. L85 London purple and water in the proportion of 1 pound to 120 gallons ifl much too strong a mixture for plum trees. One-halt of this strength is as strong a mixta] should he used. Iii summing up the situation as to the use of arsenicals against the curculio, in 1887, Ililey and Howard state: On the whole, the remedy is one which is a desirable addition to our list, although it will never become so great a success as the application of the poisons for the codling moth, and for two reasons: i 1 | The egg is deposited and the beetle gnaws preferably upon the smooth cheek of the fruit where the poison does not readily adhere and from which it is more easily washed off; I 2 i the larva eating directly from the flap doec come in contact with the poison as does the larva of the codling moth. The foregoing will give a fair idea of the rise of spraying with arsen- icals for the curculio. By about 1890 the practice unquestionably had become rather general, although jarring was still employed by man}' growers. The injury to the foliage of stone fruits by sueh arsenicals as Paris green and London purple, frequently noted by orchardists and the early experimenters, no doubt greatly retarded the adoption of these poisons. The development, however, itt 1802, by the Massachusetts Gipsy Moth Commission, of arsenate of lead, an insecticide much less caustic to the foliage than either Paris green or London purple, gave a considerable impetus to spraying for the cur- culio, especially on peaches and plums. Spraying, however, had been in effect two decades or more before its real merits on a commercial basis had been determined. The careful experiments of Forbes, Weed, Alwood, and perhaps others, had shown unmistakably that the injuries could be materially reduced by frequent spraying, and the testimony of many fruit growers was decidedly in favor of it. There were others, however, who doubted its efficiency, and continued the practice of jarring. FEEDING EXPERIMENTS WITH POISONS. The point has several times been raised in the case of arsenate of lead whether this did not act mainly as a repellent ; ami in an exper- iment by W. W. Chase a report bearing on this question is given.1 A single -.nail peach tree was covered with fine wire screen. The tree was literally soaked with lead arsenate, 3 pounds to 50 gallons of water, and after the poison had dried another application was given. The day following, May 1 1 , 372 curculios which had been con- fined 48 hours without food were liberated in the cage. Subsequent close observation failed to discover a single beetle feeding on the tree, and in fact the beetles seemed to have the strongest aversion to it. At the (Mid of 10 days all the beetles were dead, except a few which may have escaped. It would appear to the writers that in this case i Bui. 32, Georgia State Board Entomology, p. 27. 186 THE PLUM CUKCULIO. the poison was applied much too freely, and as used would undoubt- edly have acted as a repellent. In the case of Paris-green sprays in water there could be no repellent action attributed, and with arsenate of lead, as used in practice, it would seem established that its value lies more in killing of the insects than in possible repellent action. In the course of these studies numerous feeding tests have been made with the curculio, especially with different brands of arsenate of lead and other miscellaneous arsenicals. Results of a feeding test made in 1906 are shown below (Table XC), where apple, pear, peach, plum, and cherry branches bearing foliage and fruit were used. Twigs of plants placed in bottles with water were used and all were sprayed at some time with arsenate of lead at the rate of 2 pounds to 50 gallons of water, using a hand pump and Vermorel nozzle. With each fruit the poison test was made in duplicate with a single check. After the spray had dried on the foliage the branch was placed under a large cylinder with cloth over top, and 20 beetles, collected that morning by jarring, were added. Table XC. — Tests of the hilling effect of arsenate of lead on the plum curculio on specified fruits, Washington, D. C, 1906. Apple. Pear. Peach. 1 Plum. Cherry. Dates of examination. 73 9.6 'S-a -w c o o 73 96 ■8. go Oirj P. 53 -w c o o 2ra 73 a> • OT O oB Ph 73 2n 59 O "SB 73 o ■ id Ph Poisoned No. 2. Not poi- soned. Poisoned No. 1. 73 §^- 9.6 pZ ti bm June 25 6 4 4 2 16 4 10 2 2 2 16 4 .... 1 19 4 3 6 6 2 6 6 2 .... 2 1 2 10 4 4 5 3 5 6 .... 3 .... 3 .... 1 .... 2 4 4 1 4 5 1 26 4 ---- 27 5 4 "i" 28 j Total 19 1 16 4 3 17 13 7 17 3 19 17 3 13 7 26" 17 3 17 3 ?, Beetles alive at close of observations. . 18 The results uniformly show a prompt killing effect on the beetles by the arsenate of lead on the varieties of fruits used. It is also evident that the insects feed freely during midsummer. During 1910, in Georgia, numerous feeding tests were made using several of the more important brands of arsenate of lead, as well as other miscellaneous arsenicals. In Table XCI are given results of feeding tests on peach twigs taken from trees in orchards immediately after spraying, April 13 and 14, and placed under cylinders. April 16, 50 beetles were added to each cylinder and records made daily of the number of beetles dying. The poisons were used of the strength indicated in the foliage test experiments (p. 205). The killing effect of all of the poisons was fairly prompt, the various brands of arsenate of lead working fairly uniformly. Red arsenic sulphid and arsenic tersulphid were quicker in action than the lead arsenates, although, as elsewhere noted, these poisons were notably injurious to the foliage of FEEDING EXPERIMENTS WITH POISONS. 1-7 peach. Ferrous arsenate was much slower in action, but effective, as shown by comparison of the condition of beetles fed on poisoned foliage with the condition of the beetles on the check. Table XCI. Tests of killing effect of lead arsenates and other arsenicals on the plum curculio on peach. Georgia, 1910. Beetles dying from each of the arsenicals. Dates of death of Check not sprayed. Arsenate of lead. dered For- ££ S3* -! - lead. nate- P^ - nic ter- SUl- phid. 3 17 16 1 4 5 2 1 Arse- beetle. No. 1. No. 2. No. 3. No. 4. Xo. 5. Xo. 6. Xo. 7. Xo. 8. nic ter- sul- phidJ Apr. 17 ]s 4 2 8 9 7 8 2 3 3 2 1 1 3 I 4 5 12 , 7 6 5 4 1 5 6 10 7 8 5 1 8 4 4 8 3 11 6 10 1 3 2 4 16 7 4 4 7 5 1 2 5 1 4 5 5 5 7 6 ...... ""% 2 3 9 9 3 S 2 6 3 1 19 5 3 4 9 5 7 4 2 7 2 6 5 10 3 6 1 20 21 22 1 1 i 23 13 2 1 2 2 1 1 8 8 5 3 G 24 - 25 11 2C... 4 1 3 27 5 ....:. 1 5 8 28 3 3 3 1 ""% 1 2 3 29 30.... 1 2 1 7 4 5 2 3 1 1 4 3 2 May 1 1 3 4 1 5 6 " . 7 1 8 1 9 1 11 2 13 6 1 2 4 2 1 1 1 1 2 1 1 1 15 14 15 ............ 1 16 17 18 23 24 25 26 June 3 :::::: ;: 6 8 13 1 Total. 46 I 49 | 49 50 49 50 18 50 50 49 49 50 . -i'.t 50 1 Duplicate test started Apr. 20. In Table XCTI are shown results of feeding tests witli several mis- cellaneous arsenicals, as specified, used in the self-boiled lime-sulphur wash and simply in lime water. As before, twigs were cut from peach trees in sprayed plats in orchards and placed under glass cylinders. Spraying was done April 28 and 30, and 50 beetles were added to each jar April 30. The beetles in all of these tests were fresh, having been jarred from peach trees a day or so previous. An accelerated killing effect seems to have followed the use of the com- bined self-boiled and arsenical sprays, as compared with the arsenical used alone. The comparatively slow action of arsenate of iron is again noted, though when used in the lime-sulphur wash it compares favorably with arsenate of lead. 188 THE PLUM CXJRCULIO. Table XCII. — Tests of hilling effect of various arsenicals on the plum curculio on peach, Georgia, 1910. Beetles dying from each of the arsenicals. © 03 p. c I Arsenicals used in self-boiled lime sulphur. Arsenicals used without lime sulphur. Dates of death of beetle. *6 03 o o B o3 I -53 © "o3 C is © CI .§ o ^ 03 ft s 2 3 . W © © o 8 ft ©w o . "23s c ■§ oft or §! © ft o © c3 a go! 03 0 O m & © "o3 03^ 1ft O J"; »H © d o © ©^ © © t» "ft *^ ►a Oft ©3 o © "o3 a © ^ Po1 o M a TO Mav 2 3 5 6 11 9 3 2 4 4 3 11 8 2 2 5 12 9 8 1 3 1 3 11 7 15 8 1 3 1 1 1 3 3 8 7 20 6 ...... 1 1 5 2 8 1 4 2 5 4 7 1 1 4 9 4 2 4 1 5 3 16 3 2 1 8 9 5 1 2 1 3 4 3 3 1 6 4 1 3 4 3 1 5 5 10 2 9 10 8 3 2 15 3 6 5 1 4 8 4 9... 1 7 2 1 3 3 2 3 1 10 10... 4 11... 2 3 12 3 13 6 1 2 4 3 6 2 2 1 1 14 7 4 2 2 1 1 15 I 16 18 1 19... 20... 1 2 23. 1 1 1 2 24 1 25..-. 26 27 1 1 29... June 3 . . . . 1 1 1 18 6 8. ;; 13 ■ i Total 46 50 50 48 49 47 48 49 48 47 1 50 1 49 A feeding test was made with beetles in lots of 50, using twigs bearing fruit and foliage from sprayed trees in the orchard, except in case of lot 6, where foliage had been removed. Trees were sprayed, April 4 and 5, with arsenate of lead at the rate of 2 pounds to 50 gal- Tons of water, and feeding tests started April 5, except with lots 7 and 8, which were started April 7. It will be noted that all the beetles on the sprayed branches were killed within about a week, except lot 6, where fruit only was present and the period was length- ened. (See Table XCIII.) SPRAYING FOR CURCULIO ON APPLE. 189 Table XCIII. — Tests of killing effect on the plum curcu/io of arsenate of lead sprayed on peach foliage and fruit, Georgia, 1910. Beetles dying in each lot. Date of death of beetle. Lotl: Un- sprayed twigs with fruit and foliage. Lot 2: Sprayed twigs with fruit and foliage. Lot 3: Un- sprayed twigs with foliage only. Lot 4: Sprayed twigs with foliage only. Lot 5: Un- sprayed twigs with fruit only. LotO: Sprayed twigs with fruit only. Lot 7: Cn- sprayed twfgs with fruit and foliage. I.- ..t v Sprayed twigs with fruit and foliage. Apr 6 1 1 3 3 6 8 15 4 7 1 2 1 3 3 14 1 1 7 2 2 1 8 4 22 19 4 1 2 9... 2 12 10 4 Hi 11 2 1 2 I 12... 1 1 9 13... 1 5 14 15 10 . 2 3 17 .. Condition on Apr. 17. Lotl. Lot 2. Lot 3. Lot 4. Lot 5. LotO. Lot 7. Lot 8. Total died 7 42 1 47 10 30 4 50 2 40 2 37 9 4 46 10 3 Some feeding tests made by Mr. Johnson to determine the possi- bility of preventing the fall-feeding punctures of the curculio on apple are interesting: August 17, a branch of Baldwin apple tree bearing fruit, after spraying with arsenate of lead at the rate of 3 pounds to 50 gallons of water, was inclosed in a cage with 50 beetles. Twenty beetles had died by August 28. An examination of the apples showed 3 without punctures and 8 with punctures, as follows: Fruit No. 1, 5 punctures; No. 2,7; No. 3, 14; No. 4, 15; No. 5, 16; No. 6,28; No. 7,41; No. 8, 49; a total of 175 punctures on the 8 fruits. The condition of a check branch bearing 8 apples on this date w a- : Fruit No. 1,66 punctures; No. 2, 14; No. 3,45; No. 4, IS; No. 5,26: No. 6, 58; No. 7, 23; No. 8, 63; a total of 343 punctures. None of the beetles was dead in this cage and the punctures were much larger. SPRAYING FOR THE CURCULIO ON APPLE. EARLY EXP E R I M E \ TS . The first experiments of which we are aware, made to determine the value of arsenieals in the control of the curculio on apple, are those reported by Forbes in 1885, and already referred to (p. 181). In this work 8 trees were used, 4 of them being sprayed and 4 re- reserved as checks. Two of the trees were treated with Paris green, 1 with London purple, and 1 with lime. Two applications were 190 THE PLUM CUECTJLIO. made 8 times, beginning June 9 and continuing until September 3. The two trees sprayed with Paris green at the rate of 1 pound to 50 gallons of water showed a benefit in lessening curculio injury as com- pared with the unsprayed trees of about 50 per cent — more exactly, 72.70 per cent of the fruit was uninjured as against 42.70 per cent uninjured on the unsprayed trees. The trees that had been sprayed with London purple gave 61 per cent sound fruit as against 62 per cent fruit from the unsprayed trees. In conclusion Prof. Forbes states: Furthermore, if we must judge from results thus far reached, these various appli- cations are all of too slight effect upon the apple for plum curculios to make them worth use against these insects, Paris green diminishing curculio blemishes less than one-half, London purple about one-fifth, and lime not far from one-fourth. No further experiments seem to have been made until 1900, at which time Prof. Stedman began an investigation of the curculio on apple, which was continued during 1901 and 1902, the results of which are given in the bulletin of the Missouri Agricultural Experi- ment Station No. 