Digitized by the Internet Archive in 2015 https://archive.org/details/someinsectsinjur6166unit U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— BULLETIN No. 66. L. O. HOWARD, Entomologist and Chief of Bureau SOME INSECTS INJURIOUS TO TRUCK CROPS. CONTENTS AND INDEX. Issued March 17, 1910 WASHINGTON: GOVERNMENT PRINTING OFFICE. 1910 . U. S. DEPARTMENT OF AGRICULTURE, BOREAD OF ENTOMOLOGY— BULLETIN No. 66. L. O. HOWARD, Entomologist and Chief of Bureau, SOME INSECTS INJURIOUS TO TRUCK CROPS. I. THE ASPARAGUS MINER. NOTES ON THE ASPARAGUS BEETLES. By F. H. CHITTENDEN, Entomologist in Charge of Breeding Experiments . II. THE WATER-CRESS SOWBUG. THE WATER-CRESS LEAF-BEETLE. By F. H. CHITTENDEN, Entomologist in Charge of Breeding Experiments. III. THE CRANBERRY SPANWORM. THE STRIPED GARDEN CATERPILLAR. By F. H. CHITTENDEN, Entomologist in Charge of Breeding Experiments. IV. THE LEAFHOPPERS OF THE SUGAR BEET AND THEIR RELATION TO THE “CURLY-LEAF” CONDITION. By E. D. BALL, Ph. D., Special Field Agent. V. THE SEMITROPICAL ARMY WORM. By F. H. CHITTENDEN and H. M. RUSSELL. VI. THE HOP FLEA-BEETLE. By F. H. CHITTENDEN, Sc. D., in Charge of Truck Crop and Special Insect Investigations. VII. MISCELLANEOUS NOTES ON TRUCK-CROP INSECTS. By F. H. CHITTENDEN, Sc. D., in Charge of Truck Crop and Stored Product Insect Investigations WASHINGTON: GOVERNMENT PRINTING OFFICE. 1910 . BUREAU OF ENTOMOLOGY. L. O. Howard, Entomologist and Chief of Bureau. C. L. Marlatt, Assistant Entomologist and Acting Chief in Absence of Chief. R. S. Clifton, Executive Assistant. Chas. J. Gilliss, 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, librarian. Truck-Crop and Stored Product Insect Investigations. F. H. Chittenden, in charge. H. M. Russell, C. H. Popenoe, D. K. McMillan, H; O. Marsh, E. G. Smyth, Thos. H. Jones, agents and experts. E. D. Ball,® special field agent. E. G. Titus,® I. J. Condit, H. S. Heller, & W. B. Parker, collaborators. ® Resigned June 30, 1909 b Resigned January 31, 1910. LETTER OF TRANSMITTAL. U. S. Department of Agriculture, Bureau of Entomology, Washington , D. C., January 25, 1910. Sir: I have the honor to transmit herewith, for publication as Bulletin No. 66, seven papers dealing with certain insects injurious to truck crops. These papers, which were issued separately during the years 1907 and 1909, are as follows: The Asparagus Miner and Notes on the Asparagus Beetles, by F. H. Chittenden; The Water- Cress Sowbug and the Water-Cress Leaf-Beetle, by F. H. Chittenden; The Cranberry Span worm and the Striped Garden Caterpillar, by F. H. Chittenden; The Leafhoppers of the Sugar Beet and Their Relation to the “Curly-Leaf ” Condition, by E. D. Ball; The Semi- tropical Army Worm, by F. H. Chittenden and H. M. Russell; The Hop Flea-Beetle, by F. H. Chittenden; Miscellaneous Notes on Truck-Crop Insects, by F. H. Chittenden. Respectfully, L. O. Howard, Entom ologist and Chief of Bureau . Hon. James Wilson, Secretary of Agriculture . in PREFACE. The present publication comprises a series of articles which have been issued in seven parts and are now brought together as a single bulletin. It relates to a line of investigations begun in 1896, the earlier results of which were published in previous bulletins of the present series, in Yearbooks of the Department, and in circulars of the Bureau. The title, “Some Insects Injurious to Truck Crops,” is used in a wide sense and includes insects injurious to sugar beet, since the same classes of insects which affect this important crop also attack table beets and spinach. The initial article is the first treatment that has been given to the asparagus miner in a Government publication. The second article,, entitled “Notes on the asparagus beetles,” is a sequel to a general article on the asparagus beetles which appeared in the Yearbook for 1896. It places on record all important new localities to date, and furnishes similarly the latest information in regard to remedies. The importance which has been assumed by the water-cress sowbug since 1902 has necessitated the preparation of a publication covering this species, with suggestions for its control. The subject of water-cress insects has never been considered in a Department publication hith- erto, and similar treatment of the water-cress leaf-beetle to that furnished on the sowbug follows. The cranberry spanworm is given monographic treatment not hitherto furnished for it. It is an omniv- orous feeder, and has attracted attention on various crops, and especially on asparagus and strawberry. A similar article on the striped garden caterpillar, also an omnivorous form, completes Part III of the bulletin. The article representing Part IY is a detailed consideration of the sugar-beet leafhopper and of other affiliated species in their relation to the “curly-leaf ” condition of the sugar beet. It was prepared by Dr. E. D. Ball, while special field agent of this Bureau in Utah; he has been engaged on this work for a number of years. The semi- tropical army worm is the subject of Part V. It was the most trouble- some insect on truck crops in Florida during 1907, and was given detailed study from every possible standpoint by the authors. In the experiments with remedies, which were conducted by the junior v VI SOME INSECTS INJURIOUS TO TRUCK CROPS. author, Mr. H. M. Russell, a series of 15 trials was performed, proving that a spray of arsenate of lead is far superior to Paris green under local conditions. The final article of the series, entitled “The hop flea- beetle,” has been a subject of study for a number of years. Its treatment is monographic to date, and, while some of the data fur- nished are preliminary in character, it will constitute a basis for future work on the same species. This insect is given the name of flea-beetle because of the local name, “hop flea,” used in the hop-growing region of the Pacific coast, but it is also a pest in sugar-beet fields and injuri- ous to rhubarb, radishes, and other truck crops. In the preparation of the article the writer has been fortunate in obtaining the coopera- tion of various experts, including, particularly, Messrs. H. J. Quayle and Theodor Eder. Following this article are a few miscellaneous notes on truck-crop insects, the first two giving additional information in regard to the principal asparagus pests treated in Part I, the last furnishing addi- tional observations on the water-cress insects treated in Part II, with notes on the first injurious occurrence of the destructive pea moth and of a western root-maggot in the United States. F. H. Chittenden. CONTENTS." Tage, The asparagus miner ( Agromyza simplex Loew) .F. II. Chittenden. . 1 Descriptive 1 Distribution 2' Historical and biological notes 2 Recent injury 3* Remedial measures 4 Notes on the asparagus beetles F. H. Chittenden . . 6 The common asparagus beetle ( Crioceris asparagi L.) 6 The twelve-spotted asparagus beetle ( Crioceris 12-punctata L.) 9 The water-cress sowbug ( Mancasellus brachyurus Harger) . . ..F. H. Chittenden. . 11 Descriptive 11 Reports of injurious occurrence 12 Methods of control 12 The water-cress leaf-beetle ( Phxdon xruginosa Suffr.) F. H. Chittenden. . 16 Injurious occurrence 16 Descriptive 16 Literature 18 Habits of this and a related species 18 Methods of control 19 The cranberry span worm ( Cleora pampinaria Guen.) F. H. Chittenden. . 21 Descriptive 21 Distribution 23 Biologic literature 24 Unpublished office notes 25 List of food plants 25 The insect’s life history 26 Natural enemies 26 Remedies 26 Bibliography 27 The striped garden caterpillar ( Mamestra legitima Grote) F. H. Chittenden. . 28 Descriptive 28 Biologic notes 29' Natural enemies 31 Summary of habits. 32 Methods of control 32 The leafhoppers of the sugar beet and their relation to the “curly-leaf ” condi- tion E. D. Ball.. 33 Introduction 33 The beet leafhopper ( Eutettix tenella Baker) 35 Descriptive 35 Food plants 35 Distribution 36 Life history studies 36 Economic relations 41 Economic summary and proposed remedies 47 Bibliographical references 48 a The seven papers constituting this bulletin were issued in separate form on March 16, April 23, and August 31, 1907, and on January 27, January 28, May 8, and July 19> 1909, respectively. 27518— Bull. 66—10 2 vn VIII SOME INSECTS INJURIOUS TO TRUCK CROPS. The leafhoppers of the sugar beet and their relation to the “ curly-leaf ’ ’ con- dition — Continued. Page. Other leafhoppers 49 Eutettix strobi Fitch 49 Eutettix scitula Ball 49 Eutettix seminuda Say 50 Eutettix clarivida Van Duzee 50 Eutettix insana Ball, E. albida Ball, and E. pauperculata Ball 50 Eutettix stricta Ball 50 Agallia sanguinolenta Prov 51 Agallia cinerea Osborn and Ball 51 Agallia bigelovix Baker 51 Agallia quadripunctata Prov. and A. novella Say 51 Empoasca sp 51 Conclusions in regard to “curly-leaf” 52 The semi tropical army worm ( Prodenia eridania Cram.). F. E. Chittenden and E. M. Russell. . 53 Introduction 53 Descriptive 54 Origin and distribution 57 Literature and history 57 Recent injuries and biologic notes 58 Early records 62 Life-cycle periods and generations 62 Natural enemies 63 Methods of control 65 Resume of experiments and conclusions 68 Summary 69 Bibliographical list 70 The hop flea-beetle ( Psylliodes punctulata Melsh.) . . . , F. E. Chittenden . . 71 Introductory 71 Descriptive 72 Distribution 73 Recent injuries * 73 Methods of attack, food habits, and generations 76 Life history and habits 79 Notes on other species 81 Local conditions and natural influences 82 Methods of control 83 Arseni cals 83 Contact sprays 85 Bordeaux mixture 87 Mechanical and cultural methods 87 Literature 91 Bibliography 91 Summary 92 Miscellaneous notes on truck crop insects F. //. Chittenden . . 93 Successful use of arsenate of lead against the asparagus beetle 93 A note on the asparagus miner 94 Injurious occurrence of the pea moth in the United States 95 A new western root-maggot 95 Notes on water-cress insects 96 Index 99 ILLUSTRATIONS. PLATES. Page. Plate I. Leafhoppers (Eutettix spp.) and their work. Fig. 1. — Eutettix tenella: a, Adult; &, nymph; c, wing; d, e, genitalia; /, eggs (greatly enlarged); g, section of beet stem, showing fresh eggs in place; h, same, showing eggs ready to hatch; i, old egg scars on beet stems; j, small leaf of sugar beet, showing characteristic “curly- leaf ” condition; lc, enlarged section of back of an extreme case of “ curl y-leaf,” showing “warty” condition of veins. Fig. 2. — Eu- tettix strobi: a, Work of nymphs on lamb’s-quarters; 6, work of nymphs on sugar beet. Fig. 3. — Eutettix scitula: Adult. Fig. 4.- — Eutettix clarivida: a , Wing; 6, head and pronotum; c, d, genitalia. Fig. 5. — Eutettix nigridorsum: Work of nymphs on leaf of Helian- thus. Fig. 6. — Eutettix straminea: Work of nymphs on leaf of another Helian thus. Fig. 7. — Eutettix insana: Wing. Fig. 8.— Eu- tettix stricta: a, b, Genitalia 34 II. Work of Eutettix tenella on sugar beet. Fig. 1. — Three “ curl y-leaf ” beets, the result of attack by Eutettix tenella , and one normal beet from the same field, showing difference in size. Figs. 2, 3. — “Curly-leaf” beets as seen in the field. Fig. 4. — Normal beets from same field 44 III. Work of Eutettix tenella on sugar beet. Fig. 1. — A large beet becom- ing “curly.” Fig. 2. — Back of a leaf affected by “curly-leaf,” showing “warty” condition and curled edges 44 IV. Work of Eutettix tenella on sugar beet. Fig. 1.— A field of beets de- stroyed by “curly-leaf.” Figs. 2, 3. — Cages used in the life-his- tory experiments 46 V. Spraying apparatus used in hopyards in British Columbia 84 VI. View of hopyard, showing sheep keeping down weeds 88 VII. Method of capturing hop flea-beetles on tarred horse-sledges 90 TEXT FIGURES. Fig. 1. The asparagus miner ( Agromyza simplex): Fly 1 2. The asparagus miner: Larva, pupa, work 2 3. The water-cress sowbug ( Mancasellus brachyurus) 12 4. Cross section of cress pond, showing arrangement for avoiding damage by water-cress sowbug 13 5. The water-cress leaf-beetle ( Phsedon aeruginosa ): Larva, pupa, adult 17 6. The cranberry spanworm ( Cleora pampinaria ): Moth, larva, and pupa. . 22 7. The striped garden caterpillar ( Mamestra legitima ): Moth, larva, and pupa 29 8. The semitropical army worm ( Prodenia eridania): Moth, egg, egg-mass, larvae 54 IX X SOME INSECTS INJURIOUS TO TRUCK CROPS. Page. JFig. 9. The semitropical army worm: Work of larvae on “careless weed”, in potato field 59 10. The semitropical army worm: Field of late Irish potatoes, showing vines entirely stripped by larvae 60 11. The semitropical army worm: Larvae eating bark of “careless weed;” also nymph of spined soldier-bug ( Podisus maculiventris) , predaceous on larvae of Prodenin cridania 61 12. Hop flea-beetle ( Psylliodes puncfulata): Larva and adult 72 13. View of hopyard, showing how flea-beetles keep down vines 76 14. Hop leaves, showing work of flea-beetle 77 15. Work of flea-beetle after vines are grown 78 16. Trained hop shoots stripped by flea-beetle 79 17. Breeding and control cage in place over a hill 80 18. A crew spraying hops in British Columbia 86 19. Tarred catchers for hop flea-beetles 89 ERRATA Page 2, line 19, for 1861 read 1869. Page 2, footnote 0 , for 160 read 46. Page 18, line 11, for 1893 read 1903. Page 18, line 22, for letter read latter. Page 65, line 15 from bottom, for fresh air-slaked read freshly slaked. Page 68, line 8, for 6 read 50. INDEX Page. , . , 70 Actinotia derupta, bibliographic reference. . - - - 50-51 Agallia bigelovise on sea-blite (Dondia) 50-51 sugar beet ----- 50 _ 51 cincrea on sugar beet - - * * * ' 52 novella on sugar beet, habits. - quadripunctata on sugar beet, habits.... 50-51 sanguinolenta on sugar beet - 50-51 uhleri on sugar beet — - - - - - ^-5 Agromyza simplex - * 2-3 biological notes 2_2 descriptive ---- 2 distribution 2_3 historical notes - ^_4 TnCpkragus in Cauiom^'tocimsetts, and Virginia 9t remedial measures - 49 Allygus sp., oi Bruner, probably Eutettic ^ '53’ 58-60, 62, 69 Amaranth, spiny, food plant of Prodema eridama Amaranthus spinosus. ( See Amaranth, spiny.) 77 grxcians , food plant of Psylliodes punctulata retroflexus , food plant of Psylliodes punctulata ... Avateticus ( Eupodisus ) mucronatus , enemy of Prodema eridama g0 Aplixreta sp., parasite of Pegomya planipalpis. ------ 63 Aphiochxta nigriceps eating pupa? of Prodema eridama 24 2 5 Apple, food plant of Cleora pampinana ’ 51 Empoasca Army worm, semitropical. (See Prodema eridama.) 8 _ 9 93 _ 94 Arsenate of lead against common asparagus beetle ’ 26 _ 27 cranberry spanworm. 83^5, 87, 92 hop flea-beetle fi5 _ g9 semitropical army worm. . - 39 striped garden caterpillar ----- “ and Bordeaux mixture against hop flea-beetle. . - - ----- striped garden caterpillar oz resin-fishoil soap against hop flea-beetle. . 83-84 soap against common asparagus beetle ° Arsenite of copper, adhesive, against semitropical army worm ° 69 analysis - .^. ...... 83>g5 lime with soda against hop flea-beetle Asclepias incarnata. ( See Milkweed.) Asparagus beetle, common. (See Crioceris asparagi.) twelve spotted. (See Crioceris 12 -punclata.) beetles, notes on distribution and destructive occurrences ^ 100 SOME INSECTS INJURIOUS TO TRUCK CROPS. Page. Asparagus, food plant of Agromyza simplex 1-5 Clcora pampinaria 21, 25 Crioceris asparagi 6-8 12 -punctata 9 Mamestra legitima 28-32 miner. (See Agromyza simplex.) Atriplex confer tifolia, food plant of Eutettix clarivida 50 insana 50 pauperculata 50 tenella 35 food plants of Eutettix albida 50 Ball, E. D., paper, The Leafhoppers of the Sugar Beet and their Relation to the “ Curly-leaf ” Condition 33-52 Beet, food plant of Eutettix seminuda 50 Prodenia eridania 61 Psylliodes punctulata 77, 79 leafhopper. (See Eutettix tenella.) sugar, “curly-leaf” condition with relation to Eutettix tenella 33-48,52 leafhoppers 33-52 food plant of Agalliof bigelovix 50-51 cinerea 50-51 novella 51 quadripunctata 51 sanguinolenta 50-51 uhleri 50-51 Empoasca 51-52 Eutettix clarivida 50 scitula 44-45, 49-50 strobi 44-45,49 tenella 35 Psylliodes punctulata 71, 74-77, 92 Blackberry, food plant of Cleora pampinaria 24, 25 Mamestra legitima 30, 32 “Blackjack. ” (See Plnxdon betulx.) “ Blight” of sugar beet, characteristics 44-46 relation to leafhoppers 33-52 or “curly-leaf” of sugar beet around Spreckels, Cal., not work of Eutettix tenella 46 “Blue beetle.” (See Phxdon armoracix.) Boards, tarred, against hop flea-beetle 83, 88-89 Boarmia collecta= Cleora pampinaria 22 fraudulentaria= Cleora pampinaria 22 frugallaria , bibliographic reference 27 = Cleora pampinaria 22 pampinaria, bibliographic reference 27 = Cleora pampinaria 24 sublunaria, bibliographic reference 27 = Cleora pampinaria 22 Bordeaux mixture, deterrent against hop flea-beetle 87, 92 with arsenate of lead against hop flea-beetle 83-84 striped garden caterpillar. ... 32 Paris green against hop flea-beetle 83-85 Bursa bursa- pas tor is, food plant of Psylliodes convexior 81 INDEX. 101 Page. Cabbage, food plant of Mamestra legitima 30, 32 Phxdon armoracix 18 Prodenia eridania 61 ornithogalli 30 Psylliodes punctulata 77 Callitricha verna , food plant of Phxdon armoracix 19 Calosoma sayi, enemy of Prodenia eridania 64 Cardamine amara, food plant of Phxdon armoracix 19 “Careless weed.” ( See Amaranth, spiny.) Carp, suggested use against water-cress sowbug 15 Carrots, food plant of Prodenia, eridania 61 Castor-oil plant, food plant of Prodenia eridania 60 Catfish of no avail against water-cress leaf-beetle 20 suggested use against water-cress sowbug 15 “Chalcidian” parasite of Psylliodes punctulata recorded by Fitch 82-83 Chelonus sp., parasite of Prodenia eridania. 63 Chenopodium album , food plant of Eutettix strobi 49 Psylliodes punctulata 76 food plant of Eutettix scitula 44-45, 49-50 strobi 44-45 Psylliodes punctulata 77 rurale, food plant of Psylliodes punctulata 76 Chittenden, F. H., and Russell, H. M., paper, “The Semitropical Army Worm (Prodenia eridania Cram.)”. . . 53-70 paper, “Miscellaneous Notes on Truck-crop Insects” 93-97 “Notes on the Asparagus Beetles” 6-10 “The Asparagus Miner (Agromyza simplex Loew)”.. 1-5 “The Cranberry Span worm ( Cleora pampinaria Guen.)” 21-27 “The Hop Flea-beetle (Psylliodes punctulataMelsh..y , 71-92 “The Striped Garden Caterpillar (Mamestra legitima Grote)” 28-32 “The Water-cress Leaf-Beetle (Phxdon xruginosa Suffr.)” 16-20 “The Water-cress Sowbug (Mancasellus brachyurus Harger)” 11-15 Chlorid of lime, suggested remedy against water-cress sowbug 14 Chortophila planipalpis—Pegomya planipalpis 96 Clean cultivation against hop flea-beetle 89-91, 92 Cleora pampinaria 21-27 bibliography 27 biologic literature 24 descriptive 21-23 distribution : 23-24 food plants 25-26 larva, description 22 • life history 26 moth, description 21-22 natural enemies 26 pupa, description 23 remedies 26-27 synonyms 22 unpublished office notes 25 102 SOME INSECTS INJURIOUS TO TRUCK CROPS. Page. Cleora , tinctaria— Cleora pampinaria 22 Clover, red, food plant of Cleora pampinaria 25 Psylliodes punctulata 77, 79 white, food plant of Psylliodes punctulata 77, 79 Cochlearia armoracia , food plant of Phxdon armoradx 19 Collards, food plant of Mamestra legitima 30, 32 Prodenia eridania 53, 69 ornithogalli 30 Cotton cutworm. (See Prodenia ornithogalli.) food plant of Cleora pampinaria 24-26 Cowpeas, food plant of Prodenia eridania 53, 60, 69 Cranberry, food plant of Cleora pampinaria 21, 24, 25 spanworm. (See Cleora pampinaria.) Cress, food plant of Phxdon armoradx 18 water. ( See Water cress.) Crioceris asparagi 6-9 control with arsenate of lead 93-94 remedies 8-9 12-punctata 9-10 larva, young, description 10 Crucifers, preferred food plants of Psylliodes 81 Cucumber, food plant of Psylliodes punctulata 77 Cultural methods against beet leafhopper 48 hop flea-beetle 87-91 “Curly-leaf” of sugar beet around Spreckels, Cal., not work of Eutettix ten- ella 46,51-52 characteristics 44-46 conclusions 52 relation to Eutettix tenella 33-48, 52 leafhoppers 33-52 Cutworm, cotton. (See Prodenia ornithogalli.) Cymatophora pampinaria , bibliographic reference 27 —Cleora pampinaria 22 Deromyia ternata , enemy of Polistes annularis 64 Dissosteira Carolina affected by fungus ^ 31 Dock, food plant of Psylliodes punctulata 77, 79 Dondia, food plant of Agallia higelovix 51 Eutettix tenella 35 Ducks against water-cress sowbug 14 suggested remedy against water-cress leaf-beetle 20 Dyar, H. G., technical description of the egg and larval stages of Prodenia eridania 55-57 Eggplant, food plant of Prodenia eridania •. . . 