Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1970 Natural Control of Pseudoplusia Includens (Walker) in Louisiana Soybean Fields. Joseph Gaynor Burleigh Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Burleigh, Joseph Gaynor, "Natural Control of Pseudoplusia Includens (Walker) in Louisiana Soybean Fields." (1970). LSU Historical Dissertations and Theses. 1711. https://digitalcommons.lsu.edu/gradschool_disstheses/1711 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. 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University Microfilms 300 North Zeeb Road Ann Arbor, Michigan 48106 A Xerox Education Company 70-18,519 BURLEIGH, Joseph. Gaynor, 1942- NATURAL CONTROL OF PSEUDOPLUSIA INCLUDENS (WALKER) IN LOUISIANA SOYBEAN FIELDS. The Louisiana State University and Agricultural and Mechanical College, Ph.D., 1970 Entomology University Microfilms, A XEROX Company, Ann Arbor, Michigan Natural Control o.f Psuedoplusla includens (Walker) in Louisiana Soybean Fields A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Entomology by Joseph Gaynor Burleigh B. S« , University of Southwestern Louisiana, 1964 M. S., Louisiana State University, 1966 January, 1970 PLEASE NOTE: Not original copy. Some -pages have very light type. Filmed as received. University Microfilms ACKNOWLEDGMENTS The author is especially indebted to his Major Pro­ fessor, Dr. L. D. Newsom, Head, Department of Entomology, who contributed his time and advice to the preparation of this manuscript. Sincere thanks are also due to the members of the writer’s advisory committee composed of Dr. S. D. Hensley, Professor of Entomology, Dr. J. H. Roberts, Professor of Zoology, Dr. A. T). Larson, Professor of Microbiology, and Dr. J. W. Avault, Assistant Professor of Fisheries, for their constructive criticism. Grateful acknowledgment is made to Dr. P. E. Schilling, Assistant Professor of Experimental Statistics, for his assistance in analyzing the data; and to Dr. A. M. Hammond, Jr., Assistant Professor of Entomology, for his valuable criticism. Special thanks are also extended to Mr. Rodney Semar, Mr. Collins Lanclos, and Mr. Lloyd Newton, for use of their land. Thanks and appreciation are given to Mr. A. L. Wuensche and Mr. L. F. Holloway, Graduate Assistants, for aid in collecting the larvae and to Mr. J. W. Smith for assistance with photographs. Special thanks are due to the writer’s wife, Joan, for her assistance in the laboratory and during the preparation of this manuscript. TABLE OF CONTENTS Page ACKNOWLEDGMENTS ....... ii LIST OF TABLES ....... vi LIST OF FIGURES ....... ix ABSTRACT . x INTRODUCTION ........ 1 REVIEW OF LITERATURE . 4 Pseudoplusia includens (Walker). 4 Population dynamics ..... 6 Parasitism ....... S Spicaria rileyi (Farlow) Charles . 10 Massospora sp. 13 Epizootics . 14 MATERIALS AND METHODS . 16 Locations and descriptions . 16 Methods of collection . 1$ Processing the larvae . 2 0 Symptoms of Massospora infection . 2 3 Laboratory test with Spicaria rileyi . 2S Field test with Spicaria rileyi . 2 9 Population estimations . .31 Effect of parasites and fungal pathogens on the estimated populations . 3 2 Analysis of data . 3 2 RESULTS . Parasites Total insect parasitism 196$ Total insect parasitism 1969 Spicaria rileyi 196$ Spicaria rileyi 1969 Laboratory test with Spicaria rileyi Field test with Spicaria rileyi Massospora sp. 1969 Population estimations DISCUSSION Lacassine 196$ Lacassine 1969 Krotz Springs 196$ Krotz Springs 1969 Bunkie 196$ Bunkie 1969 Laboratory test with Spicaria rileyi 'Field application of Spicaria spores Populations estimations and the effect of insect parasites and fungal pathogens on these populations 72 Lacassine 73 Page Krotz Springs 73 Bunkie 76 CONCLUSIONS . S3 LITERATURE CITED . 33 APPENDIX 92 VITA .... 