64, published in 1904. Experiments in spraying apples were made in three different orchards. It was desired to test the practicability of killing the beetles while they were feeding on the leaves before the appearance of the bloom. One-half of each orchard was sprayed twice from the time the leaves opened until the blossoms opened, leaving the other half as check. These exper- iments were repeated the following year, and in addition four appli- cations were given after the falling of the blossoms at intervals of 10 days. By this means about 60 per cent of the fruit was protected in spite of reinfestation of the sprayed trees from the unsprayed part of the orchard. The desirability of spraying the entire orchard to prevent overflow was pointed out, as under these conditions the benefits would be very marked, and the great bulk of the " stings" would be prevented. In the report of the Illinois State Horticultural Society for 1902, page 158, Prof. E. S. Titus discusses the plum curculio under the caption "Insects other than the codling moth injurious to the fruit of apple," and gives results of observations made at the instance of Dr. Forbes. In regard to the use of arsenicals he says: The experiments tried in the Illinois entomologist's office several years ago showed very clearly that the curculio may be killed by spraying trees to which it resorts in early spring with Paris green or other arsenical poisons, as it feeds at that time largely on young leaves. Consequently, other things being equal, that orchard will be least infested and its fruit least injured whose trees are sprayed early in the spring, as for the codling moth or canker worm. On the whole, however, much the most promising and important measure is the prompt destruction of fallen apples to prevent the escape of the curculio larvaB into the earth, after which it is almost impossible for these larvae to go through their usual transformation. SPRAYING FOR CURCULTO OX APPLE. 191 The first attempt, however, to determine the possible value of the use of arsenical poisons in the control of the curculio on apple on a commercial scale was begun bv Prof. C. S. Crandall, of the Illinois Experiment Station, in 1903. His report of operations for that year was read before the Illinois State Horticultural Society (vol. 37, pp. 176-189). Two blocks of sixty 18-year-old trees each in two different but adjacent orchards were selected. In the Williams orchard the soil was covered for the most part with a bluegrass sod with a heavy surface mulch of dead leaves and grass. In the Blair orchard there was no sod but a scattered growth of plants, including grasses, and the surface mulch of leaves and trash was lighter. From 7 to 16 applications of an arsenical spray were given to the respective plats, including Paris green, arsenate of lead, white arsenic, and arsenite of lime, the first three treatments in Bordeaux mixture and the sub- sequent ones in water. During the course of the work 29,943 apples were examined. In commenting on the results, Prof. Crandall states that the spraying did not control the curculio. Apparently the frequent spraying had some influence because the percentage ol uninjured fruit from the plats sprayed 16 times was a little higher than from any other plats. Three reasons were assigned for the unfavorable results, namely : 1. Weather conditions of early spring and their bearing on the crop. 2. Location of the plats directly in the midst of large orchards con- tiguous to native woodlands. 3. Unusual abundance of the insects. On the Williams orchard the percentage of sound fruit varied from 1.26 to 5.29, with an average for all plats of 2.76. Results were somewhat better in the Blair orchard, the percentage of sound fruit ranging from 2.55 to 16.07, with an average for the several plats of 7.13. Prof. Crandall continued his work during 1904, as reported for the Illinois Horticultural Society (vol. 38, p. 75), and selected a somewhat isolated 5-acre orchard, thus eliminating invasion by the insect from outside sources. This entire orchard was treated, except the 13 check trees. The ground was not in sod and the orchard had never been sprayed. The spring weather was reasonably favorable and the trees bore a fair crop of fruit, and the cuTCulios were much less abundant than in 1903. The schedule of applications was the same as employed in 1903. A total of 72,922 apples was examined from all of the plats, of which 23,956 were windfalls. The treatments and results are shown in Table XCTV. 192 THE PLUM CURCULIO. Table XCIV. — Results of spraying apples for plum and apple curculios in Illinois, 1904. Plat No. Treatment. Total Total number Trees. number of fruits of fruits. punc- tured. 13 10,185 7,617 14 14,352 7,931 13 10,861 4,118 15 12,735 7,066 13 11,592 6,321 12 13,197 7,310 Percent- age of sound fruit. I... II.. III. IV. V.. VI. 3 applications Bordeaux mixture and Paris green (chock) . 10 applications Paris green, J pound to 50 gallons water 16 applications Paris green, J pound to 50 gallons water... 8 applications Paris green, J pound to 50 gallons water 7 applications arsenite of lime 7 applications arsenate of lead 25.21 44.74 62.08 44.52 45.47 44.61 All of the plats, including the check (Plat I), were sprayed three times with Bordeaux mixture and Paris green, one-fourth pound to 50 gallons of the Bordeaux, to protect from apple scab and the codling moth, and three sprayings on the checks reduced curculio injury, as shown by other trees in the orchard entirely unsprayed, 15.21 per cent. The marked influence of seasonal and local conditions on curculio injury is very forcibly shown in the Illinois results. The treatments in 1903 showed no benefit as regards control of the insect, whereas in another orchard in 1904 the saving in fruit from trees liable to injury ranged from 27.65 per cent to 54.53 per cent. Prof. Crandall states: To sum up the matter of spraying for the curculio from the standpoint of results obtained during the two seasons of 1903 and 1904, it seems possible that under favorable conditions and with a reasonable number of applications to control curculios to the extent of from 20 to 40 per cent of the possible injury. There is benefit to be derived from spraying but not that degree of benefit which would warrant commendation of spraying as the one great panacea of injury done by the curculio. In the proceedings of the Illinois Horticultural Society for the year 1904 (p. 91) Dr. Forbes, in continuation of his study of the curculio in Illinois apple orchards begun in 1901, reports results of experiments with arsenical sprays carried out in Southern Illinois and independent of the researches of Prof. Crandall, just alluded to. Four plats wrere established, including the check, and 4, 6, and 8 applications of arsenate of lead were given, beginning May 6 to 10, wdien the trees were in first full bloom, and repeated at intervals of about 10 days, ending July 28. Prof. Forbes presents the figures of yield of sound and injured fruit, though the experiment loses some of its value for the reason that the trees wrere of different varieties and the plats not all under the same conditions, being located in three different orchards, although all were on the same farm. Prof. Forbes summarizes as follows: Finally, to sum up in a word the most important practical results of the orchard experiment with arsenate of lead, we may say that four sprayings, apple trees of old varieties exposed to a very heavy attack by the plum curculio, the first spraying applied in early May just as the trees were coming into bloom and the others at intervals of 10 days thereafter, the whole operations costing 17 cents per tree, may be expected SPRAYING FOR CURCULIO OX APPLE. 193 to increase the yield of the orchard about one-half, to increase the average size of the fruit about one-fiftJ\, and so to improve the quality of the apples that they should be worth from 2\ to 3 times as much as if the orchard had not been sprayed. These experiments were also reported in a paper before the Ameri- can Association of Economic Entomologists, December, 1904, and in Bulletin 108 of the Illinois Agricultural Experiment Station, in which latter publication data are given showing the considerable movement of the beetles from the check to adjacent sprayed plats, a factor in results which lias not heretofore been given sufficient con- sideration. EXPERIMENTS BY THE BUREAU OF ENTOMOLOGY. During the past few years the Bureau of Entomology has carried out spraying experiments against the curculio in different parts of the country and under varying orchard conditions. The importance of the subject warrants the presentation of results in some detail. EXPERIMENTS AT ANDERSON, MO. The work at Anderson, Mo., was under the immediate direction of Mr. F. W. Faurot and was accomplished in cooperation with the Missouri State Fruit Experiment Station. The orchard consisted of a fair selection of varieties of 11-year-old trees in good condition. In addition to the purely demonstration spraying for insects and dis- eases, a test of dusting against spraying was planned on the Lan- singburg variety of apple. The block of Lansingburgs consisted of 6 rows across one end of an 80-acre orchard and was divided into 6 plats, including the check. In Table XCV Plat II is omitted, as it duplicates Plat III, except that a less number of treatments was given, namely 9. This variety bore a good one-fourth crop. The dust was applied with a power duster driven by a gasoline engine. The liquid spray was also applied with a gasoline-power outfit except for the application immediately following the falling of the petals. The soft condition of the ground at this time from rains necessitated the use of a barrel outfit, though the pressure as shown by the gauge was maintained at 125 pounds. The plats contained trees as follows: I, 32; III, 35; IV, 70; V, 67; VI, 12. The check trees were in two rows across the center of the block. The number of trees from which all fruit was gathered and counted throughout the season for ea 1.-.20 3 23 a« 3 ft a ft 1 255 2' 189 3 784 4 240 5 1,1 926 1,037 668 574 3,693 3,57; 1,397 1,043 757 815 1,047 426 1,205 6,690 3 0> Eh a 3 §1 2,185 1,045 5,657 1,29" 1,320 1,777 11,504 3,178 2,15 1,135 1,438 2,877 2,875,10,785 1,867 3,534 2,846 3,505 3,312 21,507 1,072 952 942 65 723 165 718 5,229 1,985 2,104 1,873 2,063 2,448 2,275 3,453 2,741 2, 565 oS ft 3.84 47.81 57.45 As wall be noted, results, so far as preventing puncturing of fruit by curculio, were decidedly poor. Plat I, receiving 13 applications of a homemade dust, was even more severely injured than the block of unsprayed trees, a condition doubtless due to its location. Best results were obtained on Plat V, which had the usual demonstra- tion treatment, giving 57.45 per cent of sound fruit as against 5.51 per cent of sound fruit on the unsprayed trees. The effect of the treatments on the curculio may be judged, per- haps, by the number of punctures per fruit. Thus, Plat I had an average of 6.22 punctures per fruit; III, 2.92; IV, 0.98; V, 0.78; and VI, 6.13. SPRAYING FOR CURCULTO ON APPLE. 195 EXPERIMENTS INT WESTERN NEW YORK AND NORTHWESTERN PENNSYLVANIA. Results of demonstration spraying for apple insects and diseases in western New York (Westfield) and northwestern Pennsylvania (North East) as bearing on the control of the curculio are given in Table XCVI. In the Westfield work the average percentage of apples uninjured by the curculio from the 5 sprayed Baldwin trees used for counts was 91.07, as against 76.21 on the 5 unsprayed count trees, the average number of punctures per fruit for the former being 0.08 and for the latter 0.237. In the case of Duchess trees at North East, Pa., notably better results are shown, which may in part be due to the earlier picking of the fruit of this variety, as avoiding late feeding punctures by the beetles. The 3 count trees of the sprayed block showed 79.04 per cent sound fruit, as against 25.44 from the 3 unsprayed count trees, a difference, in favor of two applications of poison, of 53.60 per cent of the crop. (See PI. XV). Table XCVI. — Results of spraying apples for the plum curculio. WESTFIELD, N. Y., 1908. NORTH EAST, PA., 1906. Plat No. Treatment. Variety. Tree No. Total number of apples Total number of apples punc- tured. Percent- age of sound apples. Average percent- age of sound apples. ("Four applications Bordeaux mix- 1 ture (4-4-50) plus 2 pounds 1 arsenate of lead: May 0, May ( 27, June 8, June 27. Unsprayed [■Baldwin do 1 ' i 3 I I f 1 2 1 3 4 1 5 1,658 2,356 3,380 1,204 2,829 74 244 240 156 207 95.53 89. 