53, 62, 69 Empoasca, association with so-called “curly-leaf” of sugar beet at Spreckels, Cal 46,51-52 on sugar beet, habits, remedy 51-52 Ernpusa sp., fungous enemy of Prodenia eridania 65 Enarmonia nigricana , injurious occurrence in United States 95 Entomophthora sphxrosperma , fungous enemy of Phxdon xruginnsa 96 Epitrix, host of Perilitus schwarzii (?) 82 Estigrnene ( Leucarctia ) acrxa affected by fungus 31 Eutettix albida on Atriplex 50 dari.vida on sugar beet, appearance and habits 50 INDEX,. 103 Page. Eutettix insana on Atriplex 50 nigridorsum on Helianthus, discoloration and distortion of leaves re- sulting 44-45 I pauperculata on Atriplex 50 8citula on Chenopodium and sugar beet, discoloration and distortion of leaves resulting 44-45 sugar beet, appearance and habits 49-50 seminuda on beet, appearance and habits 50 straminea on Helianthus, discoloration and distortion of leaves result- ing 44-45 stricta, bibliographic reference 48 near relative of Eutettix tenella ' 50 strobi , habits 44-46 on Chenopodium and sugar beet, discoloration and distortion of leaves resulting 44-45 sugar beet, appearance and habits 49 tenella, adult, description 35 at Lehi, Utah 36-37, 38-40 Maroni and in the Cache Valley, Utah 38 Monroe, Utah 38 bibliographic references 48 cage experiments, Lehi, Utah..... 38-40 descriptive 35 distribution 36 economic relations 41-47 summary 47-48 eggs, description 35 food plants 35 in Oregon, Idaho, and California 46-47 life-history studies 36-40 summary 40 nymphs, description 35 relation to “curly-leaf ” condition of sugar beet 33-48, 52 remedies, proposed ... 47-48 Exorista boarmiae, parasite of Cleora pampinaria. 26 Fertilizers against hop flea-beetle 88 Fish against water-cress sowbug 14-15 suggested remedy against water-cress leaf-beetle. 20 Flea-beetle, hop. (See Psylliodes punctulata.) European. (See Psylliodes attenuata.) potato, European. (See Psylliodes affinis.) punctulated. (See Psylliodes punctulata.) rhubarb. (See Psylliodes punctulata.) small-punctured. (See Psylliodes punctulata.) “Flea,” name for Psylliodes punctulata in the West 71 Fundulus diaphanus, F. dispar , and F. notatus , suggested use against water- cress sowbug 15 Fungous disease of Prodenia eridania 65 diseases of Mamestra legitima 31 enemy of Phsedon aeruginosa 96 Garden caterpillar, striped. (See Mamestra legitima.) Geranium, food plant of Cleora pampinaria. 24, 25 Goldenrod, food plant of Mamestra legitima 30, 32 104 SOME INSECTS INJURIOUS TO TRUCK CROPS. Page. Grass, food plant of Mamestra legitima 32 Grease wood. ( See Sarcobatus.) Guava, food plant of Cleora pampinaria 25 Ealtica punctulata, bibliographic reference 91 Helianthus, food plant of Eutettix niyridorsum 44-45 straminea 44-45 Hickory, food plant of Cleora pampinaria. j 25 Honey locust, food plant of Cleora pampinaria 25 Hop flea-beetle. (See Psylliodes punctulata.) European. (See Psylliodes attenuata.) “Hop-flea,” name for Psylliodes punctulata in the West 71 “Hopper-dozer.” (See Tar pan.) “Hopperettes.” (See Tarred catchers.) Hop plant, food plant of Psylliodes punctulata 71-92 Horseradish, food plant of Plnxdon armoracix 19 “Ichneumon,” parasite of Prodenia eridania 58,64 Irrigation against beet leafhopper 48 hop flea-beetle 88 as affecting “curly-leaf ’’ condition of sugar beet 41-43 Kerosene emulsion against beet leafhopper 43, 47-48 Empoasca on potatoes 52 hop flea-beetle 85-87, 92 Killifishes, fresh water. (See Fundulus diaphanus, F. dispar , and F. notatus.) Kohlrabi, food plant of Phaedon armoracix 18 Lamb’s-quarters. ( See Chenopodium.) Leaf-beetle, water-cress. (See Phxdon xruginosa.) Leafhopper, beet. (See Eutettix tenella.) Leafhoppers and their relation to “curly-leaf” condition of sugar beet 33-52 Leucania nigrofascia, bibliographic reference 70 Lime, air-slaked, with Paris green, against hop flea-beetle 83 remedy against water-cress sowbug, burns cress 97 Limnerium sp., parasite of Prodenia eridania 63 Locust, Carolina. (See Dissosteira Carolina.) Mamestra legitima 28-32 biologic notes 29-31 control methods , 32 descriptive 28-29 habits, summary 32 larva, description 28-29 moth, description 28 natural enemies 31 pupa, description 29 Ma.ncasellus brachyurus 11-15 control methods 12-15, 97 descriptive 11-12 injuries and remedies 97 injurious occurrences 12 Mangel, food plant of Psylliodes punctulata 79 Mechanical methods against hop flea-beetle • 87-89 Melcorus sp., host of Spilochalcis spp 63 parasite of Prodenia eridania 63 Milkweed, food plant of Mamestra legitima 30, 32 INDEX. 105 Page. Mustard beetle. (See Phxdon armoracix and P. betulx.) common black, food plant of Psylliodes punctulata 74-75,77 food plant of Phxdon armoracix 18 Psylliodes punctulata 77 hedge, food plant of Psylliodes punctulata 74-75, 77 white, food plant of Phxdon betulx 97 Nasturtium officinale. ( See Water-cress.) Nettle, food plant of Psylliodes punctulata 77, 79 Noctua xylina , bibliographic reference 27 Okra, food plant of Prodenia eridania 53, 69 Ophion tityri , parasite of Prodenia eridania 63 Orange, food plant of Cleora pampinaria 25 Paris green against common asparagus beetle 8 cranberry span worm 26-27 hop flea-beetle 83-85, 87, 92 semitropical army worm 65-69 striped garden caterpillar 32 and Bordeaux mixture against hop flea-beetle 83-85 flour against water-cress leaf-beetle 19 plaster or air-slaked lime against water-cress leaf-beetle 19 water against water-cress leaf-beetle 19 dry, with air-slaked lime, against hop flea-beetle 84-85 Pea moth. (See Enarmonia nigricana.) Pear, food plant of Cleora pampinaria 24, 25 Peas, food plant of Enarmonia nigricana 95 Mamestra legitima 28, 30, 32 Prodenia ornithogalli 30 Pegomya planipalpis on radish 95-96 Pepper, food plant of Prodenia eridania 53, 69 Perilitus schwarzii (f), parasite of Epitrix 82 Phyllotreta 82 Psylliodes punctulata 82 Phxdon xruginosa 16-20 beetle, description 16-17 control methods 19-20 descriptive 16-18 egg, description 17 fungous enemy 96 habits 18-19 injurious occurrence 16 larva, description 17 literature 18 Plagiodera viridis a synonym 18 pupa, description . . . 18 armoracix , habits 18-19 synonyms 18 betulx= Phxdon armoracix 18-19 on white mustard 97 cochlearix Fab., distinct from Phxdon armoracix 18 Phalxna phytolaccx, bibliographic reference 70 = Prodenia eridania 57 Phlepsius irroratus, mistaken determination of Eutettix sirobi 49 106 SOME INSECTS INJUBTOUS TO TRUCK CROPS. Page. Phyllotreta, host of Perilitus schwarzii (?) 82 Phytolacca decandr a. ( See Pokeweed.) Pigweed. (See also Amaranihus retrofexus.) food plant of Psylliodes punctulata 79 Plagiodera cochle arise Panz., Gy\\.=Phxdon armoracise 18 viridis=Phsedon seruginosa 18 Podisus maculiventris, enemy of Prodenia eridania 64 Pokeweed, food plant of Prodenia eridania 53, 58, 61-62, 69 moth, name for Prodenia eridania 57 Polistes annularis, enemy of Prodenia eridania 64 Polypeza sp., parasite of Pegomya planipalpis 96 Pontia rapse, enemy of Prodenia eridania 64 Potato flea-beetle, European. (See Psylliodes affinis .) food plant of Prodenia eridania 53, 58-59, 69 Psylliodes punctulata 77, 79 “Pretty cutworm,” manuscript name for Mamestra legitima 30-31 Prodenia eridania 53-70 bibliographic list 70 control methods 65-69 descriptive 54-57 distribution 57 early records 62 egg, description 54 fungous disease 65 generations 62-63 history 57 injury to truck crops 53-70 larval stages, description 55-57 life-cycle periods 62-63 literature 57-58 moth, description 54 natural enemies 63-65 origin 57 parasites 63 predaceous enemies 64-65 Prodenia nigrofascia Hulst a synonym 54 pupa, description 55 summary 69 nigrofascia of Hulst = Prodenia eridania 54 omithogalli , association with Mamestra legitima in damage to garden crops 30 phytolaccse, bibliographic reference 70 Psylliodes affinis, the European potato flea-beetle 81 attenuata, the European hop flea-beetle 81 chrysocephala on edible crucifers in Europe, habits 81-82 convexior, comparison with Psylliodes punctulata 73 on Bursa bursa-pastoris 81 notes on various species 81-82 punctulata 71-92 adult, habits 79-80 bibliography 91-92 control methods 83-91 descriptive 72-73 INDEX. 10 ? Page. , , . 81 Psy Modes punctulata, development 73 distribution. ... - n - M ;,v """"""I ve-7? generations habits ‘ 82 host of Perilitus schwarzii (?) ... , " 6-10 injuries, recent gQ larva, habits 79-8 J life history ' literature ~ local conditions affecting abundance ^ ^ methods of attack - 80-81 02 Quayle, H. J., account of life history and habits of Psylliodes punctulata 79-81 Radish, food plant of Pegomya planipalpis ’ ^ Psylliodes punctulata g() ^ Rape, food plant of Mamestra legitima. - - * ' ' * ‘ ’ 80 Prodenia ornithogalli “Raps-erdfloh.” (See Psylliodes chrysocephala.) Resin-fishoil soap with arsenate of lead against hop flea-beetle. . . . - - - - striped garden caterpillar. ..... oz soap and arsenate of lead against common asparagus beetle 8^9 wash against hop flea-beetle Rhubarb flea-beetle. (See Psylliodes punctulata.) ^ ^ food plant of Psylliodes punctulata ’ 4g Rolling, remedy against beet leafhopper 87 _ g g hop flea-beetle 95-96 Root maggot, a new one from the West gj Rose, food plant of Empoasca. X e il'H ( *t D a 0 nd Chittenden, F. H„ paper, “ The Semitropieal Army Worm ^ (Prodenia eridania Cram.)” - Russian thistle. (See Thistle, Russian.) 30.32 Ruta-baga, food plant of Mamestra legitima ’ g Q Prodenia ornithogalli Salt-marsh caterpillar. (See Estigmene \Leucarclia] aerxa.) Sarcobatus, food plant of Eutettix tenella 83-85 Scheele’s green against hop flea-beetle Schilbeodes. (See Catfish.) Sea-blite. (See Dondia.) gg, Semasia nigricana=Enarmonia nigricana Shad scale. (See Atriplex confertifolia.) Shepherds’ purse. (See Bursa bursa-pastoris.) 83.88-89 Sheets, tarred, against hop flea-beetle * [ Snuff, against hop flea-beetle 53 60 1 Solarium, wild, food plant of Prodenia eridania Solidago spp. (See Goldenrod.) Sowbug, water-cress. (See Mancasellus brachyurus.) Spanworm, cranberry. (See Cleora pampmana.) 6g Spilochalcis spp., parasites of Meteorus secondary parasites of Prodenia eridania 108 SOME INSECTS INJURIOUS TO TRUCK CROPS. Page. Sporotrichum minimum , fungous enemy of Mamestra legitima 31 Starwort, water. (See Callitricha verna.) Stiretrus anchorago, var diana, enemy of Prodenia eridania 64 Strawberry, food plant of Cleora pampinaria 21, 24, 25 Striped garden caterpillar. (See Mamestra legitima.) Sulphate of copper, suggested remedy against water-cress sowbug 14 Sweet potato, food plant of Prodenia eridania 53, 59-62, 69 Tar pan, or tarred wings, against beet leafhopper 48 Tarred catchers against hop flea-beetle 88-89 Thamnotettix tenellus, bibliographic references 48 Thistle, Russian, food plant of Eutettix tenella 35 Tobacco extract against hop flea-beetle 86 food plant of Mamestra legitima 30, 32 powdered, against hop flea-beetle 83 Tomato, food plant of Prodenia eridania 53, 58, 69 Trap crops against hop flea-beetle 87, 92 plants in control of asparagus miner 4-5 Truck-crop insects, miscellaneous notes 93-97 Tumbleweed. (See Amaranthus grsecians.) Turnip, food plant of Mamestra legitima 30, 32 Prodenia ornithogalli 30 Psylliodes punctulata 77, 79 mined probably by Pegomya planipalpis 96 Veronica bcccabunga , food plant of Phsedon armoracise 19 Verticillium, fungous enemy of Dissosteira Carolina 31 Estigmene (Leucarctia) acraea 31 Mamestra legitima 31 Violet, food plant of Mamestra legitima 30, 32 Water-cress, burned by lime used as insecticide against sowbug 97 food plant of Mancasellus brachyurus 11-12 Phsedon aeruginosa 16 armoraciae 19 insects, notes 96-97 leaf-beetle. (See Phaedon aeruginosa.) method of growing to avoid, damage by sowbug 13-14 sowbug. (See Mancasellus brachyurus.) Whale-oil soap against hop flea-beetle 85-87, 92 Willow, food plant of Cleora pampinaria 24, 25 Winthemia quadripustulata, parasite of Prodenia eridania 63 Xylomiges phytolaccae, bibliographic reference 70 o I U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY- BULLETIN No. 66, Part I. L. O. HOWARD, Entomologist and Chief of Bureau. THE ASPARAGUS MINER, NOTES ON THE ASPARAGUS BEETLES. F. II. CHITTENDEN, • Entomologist in Charge of Breeding Experiments. Issued March 16 , 1907 . WASHINGTON: GOVERNMENT PRINTING OFFICE. 1907 . CONTENTS. Page. The asparagus miner ( Agromyza simplex Loew) 1 Descriptive 1 Distribution 2 Historical and biological notes 2 Recent injury 3 Remedial measures «. 4 Notes on the asparagus beetles 6 The common asparagus beetle (Crioceris asparagi L. ) 6 Remedies 8 The twelve-spotted asparagus beetle ( Crioceris 12-punctata L. ) 9 ILLUSTRATIONS. Page. Fig. 1. Agromyza simplex: Fly 1 2. Agromyza simplex: Larva, pupa, work 2 hi Issued March 16, liN)?. B ' U. S. D. A., B. E. Bui. 66, Part I. SOME INSECTS INJURIOUS TO TRUCK CROPS. THE ASPARAGUS MINER. {Agromyza simplex Loew. ) The stalks of asparagus are frequently attacked by insects, ana in recent years have been reported considerably injured by the larva or maggot of a minute black fly to which the name asparagus miner has been given. The larva mines under the epidermis of the stalk, and when it has transformed to the puparium or “flaxseed” stage the thin outer skin becomes more or less ruptured and the presence of the insect is easily detected. It operates more abundantly near the base of the stalks and penetrates below the surface of the ground to a depth of 7 or 8 inches. During the year 1906 this species attracted considerable attention by its abundance in some of the principal asparagus-growing sections of New England and it bids fair to become a pest of considerable importance. It was first noticed on asparagus Fig. 1 .— Agromyza simplex: Fly, dorsal view at left, lateral view at right. Highly magnified (or ginal). in 1896, ten years earlier than the present writing, prior to which time nothing was known of its habits. It is a native species and evi- dently restricted to asparagus as a food plant. Until the year 1906 it had not been recognized as doing injury to cutting beds, although attack had been observed in various sections. The mines of the larvae about and below the bases of the stalks are frequently so abundant that they have the effect of girdling, so that the injured stalks can be readily pulled from the ground. DESCRIPTIVE. The parent insect is a two- winged fly (fig. 1), metallic black, with large prominent head and e}^es, and clear wings, the wing expanse being about one-sixth of an inch (1 mm.). 1 9 SOME INSECTS INJURIOUS TO TRUCK CROPS. The larva (fig. 2, a) is about one-fifth of an inch long and milk- white in color. Like other maggots, it is footless, large at the posterior extremity, and tapering toward the head. The puparium (fig. 2, d, e) is not unlike the “flaxseed” of the perni- cious Hessian fly, with which it has been aptly compared. At a little dis- tance, also, it suggests a Lecanium scale. This stage is remarkable be- cause of its peculiar flattened and curved position, as seen from the side. It is red in color, and meas- ures about 3.5 mm. in length and about 1 mm. in width. The egg has not been observed. This species belongs to the dipter- ous family Agromyzidae, and was described by Loew in 1861, a the locality being given as “Middle States.” DISTRIBUTION. In its injurious occurrences this species appears to be limited to the eastern United States, from New England to Tennessee. From avail- able data it is quite obvious, however, that it may be destructive over a considerable territory, including a large portion of Massachusetts and Connecticut, Long Island, the District of Columbia, Pennsylvania, and Tennessee. As it is recorded from New Jersey, it is probably injurious there, although no reports of injury in that State have reached this office. In time it will doubtless attract attention in inter- mediate points and in States farther north and west. It has also appeared in asparagus beds in California. HISTORICAL AND BIOLOGICAL NOTES. In May, 1897, and afterwards this fly was observed in abundance by the writer on terminal shoots of asparagus, particularly at Cabin John, Md. Two weeks later no more flies were seen, but June 26 they reappeared and were then usually seen in copula. It was sur- mised at the time that this second appearance indicated the first new generation of the j^ear and its abundance on asparagus seemed to show that it lived in some manner at the expense of that plant. Examination of asparagus plants at that time, however, failed to show attack. The facts which have just been narrated were published in 1898 . b Fig. 2 .—Agromyza simplex: a, larva, lateral view; b, thoracic spiracles; c, anal spiracles; . d, puparium from side; e, same from above; /, section of asparagus stalk, showing injury and location of puparia on detached sec- tion; a-e, much enlarged; /, slightly reduced (original). "Diptera America} septentrionalis indigena, Centuria octava 84, p. 160. lj Bui. 10, n. s., Div. Ent., U. S. Dept. Agric., p. 62, 1898. THE ASPARAGUS MINER. 3 In 1900 we received complaint of injuries in the District of Columbia, and from Knoxville, Tenn., and in the meantime the species came under the observation of Mr. F. A. Sirrine, who has stated a that work was first observed in asparagus fields on Long Island in 1896. This statement is made in a bulletin of six pages, which represents all that was known of the species at that time. Late in September, 1900, word was received from Mr. Frederic Voigt, Tennallytown, D. C., of injury to the stalks of asparagus on his and a neighboring truck farm. When the writer visited the field, however, although injury was apparent on the outer skin of some stalks, no living specimens could be obtained, only the dried puparia being in evidence at this time. October 2 of the same year, Mr. Samuel M. Bain, University of Tennessee, Knoxville, Tenn., sent a stalk of asparagus showing the work of this miner upon the skin, and, October 27, specimens of the dried puparia. February 18, 1901, Mr. T. Miles Brous, Bustleton, Philadelphia, Pa., wrote that this insect, which he accurately described, seemed to cause much greater trouble than the common asparagus beetle. A neighbor had lost two or three new beds of asparagus on account of its ravages. By the writer’s direction, Mr. F. C. Pratt visited a large truck farm at Brookland, D. C., where asparagus was one of the main crops, June 18, 1902. Asparagus was still being cut for market, but volunteer plants were growing here and there in fields of corn, cantaloupe, and potatoes, between rows. A few flies were seen on terminal shoots of asparagus that showed wilting, and many volunteer plants were found badly infested, most individuals having transformed to pupge. Although stems break off just below the ground, the entire colony of insects below that point is left with sufficient moisture and nourish- ment for their maintenance. The puparia were present in great numbers underneath the outer skin of the root, and as many as nine puparia were counted in a space only an inch long on one stalk. The stalks below the point of injury appeared to be perfectly sound. Larvae also were found in rotting stalks that broke off just belowground. During 1905 Mr. Ralph E. Smith reported this species as becoming abundant in California, though not of any great importance at that time. His description of the insects’ manner of work leaves no doubt as to the identit}^ of the species. 