100 v LIST OF TABLES Table Page I. The number of identified parasites collected . at Lacassine, Krotz Springs, and Bunkie, Louisiana, in 196$ and 1969. • • 34 II. The number of looper larvae collected at Lacassine, Krotz Springs, and Bunkie in 196$ and 1969, and the number that were parasitized. 3$ III. Per cent of the looper larvae that were parasi- tiz'ed at Lacassine, Krotz Springs, and Bunkie in 196$ and 1969. 40 IV. Average number of larvae collected per 100 sweeps in weekly samples-at' Lacassine, Krotz Springs, and Bunkie in 196$ and 1969* 41 V. Per cent of the looper larvae that were infected with S. rileyi at Lacassine, Krotz Springs, and Bunkie in 196$ and 1969. 44 VI. Per cent total mortality and the time required for 50 per cent mortality of P. includens larvae, treated topically with spores of S. rileyi. ..... 47 VII. Percentage of looper larvae infected with S. rilevi in the treated and untreated plots at Bunkie, Louisiana in 1969. • . • 4$ VIII. The percentage of looper larvae which died due to insect parasites, S. rileyi and unknown •causes in 196$ and Massospora in 1969, at Bunkie, La. 50 IX. Percentage of looper larvae infected with Massospora in the six study plots which were used in the Spicaria test at Bunkie, Louisiana in 1969. ..... 51 vi Table Page X. Estimated number of larvae per acre using the sweep-net and row-count calculations from Lacassine, Krotz Springs, and Bunkie in 196$ and the efficiency ratio between these two methods of collection. .... .52 XI. Estimated number of larvae per acre for each generation at Lacassine, Krotz Springs, and Bunkie, Louisiana, based upon the sweep-net collections in 19o9 « ..... 54 XII. The percentage of looper larvae which died due to insect parasites, S. rileyi, and unknown causes in 196$ and 19^9, at Lacassine, Louisiana. .57 XIII. The percentage of looper larvae which died due to insect parasites, S. rileyi, and unknown causes in 196$ and 19^9, at Krotz Springs, Louisiana. 65 XIV. Estimated number of larvae per acre, based upon 100 sweeps, and the effect of parasitism and S_. rileyi infection upon the looper population at Lacassine, Louisiana, in 196$. 74 ■XV. Estimated number of larvae per acre, based upon 100 sweeps, and the effect of parasitism and S. rileyi infection upon the looper population at Lacassine, Louisiana, in 1969. 75 XVI. Estimated number of larvae per acre, based upon 100 sweeps, and the effect of parasitism and S. rileyi infection upon the looper population at Krotz Springs, Louisiana, in 196$. 77 XVII. Estimated number of larvae per acre, based upon 100 sweeps, and the effect of parasitism and S. rileyi infection upon the looper populations at Krotz Springs, Louisiana, in 1969• . 7$ XVIII. Estimated number of larvae per acre, based upon 100 sweeps, and the effect of parasitism and S. rileyi infection upon the looper population at Bunkie, Louisiana, in 196$. 79 Table Page XIX. Estimated number of larvae per acre, based upon 100 sweeps, and the effect of parasitism, S. rileyi, and Massospora infection upon the looper population at Bunkie, Louisiana, in 1969. ^ XX. The number of looper larvae collected at Lacassine in 1963 and 1969, the number parasitized, and the per cent parasitized. 92 XXI. The number of looper larvae collected at Krotz Springs in 1963 and 1969, the number parasitized, and the per cent parasitized. 93 XXII. The number of looper larvae collected at Bunkie in 1963 and 1969, the number parasitized, and the per cent parasitized. .94 XXIII. The number of looper larvae collected in 1000 sweeps in each plot at Lacassine, Krotz Springs, and Bunkie from June 1? to September 13, 1963. 95 XXIV. The number of looper larvae collected in 1000 sweeps in each plot at Lacassine, Krotz Springs, and Bunkie from June 19, to September 24, 1969* 96 XXV. Estimated number of larvae per acre, based upon row-counts, and the effect of parasitism and S. rilevi infection upon the looper population at Lacassine, Louisiana, in 1963.