04 92.90 87.00 92.60 I 11,427 921 91.07 748 1,518 802 1,100 838 191 309 1S1 212 312 74.40 79. 60 79.00 80. 80 62. 77 II.... 5,066 1,205 76. 21 [Two applications Bordeaux mix- j ture (4-4-50) plus 2 pounds I arsenate of lead: May 24, June 7. i insprayed 1 Duchess Old- f en berg. (1 II P02 541 370 156 154 49 80.54 71 55 B I 1.713 | 359 79.04 647 L46 473 223 95 20. S9 16 7" 11.... 1,061 791 25.44 196 THE PLUM CURCULIO. EXPERIMENTS AT SILOAM SPRINGS, ARK. In the one-spray versus demonstration treatments for the codling moth and apple diseases at Siloam Springs in 1909 special attention was given to determining the effect of these treatments on the cur- culio. The results from only Plats I, IV, and V are given as consti- tuting the principal features of the work. The orchard was an isolated one and contained 344 trees and was divided into five plats. There was a miscellaneous assortment of varieties, but principally Ben Davis, on which variety all counts were made. The treatments which the respective plats received are shown in Table XCVII. Plat I shows an increase in uninjured fruit over the unsprayed plat (Plat V) of 77.20 per cent, and there is a difference in favor of Plat IV of 3.74 per cent of sound fruit. It will be noted that one drench- ing spray in this instance gave somewhat better results than five applications, though this condition is probably to be accounted for by reason of the proximity of Plat IV to the check plat. Table XCVII. — Results of spraying apples for the plum curculio, Siloam Springs, Ark., 1909. Plat No. Treatment. Variety. Tree No. Total number of apples. Total number of apples punc- tured. Total number of punc- tures. Percent- age of sound apples. Average percent- age of sound apples. One spraying only with arsenical; drenched with arsenate of lead, 1 pound to 50 gallons water, Apr. 24-25. Bor- deaux mixture only (4-4-50) May 25-26, July 2. Five applications Bor- deaux mixture (3-3-50) plus 2 pounds arsenate of lead: Apr. 24-25, May 25-26, July 2, July 22, Aug. 10. Unsprayed Ben Davis.. ....do do ( 1 2 3 4 5 6 7 8 9 10 11 ( 1 2 3 4 5 6 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11 12 . 13 5.(is9 4,813 3, 796 2,750 3,446 3,768 3,307 5,443 3,644 2,652 3,895 1,179 915 687 387 208 532 370 706 364 216 335 1,979 1,713 2,613 683 268 1,012 638 1,200 642 319 642 79.27 80.98 81.90 85.92 93.96 85.88 88.81 87.02 90.01 91. S5 91.39 I. 43,203 5,899 11,709 86.34 3,536 1,890 5,076 1,665 3,145 1,665 2,496 3,172 4,791 1,957 3,058 746 301 437 74 266 200 498 467 1,656 140 769 1,293 562 773 98 430 432 1,025 S77 3,129 254 1,429 78.90 84.07 91.39 95.55 91.54 87.98 80.04 85.27 65.43 92.84 74.85 IV.- 32,451 5,554 10,302 82.88 2,560 1,701 995 1,538 1,206 2,501 2,821 1,156 2,323 2,258 1,719 1,608 2,060 2,130 1,595 948 1,522 999 2,299 2,724 1,070 1,936 2,117 1,605 1,517 1,750 6,623 6,230 4,331 10,068 3,372 9,527 14,727 4,714 6, 143 8,707 6,921 5,984 6,739 16.79 6.23 4.72 1.04 17.16 8.07 3.43 7.43 16.65 6.24 6.63 5.65 15.04 v.... 24,446 22,212 94,086 9.14 Bui. 103, Bureau of Entomology, U. S. Dept. of Agriculture. Plate XV. Fig. 1.— Duchess Apples from Trees in Unsprayed Plat, i Original.) Fig. 2. -Duchess Apples from Trees in Plat Sprayed Against the Plum Curculio with Arsenate of Lead. (Original. BENEFITS OF SPRAYING FOR THE PLUM CURCULIO. SPRAYING FOR CURCULTO OX APPLE. 197 EXPERIMENTS IN* VIRGINIA. Experiments in Virginia during 1909 were carried out in two localities, namely, at Crozet, in the orchard of Mr. W. S. Ballard, and at Mount Jackson, in the orchard of the Strathmore Orchard Co. Orchard of Mr. W. S. Ballard. — This orchard is located in the eastern foothills of the Blue Ridge and is composed mostly of the Yellow Newtown variety, which sort was used exclusively in the experiments. The suiTOunding trees not used in the experiment were sprayed by the owner. This work formed part of the •■one-spray" experiment, and especial attention was given to determining the effect of the treatments in lessening curculio injury. Four applications gave a percentage of 86.89 sound fruit as against 54.02 on the untreated trees, a difference of 32.87 per cent. One single drenching applica- tion protected from the curculio to an extent of 73.93 per cent, an improvement over the check of 19.91 per cent. (See Table XCVIII.) Table XCVIII. — Results of spraying apples for the plum curculio, Crozet. Va.. 1 Plat No. Treatment. Variety. Tree Xo. Total num- ber of apples. Total nimi- ber of apples punc- tured. Total num- ber of punc- tures. Per- centage ofsound apples. Aver- age per- centage ofsound apples. I Four applications Bordeaux mix- 1 ture (2-2-50) plus 2 pounds ar- senate of lead: Apr. 27, May 24, [ June 2(5, and July 20 and 27". ("One spraying only, drenched with 1 Bordeaux mixture (2-2-50) phis | 2 pounds arsenate of lead, Apr. 1 -'7. Untreated 1 Xe wto \v n f Pippin. L..do do 1 2 3 4 5 6 7 8, 1 2 3 4 5 6 7 S 1 2 3 4 5 6 7 8 802 1.459 719 2.415 2,082 1,308 3.014 2,328 115 187 103 345 463 114 _ 1 252 157 .-- 163 524 162 395 2S B7. 18 85 1 B5. 71 77.21 91.28 91.14 B9. 17 14.077 1,846 2.072 86.89 II.... 2.57S 2,533 5. 105 1.31s 3,245 1 . 979 2.041 2.039 901 730 1.347 . S 719 405 521 511 1.510 1,290 2.143 360 1,095 775 823 71.17 73. 61 81.94 77.84 79. 53 74.47 74. 93 5,432 8,643 73.93 nr... 3,682 816 1,016 3.111 2,988 5 2,001 1,255 1,571 437 531 1,415 1,193 1,098 1 . 285 2.746 2,571 705 962 2,490 1,939 i . a 5 2,300 63.33 57. 33 46. 45 47. 73 54. 52 60. 00 41. 54 38. 54 19.107 15,578 ■ - 198 THE PLUM CURCULIO. Orchard of the Straihmore Orchard Co. — In the Strathmore orchard, at Mount Jackson, the curculio was notably more abundant, and the results were less favorable. The orchard had been in sod for some years and conditions were thus favorable for the insect. All trees not included in the experiment were sprayed by the owners. The results indicate the impracticability of satisfactorily reducing curculio injury by spraying alone, when conditions are extremely favorable for the insect. Three applications protected the fruit to an extent of 40.82 per cent as against 27.23 per cent on the unsprayed trees, a gain of 13.59 per cent of the crop. Curiously, the single application, given to Plat II, resulted in a higher percentage of sound fruit than the three treatments given to Plat I, namely, 57.90, an increase over the check plat of 30.67 per cent. TableXCIX. — Results of spraying apples/or the plum curculio , Mount Jackson, Va.,1909. Plat No. Treatment. Variety. Tree No. Total num- ber of apples. Total num- ber of apples punc- tured. Total num- ber of punc- tures. Per- centage of sound apples. Aver- age per- centage ofsound apples. I ("Three applications Bordeaux mix- 1 ture (1-1-50) plus 2 pounds ar- | senate of lead, Mav 6-7, 28-29, [ July 8-9. [One spraying only, with arsenical. Drenched with arsenate of lead, 2 pounds to 50 gallons of water, May 6-7. Bordeaux mixture only (2-2-50), applied May 28-29 [ and July 8-9. iBen Davis.. do .do. 1 2 3 4 5 6 8 r i 2 3 4 5 6 7 8 1 2 3 4 5 6 8 1,866 1,308 3,466 708 1,667 3,786 1,063 2,429 1,367 755 1,631 441 1,257 2,197 612 1,382 2,961 2,391 3,067 932 3,013 4,040 1,486 2,869 26. 74 42.28 52.94 37.71 24.59 41.97 42.42 43.10 16,293 9,642 20,759 40.82 II.... 3,827 3,657 675 989 1,679 3,480 969 4,299 1,507 1,788 303 494 754 1,212 447 1,735 2,7S2 1,800 633 1,032 1,449 2,159 987 3,153 00. 62 51.10 55. 11 50.05 55.09 65. 17 53.86 59.64 19,575 8,240 13,995 57.90 III... 3,926 3,109 1,840 1,508 3,189 4,153 5,121 2', 795 3,186 2,226 1,079 1,226 2,399 2,823 3,611 2,107 7,336 4,497 2,212 2.888 5,030 6,122 8,779 4,904 18.84 28.40 41.36 18.69 24.77 32.04 29.48 24.61 25,641 18,657 41,768 27.23 EXPERIMENTS AT ST. JOSEPH, MO. The work at St. Joseph also formed part of a demonstration sched- ule of spraying in comparison with the one-spray method. The orchard used had been in sod for some years, and no spraying had been done. Conditions were especially favorable for the insects, and, as shown by the tabulated results below, the injury under these conditions was very severe. The crop, moreover, was light by reason SPRAYING FOR CURCULIO OX APPLE. 199 of late spring frosts, which served to concentrate the injury. Unques- tionably a part of the loss shown was due to the apple curculio, which was abundant in that locality. At the time of the first application. May 16, the petals had just fallen from the trees. The St. Joseph results present some points similar to those obtained the same year at Mount Jackson, Va., — namely, that when the curculio is excessively abundant, satisfactory results ma}' not be obtained by spraying. Plat I, winch received 4 applications, shows only 50.10 per cent of sound fruit as against 4.05 from the unsprayed trees, representing a gain of 46.05 per cent. The single drenching application, given to Plat II, resulted in 36.80 per cent of fruit free from curculio. a gain over the unsprayed block of 32.75 per cent of the crop. Table C. — Results of spraying apples for the plum curculio. St. Joseph. Mo..l'< . Plat No. Treatment. Variety. Tree No. Total num- ber of apples. Total num- ber of apples punc- tured. Total num- ber of punc- tures. Per- centage of sound apples. Aver- age per- centage of sound apples. I fFour applications Bordeaux mix- 1 ture (4-4-50) plus 2 pounds ar- j senate of lead: May It;, June 9, [ July 9, and Aug. 6." [One application. Drenched with < arsenate of lead, 2 pounds to 50 I gallons water, May 16. >Ben Davis. . L..do .do li ( ! If 1.747 1,624 - 966 660 844 2.443 1 . 355 2.012 44.7(1 59. 35 46 54 4.950 2.470 5,810 50.10 II.... 2.769 3.019 1.909 1.749 5.0.54 4.230 31. 05 - " 788 3,658 9.290 III. 1,604 1.437 1,358 1,625 • 1 . 284 7.715 5.275 4.07 2 71 5.44 1,489 4.307 21 . 567 The records above given in spraying apple orchards for the cur- culio are assembled in Table CI, which indicates, in average per- centages, the amount of uninjured fruit from each plat from the several localities, arranged according to the number of applications given. These experiments have extended over a period of several years and were made in various places, so that the results are not entirely comparable. Even when considering the results of indi- vidual experiments, a wide variation is seen in results from orchards which received practically the same treatment for example, in the two orchards in Virginia sprayed during 1009. 200 THE PLUM CURCULIO. Table CI. — Summary of results in spraying apples for the plum curculio, in average percentages of sound fruit, various localities. Localities. Treatments. Illinois. Ander- son, Mo. West- field, N. Y. North East, Pa. Siloam SDrings, Ark. Crozet, Va. Mount Jackson, Va. St. Joseph, Mo. 1 application 86.34 73.93 57.90 36.80 79.04 40.82 91.07 86.89 50.10 5 applications 82.88 7 applications (Paris 45.47 44.61 47.80 44.52 44.74 7 applications (arse- nate of lead) 57.45 7 applications (arse- nite of lime) 8 applications 10 applications 13applications(home- made dust) 3.84 22. 15 13 applications (com- mercial dust) 62.08 25.21 Unsprayed (check)... 5.51 j 76.21 25. 44 9.14 54. 02 27. 23 4.05 CONCLUSIONS. The records above given of results of spraying apples for the con- trol of the curculio indicate clearly that the injuries of the pest may be in all cases greatly reduced, although the degree of benefit varies widely. It is apparent that account must be taken of other factors, as the relative abundance of the insects as compared with the amount of fruit present on the trees. With a small fruit crop and abundance of curculios, the most thorough spraying will not serve to bring through a satisfactory amount of sound fruit, as will be noted in the results of experiments at St. Joseph, Mo. With a large crop of fruit and an abundance of insects, results will likewise be disappointing. If the curculios for any cause are scarce and there is a large fruit crop, injury is of course much less important. In other words, the degree of success in spraying varies with the abundance of the insects, and where the latter are numerous thorough treatments seem to fail to yield a desired freedom from injury. While spraying is undoubt- edly a most important adjunct, and if persisted in from year to year may answer for its control, as its effects are cumulative, yet it is clear that other control measures should also be employed. In all cases which have come under our observations the insects have always been found most abundant in orchards which are in sod or are poorly cared for and allowed to grow up more or less in weeds and trash. Also orchards adjacent to woods always suffer severely, especially along the border. (PL XVI.) As opposed to this condition is the notably less injury in orchards kept free from weeds and trash. In such cases sprayings usually given for other orchard insects, as the codling moth, serve to keep this pest well under control. In Bui. 103, Bureau of Entomology, U. S. Dept. of Agriculture. Plate XVI. Fig. 1. -Native Plum Thicket in the South, Adjacent to Peach Orchard. (Original.) M£, J Fig. 2.