6 RECENT INJURY. During September, 1906, Messrs. J. B. Norton and A. D. Shamel, of the Bureau of Plant Industry, furnished stems of asparagus from Concord, Mass., showing severe infestation by this species, many a Bui. 189, N. Y. Agric. Exp. Sta., p. 277, Geneva, 1900. &Bul. 165, Univ. of Cal. Agric. Exp. Sta., p. 96, 1905. 4 SOME INSECTS INJURIOUS TO TRUCK CROPS. puparia being present under the mined outer skin. In the neighbor- hood of Concord, a very important asparagus-growing region where hundreds of acres are devoted to this crop, the infestation was practi- cally absolute, the insect being found even as abundantly as the common asparagus beetle, being present wherever rust was found, as also where no rust was present. The specimens submitted were about the average as regards the degree of infestation, some plants showing injury 7 inches below the surface. Severe injury was reported on the farms of Mr. Frank Wheeler and Mr. Charles W. Prescott, at Concord, Mass. The growers in that region had never noticed this insect until Mr. ShamePs examination showed that its injuries were extensive. Later Mr. Shamel reported finding infestation in every field and patch of asparagus which he ■ visited in Massachusetts and Connecticut, particularly at Suffield, Granby, and Hartford, Conn., and he believed attack to be widespread. October 26, 1906, Mr. Ralph E. Smith wrote, by request, that the conditions under which this asparagus miner was found in abundance in the yellow stalks of asparagus in California, as reported by him in an article on Asparagus Rust Control/ 4 had prevailed for two or three years. The insect was al ways very abundant at the base of these yellow, dying stalks, although the injury was attributed to the “ centipede,” reported as wireworms on a previous occasion. 6 Remedial measures. Witn our present knowledge of the life economy of this species, two methods of control suggest themselves as of greatest value, and it may be that they will prove all that is necessary under ordinary conditions. (1) In spring permit a few volunteer asparagus plants to grow as a trap crop, to lure the fly from the main crop or the cutting beds for the deposition of her eggs. After this has been accomplished the trap crop should be destroyed b}^ pulling the infested plants and burning them with their contained puparia. The time to pull the plants will vary according to localit}- and somewhat according to season also. The second and third week in June would be about the right time in and near the District of Columbia. On Long Island this work should be done a week or two later. In the northernmost range of this insect — for example, in Massachusetts — the last of June and the first of July would probably be a suitable time. (2) The second generation can be destroyed in like manner by pull- ing old infested asparagus stalks as soon as attack becomes manifest and promptly burning them also. a Bui. 172, Univ. Cal. Agric. Exp. Sta., p. 21; &Bul. 165, 1. c. THE ASPARAGUS MINER. 5 If this work were carefully done over a considerable area, it would leave little necessit} r for other methods, since it would do away with these insects in the vicinity and leave few to be dealt with another season; unless, indeed, this insect has an alternate food plant. The cooperation of neighboring asparagus growers and thoroughness are essential for success. This method will operate also against the rust which is now present in many fields infested by the miner. NOTES ON THE ASPARAGUS BEETLES. Since the publication of the writer’s general article on the asparagus beetles in the Yearbook for 1896, a many notes on their distribution and destructive occurrences have been published. Some additional data were published soon afterward. 6 The following brief review of the subject is submitted as a sequel to those articles and a summary of the further dissemination of these pests in a decade of years. THE COMMON ASPARAGUS BEETLE. ( Crioceris asparagi L. ) The predictions made by the writer in regard to the future distri- bution of the common asparagus beetle haA r e been completely fulfilled as regards its western spread, although it has not as yet been reported as far south as Kentucky-. Mr. J. G. Sanders, however, informs the writer that it has been established about Columbus, Ohio, since 1903, and Mr. Charles Dury, Cincinnati, Ohio, reported this species at Indian Hill, about 7 miles from that city, on asparagus beds in 1905. Hundreds were observed during June. The customary injury was noticed, and plants appeared as though scorched with fire. In 1897 the species was observed to have continued its spread westward along Lake Erie, and was then known in nine counties in northeastern Ohio. The fol- lowing year it was first noticed in western Virginia. In 1898 also it was reported to have been present at Benton Harbor, Mich., since 1896. By- 1899 it had made its appearance in Canada, accompanied by the twelve-spotted species, in the Niagara River region. It is interesting to note that in 1900 the present species, which had been rapidly increasing its range in the East, including New York, after occurring in injurious numbers in Maryland, was apparently totally destroyed by the hot spell of July and August that occurred in the District of Columbia and neighboring parts of Virginia and Maryland; whence the conclusion that this condition prevailed to a considerably- larger extent than came to the writer’s personal notice. In 1901 Dr. James Fletcher noted that the species, though present in the Niagara district, had not increased to the extent that was feared. It had spread to Guelph, Ontario, that year, and did much damage about St. Catharines. In 1901 its occurrence around Toronto was "Yearbook U. 8. Dept. Agric. f. 1896 (1897), pp. 341-352. 6 Bui. 10, n. 8., Div. Ent., U. S. Dept. Agric., pp. 54-59, 1898. NOTES ON THE ASPARAGUS BEETLES. noticed. It was reported also 40 miles west of Chicago, 111. It has become veiy generally distributed in asparagus- growing districts in New York State, and has reached Glens Falls, which approximates its northernmost limit in this country. In 1905 we received complaint of this insect as a pest in Illinois, at Park Ridge, and of its occurrence about Chicago. Reports from Michigan showed that it had been present there in 1904 in the vicinity of Ada, about 10 miles from Grand Rapids, and that it was a pest in that vicinity. Although the data given above indicate that the species is now well distributed throughout the Upper Austral region, for some reason its occurrence in Indiana has not yet come to our knowledge; neverthe- less although there are naturally many uninvaded localities, it is I undoubtedly established in that State, most probably near Lake Michigan. As an example of its manner of distribution, it might be noted that in May, 1905, the beetle was found for the first time in Warrenton, Fauquier County, Va., a little farther inland than it had ever been noticed in that section. Yet this species has been permanently estab- lished in the adjoining Alexandria County for many years. August 8, 1905, Air. Ralph E. Smith wrote of the occurrence of this species in California, stating that during two seasons it had been very abundant at Bouldin Island, the principal asparagus center of that- region. As Air. Smith was familiar with this insect and its occur- rence on the Atlantic coast, there is little doubt that his identification is correct. In the winter of 1904 to 1905 Bouldin Island was flooded and remained under water for over a year. It had just been reclaimed and there were no signs of the beetles'. There is, therefore, a possibility that the insect was exterminated in that region, and this includes the State, if the occurrence of the species was only local. The dying out of this asparagus beetle in small localities where it has not become thoroughly established is not without precedent, as its recorded occurrence at Rock Island, 111., many years ago, has been verified by specimens now in a Chicago museum, properly labeled as collected there by the late A. Bolter, an experienced collector of Coleoptera. indeed, it would seem that few vegetable-feeding insects are more subject to extermination in a limited locality not contiguous to one also infested than is the present species. October 26, 1906, Air. Ralph E. Smith, at the writer’s request, reported the status of this species in California. He wrote that during the summer he found the beetles again, and that they were very abun- dant in fields near Oakley, Cal. It could not be stated that the insect was of general occurrence in the State, but apparently it existed only in a few scattered colonies. As previously reported the colony at Bouldin Island appears to have been exterminated by flood, and 8 SOME INSECTS INJURIOUS TO TRUCK CROPS. the Oakley occurrence was the first that Mr. Smith had noted since. In most of the asparagus acreage of the State the insect was not yet present. Mr. Franklin Sherman, jr., has kept a careful record of the occur- rence of this species in North Carolina, and informed the writer, on the occasion of a visit in 1906, that it is common in the east-central part of the State in the trucking belt, and especially abundant at Raleigh, Wake County, Goldsboro, Wayne County, and Warsaw, Duplin County. In order to make the present account of the known distribution of this species as complete as possible, inquiry was made of the official entomologists of the States of Kentucky, Iowa, Missouri, Nebraska, and Minnesota, all of whom reported that the occurrence of this spe- cies in their States had not been brought to their attention. Mr. James G. Moore, however, assistant in horticulture at the University of Wis- consin, Madison, W is., stated that the asparagus beetle had been found in Wisconsin, but he had no special data on its distribution. REMEDIES. With regard to remedies good results have followed the experimental use of arsenate of lead. This insecticide has come into very general favor in recent years, and in the correspondence of this office we have for some time advised its employment against most leaf-feeding beetles, like the asparagus beetles. In Connecticut Dr. W . E. Britton a has made a practical test of this remedy on asparagus plants, spraying them from all four sides in succession because of the slight leaf exposure as com- pared with most other plants. The day following treatment (June I) many dead beetles and larvse were found on and under the plants. A few had survived and were feeding, but ten days later only a few living larvse could be found, and the beetles did not again become abundant on the plants during the summer. The same amount of good might be accomplished with scarcely greater expense by spray- ing from opposite sides and repeating just before the time for the last generation to develop and in time to check the beetles before they go into winter quarters. In Pennsylvania Prof. II. A. Surface, 6 in a series of experiments with Paris green and arsenate of lead, applied to asparagus plants the first week of June, 1905, found that not more than 50 per cent of the insects were killed when Paris green and lime were used. With lead arsenate 90 per cent were killed, while in one experiment, by the addi- tion of resin soap, which is used as an addition to an insecticide to « Rept. Conn. Agric. Exp. Sta. f. 1903 (1904), pp. 275, 276. & Monthly Bulletin, Div. of Zool., Pa. State Dept. Agric., Vol. IV, May, 1906, p. 8. NOTES ON THE ASPARAGUS BEETLES. 9 enable the poison to adhere better to smooth plants, 100 per cent of the insects were killed on the 50 plants treated. In this case the arsenate of lead was used at the rate of about 1 pound to 2d gallons of water, and 2^ pounds of soap were added. Arsenate of lead has been used with satisfactory results on asparagus at the rate of 1 pound in 16 to 2d gallons of water. Additional experi- ments are necessary to ascertain the exact amount of the poison that can be used economically to produce the best effect. In Professor Surface’s experiments evidently only a single spra}^ was applied. THE TWELVE-SPOTTED ASPARAGUS BEETLE. ( Crioceris 12 -punctata L. ) Nearly every year since 1896, when the distribution of the twelve- spotted asparagus beetle was recorded b} T the writer,® the appearance of this species has been noted in new localities in the United States, until it is now well distributed westward and especiall} 7 northward. In 1898 Dr. J. B. Smith stated that it then occurred throughout the State of New Jersey “south of the shale from the Atlantic coast to the Delaware.” The following year (1899) it was recorded by Dr. E. P. Felt from different counties in New York, and as far west as Buffalo. In some places the species was abundant, while in some near-by locali- ties it could not be found, showing that it was still locally distributed through New York. It was afterwards recorded present in Albany, Batavia, Leroy, Syracuse, Riverhead, Oswego, Center, Glendale, Richmond Hill, Peniield, Elmira, Geneva, Ithaca, and about Brooklyn, N. Y. It was also stated to occur in the Niagara district in Canada as far back as Hamilton, Ontario. An interesting point in regard to the occurrence of asparagus beetles in the Niagara peninsula was that the two species appeared to have arrived almost simultaneously in that region, but that the twelve- spotted form was by far the more common one. In after years dif- ferent observers noted its further spread in Canada, commenting upon the fact that it led the common species in becoming diffused by natural means. By 1902 it had appeared in Connecticut, at New Haven, and later in other parts of that State. Since some writers on these asparagus beetles have overlooked the author’s second article * 6 it may be well to mention that facts additional to those printed in the writer’s original article are given therein, including a description and illustration of the egg and its manner of deposition, and what is practically a complete account of the life his- tory of the species, the insect being found to develop and to feed where possible almost exclusively on the berry, although the beetles attack young asparagus shoots before the berries appear. « Yearbook U. S. Dept. Agric: f. 1896 (1897), pp. 350-351. & Bul. 10, Div. Ent., U. 8. Dept. Agric., pp. 57-59, 1898. 10 SOME INSECTS INJURIOUS TO TRUCK CROPS. The young larva . — The freshly hatched larva has not hitherto been described. It may be briefly described as follows: Head rounded, nearly twice as wide as long as seen from above; thoracic plates distinctly separated at the middle, with the intervening space yellow; legs infuscated, clear whitish at sutures. General color very pale yellowish, nearly white, and the surface much wrinkled. Length 1mm., width 0.35 mm. o U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— BULLETIN No. 66, Part II. L. O. HOWARD, Entomologist and Chief of Bureau. SOME INSECTS INJURIOUS TO TRUCK CROPS. THE WATER-CRESS SOW RUG. THE WATER-CRESS LEAF-BEETLE. F. H. CHITTENDEN, Entomologist in Charge of Breeding Experiments. Issued April 23, 1907. WASHINGTON: GOVERNMENT PRINTING OFFICE 1907 . CONT F,NTS. Page The water-cress sowbug ( Mancasellus brachyurus Harger) 11 Descriptive 11 Reports of injurious occurrence 12 Methods of control 12 The water-cress leaf-beetle ( Phcedon aeruginosa Suffr.) 16 Injurious occurrence 16 Descriptive 16 Literature 18 .Habits of this and a related species 18 Methods of control 19 ILLUSTRATIONS. Page. Fig. 3. The water-cress sowbug ( Mancasellus brachyurus ) 12 4. Cross section of cress pond showing arrangement for avoiding damage by water-cress sowbug 13 5. The water-cress leaf-beetle ( Phcedon aeruginosa) : larva, pupa, adult 17 in I . . . Issued April 23, 1907. *9 U. S. D. A., B. E. Bui. 66, Part II. SOME INSECTS INJURIOUS TO TRUCK CROPS. THE WATER-CRESS SOWBUG. $ (Mancasellus brachyurus Harger. ) During the past three years this isopod has attracted very consid- erable attention because of its occurrence in troublesome numbers in water cress ( Nasturtium officinale) grown for market in portions of Virginia, West Virginia, and Pennsylvania. The species is purely aquatic, thus differing from our common dooryard sowbugs, which, although most abundant in moist locations, are strictly terrestrial. It belongs to an entirely different family, the Asellidse, which contains three genera, mostly fresh- water forms, inhabitants of streams, wells, pools, and lakes. DESCRIPTIVE. This species is so distinct from the more common sowbugs (Onis- cidse) that a brief description will suffice. Its general appearance is shown, dorsal view, in figure 3. The body is much depressed, and the legs are long and strong. Seen from the side, it is decidedly shrimplike. The peculiar structure of the antennae may be noticed in the illustration. They terminate in long flagella, composed of many joints. When mature this sotvbug attains a length of 13 or 14 millimeters, or a little upward of half an inch, and is a little more than twice as long as wide, and gray in color. This creature is not an insect, but a crustacean, and therefore classed with crayfish and crabs. A detailed description is given by Miss Richardson, a who briefly men- tions McKees Spring, Gaylord, and Lexington, Va., as localities where this sowbug was “ reported injurious to water cress.” By recent correspondence we have obtained necessary information in regard to the habits and manner of operation of this sowbug, and we have also been successful in ascertaining what promises to be a very perfect remedy for the pest in its occurrence in streams and in spring water. It appears to affect cress only below the surface of the water, attacking the roots and lower leaves, and cutting off the stems « Monograph of the Isopods of North America. By Harriet Richardson. Bui. 54, U. S. National Museum, Washington, 1905, pp. 411-412, figs. 400-461. 