— Woods and Thicket Adjacent to Plum Orchard, Furnishing the Beetles with Excellent Hibernation Quarters. iOriginal.i CONDITIONS FAVORING THE PLUM CURCULIO. SPRAYING FOR CURCULTO OX APPLE. 201 fact it may be said as a general statement that the curculio will never become seriously troublesome in apple orchards given the usual routine attention in cultivation, spraying, pruning, etc., now- considered essential in successful fruit growing. Serious losses from the curculio are almost conclusive evidence of neglect, which is besl and most quickly corrected by the adoption of proper orchard prac- tice. The following schedule of spraying is recommended for apple orchards and should control the plum curculio as well as the numer- ous other insects mentioned. Where the curculio is excessively troublesome a treatment about midway between the third and fourth would probably be advantageous. SCHEME FOR SPRAYIXG APPLE ORCHARDS.1 First treatment. — Spray with arsenate of lead in Bordeaux mix- ture or dilute lime-sulphur solution for apple scab when cluster buds are out, but before the blossoms open. This treatment is valuable against the bud moth, cankerworms, plum and apple curculios, tent caterpillar, etc. Second treatment. — As soon as the petals have fallen, spray very thoroughly with arsenate of lead in Bordeaux mixture or dilute lime- sulphur solution so as to place a dose of poison in the calyx cup of each young apple. Larva? of the codling moth, the principal cause of wormy apples, hatching some three or four weeks later, mostly enter the fruit at the blossom end, and are thus killed. This is the most important of all treatments for the codling moth and is valua- ble in destroying the lesser apple worm (Enarmonia prunivora), plum and apple curculios, cankerworms, tent caterpillars, etc. Tldrd treatment. — Three or four weeks after blossoms have fallen use arsenate of lead in Bordeaux mixture or dilute lime-sulphur solution, thoroughly coating the foliage and young fruit. This is valuable against the codling moth and affords further protection against the insects above mentioned. Fourth treatment. — An additional application of the arsenical in a fungicide may be necessary, nine or ten weeks after the blossoms fall, for the second brood of the codling moth, and. in the Middle and Southern States especially, a fifth treatment is advisable two or three weeks later. In orchards not infested with the bud moth and canker- worms the first treatment may be omitted. The second, third, and fourth applications will suffice to give protection from most insect pests of the fruit and foliage, supplemented by the fifth for the ter- ritory indicated. i Excellent results in control of the curculio and the Codling moth have been obtained from a single application of an arsenical after the falling of the petals. The one-spray treatment is most likely to he ot value for varieties not subject to scab and bitter rot. The reader should obtain copies Of rej>orts on one-spray method, being Tart VII of Bulletin 80 and Cart 11 of Bulletin 116 of this bureau. 202 THE PLUM CURCULIO. SPRAYING PEACHES WITH ARSENIC ALS. Until within recent years comparatively little experimentation has been done with arsenicals for the control of the curculio on the peach. During the past five or six years, however, the subject has received attention at the hands of different investigators, and suffi- cient data have been accumulated to indicate about how much pro- tection may be expected. Paris green and London purple were undoubtedly early used on the peach, beginning with the first employment of these arsenicals against this insect. It was soon noted, however, that the foliage of peach was more sensitive than that of other deciduous fruits, and for this reason spraying of peaches seems not to have been practiced to any great extent. This foliage injury from arsenicals had been frequently commented upon and was pointed out by Dr. Forbes in 1888 and 1889, and also by Prof. Weed, who gave experience of a Marion County, Ohio, fruit grower, as follows: We accidentally stumbled over the fact that from 60 to 70 gallons of water to one- half pound of poison in solution was strong enough to fully check the curculio and all or more than the peach tree would stand. We destroyed a plum tree and several peach trees with our experiments, and know that 100 gallons to 1 pound of poison in solution is too strong for the foliage of some varieties of apples and that it will kill a peach or plum tree. My own opinion is that one-half pound of poison to 60 gallons is safe, and if applied at the time of the usual bloom of apple and the second time 10 days later will destroy the leaf -eating insects and the codling moths, but for plum and peach one-fourth pound to 40 gallons of water is strong enough and will, if applied twice, effectually check the ravages of the curculio without destroying the foliage. Despite frequent serious defoliation of trees some peach growers undoubtedly continued the use of Paris green and London purple, especially in the Northern States. In the South comparatively little spraying was done, so far as available records indicate. The control of the curculio on peach was therefore largely limited to the practice of jarring, and this work was not very generally followed, the insect being allowed to continue its depredations unchecked. With the increase of commercial peach culture in certain of the Southern States, notably in Georgia, and in view of the favorable conditions for the multiplication of the pest, its injuries became especially serious, not only on account of the fruit destroyed by it, but by reason of the prevalence in that section of a serious fungous disease of the fruit at about ripening time, namely, the so-called brown-rot, which the work of this insect, by its punctures, greatly favored. Considerable attention has been given during recent years to determining, if possible, ways in which Paris green and also copper fungicides may be safely used on the peach, notably by Messrs. SPRAYING PEACHES WITH ARSENICALS. 203 Gillette, Galloway, Woods, Fairchild, Sturgis, Baine, and Iledrick. It was found that the addition of lime to the Paris green or London purple spray greatly reduced its causticity, and the use of Paris green in this way was recommended for peach by Haywood, who says: In spraying peach trees, none of the Paris greens bought upon the market should be used without the addition of lime. For peach trees sprayed with the use of lime, the amount of soluble arsenic oxid allowable lies between 3 and 6 per cent, a fair average being Ah per cent.1 Nevertheless, even with the use of lime two or three applications of a Paris-green spray very generally resulted in defoliation of the trees, and in recommendations for the use of arsenicals on peaches this risk was very generally pointed out and understood by the majority of peach growers. The development of arsenate of lead, a stable compound con- taining practically no free arsenic, it was thought would furnish an arsenical which might be used without injury on peaches. Experi- ments to determine its usefulness were at once begun by entomolo- gists, and while it was noticeably less injurious than Paris green or London purple, yet in the South especially several applications, as deemed necessary for the control of the insect, caused a considerable amount of foliage to fall and often resulted in burning of the fruit. Arsenate of lead, however, was generally recommended for peach spraying by the manufacturers and also with caution by many entomologists and horticulturists. Not a few orchardists who tried the poison experienced disastrous results, whereas comparatively little injury was noted by others, who preferred to take the risk of foliage and fruit injury in preference to suffering the ravages of the curculio. In a word, opinion was divided as to the advisability of spraying peaches with arsenate of lead, with perhaps on the whole a distin< ( prejudice against it. In the course of the present curculio studies particular attention has been directed to the question of arsenical injury to peaches. During 1906 green arsenoid, Paris green, and arsenate of lead (both commercial and homemade) were tried on peaches according to a uniform plan of treatment in the Southern. Middle, and Northern States, in order to secure if possible comparative data from these regions. In all localities the green arsenoid and Paris green (.'> applications each of 4 ounces to 50 gallons of lime water) proved injurious, defoliating trees almost completely. In northwestern Pennsylvania neither the commercial nor the homemade lead arsenate (3 applications at the rate each of 2 pounds to 50 gallons of lime water) caused noticeable injury. In Virginia the homemade lead I Bui. 82, Bur. Cheiu., U. S. Dept. Agr., p. 33, llJ04. 204 THE PLTJM CURCTJLIO. arsenate largely defoliated the trees and burned the fruit. There was, however, little foliage injury from the commercial arsenate of lead, though the fruit was injured and nearly all fell from the trees before ripening. In Georgia both forms of arsenate of lead defoliated the trees almost completely and injured the fruit to a serious extent, the homemade lead arsenate being the more injurious. Also, during 1906, in Virginia, several other commercial brands of arsenate of lead were tried and no difference between them could be distinguished as to their effect on foliage and fruit. Arsenic sulphid in paste form, at the rate of 2 pounds to 50 gallons of lime water, was applied once and quickly defoliated the trees, killing the twigs and smaller branches, resulting finally in the death of several of the trees sprayed. During 1907 eight additional brands of arsenate of lead were tried in Virginia with from 1 to 4 applications in strength, varying from 1 to 3 pounds per 50 gallons of water. These were used with and without lime. Two applications at the rate of 2 pounds to 50 gallons of water, plus 2 or 3 pounds of stone lime, were found reasonably safe; and this treatment was adopted for recom- mendation to growers, although the risk of possible injury was pointed out. In cooperation with the Bureau of Chemistry an inquiry was started in 1907 to determine if possible the reasons for injury to peach foliage from arsenate-of-lead sprays. The results of the work during 1907 and 1908 have been stated by Messrs. J. K. Haywood and C. C. McDonnell,1 and conclusions were presented from the ex- periments in 1909. These studies have been extensive and are interesting as bearing on the causes of the decomposition of lead arsenate when sprayed on peach trees, resulting in injury to foliage and fruit. The idea of decomposition of the poison by the action of the carbon dioxid of the air was disproved by numerous tests, but it was found, in an examination of water used in spraying, that this contained a sufficient quantity of sodium chlorid (common salt) to decompose an appreciable quantity of the lead arsenate; and it was concluded that if certain salts commonly present in water were present in more than very small quantities they would exert a solvent action on the arsenate of lead. Concerning this matter Messrs. Haywood and McDonnell state.: (1) When applied with spring water (analysis of which has been given), some injury to foliage resulted, but it was not nearly so marked as in the preceding year, and a longer time elapsed before the injury was noticeable. (2) When applied with distilled water very slight injury occurred, noticeably lees than when the spring water was used. (3) When applied with distilled water to which 10 grains per gallon of sodium chlorid had been added, rather serious injury resulted. When distilled water con- i Bui. 131, Bur. Chem., U. S. Dept. Agr., p. 49, 1910. SPRAYING PEACHES WITH APwSEXICALS. 205 taining 40 grains of sodium chlorid per gallon was used, the injury was very much increased, practically 50 per cent of the foliage being affected. (4) When applied with di-rilled water containing 10 grains of sodium carbonate pel gallon, injury was noticeable 14 days after the first application, and 7 days after the third application the trees were almost completely defoliated. (5) Applied with distilled water containing 10 and 40 grains of sodium sulphate per gallon, some injury resulted, but this was not so marked as that produced in the presence of sodium chlorid. In similar experiments where lime was added at the rate of 4 pound Ion-, injury to the foliage was almost entirely prevented. In view of the above observations as to the possible importance of the water used in spraying, the Bureau of Entomology carried out spraying experiments in orchards in Georgia during 1910, employing 9 well-known brands of arsenate of lead, using these in ordinary well water and also in rain water, which it was thought would be entirely free from sodium chlorid and other salts. Three applications of the sprays were made, the milk of lime made from 2 pounds of good stone lime being added to the spray in each case. With all of the brands of arsenate of lead, the first two applications did no appre- ciable injury. The third application, given a month before ripening of the fruit, however, resulted in serious injury, which began to show after a rainy spell about a week after the applications. There appeared on the fruit brown sunken spots, which rapidly increased in size, causing the fruit to crack and drop to the ground until by picking time only 25 per cent still remained on the trees. This was barely fit for market purposes, having a dark red, almost black, appearance on the side exposed to the sun. These trees were 50 to 90 per cent defoliated. Xo difference in injury was to be detected from the use of rain water against ordinary well water. These same brands of lead arsenate were used on trees alongside in the self-boiled lime-sulphur wash ol the formula: Sulphur, 8 pounds; stone lime, 8 pounds; water to make 50 gallons. In these tests none of the fruit was burned enough to canst4 it to drop, all of it being merchantable. Some specimens, however, were so highly colored that they were placet 1 in the second grade. About 20 per cent of the foliage on these lime-sulphur plats showed some injury. but none of it dropped. As regards the comparative injury from the different brands of arsenate of lead, very little difference could be detected, save in the case of one brand, which showed up about the same amount of injury as in the case of the other brands when applied in lime-sulphur wash. It was tested, however, on trees in another part of the orchard, as it was received too late to be included in the block where the balance of the lead arsenates were tried. In addition to tests of lead arsenates, certain other arsenicals were tried to determine their effect on the foliage and fruit. The toxicity of these arsenicals was at the same time being determined in the 206 THE PLUM CURCIJLIO. laboratory by feeding tests with the beetles. (See p. 186.) In each case the miik of lime from 2 pounds of stone lime was used to each 50 gallons of spray. Arsenic sulphid (As2S2), f pound to 50 gallons of water, was applied once April 29. By June 5 the plat treated with the poison in rain water showed injury to almost all of the leaves, with con- siderable foliage fallen, and this same condition prevailed on the plat treated with the poison in well water. On the lime-sulphur plat less than one-half as many leaves were injured and very few leaves had fallen. Arsenic tersulphid (As2S3), 6 ounces to 50 gallons of water, applied April 13 and 24, showed by May 10 about 75 per cent of defoliation of all the trees on the 3 plats. Red sulphid of arsenic (As2S2), 6 ounces to 50 gallons of water, applied April 13 and 29, showed on all plats by June 5 a condition similar to the arsenic tersulphid plat, though new foliage was coming out. Sulpho-arsenate of soda, 6 ounces to 50 gallons of spray, showed by June 5 about 60 per cent of the foliage fallen, with those remaining badly burned and shot-holed. This condition was true oil the 3 plats where the poison was used in well water, rain water, and the self- boiled lime-sulphur wash. Arsenate of iron in paste form, 2 pounds to 50 galloons of water, applied April 29 and June 16, resulted in no foliage and fruit injury whatever throughout the season. Arsenate of iron in powdered form, 1 pound to 50 gallons of water, applied to the trees April 13 and 29 and June 16, also resulted in no injury on any of the plats throughout the season. Tests of the killing effect of arsenate of iron on the beetles in the laboratory indicated, however, that it is a very slow-killing agent; but it is probable that the beetles after first eating of the poison are rendered incapable of further .important injury. Additional tests are planned with this poison on a commercial scale in orchards. During 1908 and 1909 feeding tests with beetles and also with various caterpillars were made, using various compounds regarded as more or less toxic, with a view to their possible substitution for arsenicals for use on the peach. Among those tried were the f olio wing : Black sulphid of antimony (SboS3V Barium sulphid (BaS). Barium carbonate (BaC03). Copper sulpho-cyanid (Cu4SCNfl). Carbonate of lead (PbC03). Lead oxid (PbO). Zinc oxid (ZnO). Zinc cyanid (ZnCN). SPRAYING PEACHES WITH ABSEHTICAL6. 207 None of these, however, gave sufficient promise to warrant field tests. From the foregoing it will be noted that severe injury has resulted from the use on peach of green arsenoid, Paris green, zinc sulphid, red sulphid of arsenic, tersulphid of arsenic, and sulpho-arsenate of soda. Injury from arsenate of lead has been variable, according to season, and especially depending upon the number of applications made. Two early treatments of the poison at the rate of not over 2 pounds to 50 gallons of water, with an equal or greater quantity of lime added, have on the whole caused comparatively little injury, although in some years injury has been fairly well marked. Three applications of lead arsenate in limewater, however, have rather uniformly been injurious. No important difference in the burning effect of the different brands of arsenate of lead has been detected: and according to the tests made in 1910 in the comparison of rain water and w7ell water no difference between them was discernible. The time between the applications of the poison and the appear- ance of injury to the foliage varies, depending upon the arsenical in question. Thus Paris green, green arsenoid, and sulphid of arsenic promptly show a shot-holing and yellowing of the leaves. which later drop more or less completely. (See PL XVII, figs. 1-6.) The injury resulting from lead arsenate is about the same, only it is slower to appear. In the case of twTo applications dropping of the leaves may be so gradual as not to attract attention and may be largely compensated for by the production of new foliage. A third application, however, is generally followed by a decided and prompt dropping of the foliage, usually within 10' days or 2 weeks, leaving the branches more or less bare and the fruit exposed to the sun. Arsenate of lead also produces a notable reddening of the fruit, though this reddening is due in part to an increased amount of sun- shine following the thinning of the leaves. This increased coloring is the subject of common remark by growers, and if but one or two applications of the poison have been made is not so pronounced as to detract from the appearance of the fruit. A third application, how- ever, very generally results in an intense dark-red coloring and the associated changes brought about very often result in brown depressed areas of variable extent and a. cracking on the sunny side o( the peach. Fruit so injured is worthless and mostly drops before ripen- ing time. (See PI. XVIII, fig. 1.) For the proper control of the curculio on peach three or four applica- tions of the poison would be desirable. However, in view o( the injury resulting from more than two treatments, recommendations have been limited to two timely applications of the poison, and always with the addition of limewater. This treatment gave a considerable degree oi protection and has recently come into a rather extended use by peach growers. 208 THE PLUM CURCULIO. SOME RESULTS OF SPRAYING PEACHES FOR THE CURCULIO. In the following tables some results of spraying peaches for the curculio are presented. The benefits are seen to vary from season to season, as in the case of the apple, depending upon the abundance of the insects. On account of the difficulty of taking note of punc- tures in the fuzzy peaches, the results are based on records of actual infestation of fruit by larvae or indications of the presence of the latter. The results obtained by tins method of computation on the different plats should be entirely comparable. Examinations were made of all drop fruit during the season, as well as of the ripe fruit at picking time. One of the most important results in spraying for the curculio is the reduction of brown rot. The punctures of the curculio in the fruit form an easy point of infection, and very notable benefits in the reduction of brown rot may be observed in orchards sprayed only for the curculio. In Table CII are given results of spraying of peaches in 1906 on the Arlington Farm, Va. The orchard used contained about 500 trees and was an isolated one, but adjacent to a thick growth of young trees and bushes. Not all of the trees were treated, each plat con- taining some 50 trees. The applications were made on the dates indicated in the table. It was also thought desirable to determine the possible benefit of spraying the trees heavily with simply lime- water, inasmuch as this method of curculio control has been some- what exploited. Table CII. — Results of spraying peaches for lite plum curculio, Arlington Farm, Va. 1906. The curculio was not especially abundant in tins orchard during 1906; as shown by the condition of the check, about 25 per cent of Bui. 103, Bureau of Entomo.ogy, U. S. Dept. of A£ PLATE XVII. Bui. 103, Bureau of Entomology. U. S. Dept. of Agriculture. Plate XVIII. Fig. 1.— Elberta Peach Sprayed Three Times with Arsenate of Lead, Showing Burning and Cracking Effects of the Poison. (Original.) Fig. 2.— Japanese Plums, Showing Burning from one Application of Arsenate of Lead. (Original.11 ARSENICAL INJURY TO FRUIT SPRAYING PEACHES WITH AESENICALS. 209 the fruit was infested. Nevertheless, the results show a certain benefit, there being a gain in uninjured fruit on the plat treated with arsenate of lead of 20.63 per cent, and on Plat II, treated with lime, of 10.76 per cent. Results obtained also in 1906 at Myrtle, Ga., are shown in Table CIII. The trees treated were located in an 8-acre block of the Georgia Belle variety, composing a 200-acre orchard. The treated area, however, was on one side of the orchard and fairly well separated from the main body of the trees. Conditions for the curculio were here ideal on account of adjacent woods, and the presence here and there through the orchard of terraces which had become overgrown with bushes, weeds, etc. Each plat comprised 50 trees. The dates and character of applications are shown in the table, as well as the number of trees on which records were taken. The average percentage of sound fruit on the untreated trees was 67.59 per cent. As compared with this injury there is a gain in sound fruit on Plat I, sprayed with arsenate of lead, of 21.04 per cent, and on Plat II, sprayed with lime, of 2.20 per cent. Results of spraying peaches at Mayfield, Ga., for the curculio in 1 908 are shown in Table CIV. This work was carried out by the office of the Georgia State entomologist according to a plan furnished by this bureau. Each plat contained 60 trees of the Elbert a variety, and while a sufficient number of trees was not used for making counts of the fruit, the results are nevertheless significant. Table CIII. — Results of spraying Georgia Belle peaches for the plum curculio, Myrtle, Ga., 1906. Plat Treatment. Tree Fruit from ground. Fruit from - tree. Total num- ber of fruits. Total num- ber of Per- cent- Aver- age per- No. No. Total. In- fested. T»«- i. fruits in- fested. sound age of fridt. sound fruit. I Three applications homemade ar- senate of lead 2 pounds to 50 gallons of water plus 3 pounds stone lima: Apr. 10, 21, and- 30. Three applications of whitewash. 