11 12 SOME INSECTS INJURIOUS TO TRUCK CROPS. near the bottom, causing bunches of the plant to float. In portions of streams where these sowbugs have been found most abundantly they are frequently seen crawling m a thick mass at the bottom. They feed, so far as known, exclusively on cress, not being reported as attacking any other form of vegetation. REPORTS OF INJURIOUS OCCURRENCES. This sowbug has been observed as a pest since 1902. Our first report of its pernicious habits was made in 1901, when Ave received specimens through Mr. J. W. Bryan, Anacostia, D. C., from Hall- town, W. Va., where it was very injurious to wateS cress. In March, 1905, Mr. Powell Arnette reported injury at Gaylord, Va., to cress grown in spring water. The sow bu|>'s were always found in the water and did not attack cress above the surface. After destroying the last vestige of cress in one of his ponds they remained on the bottom “ a foot deep,” crawling about on the mud. During 1906 (June 18) Mr. John IT. Reed, Carlisle, Pa., wrote in regard to this species and its destructive work on water cress in his locality. Specimens were re- ceived August 11. The sowbug was ob- served principally on the roots and lower leaves, crawling up along the stem and cutting off the leaves. August 10 Mr. George C. Jordan, Washington, D. C., sent specimens from Basic City, Va., stating that this “ water bug ” was devouring his cress beds, and, since a million or more were colonized on the plants, there would be no crop at the rate they were reproducing. When the plants were lifted the sowbugs were observed to drop from them. Fig. 3. — The water-cress sowbug ( Mancasellus brachyurus). En- larged (after Richardson). METHODS OF CONTROL. Three ways of controlling this species are suggested. The first and most important consists in a method of growing the water cress so as to eliminate injuries by the sowbug. The second falls under the head of direct remedies, and none of these has as yet given sat- isfactory results. The third consists in the use of fish or fowls as destroyers. This last means of eradicating the pest has not yet had a fair trial. The following description of a successful method of disposing of the cress sowbug has been placed at our disposal by Messrs. B. Bryan THE WATER-CRESS SOWBUG. 13 & Son, who are practical cress growers and. have had several years’ experience with the pest : A METHOD OF GROWING WATER CRESS TO DISPOSE OF THE SOWBUG. The damage done by the sowbug to water cress has made it our greatest enemy in cress growing, and only after fighting it for four years have we suc- ceeded in finding a way to keep down its numbers so as to be sure of a crop. As cress is ordinarily grown — in lakes or streams of spring water anywhere from 6 inches to 3 feet in depth — it seems impracticable to apply any insecti- cide. At first we tried to catch the bugs with wire-netting traps placed where the whole stream of water had to pass through them, but the bugs remained among the cress, and we caught only about 20 per cent. Later, in using copper sulphate to kill moss in the cress, we found that it also killed the sowbugs, snails, etc., when applied freely. Further experiments, however, proved that bluestone could not be applied in deep running water any better than the insecticides previously tried, and when applied in shallow or still water it injured the cress. The method we are employing at present to fight the sowbug is largely a matter of arrangement of cress beds (see fig. 4), and can be used only where the bottoms of the beds can be graded and drained or where level land adjoins the source of the water supply. We dug long trenches in level land, making them 16 feet wide and about 15 inches deep. Lengthwise they were graded to give a fall of 3 inches in 100 feet, and crosswise to make the center of the trench several inches deeper than the sides. In the center and running the full length of the trench a trough made of three 10-incli boards was sunk below the bottom of the trench in such a way that all of the water might be drained out of the trench through it. Then, with the upper and lower ends of the trench and trough arranged to be opened or closed, the trench could be filled or emptied at will and the flow of water regulated up to 8 inches in depth over the cress. Of course fertile soil was put in the trenches and the cress could be planted either before or after the water was turned in. With cress beds arranged as above, manipulation to dispose of the sowbugs is simple. By cutting off the water supply and allowing the water to pass out at the lower end of the trench, the sowbugs will collect in the trough, following the receding water, as they can live only in water. No little puddles should remain among the cress, as the bugs will collect in them instead of in the trough. It will be found necessary, also, to use boards to walk on in gathering the cress, as prints of one’s boots in the beds would make holes for the bugs to shelter in. The bugs do not move until nearly all of the water is drawn out of the trench. Thus they are collected in a small amount of water in the trough and can then be readily killed with a liberal amount of bluestone, either solid or in solution. i 14 SOME INSECTS INJURIOUS TO TRUCK CROPS. To make the work thorough, water should not be turned into the trench again for twelve or twenty-four hours, in which time the few bugs left among the cress stems will die or find their way to the trough. The trenches can be cleared of bugs in warm weather as frequently as desired, but less danger is done the cress crop if the work is done just after gathering the cress. The same method of disposing of the sowbugs could be used in greenhouses in the winter, but cress grown in the open air could not be exposed in freezing weather, making the remedy inapplicable in cold weather. We have not used water in these trenches deeper than 10 inches, and are not able to say how a larger or more rapidly flowing supply of water would act, nor have we grown winter cress in them, as our water supply is insufficient for that purpose. OTHER REMEDIES. About the only other remedies which we have been able to suggest are the use of a substance, such as sulphate of copper or chlorid of lime, which might be placed in the water to destroy the pest. As the former has already been tested by Messrs. B. Bryan & Son (see page 13), it need not be mentioned further. Mr. John H. Reed states that a grower at Healing Springs, Va., has a remedy consisting of a poisonous material which is placed in the water, but he does not know the ingredients nor whether there would be danger to stock drinking the water below the spring. He writes also of the possible use of chlorid of lime. A tank of bleach composed principally of chlorid of lime ran into a creek at Mount Holly Springs, Pa., killed everything that was living in that stream for about half a mile downward, but did not poison stock that drank the water. The bleach came from a paper-mill tank which had burst. If chlorid of lime is tested it should be used on a very small scale at first to note the effect on plant life. It is apt to be harmful to trout and other fish present. Mr. Reed also suggested the employment of ducks to destroy the pest, but this would necessitate the abandonment of cress culture for a season, as the ducks would injure the condiment both by eating it and by fouling the water. Among other remedies, we have recommended draining off the water where possible and exposing the sowbugs to the drying effects of the sun. FISHES AS A POSSIBLE MEANS OF DESTROYING THIS ISOPOD. In response to inquiry, the following information was received from the Bureau of Fisheries, through Mr. Lawrence O. Murray, Acting Secretary, Department of Commerce and Labor, in regard to the fishes which might be found useful in the destruction of this aquatic isopod in its occurrence on water cress: Among the fishes which would probably prove most useful for this purpose and with which it is suggested that the Department may wish to experiment THE WATER-CRESS SOWBUG. 15 are the fresh-water killifislies Fundulus notatus, F. diaplianus, and F. dispar. The first occurs from Michigan to Alabama, Mississippi, and Texas, and is rather common in small lowland ponds. The second is found from Maine to North Carolina in river mouths, in the Great Lakes, and in practically all of the small lakes in the upper Mississippi Valley. The third occurs in smaller lakes and ponds from northern Ohio to Illinois and south to Mississippi. Specimens of each of these species could be obtained at any one of several small lakes in the northern part of Indiana. It is probable that some of the catfishes might also be useful in this connec- tion, and it is suggested that it might be worth while to try one or more of the small species known as “ mad Toms,” belonging to the genus Schilbeodes. One or more species of this genus can be found in almost any small, sluggish stream in Pennsylvania. Virginia, and West Virginia. The writer believes that carp should prove of value in keeping- down this cress sowbug, there being one drawback, however, that the carp must be watched to see that they do not develop too rapidly and that they do not attack the cress or make the water muddy. Cat- fish have been tried and found wanting in the case of the water-cress leaf-beetle, which will be considered elsewhere (pp. 16 - 20 ). THE WATER-CRESS LEAF-BEETLE. ( Ptiasdon ceruginosa Suffr.) INJURIOUS OCCURRENCE. Among plant- feeding native insects which have recently appeared in new roles is a little blackish leaf-beetle, Plicedon ceruginosa Suffr., which was reported for the first time as injurious to water cress {Nasturtium ojjicmale) in Pennsylvania, in 1903. During September Mrs. Hannah B. Hannum, Brandywine Summit, Pa., sent larva? and adults of this species, with statement that they were devastating her water-cress pond. Both larvae and beetles fed chiefly on the lower side of the leaves. In confinement they con- tinued feeding, attacking the stalks also. The larvae all reached development about the same time, being fully matured September 11 and 12, on the last of these two days crawling about the rearing jar and ceasing to feed. The pupal period was not observed, but it probably lasted ten days or a fortnight, as the weather was cool. The beetles continued for some time in our rearing cages, -frequently pairing, but depositing no eggs. August 19, 190-1, Mrs. Hannum sent additional specimens of this species in the beetle and nearly grown larval stages. It was noticed that the beetles did not swim rapidly, but steadily, and they were seemingly not discomposed by being somewhat out of their natural element. It seems probable that they fly from plant to plant, and like most beetles undoubtedly are able to float for many hours, and perhaps even swim short distances until they reach a landing place. September 13 our correspondent sent still another lot of this species, mostly beetles, but a number of larvae were included. Specimens of the larvae of a syrphus fly accompanied this sending and probably fed at times on the small larvae of the beetle. DESCRIPTIVE. The beetle . — This species belongs to the tribe Chrysomelini of the ■ family Chrvsomelidae. It is classified in our publications on the j Coleoptera of America north of Mexico with Plagiodera, but Eu- I ropean systematists place allied forms in the genus Phaedon Latr., j which now comprises seven species occurring in our country. They j are very small semiglobose forms. The outline is oval, with the thorax 1C, THE WATER-CRESS LEAF-BEETLE. 17 narrowed anteriorly and the apex margined. The elytra have eight punctate striae, with a short subsutural and submarginal row of punctures. The third joint of the tarsi is emarginate apically. The present species measures a scant one-eighth of an inch in length (3 mm.) , is shining bronzy black, and has the elytral intervals apparently smooth, but in reality faintly rugulose when highly mag- nified, while the thorax is microscopically reticulate. The original description appeared in 1858. a The egg . — The eggs have not come under observation. They prob- ably resemble those of the European Ph. armor ados L., described by Fryer as “ elongated oval and of a dark orange color.” Fig. 5. — The water-cress leaf-beetle (Phcedon ceruginosa) : a, adult; b, larva, from above; o, same, from side; d, pupa. Enlarged twelve times (original). The larva . — The larva appears somewhat like that of a related genus, Galerucella, only that it is very much smaller. It is about three or four times as long as wide, depending upon whether it is somewhat contracted or fully extended. The head is subtruncate in front, with the antennae lateral (in preserved specimens). The head is shining black, and the remainder of the body very dark brown or brownish black relieved by lighter areas between the segments. The first thoracic segment is a little wider than the head ; the sec- ond considerably wider than that, and the third widest, being nearly as wide as the first two abdominal segments. The second abdominal is widest, and at the same time the widest part of the body. The surface is sparsely covered with long hairs placed on piliferous tu- bercles, which are arranged some distance apart, as shown in figure 5, h. The tubercles on the sides of the dorsum are sometimes very prominent, and the larva is able to extend these, possibly, at will. From the abdominal segments large tubercular sections bearing hairs at their summit extend on each side. The anal segment is pale, like the ventral surface, which bears dark piliferous tubercles. Length, 5 mm. ; width, 1.2-1. 5 mm. a Ent. Zeitung, Stettin, Yol. xix, pp. 395, 396, 1858. 18 SOME INSECTS INJURIOUS TO TRUCK CROPS. The pupa . — The *pupa is illustrated by figure 5, d , which will answer better than a verbal description. The color is yellow, and the length is slightly less than that of the adult. The distribution of this species is probably moderately wide and additional study must be given this subject. At present we know of its occurrence in the District of Columbia, in Massachusetts, and probably in West Virginia. LITERATURE. Brief mention of the occurrence of this leaf-beetle as an enemy of water cress in Pennsylvania in 1893 was made by the writer,® but Mr. Frederick Knab, of this office, mentioning the same species as Plagiodera viridis , has recorded b its occurrence in great abundance upon water cress near Springfield, Mass., in 1902. The identity of the species in question has been verified by the comparison of speci- mens, and Mr. Knab’s record was evidently made on the assumption of Crotch c that aeruginosa was merely a variety of viridis. HABITS OF THIS AND A RELATED SPECIES. We can not at the present writing give an approximate statement of the life history of Phcedon aeruginosa , and hence must depend on what is known of the related Ph. armor acice, which is common to both continents/ This letter has evidently been introduced into this country, but its habits have apparently not been studied here. It is known in England as the blue beetle and mustard beetle/ and is of considerable importance locally, in some seasons ravaging entire fields of mustard, cress, cabbage, and kohlrabi. It passes the winter as adult, reappearing in spring on cruciferous plants. F^er stated that in the three years prior to 1881 the Isle of Ely, England, suffered from the ravages of this species, entire fields being injured. Mustard was attacked at about the time of the formation of the seed pod and after the stalks were stripped nearly to the cuticle the beetles trans- ferred their attention to kohlrabi, which they completely consumed, at first attacking the leaves and afterwards the bulbs, leaving nothing but bare stalks. The water-cress leaf-beetle is doubtless no exception to the general rule among most Chrysomelidae and other species of Phsedon, in laying its eggs on the under side of the leaves. Both larvae and a Ybk. U. S. Dept. Agric. f. 1903 (1904*), p. 504; 6 Entomological News, March, 1903, p. 89 ; c Crotch, Proc. Acad. Phila., 1873, pp. 54, 55 ; d Pluedon armoracice L. syn. : Plagiodera cochlcariw Panz., Gyll. ; Phcedon bctulce Kiist. It is not the same as cochlearur Fab. s Fryer and others have given accounts of this species in The Entomologist (Vol. XIV, pp. 44, 187, etc.). THE WATER-CRESS LEAF-BEETLE. 19 adults attack the cuticle of the stem after feeding on the leaves, as has been noticed in the case of armoracice. E. A. Fitch has ob- served the partiality of the latter for water cress and other crucif- Brs which grow in watery places and mentions the destruction of an entire crop of horseradish. Kaltenbach a records, according to Gyllenhall and his own obser- vations, Veronica beccabunga , Cardamine amara , and Cochlearia 'irmoracia or horseradish as food plants, and states that the larva undergoes metamorphosis in the earth, the pupa state lasting four- teen days. Cornelius b is cited as having observed two generations, the spring generation being found in May and June and the second in September. Thomas H. Hart records the water starwort of England ( Callitricha verna) as another host plant. T. R. Billups, 0 an ento- mologist as well as truck grower, mentioning this species as Phcedon hetulce , states that it is “ one of the greatest insect pests the market gardeners around London have to contend with.”' Our American species undoubtedly hibernate as adults and appear in early spring under boards and similar shelter. METHODS OF CONTROL. How to successfully control this insect under ordinary conditions is quite a problem. Paris green was tried by our correspondent, mixed with flour and sprinkled over the plants when the dew was on, and this reduced the numbers of the insect somewhat. Owing to the moist condition of the plants, however, the flour formed a paste which stuck like glue, and it was therefore abandoned. Applied in water it rolled off the plants. We were not informed if this appli- cation was made with a spraying machine. If the plants were sprayed lightly with a fine spray, it might answer, or, better, Paris green dry with only 20 parts of flour, or plaster or air-slaked lime. An arsenical should not be used within about a week of the time of cutting the cress for market. In the case of Paris green there is practically no danger of poisoning even if it were used later, as the washing which is given the cress will carry away all perceptible traces of the poison. If conditions should be such that the pond or stream in which water cress infested by this species is growing could be completely overflowed, it would cause the insects to rise to the surface, and in the case of running water would wash them downstream. . Flooding alone might not entirely solve the problem, as these beetles are able to survive considerable immersion. When the cress is grown in sufficiently large bodies of water ex- « Pflanzenfeinde, p. 26; & Stett. Ent. Zeit., 1863, p. 123; c The Entomologist, Vol. XIV, 1881, p. 236. 