15 pounds lime to SO gallons water (no arsenical): Apr. 3, 13, and 21. f 1 2 3 4 5 6 8 9 10 11 . 12 f 1 2 3 4 ■") 6 8 <> 10 ii 12 18 28 47 39 33 10 38 14 42 23 14 27 4 6 7 13 10 4 22 3 16 11 4 14 121 171 144 135 L80 81 213 • 92 4s 134 27 4 4 9 5 5 8 5 L6 15 8 139 199 191 174 213 91 25 1 94 11.") ltd 31 10 11 22 1.") 9 30 8 26 11 22 94.97 94. 24 90. 10 >^04 91.48 ::::::: 333 114 1.665 113 88.63 II.... 2 10 f>f> 10 33 17 28 27 22 27 .V) 1 4 10 fi 20 1 16 15 12 1 13 24 32 29 89 59 144 46 Id 31 220 2 12 9 3 23 ;> ii 3 50 26 42 143 3'.) 102 7ti id 171 23 270 3 16 L9 3.; 17 39 50 21 3] ^7 88 61.90 So. 71 7ti. 92 85. 70 ::.< I 57. u 70. 76 69. 1 1 69. 56 87.74 : 299 810 i>.'.; 335 17262°— Bull. 103— 12- -11 210 THE PLUM CURCULIO. Table CIII. — Results of spraying Georgia Belle peaches for the plum curculio, Myrtle, Ga., 1906— Continued. Plat No. Treatment. Tree No. Fruit from grounds. Fruit from tree. Total Total num- ber of fruits in- fested. Per- cent- age of sound fruit. Aver- age per- Total. In- ested. Total. In- fested. ber of fruits. cent- age of sound fruit. III. . . f 1 2 3 4 5 6 7 8 9 10 11 . 12 34 29 70 69 81 28 18 14 22 16 21 17 14 . 22 33 33 48 16 14 11 12 6 18 9 42 25 185 224 187 98 46 75 58 80 29 75 18 17 28 52 48 26 17 20 14 6 7 11 76 54 255 293 268 126 64 89 80 96 50 92 32 39 61 85 96 42 31 31 26 12 25 20 57.89 27.77 76.08 70.98 64.17 66.66 51.56 65. 16 67.50 87.50 50.00 78.26 419 236 1,124 264 1,543 500 67.59 Table CIV. — Results of spraying Elberta peaches for the plum curculio, May field, Ga. 1908. Plat No. Treatment. Tree No. Fruit from ground. Fruit from tree. Total num- ber of fruits. Total num- ber of fruits in- fested. Per- cent- age of sound fruit. Aver- age per- Total. In- fested. Total. In- fested. cent- age of sound fruit. I Four applications, 2 pounds arsenate of lead plus 3 pounds stone lime per 50 gallons of wa- ter: Apr. 2, 11, 17, and 25. Three applications, 2 pounds arsenate of lead plus 3 pounds stone lime per 50 gallons of wa- ter: Apr. 2, 11, and 17. Two applications, 2 pounds ar- senate oi lead plus 3 pounds stone lime per 5C gallons water: Apr. 2 and 11. n 1! (.1 l 2 1 3 4 I 5 156 100 194 14 11 19 336 110 437 137 32 127 492 210 631 151 43 146 69.31 79.53 76.86 450 44 883 296 *1,333 340 74.41 II.... 98 188 228 296 12 9 18 34 322 213 361 331 137 107 140 154 420 301 589 627 149 116 158 188 64.52 61.46 73.18 70.02 810 73 1,227 538 2,037 611 70.00 III... 136 135 163 61 46 16 26 3 184 299 336 145 97 38 132 45 320 434 499 206 143 54 158 48 55.31 87.56 68. 34 76.70 495 91 964 312 1,459 403 72.30 IV... 119 86 133 85 134 87 59 39 61 82 75 10 278 125 143 64 9 197 122 126 194 96 411 210 277 151 68 236 183 208 22. 17 29.17 42.58 12.86 24.91 557 328 631 518 1,188 846 28.78 It will be noticed that on the unsprayed block only 28.78 per cent of the fruit was uninfested. Plat I, which received 4 applications of arsenate of lead, shows a gain in sound fruit of 45.63 per cent. Plat II, which received 3 applications, of 41.22 per cent, and Plat III, receiving 2 applications, a gain of 43.52 per cent. According to the notes accompanying this experiment very serious injury followed the SPRAYING PEACHES WITH ARSENICALS. 211 4 applications given Plat I, and the injury to Plat III was also so severe as to render unsafe such a number of applications. Table CV gives results of spraying Elberta peaches for the curculio at Baldwin, Ga., in 1910. (See PI. XIX.) These plats contained some 200 trees each and counts were made of fruit produced through- out the season on 12 trees from each plat. Two applications of arsenate of lead were made, the first in water and the second in the self -boiled lime-sulphur wash (see p. 212). At the time of the first application, April 7-8, the blossoms of the trees had just fallen. The unsprayed block (Plat II) yielded 56.85 per cent of sound fruit as compared with 89.85 per cent of sound fruit from the sprayed block, a gain of 33 per cent. Table CV. — Results of staying Elberta peaches for the plum curculio, Baldwin, Ga., 1910. Fruit from Fruit from Plat No. Treatment. Tree No. ground. tree. Total Total p °um"f ceSt- btrof ~£"f f™* Sfund feSed. fruit' age per- Total. In- fested. Total. In- fested. ber of fruits. cent- age of sound fruit. f 1 447 7 589 26 1,036 33 96.81 9 119 8 465 45 584 53 90.92 I First application Apr. 7-8, ar- 3 177 10 388 65 565 75 86. 72 senate of lead 2 pounds to 50 4 363 24 606 76 969 100 8S.63 gallons water; second applica- 0 161 10 335 61 496 71 85.68 tion, 2 pounds arsenate lead in 0 96 12 409 26 505 38 92. 47 self-boiled lime-sulphur wash 7 99 2 358 38 457 40 91. 23 (8-8-50), Apr. 27-28; third ap- plication, lime-sulphur wash 8 222 22 293 33 515 55 89. 32 9 702 25 412 123 1,114 148 86. 71 only (8-8-50), June 17-18. 10 224 6 476 83 700 89 87. 28 11 68 7 410 50 478 57 88.07 I 12 348 17 456 58 804 75 90. 67 3,026 150 5, 197 684 8.223 834 j S9.S5 f 1 188 115 324 178 512 293 42.77 2 187 83 385 132 572 215 82.41 3 147 85 280 155 427 240 43.79 4 839 114 648 239 1,487 353 76.26 5 76 56 129 79 205 135 34.14 u.... Untreated 6 7 605 192 165 71 471 177 189 94 1.076 369 354 16S 67.10 55. 28 * 318 oo 299 147 617 202 67.26 9 68 67 388 251 456 318 30. 26 10 143 67 176 137 319 2H 36.05 11 214 110 347 231 561 341 39.21 I 12 .'74 100 283 168 557 268 51.88 3,251 1.088 3,907 2.000 7. 158 The recent development, by Prof. W. M. Scott of the Bureau of Plant Industry of this department, of the self-boiled lime-sulphur wash as a fungicide for the control of brown rot and the scab of peach at once gave an enormous impetus to peach spraying. The desirability of combining arsenate of load with the self-boiled lime- sulphur wash led to many tests to determine its practicability. Such a combination, while resulting in important chemical changes, has in actual practice resulted in a spray which appears to be perfectly safe to peach foliage and fruit. Experience during the past 3 years 212 THE PLUM CUECULIO. with this combined spray on peaches under varying climatic condi- tions seems to leave no doubt that by this combination the injurious properties of the arsenate of lead, as when used alone, are so reduced as to be practically negligible. This probably results from the ex- cess of lime in the self-boiled wash. In Circular 120 of this bureau, published in the spring of 1910, a schedule of applications for this combined spray was given, including 2 applications of arsenate of lead with an additional one of the lime-sulphur wash alone. This schedule was followed by many orchardists in the South and a large aggregate of trees was thus treated. The results have been uni- formly satisfactory, so far as controlling the curculio and the diseases are concerned, and without noticeable injury to the foliage and fruit above referred to. It may therefore be assumed that a satisfactory combined spray for the insect and the brown rot and scab of the peach has been established, as has so long been in use on other deciduous fruits. Results of further experiments with this combined spray for the curculio, brown rot, and scab during 1910 have been given in Far- mers' Bulletin 440, fully confirming previous results as to its great usefulness for the practical control of these three troubles. It is practically certain that its use will be equally effective in preventing losses to other stone fruits, as plums, cherries, apricots, etc. Direc- tions for making the self-boiled lime-sulphur wash and arsenate of lead spray, with a schedule of treatments for peaches, are quoted from the bulletin above referred to. DIRECTIONS FOR THE PREPARATION OF SELF-BOILED LIME-SULPHUR WASH. The standard self-boiled lime-sulphur mixture is composed of 8 pounds of fresh stone lime and 8 pounds of sulphur to 50 gallons of water. In mild cases of brown rot and scab a weaker mixture con- taining 6 pounds of each ingredient to 50 gallons of water may be used with satisfactory results. The materials cost so little, how- ever, that one should not economize in this direction where a valu- able fruit crop is at stake. Any finely powdered sulphur (flowers, flour, or " commercial ground" sulphur) may be used in the prepa- ration of the mixture. In order to secure the best action from the lime, the mixture should be prepared in rather large quantities, at least enough for 200 gal- lons of spray, using 32 pounds of lime and 32 pounds of sulphur. The lime should be placed in a barrel and enough water (about 6 gallons) poured on to almost cover it. As soon as the lime begins to slake the sulphur should be added, after first running it through a sieve to break up the lumps, if any are present. The mixture should be constantly stirred and more water (3 or 4 gallons) added Bui. 103, Bureau of Entomology, U. S. Dept. of Agriculture. Plate XIX. Fig. 1.— Gasoline Power Outfit in Operation. (Original.) Fig. 2.— Determining Results of Spraying, Each Peach Being Cut Open. Original.) FIELD EXPERIMENTS IN GEORGIA FOR CONTROL OF PLUM CURCULIO AND PEACH DISEASES. SPRAYING PEACHES WITH ARSENICALS. 213 as needed to form at first a thick paste and then gradually a thin paste. The lime will supply enough heat to boil the mixture sev- eral minutes. As soon as it is well slaked water should be added to cool the mixture and prevent further cooking. It is then ready to be strained into the spray tank, diluted, and applied. The stage at which cold water should be poured on to stop the cooking varies with different limes. Some limes are so sluggish in glaking that it is difficult to obtain enough heat from them to cook the mixture at all, while other limes become intensely hot on slaking, and care must be taken not to allow the boiling to proceed too far. If the mixture is allowed to remain hot for 15 or 20 minutes after the slaking is completed, the sulphur gradually goes into solution, combining with the lime to form sulphids, which are injurious to peach foliage. It is therefore very important, especially with hot lime, to cool the mixture quickly by adding a few buckets of water as soon as the lumps of lime have slaked down. The intense heat, violent boiling, and constant stirring result in a uniform mixture of finely divided sulphur and lime, with only a very small percentage of the sulphur in solution. The mixture should be strained to take out the coarse particles of lime, but the sulphur should be carefully worked through the strainer. DIRECTIONS FOR USING ARSENATE OF LEAD. Many experiments have shown that well-made arsenate of lead is much the safest of all arsenicals at present available for use on the peach. Arsenate of lead is to be found on the market both as a powder and as a putty-like paste, which latter must be worked free in water before it is added to the lime-sulphur mixture. The paste form of the poison is largely used at the rate of about 2 pounds to each 50 gallons of the lime-sulphur wash and is added, after it has been well worked free in water, to the lime-sulphur spray previously prepared. As there are numerous brands of arsenate of lead upon the market, the grower should be careful to purchase from reliable firms. A decided change in color will result when the arsenate of lead is added to the lime-sulphur mixture, due to certain chemical changes which, in the experience of the writers, do not injuriously affect the fungi- cidal and insecticidal properties of the spray or result in important injury to the foliage. In large spraying operations it will be more convenient to prepare in advance a stock mixture of arsenate of lead, as follows: Place 100 pounds of arsenate of lead in a barrel, with sufficient water to work into a thin paste, diluting finally with water to exactly 25 gallons. When thoroughly stirred, each gallon of the stock solution will thus contain 4 pounds of arsenate of lead, the amount necessary for 100 214 THE PLUM CURCULIO. gallons of spray. In smaller spraying operations the proper quantity of arsenate of lead may be weighed out as needed, and thinned with water. In all cases the arsenate of lead solution should be strained before or as it is poured into the spray tank. The necessary care should be exercised to keep the poison out of the reach of domestic and other animals. Powdered arsenate of lead is used at about one- half the strength of the paste form. SCHEDULE OF APPLICATIONS. Most of the peach orchards in the eastern half of the United States should be given the combined treatment for brown-rot, scab, and curculio. This is particularly true of the southern orchards, where all these troubles are prevalent. In some of the more northern orchards the curculio is not very troublesome, but as a rule it will probably pay to add the arsenate of lead in at least the first lime- sulphur application. The self-boiled lime-sulphur mixture referred to in the following outlines of treatment should be made of a strength of 8 pounds of lime and 8 pounds of sulphur to each 50 gallons of water, and the arsenate of lead should be used at the rate of 2 pounds to each 50 gallons of the mixture or of water. When the poison is used in water there should be added the milk of lime made from slaking 2 to 3 pounds of good stone lime. When used in the lime-sulphur mixture additional lime will not be necessary. Midseason varieties. — The midseason varieties of peaches, such as Reeves, Belle, Early Crawford, Elberta, Late Crawford, Chairs, Fox, and Beers Smock, should be sprayed as follows : (1) With arsenate of lead alone, about 10 days after the petals fall (PI. XX), or at the time the calyxes are shedding. (2) With self -boiled lime-sulphur and arsenate of lead, two weeks later, or four to five weeks after the petals have been shed. (3) With self -boiled lime-sulphur alone, four to five weeks before the fruit ripens. Late varieties. — The Salway, Heath, Bilyeu, and varieties with a similar ripening period should be given the same treatment prescribed for midseason varieties, with an additional treatment of self -boiled lime-sulphur alone, to be applied three or four weeks after the second application. Early varieties. — The Greensboro, Carman, Hiley, Mountain Rose, and varieties having the same ripening period should receive the first and second applications prescribed for midseason varieties. Where the curculio is not particularly bad, as in Connecticut, western New York, and Michigan, the first treatment, which is for this insect only, may be omitted. Also for numerous orchards throughout the Middle States where the insect, especially in the younger orchards, is not yet very troublesome, orchardists should Bui. 103, Bureau of Entomology. U. S. Dept of Agriculture. Plate XX. Size of Peaches at Time of First Spraying with Arsenate of Lead, Showing on the Left the Earliest and on the Right the Latest Stages in De- velopment when this Treatment Should be Given. Original.) SPRAYING PLUMS AND CHERRIES. 215 use their judgment as to whether the first application may be safely omitted. Where peach scab is the chief trouble, and brown-rot and curculio are of only minor importance, as may be the case in some of the Allegheny Mountain districts, satisfactory results may be had from two applications, namely, the first with self-boiled lime-sulphur and arsenate of lead four to five weeks after the petals fall, and the second treatment of the above schedule with self -boiled lime-sulphur alone three to four weeks later. These two treatments, if thoroughly applied, will control the scab and brown-rot, especially on the early and midseason varieties, and will materially reduce curculio injuries. Even one application of the combined spray made about five weeks after the petals fall would pay well, although this is recommended only lor conditions where it is not feasible to do more. SPRAYING PLUMS AND CHERRIES. The first important tests of arsenicals in the control of the curculio were made on plums and cherries. In 1887 Mr. W. B. Alwood, work- ing under the direction of the entomologist of tins department, made some limited tests on the grounds of the Ohio Agricultural Experi- ment Station, spraying Green Gage plum trees with Paris green at the rate of 1 pound to 50 gallons of water. Fully 50 per cent of the foliage and much of the fruit fell from the trees as a result of the treatment . Xo definite conclusions were drawn from the experiment. May 17 of the same year 17 cherry trees were also sprayed with Paris green, 1 pound to 50 gallons of water, and the results in this instance also were not fully determined. During the same year Prof. A. J. Cook in Michigan sprayed 4 plum trees May IS with Paris green at the rate of 1 tablespoonful to 6 gallons of water. Xo trees were kept lor comparison, and no definite conclusions were thus to be drawn. During 1888 Prof. II. Osborn, then an agent of the Division of Entomology, carried out in Iowa some thorough spraying experiments, using 11 plum trees of several varieties, leaving 10 trees unsprayed as a check. London purple was used at the rate of one-half pound to 100 gallons, applications being made June 1 and 11. Concerning results, Prof. Osborn stale-: Combining the entire count of all varieties, and we have for the sprayed frees a final of 32.48 per cent punctured, or stung, and 5.7] percenl containing larvae, against a final of 41.86 per cent stung and 10.39 per cent containing larva1 for the check trees. During the same year Prof. Weed in Ohio began a series oi tost-* o\ arsenicals on cherry and plum, which were continued during 1889 and 1890, during which latter year the work was carried out on a commercial basis in a plum orchard o( 900 trees in the fruit districts along the south shore of Lake Erie. These careful experiments of Prof. Weed clearly showed that a considerable benefit from spraying was to be derived and were altogether the most extensive and com- plete heretofore presented. 216 THE PLUM CUBCULIO. In Bulletin 9 of the Iowa Agricultural Experiment Station, page 383 (1890), Prof. Gillette gives results of experiments on plums with London purple on the plum curculio and plum gouger. The poison was applied with a hand pump to 23 trees at the rate of 1 pound to 120 gallons May 4 and 11. The leaves were badly burned. After May 25 all drop fruit on 5 trees each of the sprayed and unsprayed blocks was examined. A total of 21,000 plums was examined, and a benefit was determined of 1.1 per cent in favor of spraying. SOME RESULTS OF SPRAYING PLUMS. At Fort Valley, Ga., during 1905 Mr. Beattie carried out some spray- ing tests on Japanese plums. The plats were, however, small and there was considerable overflow from the surrounding unsprayed trees. Plats were laid off, extending across three varieties, namely, Wickson, Ked June, and Satsuma, in which order the varieties are given in the table. The entire crop throughout the season from three trees of each variety was counted with the exception of Plat I, where only 2 trees were used. Plats received from 1 to 3 applications of arsenate of lead in water, without addition of lime. According to Mr. Beattie's notes practically no injury resulted to the foliage from the sprays. The results are given in Table CVI. Table CVI. — Results of spraying Japan plums for the plum curculio, Fort Valley, Ga., 1905. Treatment. 6 Eh Fruit from ground. Fruit from tree. 3 ft '3 2 £ jj o Eh -d ai in !s '3 o Eh u i> — , a ■4-» W o &H 3 C3 O fl+3 o 3 O) a a o r Plat No. Cl o 3 Ph T3 a> w a o "3 o Eh 3 o a Ph a "3 -d B o CO "3 o Eh 60 3 8 ±3 o 3 I One application, ar- senate of lead, 2 pounds to 50 gal- lons water, Mar. 19. Two applications ar- senate of lead, 2 pounds to 50 gal- lons water, Mar. 19 and Apr. 20. Three applications arsenate of lead, 2 pounds to 50 gal- lons water, Apr. 4 and 20, May 4. 1 f 2 3 1 r 2 3 li 52 236 44 213 2 114 54 350 152 60 37 4 26 300 178 360 204 296 81 217 28 414 232 710 288 257 116 404 212 41 326 538 500 298 442 942 46.92 39.41 II.... 255 372 210 211 345 172 71 38 32 326 410 242 430 31 73 28 11 15 527 35 200 957 66 273 685 403 283 239 356 187 598 73 232 1,283 476 515 837 728 141 978 534 54 762 1,296 1,371 782 903 2,274 39.70 41.20 III... 88 153 108 69 138 92 72 65 53 160 218 161 90 90 72 25 30 8 270 194 313 360 284 385 178 243 180 94 168 100 342 259 366 520 502 546 349 299 190 539 252 63 777 1,029 601 362 967 1,568 61.67 24.48 68 105 72 45 87 58 31 30 10 99 135 82 40 105 118 9 17 36 35 91 6 75 196 124 108 210 190 54 104 94 66 121 16 174 331 206 IV... 245 190 71 316 263 62 132 395 508 252 203 711 28.55 66.58 SPRAYTXO PLUMS AND CHERRIES. 217 Curculio injury on all of the plats was severe. On the check there was only 28.55 per cent of fruit free from punctures and infestation. On the plat sprayed 3 times, 61.67 per cent of the plums were sound, a gain in sound fruit over the check of 33.12 per cent. Two applica- tions gave a gain of 11.15 per cent and the single treatment showed an increase over the check of 18.37 per cent, a difference doubtless due to location. A more exact idea of the commercial benefits of spraying, however, may be had by a consideration of the relative amount of ripe fruit at picking time showing the punctures of the insect, as being more or less deformed and unsalable, for it will be understood that not all ripe fruit showing punctures is unsalable. On the check plat (IV) of the ripe fruit at picking time 66.58 per cent were punctured, as against 24.48 per cent on Plat II, receiving 3 applications. Plats I and II show about the same amount of punc- turing on the ripe fruit, namely, 39.41 and 41.20 per cent, respectively. During 1906, at North East, Pa., an orchard of about two hundred 16-year old plum (York State prune) trees were sprayed by Mr. Johnson, using Bordeaux mixture plus 3 pounds arsenate of lead. Through an error only one tree was left unsprayed for comparison. All of the fruit throughout the season was carefully examined from this tree and an adjacent unsprayed tree, and the results are shown in Table CVII. Previous to this season the owner had followed the jarring method, but by reason of the favorable results spraying was subsequently followed. This same orchard was sprayed during the following year by Mr. Johnson, and results taken on five sprayed and five unsprayed trees are shown also in the table. Table CVII. — Results of spraying York State prunes for the plum curculio during the seasons 1906 and 1907, Xorth East, Pa. 1906. Fruit from ground. Fruit from tree. - _■ '- — - - 3 Trees. Treatment. - a 3 H a •d o — - 3 - II g - 3 s 1 — ~ a ■ - a Ph C l-H s ~ - d : OQ r- - bi e .- - - 1 Three treatments, Bordeaux m i x- ture (4-4-50) plus 3 pounds arsenate 44s 393 1,207 1,655 0 1,708 517 3,364 of lead: May 25, June 7 and 19. One untreated 1,621 1 . 4 16 2,153 272 0 1,446 54,61 1907. 5 Twoapplicat ions, Bordeaux mix- 4:;:. 344 u 0 44S 16, ttS 16. 941 97.35 ture (4—i-5(>) plus 3 pounds arsenal i' of lead: June S and Julv 3. Five untreated 581 490 7,481 - 57 0 I 15,634 16, 873 •6.06 218 THE PLUM CURCULIO. During 1906 there was a gain in sound fruit on the sprayed trees of 50.02 per cent as compared with the check of 50.01 per cent. The difference the following year, however, was small, 1.27 per cent, as the insects were comparatively scarce, no doubt following their practical extermination in the orchard the year previous. Extensive plum-spraying experiments were begun at Barnesville, Ga., in 1910. The work, however, was stopped by the loss of practi- cally all of the fruit from the effects of a heavy wind storm. RESULTS OF SPRAYING CHERRIES. A block of Montmorency cherry trees at North East, Pa., was sprayed June 11 with 3 pounds of arsenate of lead to 50 gallons of water plus 3 pounds of stone lime. Another block received an addi- tional application June 25, while a third block (4 rows through center of orchard) was left unsprayed. When fruit was gathered, July 18, three trees on the first-mentioned plat gave a total of 16 wormy cherries and 43^ pounds of sound fruit. The same number of trees on the second block, having 2 applications, gave 10 wormy cherries and 53 pounds of sound fruit. The 3 trees on the check plat gave 74 wormy cherries and only 16 pounds of sound fruit. The trees were chosen as nearly alike as possible and the results may thus be fairly compared. As compared with the check, the plat treated twice shows an increase in sound fruit of 37 pounds and from the plat sprayed once a gain of 27.5 pounds. More data are needed to show the protection from curculio which will follow spraying plums and cherries, though this will without doubt be quite as marked as with peaches. The same spraying schedule indicated for early peaches will be suitable for plums and cherries, and the arsenical should be used in the self-boiled lime- sulphur wash. ECONOMIC BIBLIOGRAPHY.1 1736-7. Collinson axd Bartram. — Darlington's Memorials of Bartram and Mar- shall, p.. 85. Remedy for insect that annoys plums, apricots, and nectarines. Id.