20 SOME INSECTS INJURIOUS TO TRUCK CROPS. periments should be made with some of the fish mentioned on page 15 as possibly useful for destroying cress insects. Ducks might also be found valuable. Catfish were tried, but without avail. Mrs. Hannum has recently written that she attained the greatest success by growing the water cress in running water which carried the beetles away. In cold weather it was necessary to plant in houses where the cress did well until the coming of warm and dry weather, when the beetles would sometimes clean it out almost en- tirely, leaving only the roots. By tearing the cress out of the houses and in ponds which were not exposed to running water she could replant her beds, and hoped in time to get rid of the pest. O • . .. U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY- BULLETIN No. 66, Part III. L. O. HOWARD, Entomologist and Chief of Bureau. SOME INSECTS INJURIOUS TO TRUCK CROPS. THE CRANBERRY SPANWORM. THE STRIPED GARDEN CATERPILLAR. F. H. CHITTENDEN, Entomologist in Charge of Breeding Experiments. Issued August 31 , 1907 . WASHINGTON: GOVERNMENT PRINTING OFFICE 1907 . CONTENTS. The cranberry spanworm ( Cleora pampinaria Guen.) Descriptive Distribution Biologic literature Unpublished office notes List of food plants The insect’s life history Natural enemies Remedies — Bibliography The striped garden caterpillar ( Mamestra legitima Grote) Descriptive . Biologic notes Natural enemies Summary of habits Methods of control Page. 21 21 23 24 25 25 26 26 26 27 28 28 29 31 32 32 ILLUSTRATIONS. Page. Fig. 6. The cranberry spanworm (Cleora pampinaria ) : Moth, larva, and pupa 22 7. The striped garden caterpillar (Mamestra legitima) : Moth, larva, and pupa 29 hi U. S. D. A., B. E. Bui. 66, Part III. Issued August 31, 1907. SOME INSECTS INJURIOUS TO TRUCK CROPS. THE CRANBERRY SPANWORM. ( Cleora pampinaria Guen.) A brownish spanworm has been observed by the writer during recent years on asparagus in the District of Columbia in such numbers as to indicate that it is especially attached to this crop, at least in this region. In consideration of the fact that so few insects attack asparagus, the accompanying account has been prepared. The spe- cies appears to have attracted no attention since 1884, 7 ° when it was considered in relation to its appearance in cranberry bogs. From material recently collected, several facts hitherto unrecorded have been gained, and there are a number of unpublished notes of the Bureau showing a tendency on the part of the species to become omnivorous. At any rate it is not confined to cranberry, as the name given above would imply, nor to strawberry, as might be in- ferred from another name, u brown . strawberry spanworm,” which has also been given it. The list of food plants which will pres- ently be furnished shows a considerable range. Owing to the fact that the insect has not often been observed concentrated on any single crop, little mention of it has been made in literature by economic writers. Cranberry is a favorite food plant, and is sometimes in- jured to a considerable extent, especially in Massachusetts. DESCRIPTIVE. This insect belongs to the lepidopterous family Geometridse, the larvae of which are well known under the common names of span- worms, measuring-worms, inch-worms, and loopers. The moth which produces this spanworm is quite variable in color and markings. The average expanse of wing is from a little less than an inch to upward of an inch and a fourth (22-32 mm ), but may exceed this, attaining, according to Dr. A. S. Packard, 4 a measurement of an inch and a half. The ground color of living specimens is pale a The numbers in superior type refer to corresponding numbers in the ' appended bibliography, p. 27. 21 22 SOME INSECTS INJURIOUS TO TRUCK CROPS. leaden gray, and of old mounted material a duller gray, thickly dif- fused with black and brown dots and other markings more or less con- stant, forming irregular lines across both fore-wings and hind-wings. On both there is a marginal regular scalloped black line and within this a strongly dentate or zigzag white line. The general pattern of the wings varies considerably from that- shown in figure 6, a , which represents the female. The color of the body is similar to that of the wings. The first abdominal segment is white above. The sexes can be readily distinguished by the antennae. Those of the female are filiform and tessellated and those of the male rather strongly pectinate, or feathered. The structure of the latter is shown at e and /, figure 6. “ It may be known,” says Packard, “ by the very distinct line at the base of the abdo- ¥ hJS men, the basal wing beyond be- ing usually white, and the underside of the wings having a broad marginal shade, while the third line on the fore - wing is deeply but quite regularly sinuate and near the costa acutely dentate.” A number of synonyms are credited to Cle- ora 'pam'pinaria. It has indeed received five specific names. As three of these were given by Guenee, it is of itself indicative of the varia- tion of the moth. The list follows : Boarmia sublunaria Gn., Spec. & Gen., IX, 248 (1857) ; B. frugallaria Gn., Spec. & Gen., IX, 240 (1857) ; B. collecta Wlk., Cat. Brit. Mus., XXI, p. 397 (1800) ; Cleora tinctaria Wlk., Cat. Brit. Mus., XXI, p. 480 (1800) ; Boarmia fraud ulentaria Zeller, Verb, zool.-bot. Ges. Wien, XXII, p. 492 (1872) ; Cymato- phora parnpinaria Pack., Mon. Georn., p. 432 (1870). Fig. 6.— The cranberry span worm ( Cleora pampinarici): a, Female moth; b, larva, dorsal view; c, larva, lateral view; d, pupa; e, male antenna; /, enlarged joints of same. All enlarged; e,f, more enlarged (original). The e(j(j appears not to have been described. The larva . — The larva resembles those of other geometrids in being of elongate form, about nine times as long as wide, with the three pairs of thoracic or front legs bunched closely together near the head, and in having only two pairs of prolegs, or unjointed legs, at the THE CRANBERRY SPANWORM. 23 opposite extremity. The color varies to a considerable extent from mottled pale yellowish to brown, often with an olivaceous or greenish tint. Those which have been recently captured in the District of Columbia are reddish brown, mottled, streaked, and lined with lighter yellowish, red, and black. The head is strongly marked w T ith trans- verse irregular black bands. The thoracic segments are marked above by a pair of thin median longitudinal lines. The second abdominal segment bears on the dorsal surface a pair of prominent, widely separated, mostly black tubercles, but in some individuals these are wanting. The penultimate segment also bears above a smaller pair of black tubercles. The larva when fnll grown measures an inch to upward of an inch and a fourth in length (25-33 mm ) and the greatest diameter is about one-eighth of an inch (3 mm ). The singu- lar construction of the legs, or rather the lack of the intermediate legs usually present in caterpillars of other families, is the cause of the peculiar motions of the spanworms in crawling about in search of food, which have given them their popular names. When in motion a larva extends its body to full length, then brings the posterior legs close to the anterior ones, causing the body to loop in the center. The body is then stretched out again, these actions being repeated alternately. When this spanworm is in repose it attaches itself to the foliage — for example, to the stem of asparagus — by means of its anal pair of legs and stretches out its body rigidly and at an angle so that its natural colors harmonize with the foliage or with the landscape. On this head Doctor Smith has remarked that on a section of cran- berry bog on which this species is feeding the observer may stand in the midst of thousands of them and see none until something starts them into motion. Then it appears almost as though the entire bog were alive. As the spawnworms hang somewhat tenaciously to their food plants, they are undoubtedly present frequently in numbers without anyone being the wiser. The half-grown larva is described by Doctor Forbes. 8 The pupa , shown, ventral view, in figure 6 at d , is of robust form, light greenish brown in color, and a little less than half an inch in length (12 mm ) and about a third of that (4 mm ) in width. DISTRIBUTION. The wide distribution of this insect is shown by the following list of localities, based upon Doctor Packard’s list, where the authorities for each locality are given : Maine ; Amherst, Cape Cod, Cotuit, Xatick, Mass.; West Farms, Center, Albany, and Brewster, N. Y. ; Philadelphia, Pa.; Lansing, Mich.; Dayton, Ohio (Pilate); Glen- coe, Nebr. ; Cadet, Mo.; Centralia and elsewhere in Illinois; Wash- ington and Brookland, D. C. ; Georgia; Calhoun, Dawson, and De- 24 SOME INSECTS INJURIOUS TO TRUCK CROPS. mopolis, Ala. ; Lake Bearsford, Florida ; Bastrop County and else- where in Texas. The above localities indicate a distribution ranging from the transition life zone through the upper to the lower austral. The occurrence of the species in Florida, Alabama, and Texas would indicate that it is to be found throughout the Gulf region. The insects observed by Glover were stated to ajipear in the Carolinas, Georgia, and Florida in early October. BIOLOGIC LITERATURE. The spanworm under consideration was described under the name cf Boarmia pampinaria by Guenee in 1857. 2 In 1876 Dr. A. S. Packard gave a detailed description of the moth, with a consideration of its distribution and remarks on the larva and pupa, the former being stated to feed on pear. 10 In 1881 Dr. G. H. French 6 had a note on the larva observed feeding on willow and geranium; larvse transformed to pupse September 16 and October 2, and the imagoes issued April 17 of the following year. During the year 1883 this species was observed by Dr. J. B. Smith, 7 then a temporary agent of this office, doing injury at Cotuit, Mass. During that year the spanworms were so abundant in the cranberry bogs in that vicinity that their numbers could be compared only to the army worm (Heliophila unipuncta Haw.). In the case in question they began in a space about a rod square, devoured that, and spread in a direct line across the bog. The number of moths that would have been produced from these insects should they have been permitted to transform was described as being 44 frightful.” A rather full account by Dr. S. A. Forbes followed in 1884, 8 in which the statement was made that the larva was found in midsummer feeding on leaves of strawberry in southern Illinois. Larvie obtained August 1 pupated on the 11th, and the moths emerged on the 22d, giving eleven days as the pupal stage at that season. Larvae collected September 6, about half grown, were believed to represent a second generation. The larva of this species came under the observation of the writer on asparagus first in 1897. 11 In 1899 Doctor Lugger 12 stated that the caterpillars were found on apple and blackberry, and that there were at least two generations annually. As this is one of the commonest species of its genus, of wide dis- tribution, and authentically determined as living on. cotton, there seems little doubt that it was the type of Glover’s account of 44 the larger spanworm,” figured and described in his accounts of insects frequenting the cotton plant, published in 1856 1 and again in 1878. 5 A curious blunder was made by M. I). Landon, who figured this species as the 44 cotton caterpillar ( Xoctua xylina )” in 1865 , 3 this illustration being a crude copy taken from Glover’s first or 1856 account of this spanworm. THE CRANBERRY SPANWORM. 25 UNPUBLISHED OFFICE NOTES. June 5, 1879, we received from Mr. William Trelease, then at Dawson, Ala., larvae found feeding on cotton. June 12 a larva kept under observation changed to pupa, and on June 26 the moth issued, this individual having passed 14 days as pupa. The same year the moth was reared on several occasions from material obtained on red clover in the District of Columbia by Messrs. Pergande and Howard. June 28 the moth issued from the pupa. August 15 the larva was observed feeding; changed to pupa August 25, and issued as moth March 1 of the following year. August 29 the larva was observed feeding; changed to pupa September 4, the moth issuing March 22 of the next year. February 6, 1880, we received from Lake Bearsford, Fla., from Prof. J. H. Comstock, a larva obtained on orange. There are also reared specimens of moths in the U. S. National Museum bearing labels showing the rearing of moths and occurrence of larvae on different plants, as follows: On locust, May 6, 1893, District of Columbia; hickory, November 24, 1894, Cadet, Mo., and August 4 of the same year on pear, locality presumably the District of Columbia. There is also a specimen labeled “ on guava,’’ proba- bly from Florida. August 6, 1904, specimens of this spanworm were received from Calhoun, Ala., where they were found feeding on cotton and were mistaken for the cotton leaf-worm ( Alabama argillacea IIbn.). The adult issued August 29. Larvae were about full-grown when received, August 9, and it seems probable that they underwent a short stage of aestivation before transforming to pupae, as the pupal stage is less than 20 days in midsummer. During the first two weeks of October for several years larvae have been observed on asparagus grown in the District of Columbia, the species appearing in moderate numbers. The first moth that has been reared from October-collected larvae appeared in January, and others appeared in February. As this was in confinement the dates were not natural ones. LIST OF FOOD PLANTS. It is, as previously remarked, owing to the omnivorous habit of this species, causing a distribution of attack, that noticeable injury has not been ascribed to it elsewhere than in cranberry bogs. It is com- mon enough in the vegetable and truck garden, but not confined to any particular place on the farm, occurring in orchards, on forest and shade trees, and on other plants. The list of observed food plants includes asparagus, strawberry, blackberry, ornamental geranium, apple, pear, orange, willow, hickory, cranberry, honey locust, cotton, clover, and guava. As a rule the larvae confine themselves to the 26 SOME INSECTS INJURIOUS TO TRUCK CROPS. foliage of these plants, but Glover states that they sometimes feed upon the petals of the flowers of cotton, although doing little harm to the general crop. THE INSECT’S LIFE HISTORY. Our knowledge of the life history of this species is somewhat incomplete. The repeated rearing of moths in early spring and the occurrence of larvae in the latter part of June in Massachusetts as recorded by Smith, as also in the District of Columbia and elsewhere as late as October, noted by the writer and others, show at least two generations in the Northern States, while the record of the occur- rence of the moths in March in Texas (by Belfrage) would indi- cate that in the Gulf States there may be an additional generation. It would seem practically impossible for larvae hatching from eggs deposited in early spring to require until late October to attain maturity, hence the natural inference of two generations for a climate like the District of Columbia. The cranberry growers of Massachusetts claim two generations for that State, one appearing as larvae in June and early July, the other in the latter part of August, The eggs are unknown, and the periods of egg and larva have not been ascertained, but the pupal condition has been observed to be passed, for the first generation, in from 11 to 14 days, while the over-wintering pupa consumes five or six months in the District of Columbia, a shorter time farther south, and a longer time northward. The date of the appearance in the North of the first moths has not been learned positively nor the natural time of emergence of the first new generation of moths. NATURAL ENEMIES. Doctor Smith 7 has stated that the larvae of this span worm are checked by parasites, 'but that in some localities almost every year they become numerous enough to be destructive. In some years, however, in the cranberry bogs of New Jersey they are not seen at all, showing great scarcity, due probably in part, at least, to natural causes. Only one parasite for this species is known, namely, Ex orista Jjoarmice Coq., a tachina fly reared at this Department from Cotuit and other localities in Massachusetts several years ago. REMEDIES. This species is not difficult to control ou asparagus or other truck crops. As it feeds in free exposure on the foliage, spraying with Paris green or arsenate of lead will destroy it, and when either of these insecticides is used for the asparagus beetles it will kill all of the spanworms which may be present. The Paris green may be THE CRANBERRY SPANWORM. 27 used at the rate of 1 pound to about 100 to 150 gallons of water, and the arsenate of lead at the rate of about 1 pound to 25 to 50 gallons of water. The same remedies will apply equally well to the occur- rence of this species in cranberry bogs. BIBLIOGRAPHY. 1. Glover, Townend. Report Commissioner Patents, p. 92, Plate VIII, fig. 4, 1855 (1856). Probably Ibis species. Appears in Carolinas, Georgia, and Florida early in October and feeds upon the petals of the cotton flower ; larva and adult described and figured. 2. Guenee, M. A. Species General cles Lepidopteres, Yol. IX, Plialenites, pp. 245, 246, 248, 1857. Original description as Boarmia pampinaria from near Baltimore, as B. frugal - laria from Georgia, and as B. sublunaria from North America. 3. Landon, M. D. Rept. Comm. Agr. f. 1864 (1865), p. 90. Erroneously figured as the “cotton caterpillar ( Noctua xylina).” 4. Packard, A. S. Report I T . S. Geological Survey Terr., Hayden, Yol. X, pp. 432, 442, Plate XI, fig. 20, 1876. Technical and detailed description of moth ; synonymy ; distribution and note on larva and pupa, the former feeding on pear. 5. Glover, Townend. Cotton and its principal injurious insects< Washington, D. C., Plate VII, figs. 6, 7, 8, 1878. Figures larva, chrysalis, and moth ; found early in October in Georgia feeding on flowers of the cotton plant. 6. French, G. H. Papilio, Yol. I, p. 82, 1881. Notes on larva found feeding on willow and geranium. 7. Smith, J. B. Bui. 4 (o. s.), Div. Ent., U. S. Dept. Agr., pp. 26-28, 1884. A two-page account in reference to injuries to cranberries ; description of larva ; referred to as Cymatophora pampinaria ; remedies. 8. Forbes, S. A. Thirteenth Rept. State Entomologist Illinois, pp. 76-78, 1883 (1884). A rather full account. Larva found frequently in midsummer in southern Illinois feeding on leaves of strawberry ; description of larva, pupa, and imago (quoted from Packard). 9. Forbes, S. A. Trans. Miss. Valley Hort. Soc., Yol. II, p. 235, 1884. Quotations of first two paragraphs of No. 8. 10. Packard, A. S. Fifth Report U. S. Ent. Commission, p. 654, 1890. Included in a list of insects affecting honey locust ( Gleditschia triacanthos) . 11. Chittenden, F. FI. Bui. 10, n. s., Div. Ent., U. S. Dept. Agr., p. 61, 1898. An unknown geometrid larva feeding on asparagus ; subsequently ascertained to be this species. 12. Lugger, Otto. Fourth Rept. Entomologist State Exp. Station Minn., pp. 187, 188, fig. 188, 1898 (1899). Notes on the moth ; caterpillar found on the apple and blackberry. Short gen- eral account. 13. Smith, J. P>. Farmers’ Bulletin 178, U. S. Dept. Agriculture, pp. 19-21, 1903. Account of injuries to cranberry, life history, and remedial measures. THE STRIPED GARDEN CATERPILLAR. ( Mamestra legitima Grote.) A strikingly beautiful black and yellow striped caterpillar is fre- quently found in gardens, and occasionally in such numbers as to attract attention. It is a general feeder, like most of its kind, but is somewhat partial to asparagus, cruciferous plants, peas, and other leguminous vegetables. Its occurrence in the District of Columbia in some numbers, especially on asparagus, has permitted a study of the species, which adds somewhat to what has previously been published. Only a few short notices of this insect have appeared in publications of the Department of Agriculture or elsewhere, to the writer’s knowl- edge. The following somewhat brief account is therefore presented. This species is a noctuid, related to the cutworms, and is congeneric with the zebra caterpillar ( Mamestra picta Harr.). The moth was originally described in 1864,® the species at that time being known from the middle and eastern States, where it was stated to be com- mon. It is also recorded as occurring in the northern States. Evi- dently, considering its numbers in the Gulf region, it may be found in most States east of the Mississippi River Valley. DESCRIPTIVE. The moth is quite prettily marked, as can be seen by referring to figure T > a. The prevailing tint of the fore-wings is a light lead color, marked with velvety-black and brown spots, the pattern varying somewhat but usually about as figured. The lower wings are fawn colored, with dusky margins, and the veins are moderately prominent. The females, as is usual with this group, have the abdomen as illus- trated, while the males have abdomens with bushy tips. The wing expanse is a little more than an inch and a quarter. The eggs . — No description of the egg is available at the present writing. The larva is also a pretty form and its markings recall the zebra caterpillar. It will be noticed by the figure (fig. T, &, c) that there is considerable difference, however, and the two species are not at all likely to be confused by anyone who carefully examines them. The present species has a larger and wider head and is darker than is usual with the common zebra caterpillar. The appearance of the head from in front is shown at d. The stripes with which the body is "Apamea legitima , Proc. Ent. Soe. Phila., Vol. Ill, p. 82. 