— p. 93. An account of the destruction by an insect of plums and nectarines. Id.— p. 120. Advice against the planting of sloes, as they are "liable to be bitten with the same insect as the rest of our stone fruits.'' 1749. Kalm, Peter. — Travels into North America. 7. Account of plum curculio and remarks on remedies. 222 THE PLUM CURCULIO. 1850. Simpson, H. B— The Southern Planter, vol. 10, no. 9, p. 265. (From Hovey's Magazine of Horticulture.) An account of the habits of the curculio with remedial measures for its control. 1850. Drake, R. H.— The Cultivator, vol. 7, no. 1, p. 47. Remarks on jarring against the plum curculio. (Uses a large umbrella to catch falling insects.) 1850. Harris, Thaddeus Wm. — Injurious insects. f the curculio again. Observations during summer of L869. 1869. Riley, C. V. — 1st Ann. Rept. on noxious insects, etc., of the State of Missouri. <4th Ann. Rept. St. Bd. Agr., 1868, pp. 50 52, 6 figB. Excellent account of plum curculio ami resumA. 17262°— Bull. 103—12 15 226 THE PLUM CURCULIO. 1869.* Riley, C. V.— Prairie Farmer, July 10, vol. 40, n. s. vol. 24, p. 218, fig. Apple leaf crumpler mistaken for curculio. Correspondence: Improper use of the word Curculio; means against. Figs. Id.*— Reply: Recommends jarring against plum curculio. 1869. Walsh, B. D., and Riley, C. V.— Plums for the million. ., p. 420, June 26. 1897. Johnson, W. G. — Destructive insects and methods of controlling them. ^American Gardening, no. 1, p. 22, January 2. Id.— March 13, p. 174, 1 fig. 1897. Bogue, E. E. — Some injurious orchard insects. be guarded against.<5th Bien. Rept. Cal. St, Bd, Hort,, 1895-1896, p. 25. 1898. Smith, J. B. — Report of the entomological department oi the New Jersey Agricultural College Experiment Station for lS97. ( Jrateegus, food plant of plum curculio 33 Oryptorhynchus argula= Conotrachelus nenuphar 14,16 Cultivation for destruction of plum curculio pupse 17(i 17S Curculio, common name for plum curculio 14 nenuphar =Conotrach< I us nenuphar 14 original description L3 14 origin of name It L5 persiav= Conotrachelus nenuphar 14 plum. (See Plum curculio.) 246 THE PLUM CUKCULIO. Page. Currant, place of oviposition of plum curculio 33 Diospyros virginiana. (See Persimmon, wild.) Dorymyrmex pyramicus, enemy of plum curculio 152 Eggplant, host plant of Trichobaris trinotata 143 Enarmonia prunivora, larvae with those of plum curculio in black knot 142 spraying with arsenicals 201 Epicserus imbricatus mistaken for plum curculio 29 Epiurus sp. (See Pimpla.) Eurytoma, parasite of plum curculio 148 Evarthrus obsoletus, enemy of plum curculio 154 orbatus, enemy of plum curculio 154 Ferrous arsenate against plum curculio 187 powder, against plum curculio 188 and self-boiled lime-sulphur against plum curculio. . 188 Fowls, enemies of plum curculio 154 Fruit curculio, common name for plum curculio 14 Fruits, smooth-skinned, preferred for oviposition by plum curculio 33 Gooseberry, place of oviposition by plum curculio 33 Grape, larvae of plum curculio fail to mature therein 38 place of oviposition by plum curculio 33 Grosbeak, rose-breasted. (See Zamelodia ludoviciana.) Harpalus j annus, enemy of plum curculio 153-154 pennsylvanicus, enemy of plum curculio 153-154 Heliophila unipuncta, possible host of Myiophasia senea 149 Hickory, host tree of Conotrachelus elegans 149 Huckleberry, larvae of plum curculio fail to mature therein 38 place of oviposition of plum curculio 33 Hylocichla fuscescens, enemy of plum curculio 154 g. pallasi, enemy of plum curculio 154 Icterus galbula, enemy of plum curculio 154 spurius, enemy of plum curculio 154 Jarring against plum curculio 168-176 present status 172-176 "Kerkelo," common name for plum curculio 14 Lacewing fly larvae, enemies of plum curculio 152 Lanivireo fiavifrons, enemy of plum curculio 154 Lead arsenate. (See Arsenate of lead.) oxid against plum curculio 206 Lime against plum curculio on apple 189-190 bluestone, and Paris green dust, homemade, against plum curculio on apple 194, 200 sulphur and arsenate of lead against apple insects 201 self-boiled, and arsenate of lead against plum curculio on peaches. . 205, 211-216 arsenicals against plum curculio 187-188, 205-215 directions for preparation 212 Little Joker, common name for plum curculio 14 Turk, common name for plum curculio 14 London purple against plum curculio 182-185 on apple 189-190 peaches 202, 203 Metadexia basalis, parasite of Conotrachelus juglandis 150 probably = Cholomyia inxquipes 150 INDEX. 247 Page. Microbracon mellitor, parasite of plum curculio 148 Musca longipes=Cholomyia inxquipes 150 Myiophasia xnea, host of Calyptus tibiator 149 parasite of Ampeloglypter sesostris 149 Anthonomus grandis 149 Balaninus uniformis 149 Chalcodermus seneus 149 . sp 149 Conotrachelus elegans 149 plum curculio 149-150 Sphenophorus parvulus 149 possible parasite of Heliophila unipuncta 149 Nectarine, food plant of plum curculio 33 order of preference in oviposition by plum curculio 33 Nenuphar, common name for plum curculio 14 Oriole, Baltimore. (See Icterus galbula.) orchard. (See Icterus spurius.) Paris green against apple curculio 192 plum curculio 178-185 on apple 189-192, 200 peaches 202-207 and Bordeaux mixture against apple curculio 192 plum curculio 183 on apple 191-192, 194 injurious effects on peach '. 207 lime, and bluestone dust, homemade, against plum curculio on apple 194, 200 Peach curculio, common name for plum curculio 14 food plant of plum curculio 33 order of preference in oviposition by plum curculio ." 33 shoots, ovipositing place of plum curculio * 38 weevil, common name for plum curculio 14 worm, common name for plum curculio 14 Peaches, spraying with arsenicals against plum curculio 202-215 susceptibility of different varieties to plum curculio 36 Pear, bark, ovipositing place of plum curculio, according to Fitch 38 food plant of plum curculio 33 larvae of plum curculio usually unable to mature therein 38-39 order of preference in oviposition by plum curculio 33 Pears, susceptibility of different varieties to plum curculio 36 Pegomyafusciceps, association with plum curculio in fruit 151 Persimmon, larvae of plum curculio fail to mature therein 38 wild, place of oviposition by plum curculio 33 Pimpla (Epiurus) sp., parasite of plum curculio 148 Plowrightia morbosa. (See Black knot.) Plum curculio, adult (see also Plum curculio, beetles). activity in egg laying and feeding by day and night . . . 107-110 choice of food 96-97 description 33 egg and feeding punctures, position on fruit and variation in form 103-106 laying operation 99-102 248 THE PLUM CURCULIO. Page. Plum curculio, adult, extent of feeding of respective sexes 98-99 period of emergence 92-95 proportion of sexes 95-96 relative number of feeding and egg punctures 106-107 appearance of beetles in spring, relation of temperature thereto. 118-120 time 112-118 beetles (see also Plum curculio, adult). appearance in spring, relation of temperature thereto . . 118-120 time 112-118 from emergence to hibernation 127-129 occurrence in orchards 120-125 bibliography 219-241 classification '. 13-14 description 30-33 distribution 19-27 according to life zones 25 egg and feeding punctures, position on fruit and variation in form 103-106 relative number 106-107 description 30 laying and feeding activity by day and by night 107-110 operation 99-102 length of stage 48-54 number deposited 39^8 enemies, natural 139-154 feeding and egg laying activity by day and by night 107-110 punctures, position on fruit and variation in form 103-106 relative number 106-107 food plants 33-39 fruit punctured or infested, percentage 134-139 generations, number annually 125-127 habits 39-112 hibernation 129-132 mortality during period 132-134 history 15-19 insects likely to be mistaken therefor 28-29 introductions reported 26 larva, description 30-32 habits of those just hatched and course taken in fruit — 54-55 instars 55-56 larvae, death in fruit 56-59 fruits in which they fail to mature 38 manner of leaving fruit and entering soil 64-65 normal emergence from fruit during season 60-64 undersized, desertion of fruit 59-60 life history 39-112 limit of occurrence, northern 24-25 southern 25 western 21-24 losses due thereto 27-28 mortality during hibernation 132-134 names, common 14-15 ixdex. 249 Page. Plum curculio, natural enemies 139-154 occurrence of beetles in orchards 120-125 parasitic enemies 140-152 percentage of fruit punctured or infested 134-139 predaceous insect enemies 152-154 pupa, description 32 length of stage and time spent in soil, before and after pupation 83-87 time spent in soil 7 pupae, cultivation for destruction 176-178 pupal cell, depth 87-88 remedial measures 155-218 historical 155-167 remedies, cultivation for destruction of pupae 176-178 jarring 1 68-176 feeding experiments with poisons 185-189 premiums therefor 167-168 Ransom chip process 168 spraying with arsenicals 178-185 seasonal history 112-134 spraying scheme for apple orchards 201 of apple at Anderson, Mo 193-194 St. Joseph, Mo 198-199 Siloam Springs, Ark 196 conclusions 200-201 early experiments 189-193 experiments by Bureau of Entomology 193-200 in Virginia 197-198 western New York and northwestern Pennsylvania 195 peaches with arsenicals. . .» 202-215 plums and cherries 215-218 synonymy 13-14 time for transformation from e^ to adult 110-112 oi appearance of beetles in spring 112-120 spent in fruit, egg and larval stages combined 65-73 transformations in ground, effect of soil conditions thereon 8S-92 food plant of plum curculio * 33 gouger. See Anthonomus Scutellaria.) moth, so-called. (See Enormonia prunivo order of preference in oviposition by plum curculio weevil, common name for plum curculio 14 Plums, cultivated, variation in susceptibility to plum curculio 34-36 I' - - also Arsenicals, etc ainst plum curculio, feeding experiments 185,188 Porrjni conotracheli. (See Thertilochu* conotrocheli.) Potato-stalk weevil. (See Trichobaris trinotata.) Premiums for remedies for plum curculio ]< Prunus americana, food plant of plum curculio angtutifolia, food plant of plum curculio do in, xtan. food plant of plum curculio 36 hortulana, food plant of plum curculio 36 simonii, apparently not injured by plum curculio 35 250 THE PLUM CUKCULIO. Page. Prunus triflora, food plant of plum curculio 35 umbellata, food plant of plum curculio 36 Quince, food plant of plum curculio 33 order of preference in oviposition by plum curculio 33 Ransom chip process against plum curculio 168 Rhynchdenus argula= Conotrachelus nenuphar 14 cerasi= Conotrachelus nenuphar 14, 16 Riparia riparia, enemy of plum curculio 154 Rose-beetle, Fuller's. (See Aramigus fulleri.) Sigalphus curculionis. (See Triaspis curculionis.) Snout-beetle, imbricated. (See Epicxrus imbricatus.) Soda, sulpho-arsenate, against plum curculio 188 on peaches 206 and self-boiled lime-sulphur against plum curculio 188 injurious effects on peach 207 Sphenophorus parvulus, host of Myiophasia senea 149 Spraying with arsenicals against plum curculio 178-185 on apple, early experiments. 189-193 experiments by Bu- reau of Entomolo- gy 193-200 cherries and plums 215-218 peaches 202-215 Strawberry, place of oviposition by plum curculio 33 Swallow, bank. (See Riparia riparia.) Temperature, relation to time of appearance of plum curculio in spring 118-120 Tent caterpillar, spraying with arsenicals 201 Thelairodes basalis= Cholomyia inxquipes 150 Thersilochus conotracheli, parasite of plum curculio 147-148 Thrips, enemy of plum curculio 152 Thrush, hermit. (See Hylocichla g. pallasi.) Tmetocera ocellana. (See Bud moth.) Toad, enemy of plum curculio 154 Triaspis curculionis, parasite of Anthonomus grandis 143 Balaninus sp 143 Conotrachelus affinis 143 elegans 143 juglandis 143 plum curculio 142-146 stalk-borer on Ambrosia 143 Trichobaris trinotata 143 var. rufus, parasite of plum curculio 146-147 Trichobaris trinotata, host of Triaspis curculionis 143 on eggplant 143 "Turk, " common name for plum curculio 14 Veery. (See Hylocichla fuscescens.) Vireo, yellow-throated. (See Lanivireo Jlavifrons.) Zamelodia ludoviciana, enemy of plum curculio 154 Zinc cyanid against plum curculio 206 oxid against plum curculio 206 sulphid, injurious effects on peach 207 o