28 THE STRIPED GARDEN CATERPILLAR. 29 ornamented are black and yellow, as with the zebra caterpillar, but the lateral stripe is divided into two portions, the upper one lighter than the lower, and the entire lateral surface when marked consists of regular stripes, whereas in the other species these stripes are broken up. The pupa, when mature, is nearly black in color, and has the appearance illustrated (fig. 7, e). It measures about five-eighths of an inch in length, including the tips. BIOLOGIC NOTES. This species was briefly mentioned as having been found by the writer in the larval condition on asparagus at Marshall Hall, Md., in October, 1896.® At that time it was impossible to ascertain whether or not it bred from eggs deposited on this plant, but later observations conducted in company with Mr. F. C. Pratt during the first and sec- ond weeks of October show con- clusively that such must be the case, as larvse were found in the greatest abundance on three large patches of asparagus at Brookland, D. C. They usually occurred singly, but occasionally in pairs. During the heat of the day, in the moderately cool and seasonable Indian summer weather usual at Washington at that time of the year, many larvae would be found stretched out upon dry sprigs of asparagus, and in spite of their bright colors they would easily have escaped the observation of anyone without experience in insect col- lecting. The larva, in fact, furnishes a good example of protective coloration. An individual would be in plain sight, and then if one’s eyes were directed elsewhere for a moment it would sometimes be difficult to find it again, although it might be within a foot of the observer. Larvae obtained October 7 and later were kept feeding on asparagus in our rearing cages until the third week of October, when they de- scended to the earth and soon afterwards assumed the pupal condition. The exact date of the assumption of the chrysalis form was not ascen- ts Bui. 10, n. s., Div. Ent., U. S. Dept. Agr., p. 60. Fig. 7. — The striped garden caterpillar ( Mamestra legitima) : a. Adult ; 6, larva from above ; c, same from side ; d, head of same from front : e, pupa. All natural size except d, which is enlarged (from Howard). 30 SOME INSECTS INJURIOUS TO TRUCK CROPS. tained, but it was about the 21st of October, which would give a period for the pupa of ten months, as the moths of this lot began issuing August 21. a One individual transformed to pupa October 17 and the imago issued August 24 of the following year. October 15, 1898, the larva was brought to the writer by Mr. P. H. Dorsett, from his greenhouse at Garrett Park, Md., where the species was feeding on the foliage of violet. The same year, November 3, this larva was found rather abundantly by Doctor Howard in tobacco fields in southern Virginia, near the North Carolina border line, upon the leaves, which in some cases were badly ragged. 6 The first moths issued in July. During 1900 and 1901 correspondence was had in regard to this caterpillar with Mr. IT. Walter McWilliams, Griffin, Ga., who sent specimens, as also larvae of the so-called cotton cutworm ( Prodenia ornithogalli Guen.), with which the insect was associated in both years. The caterpillars were noticed there in greatest numbers during November, and both species were reported as destroying a number of garden crops, among which were cabbage, collards, turnip, ruta-baga, rape, peas and related plants, as also some other vegetables. Mature larvae were seen as late as the last week of November. Among other office records are two which also have a bearing on the biology of this species. One of these was made by Mr. Theo. Pergande, who found the larvae in the District of Columbia feeding on blackberry and on flowers of a goldenrod ( Solidago sp.). The other is a short note by Mr. F. M. Webster upon the rearing of the moth in spring from the seed pods of milkweed ( Asclepias incar-, nata ), near Lafayette, Ind. “ The larva appeared to subsist upon the seeds, the pods being attached unopened to the wrecked plant.” c October 21 the larva was found at Washington, D. C. We have no further records in regard to the habits of this species other than the capture of moths in the District of Columbia July 25, August 22 and 25, and September 2, and there are specimens also in the U. S. National Museum from Lewis County, N. Y., July 4, collected by O. Meske, and others from New Jersey without definite locality. The species is also said to occur at Portland, Oregon. It is interesting to note that among these specimens are inflated larvae and mounted heads labeled u pretty cutworm,” which might be termed a manu- « The rearing jar was kept under somewhat unnatural conditions, at times too warm and dry, but the effect of one condition might have been counteracted by another, and the date of issuance of the adults was not far from that which would be assumed in nature — more likely earlier than otherwise. & Yearbook U. S. Dept. Agric. for 1808, p. 142. c Insect Life, Vol. II, p. 382, 1800. THE STRIPED GARDEN CATERPILLAR. 31 script name, as 1 do not find this insect mentioned under this cogno- men in print. With present knowledge of the species it can not properly be classified as a cutworm. Among the files of the Department of Agriculture there are a few notes which are of interest as showing the cycle of periods from egg to about the last stage of the larva. These notes were made in 1882 by Mr. Albert Koebele, and the mounts which were made with them are not sufficiently fresh for description. From these notes the fol- lowing is taken : Moths collected at sirup, near the District of Columbia, Septem- ber 16, were placed in a rearing jar with grass, where two batches of eggs were laid between 11 and 12 o’clock at night, one of these being deposited around the stem of grass. September 18 the eggs hatched, showing the egg period to be only 2 days. On the 21st the larvae had completed the first molt, making the first larval instar 3 days. September 23 the second molt was observed, which gives 2 days as* the second larval instar. September 27 lar vse changed their third skin, leaving 5 days as the period of the third instar. October 1 the fourth molt occurred, making 4 days for the fourth instar. By October 9 all the larvae had changed the fifth skin, when they developed cannibalistic tendencies and were removed to a larger jar. The period of this instar was 8 days. The remaining larvae refused to eat and finally died, so that the complete life cycle could not be ascertained. NATURAL ENEMIES. Soon after bringing larvae in from the field some were noticed to be dying from fungous attack. In the asparagus fields Estigmene (Leucarctia) acrcea Dru, and Dissosteira Carolina L., the salt-marsh caterpillar and Carolina locust, respectively, were also dying in con- siderable numbers, and it was conjectured that the disease might have originated with these and spread to the Mamestras. After the dis- eased caterpillars had been frequently removed, however, the fungous attack abated. Specimens of infected larvae Avere referred to the Bureau of Plant Industry, and the fungus was identified by Mrs. Flora W. Patterson, assistant pathologist, as an undescribed species of Verticillium. At another time larvae which showed signs of dis- ease after capture were examined by Mrs. Patterson, who recognized the presence of the fungus Sporotrichum minimum Speg. A larva, when placed with diseased insects, including some of its own species, did not contract the fungous disease, from which it seems probable that the disease is not readily communicable, and hence of no use as a possible means of destroying this species. 32 SOME INSECTS INJURIOUS TO TRUCK CROPS. SUMMARY OF HABITS. From present knowledge of the caterpillar two generations annually are indicated, although only one has been observed. Moths have been reared by the writer in July and August and they have been captured out of doors during the same months and in' September. From available data it would appear that an average life history would be about as follows : Egg period, 3 to 5 days ; first larval instar, 3 days ; second larval instar, 2 days; third, 5 days; fourth, 4 days; fifth, 8 days, and pupal stage, 7 to 10 months. Hibernation occurs in the pupal stage. The observed food plants include asparagus, cabbage, collards, turnip, ruta-baga, rape, peas and related plants, greenhouse violet, tobacco, grass, and blackberry. Of wild plants, golden-rod and milkweed have been observed, the larva attacking the flowers of | the former and the seed,, pods of the latter. METHODS OF CONTROL. Although the early habits of this species as it occurs in the field have not been observed, there is no doubt that, like the zebra cater- pillar, the young when first hatched are gregarious for some time, and hence may be easily discovered and destroyed by mechanical means or by arsenicals. All of the caterpillars of this class readily succumb to arsenical poisons, and for this species in its occurrence on asparagus and some other plants arsenate of lead is to be preferred. It may be used at the rate of about 1 pound combined with 15 to 25 gallons of water or Bordeaux mixture. If an adhesive resin soap, such as resin fish-oil soap, is added, it makes this mixture all the more permanent, and a single application is then all that is necessary. Paris green may be used in the same manner at the rate of 1 pound to 100 or 150 gallons of water. It is evident that this species, like I the zebra caterpillar, does no particular harm as a rule in its first i generation, but is much more abundant in the second or late fall gen- j eration, when certain plants are injured by it. Owing to the diffi-l] culty of locating the larger larvae, it is evident that hand-picking f would not be applicable for them in their later stages. O U. S. DEPARTMENT OF AGRICULTURE, BUREAU OF ENTOMOLOGY— BULLETIN No. 66, Part IV. L. O: HOWARD, Entomologist and Chief of Bureau. INSECTS INJURIOUS TO TRUCK CROPS. AND THEIR RELATION TO THE “CURLY -LEAF” CONDITION. E. D. BALL, Ph. D., Special Field Agent. Issued January 27 , 1909 . WASHINGTON: GOVERNMENT PRINTING OFFICE. 1909 . CONTENTS. Page. Introduction 33 The beet leafhopper ( Eutettix tenella Baker) 35 Descriptive 35 The adult 35 The eggs 35 The nymphs 35 Food plants 35 Distribution 36 Life history studies 36 Record at Lehi, Utah 36 Record at Monroe, Utah 38 Other records in Utah 38 Cage experiments, Lehi, Utah 38 Summary of iife history 40 Economic relations 41 Characteristics of 1 1 curly-leaf ”... 44 Other records 46 Economic summary and proposed remedies 47 Bibliographical references 48 Other leafhoppers . - 49 Eutettix strobi Fitch 49 Eutettix scitula Ball 49 Eutettix seminuda Say 50 Eutettix clarivida Van Duzee 50 Eutettix insana Ball, E. albida Ball, and E. pauperculataBedl 50 Eutettix stricta Ball 50 Agallia sanguinolenta Prov 51 Agallia cinerea Osborn and Ball 51 Agallia bigelovise Baker 51 Agallia quadripunctata Prov. and A. novella Say 51 Empoasca sp 51 Conclusions in regard to “curly-leaf” 52 66 —iv III ILLUSTRATIONS. PLATES. Plate I. Leafhoppers ( Eutettix spp.) and their work. Fig. 1. — Eur tettix tenella: a, Adult; b, nymph; c, wing; d, e, geni- talia; /, eggs (greatly enlarged) ; g, section of beet stem, showing fresh eggs in place; h, same, showing eggs ready to hatch ; i, old egg scars on beet stems ; j, small leaf of sugar beet, showing characteristic “ curly-leaf ” condition ; fc, enlarged section of back of an extreme case of “ curly- leaf, showing “ warty ” condition of veins. Fig. 2. — Eutettix strobi: a. Work of nymphs on lambsquarters ; b, work of nymphs on sugar beet. Fig. 3. — Eutettix scit- ula: Adult. Fig. 4. — Eutettix clarivida: a, Wing; b, head and pronotum ; c, d, genitalia. Fig. 5. — Eutettix nigridor- sum: Work of nymphs on leaf of Helianthus. Fig. 6. — Eutettix straminea: Work of nymphs on leaf of another Helianthus. Fig. 7. — Eutettix insana: Wing. Fig. 8. — Eutettix stricta: a, b , Genitalia II. Work of Eutettix tenella on sugar beet. Fig. 1. — Three “curly-leaf” beets, the result of attack by Eutettix tenella, and one normal beet from the same field, showing differ- ence in size. Figs. 2, 3. — “ Curly-leaf ” beets as seen in the field. Fig. 4. — Normal beets from same field III. Work of Eutettix tenella on sugar beet. Fig. 1. — A large beet becoming “ curly.” Fig. 2. — Back of a leaf affected by “ curly-leaf,” showing “ warty ” condition and curled edges IV. Work of Eutettix tenella on sugar beet. Fig. 1. — A field of beets destroyed by “ curly-leaf.” Figs. 2, 3. — Cages used in the life-history experiments 66 — iv IV Page. 34 44 44 4G U. S. D. A., B. E. Bui. 66, Part IV. Issued January 27, 1909. SOME INSECTS INJURIOUS TO TRUCK CROPS. THE LEAF HOPPERS OF THE SUGAR BEET AND THEIR RELATION TO THE “ CURLY-LEAF ” CONDITION. By E. D. Ball, Ph. D., Special Field Agent. INTRODUCTION. Ever since the introduction of the sugar beet into the intermountain region more or less loss has resulted each season from a condition called “curly-leaf,” or “blight.” (See PL I, fig. 1, j ; Pis. II, III; PI. IY, fig. 1.) Around Grand Junction, Colo., the beet growers have suffered frequent losses from this source. Supt. George Austin, of the Utah Sugar Company, reported a serious loss around Lehi, Utah, in 1897. In 1903 the beet crop in Sevier County, Utah, was somewhat injured, the next year the damage was worse and more widespread, while in 1905 it extended throughout the State of Utah and the adjoining portions of Colorado and Idaho. Until 1905 the condition had been looked upon as a result of some fungous or bacterial disease, or due to a soil or climatic condition. During that season it was noticed for the first time that a leafhopper ( Eutettix tenella Baker) was present in large numbers in the fields where this damage was the worst, and the writer, in connection with his duties as entomologist of the Utah Agricultural Experiment Sta- tion, commenced an investigation of the insect and its relation to the damage. It was then too late to work out its life history, so most attention was paid to a study of its relation to the “ curly-leaf ” condi- tion and to experiments with remedies. This investigation was con- tinued in 1906 and 1907, in cooperation with the Bureau of Entomol- ogy, and the life history was worked out. Owing to the small num- ber of insects appearing these two seasons, little more was done with remedies, but many new facts were learned in regard to methods of attack and the causes of the injury. The writer’s attention was first called to the “ curly-leaf ” in August, 1900, by Prof. F. H. Shaw, then chemist of the Grand Junc- tion (Colo.) Sugar Factory. A careful examination was made at this time and again in succeeding years, but no explanation was found 66 — iv 33 34 SOME INSECTS INJURIOUS TO TRUCK CROPS. for this condition. These examinations were, however, always made late in the season after the curly-leaf character had become general and after the greater number of insects had disappeared. Examina- tion of the beets always revealed a few specimens of Eutettix tenella along with other leaf hoppers and miscellaneous insects, but never in sufficient number to cause suspicion. Late in June, 1905, reports began to come in to the Utah experiment station of the appearance of an insect in the beet fields of the southern and central portions of the State, and on July 8 the writer, in com- pany with Mr. George Austin, visited the fields around Lehi and there found the beet leaf hoppers, associated with smaller numbers of false chinch bugs (Nysius) and leafhoppers of the genus Agallia, causing serious damage to the young plants, especially in the late-planted fields. From the size of the beets and the number of the beet leafhoppers present when first examined in 1905, the prediction was made that the insects would not be able seriously to retard the further growth of the beets. This prediction was based on the ordinary amount of damage done by insects of sucking habits. That the number of insects found would be able to injure or even seriously retard a very young beet was recognized, but that the same number could have any appreciable effect on large beets was contrary to all expectations based on a knowl- edge of similar attacks by Nysius, Agallia, and other sucking insects. The trouble soon afterwards appeared in the Cache Valley, Utah, and was under observation there throughout the remainder of the sea- son, while several trips were made to various parts of the State. Wherever it appeared it gradually grew worse, and although the year 1905 started with everything favorable in the early season, the Utah beet crop fell below the average about 75,000 tons. This, however, did not anywhere represent the entire loss, as both sugar content and purity of the beets harvested fell far below the average, entailing fur- ther loss to the sugar companies and bringing the total to more than half a million dollars. In Sanpete and Sevier counties, in the southern part of Utah, a large part of the acreage was abandoned early in the season, while the rest barely paid the expense of harvesting. In Utah County the crop varied from a total loss on a few late fields to a full crop, with an average of more than a half crop harvested. In the Cache Valley, in the northern part of the State, the loss was about one-third in tonnage, and in Weber and Boxelder counties less than that. In 1906 a very small number of leafhoppers appeared, and, as the season was cool, even where they were most abundant little damage was done. A careful study was made of the life history and distribu- tion of the species, and a number of tests were made of its injury to the beets. 66— iv Bui. 66, Pt. IV, Bureau of Entomology, U. S. Dept, of Agriculture. Plate I. Leafhoppers (Eutettix spp.) and Their Work. Fig. 1 .—Eutettix tenella: a, Adult; b, nymph; c, wing; d, e, genitalia; /, eggs (greatly enlarged); g, section of beet stem, showing fresh eggs in place; h, same, showing eggs reaay to hatch; i, old egg-scars on beet stems; j, small leaf of sugar beet, show- ing characteristic “curly-leaf” condition; k, enlarged section of back of an extreme case of “curly-leaf,” showing “warty” condition of veins. Fig. 2 . — Eutettix strobi: a, Work of nymphs on lambsquarters; b, work of nymphs on sugar beet. Fig. 3. — Eutettix scitula: Adult. Fig. 4 . — Eutettix clarivida: a, Wing; b, head and pronotum; c, d, genitalia. Fig. 5 . — Eutettix nig ridorsum: Work of nymphs on leaf of Helianthus. Fig. 6 . — Eutettix straminea: Work of nymphs on leaf of another Helianthus. Fig. 1 —Eutettix imana: Wing. Fig. 8 . — Eutettix strieta: a, b, Genitalia. (Author’s illus- trations.) LIBRARY SITY OF ILLINOIS UREJANA LEAFHOPPERS OF THE SUGAR BEET. 35 THE BEET LEAFHOPPER. ( Eutettix tenella Baker.) DESCRIPTIVE. The adult (PI. I, fig. 1, a) is a small, pale yellowish-green species, little larger than an Empoasca or Typhlocyba, with which it might easily be confused in the field were it not for the stouter build and greater activity. When fresh or when flying this leafhopper appears almost white, and for this reason it has often been called the “white fly.” (Wing, PL I, fig. 1, c; genitalia, PI. I, fig. 1, d , e .) The eggs (PI. I, fig. 1, f) are white, elongate, slightly curved and tapering at one end, and are thrust into the leaf stem in a slightly downward direction. At first they are scarcely visible (PL I, fig. 1, g ), but as the stem grows they are pushed out with the opening up of the injured spot until at hatching time they are often half free (PL I, fig. 1, h). After the eggs hatch, the egg scars continue to en- large and remain throughout the season as irregular, elongate, crater- like swellings (Pl. I, fig. 1, i). The eggs are deposited on all parts of the leaf stem, usually one in a place. In the cages they were often placed close together, very likely in this case by different insects, however, and a number were insetted into the midrib and secondary veinlets of the leaf and a few into the leaf margin near the base. The nymphs (Pl. I, fig. 1, h) are very active, pale creamy white or variously colored forms. The commonest form is pale creamy in color with a brown saddle on the middle of the abdomen and various mottlings on the prothorax and wing-pads. Some have the same pat- tern with a reddish ground color, more are creamy yellow, and occa- sionally one is seen with a broad and somewhat irregular dark stripe down the back. When small the nymphs will be found most com- monly down in the unfolding leaves at the center of the beet, but as they grow older they spread out over the plant. FOOD PLANTS. The original food plant of this species is still in doubt. In the spring it was found on greasewood (Sarcobatus), sea-blite (Dondia), several species of Atriplex, Russian thistle, and rarely on other plants of these two families occurring on the waste land. As these places dried up, most of the leafhoppers went to the sugar beets in the areas under observation. In one case, however, the species was found in some numbers on greasewood during egg-laying time, which would suggest this plant as its original host. Its known distribution is all within the area in which this plant is abundant. 36 SOME INSECTS INJURIOUS TO TRUCK CROPS. DISTRIBUTION. This leaf hopper is apparently a native of the southwestern part of the United States. It has been collected from about the region of Denver, Colo., south along the edge of the mountains, through New Mexico, and west through Arizona, Utah, and southern Idaho to the coast in California and Oregon. Though confined to the mountain region, its distribution is restricted to the lower levels, and it is never taken op the mountains themselves. From this region it has not spread very far up to the present time. It was taken at Fort Collins and Lamar, Colo., in 1901 — in one case 100 miles north of its known habitat, on wild plants, and in the other an equal dis- tance east, but was rare in both situations. In Utah it has spread to the northern line of the State and into Idaho as far as that par- ticular beet area has been extended, while it has not as yet been taken from the wild plants north of Ogden, Utah. LIFE -HISTORY STUDIES. Search was made for this species as soon as the growing season commenced in the spring of 1906, but no specimens were discovered in the Cache Valley, Utah, up to the time the beets came up. A trip to Sevier County, Utah, at the time the very earliest beets were just showing (April 22) failed toxlisclose a single individual, either in the beet fields or in waste places or hedgerows adjacent to the beet-growing districts. The first specimens discovered this sea- son were found at Thompsons, Utah, May 3, feeding on Russian thistle, and a few days later the insect was found on the same plant and on an annual saltbush (Atriplex) at Grand Junction, Colo. Beet fields were examined at Grand Junction, Colo., May 8, and in Utah at Lehi, May 9; Smithfield, May 12; Garland, May 13; Lehi, May 17 ; Corinne and Penrose, May 22 ; and Provo and Lehi, June 1, without finding a single leafhopper on any of them. The beets were not up at Lehi on May 9, nor at Smithfield, but the fields were examined carefully, especially where weeds were beginning to appear. Fields at Logan, Utah, were under observation during all this time and up to July 1, but no leaf hoppers were found. RECORD AT LEIII, UTAH. On June 21 a field was examined at Lehi in which there was an average of one or two leafhoppers to a beet. They were all adults and two-thirds of them females. The beets in this field were from 6 to 10 inches across, and no sign of injury was observed. On exam- ining the other fields in the valley a very much smaller number of leafhoppers was found. Some fields had one individual to 10 beets, 0G— iv LEAFHOPPERS OF THE SUGAR BEET. 37 while some had none at all. The average would not have been more than one leafhopper to 25 beets. They were most numerous on the higher, drier fields, and on the early beets. Two patches of very late beets close to the first one visited had no leaf hoppers at this time. Eight females from this field were dissected, and fully developed ^sm’s were found in each one, 9 in one, 7 in another, and from 2 to 4 in each one of the others. Only large eggs could be seen with the lens used, and probably some of these wpre crushed while being re- moved. The fact that all females had fully developed eggs and that there were more females than males indicated that these adults had been out a long time and were not new ones of a brood that had just flown in from surrounding wild land. On June 29 a few were found in the late beets, but no nymphs were found anywhere. July 10 the adults were present in about the same numbers as be- fore, the females still containing eggs, and a few very small nymphs were found. July 23 the adults were slightly less numerous, and the nymphs from small to one-third grown and quite abundant. A few of them were nearly grown, but no fresh males could be found. More nymphs were found on the early beets, more “ curly leaf ” on the late ones. August 3 the nymphs were mostly about two-thirds grown, some were small, and some full-grown. Large numbers of adults of the new brood were out, about half of the leafhoppers being adult at this time. August 14 the adults were abundant. The leafhoppers were nearly all adults or large nymphs, but a few small nymphs were still to be found. On August 29 the insects were mostly adult, males being still in the majority, but there was still quite a number of full-grown nymphs. Many females were dissected and a few found that had from 4 to 7 large eggs, but the rest had no sign of any. These few were probably the last remnant cf the over- wintered brood of females. September 12 the adults were still common and more males than females were taken by sweeping. Large nymphs were still present in small numbers. Ten females were dissected, but no eggs found, and the abdomens were all small. Evidently there was to be no egg laying for some time, probably not that season. Note. — The season opened unusually late at Lehi in 1906, and these dates would be from one to two weeks late for an ordinary season. 63754— Bull. 66, pt 4—09 2 38 SOME INSECTS INJURIOUS TO TRUCK CROPS. RECORD AT MONROE, UTAH. In Monroe, Sevier County, the season opened early, and the beets were nearly all planted in April. An examination April 22, as men- tioned above, failed to discover a single leafhopper. On June 26, on a second visit, nearly all the beets were in fine shape, with leaves touching in the rows, and only lacking a few inches of touching across rows. The leaf hoppers were present in every patch, both adults and very small nymphs, and occasionally a larger nymph was seen. Mr. Fred Gould, field superintendent, said that he had observed the adults for some time. There were more leaf- hoppers on the older patches than on the late planted ones, indicating that they had migrated in before the younger beets were far enough advanced to attract them. On July 25 the leafhoppers had increased in numbers, averaging from 10 to 20 to a beet on the earlier patches. Adult males were com- mon, showing that the nymphs had commenced to change to adults again. All stages of nymphs were still common, however. On September 14 the numbers of leafhoppers were beginning to decrease. Several countings gave an average of 7 males to 5 females and 5 large nymphs. The dissection of a number of females showed no eggs developed as yet, and there seemed little doubt that they would hibernate. OTHER RECORDS IN UTAH. A field belonging to a Mr. Irons at Moroni, Sanpete County, was visited June 27, and an average of one leafhopper to every two beets was found. Mr. Irons, who is a very careful observer, said that they had been there for some time. A careful search was made for the nymphs, but none was found. This was by far the Avorst infested field in the county, the average being less than one insect to ten beets. July 26 adults and nymphs were about equally common, and few of either. In the Cache Valley and the rest of the northern end of the State the leafhoppers did not appear in sufficient numbers to enable one to make any life-history notes. On this account all cage experiments were transferred to Lehi. CAGE EXPERIMENTS, LEHI, UTAH. The field observations on life history were all checked by cage experiments (FI. IV, figs. 2, 3). Cages 1 to 3 were failures, through the adults escaping from the material used. Later a very fine silk scrim was used and proved satisfactory for the life-history work, but was too closely meshed to obtain normal temperature and moisture conditions inside. All cages were run in pairs on similar beets, one with insects and one without, as a check on the injury to the beet, co — iv LEAF HOPPERS OF THE SUGAR BEET. 39 Cages and 5 (glass globes upon beets about 8 inches in diam- eter). — On July 10, 16 adult leafhoppers, 12 of which were females, were introduced into cage 4. Previous dissections had shown that all females were bearing eggs, and the presence of a very few small nymphs in the field proved that the earliest ones began depositing eggs some time before. It was therefore expected that some of the females introduced would begin depositing at once. On July 23 these cages were examined, and in the one containing the leafhoppers the stems were found to be fairly covered with egg scars. Two of the stems were removed and preserved, and found to contain 161 eggs — not more than one-sixth of the total number pres- ent. A number of females were seen in the cage, but no nymphs. July 27 the stems showed still more egg scars, and there was quite a number of small nymphs that had apparently been out several days. The insects had been in the cage only seventeen days, so these eggs must have hatched within thirteen to fifteen days from the time of laying, under the conditions found in the cage. Another stem was removed and preserved, and the rest left as before. On August 3 another stem was removed. The eggs had almost all hatched by this time. Some had dried up and a few were found just ready to hatch. A few were sticking out of the stalk and looked quite fresh, but were probably infertile. Some of the leaves had wilted and died, and the remainder were literally alive with small to half-grown nymphs, together with a few adults, no doubt the remaining parents. These half-grown nymphs were no doubt those hatched between July 23 and 27, and would thus be between eight and eleven days old, roughly indicating a nymphal period of between sixteen and twenty-two days under these conditions. On August 14 this cage was visited again, and the beet found dead and dry. From appearances it had been dead several days. The few leafhoppers that survived were adults and large nymphs. They were so few in number that it was impossible to tell whether they were the surviving parents or a new generation, so they were released. Cages 6 and 7 (silk scrim 2 feet square). — On July 23, 18 nymphs varying between one-third and two-thirds grown were introduced into cage 6. These were intended to represent the larger ones found in the field at that date. On July 27 no adults could be seen. On August 3 most of the nymphs had changed to adults. This period of eleven days was, then, more than one-third and slightly less than two-thirds of the nymphal period. This gives about the same result as the test in cage 4. Cages 8 and 9 (silk sorim with glass top). — On August 3, 40 leaf- hoppers w T ere introduced into cage 8 ; of these 23 were females, 66— iv 40 SOME INSECTS INJURIOUS TO TRUCK CROPS. apparently all fresh, 10 were males, and 7 were large nymphs, the aim being to get as many of the earliest ones of the maturing brood as possible without introducing any belated ones of the parent brood. By this method it was hoped to get the succeeding brood, if there was to be one, as soon in the cages as it appeared in the field, and thus establish a minimum time between broods. On August 14 this cage was examined, and all leafhoppers seen were adults. There were no signs of egg scars or of damage. On August 30 but few leafhoppers could be seen, and no egg scars or damage. On September 12 the leafhoppers were almost all gone, and no eggs had been laid, either in the cage or field, and dissection showed that the females had no visible eggs in the abdomen up to date. It was thought at this time that the adults would lay eggs in the fall and then die. Accordingly a new lot was started, as shown below. Cages 10 and 11 (large lantern globes). — On August 30, 30 leaf- hoppers were introduced into No. 10, of which 12 were females. In No. 11 one female and several males were introduced. On September 12 no egg scars could be found in either cage. Cages 13 anti 11+ (silk scrim with a glass top).— On September 12, 20 leafhoppers, nearly all of which were females, were placed in cage 13. On October 20 the field of beets was harvested. The cages were removed and the beets labeled and sent on for examination. Each leaf and stem, and even the parts of the beet itself protruding from the ground, were examined carefully, but no sign of any egg scars could be found on these beets or on those from the previous cages. Many of the leafhoppers were alive at the time the cages were re- moved, and there seems to be no doubt that they must hibernate as adults. SUMMARY OF LIFE HISTORY. By the time the beets were thinned the leafhoppers began to appear in the fields and by the middle of June were well distributed. They gradually increased in numbers for some time after this. Egg la}dng began at Lehi, Utah, late in June and continued until late in August, each female depositing about 80 eggs, the period of deposition ex- tending through several weeks, the greater number of the eggs, how- ever, being deposited in the ten days preceding the middle of July. The nymphs appeared in small numbers by July 10, and were still to be found in small numbers in September. A great majority of them emerged from the eggs the last ten days in July and changed to adults some twenty days later. The first adults appeared from these nymphs the last of July and continued to increase in number through August. The egg stage in the cage experiments was between thirteen and fifteen days; the larval stage between sixteen and twenty-two LEAFHOPPERS OF THE SUGAR BEET. 41 ECONOMIC RELATIONS. The first fact observed in 1905 was that different fields were affected very differently, and much time was spent in studying conditions in an attempt to discover just what combination of factors was neces- sary to produce the “ curly-leaf,” so fatal to the beets. Even in the worst fields examined there would be here and there a beet that was apparently untouched and growing as usual, while in the best fields only here and there could an affected one be found. As a result of the season’s observations there seemed to be little question that the “ curly-leaf ” condition was the result of the attack of the leafhoppers combined with the effect of a very hot, early season. In many plaves it was noticed that along the edges of the fields where the beets had any shade — such as would be furnished by a hedgerow, or even by a vigorous stand of sweet clover on a ditch bank — there would be a marked difference for the first few rows. In Sevier County, where many of even the early-planted fields were abandoned and where the rest averaged from 2 to 4 tons per acre, one field was seen that did not show much damage and yielded 12 tons per acre. This field had a block of tall poplar trees on the south and a row of equally tall ones on the west side. In other places it was observed that the fields that were the weediest had better beets than those that had been well cultivated. Under ordinary condi- tions the results in all these cases would have been just the reverse, and the only explanation that seemed plausible was that the shade of the trees and of the weeds kept the ground from becoming quite so hot and thus allowed the beets to overcome the effects of the leaf- hoppers. In ordinary practice the beets are not irrigated until they have made considerable growth; thus the taproot is forced to de- scend for water, and a long, symmetrical beet results, while if watered too soon the beets are short and sprangly. In one place, in 1905, it was found that the water had escaped from a ditch and irrigated one corner of a field much earlier than it had been applied to the rest, and this corner was the only place that was not seriously affected with the “ curly-leaf.” In another place the water supply failed just as they started to irrigate the field, and the remainder was not irrigated until a week later. The difference in the amount of u curly-leaf ” on these beets showed plainly to the end of the season just how far the early water reached. At first these differences were attributed to the effect of the early water on the beet itself, but on further investigation a number of fields was found where subirrigation was depended upon entirely and where, ordinarily, fine beets were raised. In these fields the taproots of the beets were found to extend into a stratum of satu- rated soil and yet the beets were badly affected and continued to grow 66— iv 42 SOME IK SECTS INJURIOUS TO TRUCK CROPS. worse throughout the season. The only explanation found for that condition was that, while the beet had plenty of water, still the top soil was dry and dusty, and the ground was as hot as in an ordinary field, while in the fields that were irrigated early the evaporation from the moist surface kept the temperature down until the beets were large enough to shade the ground. This would also explain the fact that everywhere in the State, except in Sevier County, the late beets were affected much worse than the early ones. In other portions of the State the early beets were large enough to shade the ground in the rows by the time the hot weather and leafhoppers appeared. In Sevier County, on the other hand, the hot, dry weather came on earlier and the leafhoppers were so much more numerous that even the earliest beets could not withstand their attack when exposed to the .full force of the sun. The unusual numbers of the beet leaf hopper were apparently largely the result of a winter and spring favorable for the preserva- tion of insect life, as almost all injurious insects were present in in- creased numbers during that season (1905). The leafhoppers had, however, evidently been increasing for several years and had even before this reached destructive numbers in Sevier County, as the beet growers there had been suffering increasingly from what they called “ blight ” for two years previous to this, and this increase in the number of insects, followed by a winter favorable to their sur- vival, resulted in the outbreak of 1905. The leafhoppers were present in every field examined in Utah that season, and occurred in the greatest abundance in the areas in which the “ curly-leaf ” was worst. The average number of adults of the over- wintered brood to a beet varied from 3 or 4 up to 10 or 15, and probably even more than that in Sevier County, judging from the number found there later. No serious damage was done where there were only the smaller numbers, and even where the damage was worst it seemed to depend more upon how early they appeared and the tem- perature and moisture of the locality at that time than on the actual number above an average of possibly 5 or 6 to a beet. In 1900 they appeared in very small numbers. The field at Lehi, Utah, where the experiments were conducted, was by far the worst found, and here they averaged only about 1 or 2 to a beet, while the average of the valley would not have been more than 1 to every ten or fifteen beets, and the average of the State was even less. A field in Boxelder County, Utah, was examined in August, 1905, in which the leafhoppers had recently appeared in large numbers, averaging 100 or even 200 in some places' to the beet. The beets were large enough then to shade the ground, and the field was well irri- gated from that time on. Almost no curling of the leaves could be 00 — iv LEAFHOPPERS OF THE SUGAR BEET. 43 found in this field, and in the. fall the yield was nearly up to the average. This was the only field examined in which the leafhoppers did not appear until after the. adults had hatched out. On the other hand, many fields were examined in which the leafhoppers had been present early in the season but had almost disappeared after the nymphs had matured, and yet in these fields the curling continued to develop throughout the season and the beets grew worse instead of recovering. Spraying with kerosene emulsion was tried on a field in the Cache Valley, Utah, in 1905. This field contained numerous adults and nymphs in all stages. Four nozzles were used, each one set about 18 inches above the row and pointing obliquely down and forward, and just in front of them a bar drew the beet tops over and caused the leafhoppers to jump just as the spray struck them. An emulsion diluted with 15 parts of water had little effect on the adults, and only killed a few of the smaller nymphs. Most of the nymphs would kick about on the ground and some would become quite still, but a little later most of them would recover and hop away. An emulsion diluted with 8 parts of water produced the same effect on the adults that the weaker dilution did upon the nymphs, and killed the ma- jority of the nymphs that it struck. Many of the latter would, how- ever, escape the spray on account of the broad leaves of the beet, and the results were not considered entirely satisfactory. In the cage experiments it was expected that the number of leaf- hoppers necessary to cause “ curly-leaf ” on different-sized beets would be ascertained, but owing to the fineness of the gauze neces- sary to hold them the temperature and moisture could not be con- trolled and no “ curly-leaf ” was produced.® The damp conditions of the cages also made it difficult to keep the insects for any length of time. In one experiment 16 leafhoppers, 12 of which were females ready to deposit eggs, were placed on a beet with a top 8 inches in diameter a This manuscript was originally prepared and submitted at the close of the season of 1906. Some revision was made to include the important facts of the work of 1907, but the main discussions, including the above paragraph, were written in 1906. Since that writing “ curly-leaf ’’lias appeared in cages arranged by Prof. E. G. Titus in joint investigations with the writer. Mr. H. B. Shaw, assistant to Dr. C. O. Townsend, in charge of Sugar Beet Investigations, Bureau of Plant Industry, U. S. Department of Agriculture, has also succeeded in pro- ducing “ curly-leaf ” under experimental conditions. He writes me under date of October 23, 1908, that curly top or “ curly-leaf ” appeared in the cages on the experimental plat at Garland, Utah, in which he introduced the beet leaf- hoppers, and that later he sent a number of leafhoppers to the office of Sugar Beet Investigations, Bureau of Plant Industry, where 6 of them were placed in a cage with 11 young beets, 9 of which showed distinct symptoms of “ curly- leaf ” within five weeks after the insects were introduced. 66— iv 44 SOME INSECTS INJURIOUS TO TRUCK CROPS. and consisting of a dozen or more leaves. Over another beet of the same size a check cage was placed. Seventeen days later the eggs had just begun to hatch, and already the beet in the cage without any hoppers was nearly twice the size of the first one. The beet on which were the leafhoppers continued to grow for a week or more, then practically stood still, and on the seventeenth day it was apparently smaller than when examined five days before. Seven days later a large number of nymphs had hatched out, the outer leaves were dead, and the rest looking sickly; ten days later than this the cage was examined again and the beet was dead and dry, while the beet in the check cage had again doubled in size. Twelve leafhoppers and their eggs stopped the growth of a beet in less than two weeks, and they, together with their progeny, killed it in less than two weeks more. The same number of adult specimens of Agallia, Nysius, or Empoasca, would scarcely have made an impression on a beet of that size. CHARACTERISTICS OF “ CURLY-LEAF.” The first symptom of “ curly-leaf ” or “ blight ” of the beet is a thickening of all the smaller veinlets of the leaf, giving it a rough- ened appearance on the underside. This is followed by a curling of the edge (PI. Ill, fig. 1) and a final rolling up of the leaf (PI. I, fig. I, j; PL II, figs. 2, 3; PI. Ill, fig. 2), the upper surface always being rolled in. As this progresses the small veinlets grow still larger and more irregular, knotlike swellings appear at frequent intervals (PL III, fig. 2), and in extreme cases little nipplelike swellings appear, extending to a height of nearly one-fourth of an inch (Pl. I, fig. 1, Jc). This will be noticed first upon a medium-sized leaf, gradually spreading to the younger ones, while at the same time the beet almost stops growing and a large number of fibrous roots are sent out (PL II, fig. 1). These roots are not confined to two irregular lines as in a healthy beet. The beet often continues in this way throughout the season, in bad cases it shrivels and dies, while in a few instances there is a partial recovery and a new set of leaves, though the sugar content remains very low. Many of the species of this genus of leafhoppers produce a discoloration or distortion of the leaves of their food plant. This appears to be of the same nature as the work of the gall-forming species, and is a process little understood. The wrinkling and folding of the leaves by some of the species is very similar in appearance to the work of some gall-forming aphides. Some species also produce a change in color similar to that produced in many galls. In the case of Eutettix strobi (PL I, fig. 2 a, b) and E. scitula on the Chenopodium or on the sugar beet and of E. nigridorsum and E. 8trarninea (PL I, fig. 6) on the Helianthus the discoloration appears as 60 — iv Bui, 66, Pt. IV, Bureau of Entomology, U. S. Dept, of Agriculture Plate II. Work of Eutettix tenella on Sugar Beet. Fig. 1. — Three “curly-leaf ” beets, the result of attack by Eutettix tenella , and one normal beet from the same field, showing difference in size. Figs. 2, 3.—“ Curly-leaf ” beets as seen in the field. Fig. 4. — Normal beets from same field. (Original.) library 'XY OF ILLINOIS URBAN/L Bui. 66, Pt. IV, Bureau of Entomology, U. S. Dept, of Agriculture. Plate III. Work of Eutettix tenella on Sugar Beet. Fig. 1. — A large beet becoming “curly.” Fig. 2. — Back of a leaf affected by “curl y-leaf,” showing “warty” condition and curled edges. (Original.) LIBRARY u:;iv:nsiTY of Illinois URCANA LEAFHOPPERS OF THE SUGAR BEET. 45 soon as the little nymphs begin to feed, and this is soon followed by the distortion of the leaf in a certain definite way in each case. That this is not caused by the mechanical injury of the puncture or due alone to the loss of sap seems to be abundantly proved by the fact that the Chenopodium is often attacked by other sucking insects in much larger numbers without producing either the red pigment or the gall-like distortion. The fact that a certain characteristic color and appearance are always produced by a given species, no matter whether on a Chenopodium or on a sugar beet, and that the color and form vary for the different species of the same genus even when working on the same plant, would indicate that there is some definite agency back of it all. It has also been noticed that in all this group the greatest amount of damage is done in hot, dry situations. Whether or not the “ curly -leaf ” condition is entirely the result of the change in the beet caused by the attack of the beet leaf hopper is still an open question, but that there is some relationship between the leafhopper attack and the “ curly-leaf ” does not seem to admit of a doubt in the light of the facts brought out in the investigations. The amount of damage in a given valley was directly proportional to the number of leaf hoppers present, the injury appeared only after the appearance of the leafhoppers, and the “ curly-leaf ” condition is known to occur only on beets growing within the range of this insect. Attention was not called to the damage early enough in 1905 to ascertain whether or not the “ curly-leaf ” appeared before the first appearance of the nymphs. At Lehi, Utah, the “ curly-leaf ” ap- peared very soon after the first nymphs. In the Cache Valley, Utah, the nymphs were common by the time the first curling was noticed. In 1906 very careful watch was kept in all parts of the State for the very first sign of leaf -curl, and in no case did it appear (except on the mother beets) until after the nymphs began to hatch out. In fact, in almost every case examined the cast skins of nymphs could be found on the back of curled leaves, while on healthy beets these were very seldom found. In all observations of both years more leafhoppers were found on the curled beets than on others. At first this was thought to show a gregarious habit in the adult, but it may be due to the fact that a given female lays most of her eggs on a single plant and the nymphs tend to remain there. In Eutettix strobi and the other leaf-curling forms, where the nymphs are brightly colored and depend on their discolored spots for protection, it is not unusual for a given nymph to pass its whole life on a single leaf, or on two or three adjoining ones; in most cases but a single nymph will be found on a plant, and sometimes the adult and the nymphal skin of each stage may be found under a single leaf. It is very likely that the same habit persists in Eutettix tenella and that this fact, in part at 66 — iv 46 SOME INSECTS INJURIOUS TO TRUCK CROPS. least, accounts for one beet being badly affected while the adjacent ones are unharmed. In the case of Eutettix strobi and its allies, where most of the leaves of a small plant are affected by the dis- tortion, the plant usually shrivels up and dies, but where only one or two leaves on a large plant are distorted the plant does not appear to be affected at all, and in no case does the color appear in any of the new leaves. In several cases small beets have been seen in which every leaf has been deformed by the work of strobi , and they had apparently stopped growing. In the case of the “ curly-leaf,” however, the abnormal condition apparently spreads from leaf to leaf until finally the whole plant is affected, even though the leafhoppers may have disappeared before the process is complete. This was abundantly demonstrated by the mother beets set out in the spring of 1906. These beets were selected from the best-looking beets of 1905, and would naturally have been ones that showed little or no effect of the “ curly-leaf ” the season before. In every case observed the first leaves sent up by these beets were as curly as the average of the year before, and most of them formed stunted lettucelike heads, and later withered and died. Some, however, survived through the season, and a few sent up stunted blos- som stalks, but as a seed crop they were an entire failure. This curl- ing took place before any leafhoppers were found in the beets, and in rows adjoining young beets that were not at all affected and did not become affected during the season. This would indicate that the agency, whatever it may be, that causes “ curly-leaf ” remained in the beet itself over winter and was transmitted to the first leaves in the spring. In early September, 1907, the sugar-beet region around Spreckels, Cal., was visited by the writer and a number of cases of what was commonly called “ blight ” or “ curly-leaf ” were examined. These, however, proved to be quite different in character from the “ curly- leaf ” condition caused by Eutettix tenella. The leaves of the beet were found to be covered with pale spots, the edges were turned down instead of up, and the whole appearance was quite different. A care- ful search was made over many acres for specimens of tenella , but none was found; instead a species of Empoasca was always found associated with this appearance of the beets. The matter will be dis- cussed further in connection with that species (p. 51). OTHER RECORDS. Prof. E. G. Titus reports that on a trip through the sugar-beet regions of the West in September, 1904, he found Eutettix tenella at La Grande and Echo, Oreg. At La Grande little damage was done, while at Echo one field of 10 acres was so seriously injured by what co — iv Bui. 66, Pt. IV, Bureau of Entomology, U. S. Dept, of Agriculture. Plate IV. Work of Eutettix tenella on Sugar Beet. Fig. 1.— A field of beets destroyed by “ curly -leaf.” Figs. 2, 3. — Cages used in the life-history experiments. (Original.) LIBRARY ; ;..;r.SITY OF ILLINOIS URBANA LEAFHOPPERS OF THE SUGAR BEET. 47 was then called 44 blight ” that it was not harvested. Many of the beets had died and the rest were small and stunted, while the leaf- hoppers could be swept up in numbers. In California 44 curlv-leaf ” conditions were seen by Professor Titus at Oxnard and Spreckels and reported to be quite serious on the higher lands back of Salinas. Whether this was the true 44 curly-leaf ” or the type found there this year was not determined. In August, 1907, another trip was made by him through the same territory and a few specimens of Eutettix tenella taken at Payette, Idaho. Little damage was being done that season, but field men re- ported considerable loss in 1905 in both Payette and Blackfoot, Idaho. A few E. tenella were taken at Union, Oreg., and Echo, Oreg., in August, 1907, only slight damage showing in either place. Large nymphs were taken with the adults. In California a number of places were visited by Professor Titus in August, 1907, but no specimens of Eutettix taken. In September another trip through the California districts was made, and a few specimens of E. tenella were taken at Chino on the 13th. No very definite cases of 44 curly-leaf ” were noticed. ECONOMIC SUMMARY AND PROPOSED REMEDIES. The 44 curly-leaf ” condition or 44 blight ” of the sugar beet, as it occurs in Utah and the surrounding region, appears soon after an attack of the beet leafhopper ( Eutettix tenella Baker). Its severity is conditional upon the number of insects present, upon the time of their appearance, upon the size of the beets, and upon the temperature of the surface soil, together with the temperature and moisture of the surrounding air. More should be known about the places of hibernation and early spring history of this insect. It could not be found in the rubbish around the fields in early spring, and only a few specimens were found in waste places up to the time they appeared on the beets. When once the place where the greater number of them pass the winter is discov- ered, it may be possible to destroy them there or on their spring food plants before they migrate to the beets. After they have appeared on the beets it will be necessary to be very prompt in the matter of remedies if the injury is to be prevented. A thorough spraying with kerosene emulsion at a strength of 1 part of the stock solution a to 5 parts of water would destroy most of the insects that it hit, and by using a drag in front of the nozzles to turn the leaves over and cause the insects to jump, most of them could be reached. Where the insects a For directions regarding the preparation and use of kerosene emulsion see Farmers’ Bulletin 327, U. S. Dept, of Agriculture, pp. 20-21, and Circular 80, Bureau of Entomology. 66 — iv^ 48 SOME INSECTS INJURIOUS TO TRUCK CROPS. were coming in in numbers this spray would need to be followed by a second one 10 days later. Several mechanical devices have been used to catch different leaf- hoppers, and no doubt several of these could be used against this insect with advantage. The tar pan, or “ hopper-dozer,” drawn over the beets two or three times in the first few weeks would capture a large number of them. The females, before the eggs are laid, are quite heavy and do not jump or fly as readily as the males and would be ^easily caught. A modified form of this machine, consisting of a couple of tarred wings to be drawn along on each side of a row of beets, while a drag agitated the tops and caused the insects to fly, would probably capture more than the simpler tar-pan. If the insects appeared while the beets were quite small, they could be largely destroyed by rolling when the weather was cold or damp and the insects sluggish. A number of preventive measures may be used to assist the beets in withstanding the attack of the leafhoppers. In some sections early planting will produce beets large enough to shade the ground by the time the beet leafhoppers appear, and thus reduce the temperature below the danger line. In a few places, like the Grand Junction dis- trict in Colorado and Sevier County in Utah, early planting alone would not avail, as the insects appear soon after the earliest beets come through the ground. For such sections early and frequent irri- gations would assist in keeping the ground cool until the beets grew large enough to shade it and thus take care of themselves. All preventive measures will depend for success upon some method of controlling the temperature in the field so that the ground may not be hot and dry at the time the leafhoppers appear. BIBLIOGRAPHICAL REFERENCES. 1895. Gillette, C. P., and C. F. Baker. — A preliminary list of tlie Hemiptera of Colorado. < Bui. 31, Colo. Agric. Exp. Sta., p. 100. On sugar beets in Colorado. Mention as Thamnotettix tenellus Uhl. MSS. 1896. Baker, C. F. — New Hemiptera.