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Information to Users INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6” x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Bell & Howell Information Company 3 0 0 North Z eeb Road. Ann Arbor. Ml 4 8106-1346 USA 313/761-4700 800/521-0600 Order Number 9130518 Studies of epidemiology of maize streak virus and itsCicadulina leafhopper vectors in Nigeria Mbey-yame, Asanzi Christopher, Ph.D. The Ohio State University, 1991 UMI 300 N. Zceb Rd. Ann Arbor, MI 48106 STUDIES OF EPIDEMIOLOGY OF MAIZE STREAK VIRUS AND ITS CICADULINA LEAFHOPPER VECTORS IN NIGERIA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University by Asanzi Christopher Mbey-yame Ir. M.S. ******* The Ohio State University 1991 Dissertation Committee Approved by Dr. L.R. Nault Dr. D .T. Gordon Dr. D.J. Horn Dr. D.L. Denlinger Department of Entomology This dissertation is dedicated to my family ii ACKNOWLEDGEMENTS I am greateful to all those who provided me with their assistance and expertise throughout the realization of this work. Dr. Lowell R. Nault, my advisor, for his guidance, advice and constructive suggestions which improved the quality of this work. Dr. D.T. Gordon for his deep commitment in this Research and innovative suggestions in the elaboration of this document. Dr. Nilsa A. Bosque-Perez for her enthusiastic supervision of this Research at the International Institute of Tropical Agriculture, support and useful suggestions. I owe a lot of gratitude to Drs. David Horn and David Denlinger for their support and helpful comments. I express sincere thanks to Dr, Larry Madden, Mr. Bert Bishop and Mr. Peter Walker for their assistance and advice on statistical problems. I express my sincere appreciation to Dr. H. Gasser for his patience and understanding, to Dr. G. Thottappilly for his contributions in some aspects of this work and to Dr. I. W. Buddenhagen for useful discussions at the early phase of this research. I am Indebted to IITA Maize Research and Training Program staff for their support during my entire stay in Ibadan. I thank the Government of Zaire for giving me this life time opportunity and the USAID for providing me with financial support. I am grateful to friends and collegues Kasongo Ngindu and Muyolo ill Gilumbu for their help in the preparation of this document and to Dr. Mabaya Nyabul and Muwala Bolmakob for their moral support. Finally, I thank my wife Musitu Jannet, my children Esperance, Mireille, Philip and Mamie-Ange, my sister Jolie and ray nephew Alson for their patience, sacrifices and above all their loveand, constant support throughout this long ordeal. iv VITA December 12, 1947 ........................... .. Born - Mikingi, Kwilu 1975 ....................................... .. Ir. , Faculty of Agronomy National University of Zaire (UNAZA) 1975-1979 ...................................... Research Assistant, National Maize Research Program, Department of Agriculture 1982 .......................................... M.Sc., Entomology, University of Nebraska, Lincoln 1982-1986 ...................................... Entomologist, National Maize Reseach Program, Department of Agriculture 1988-1990 ...................................... Research fellow at the International Institute of Tropical Agriculture, Ibadan, Nigeria Major Field: Entomology v TABLE OF CONTENTS DEDICATION ............................................................ ii ACKNOWLEDGEMENTS .................................................. iii VITA .................................................................. iv LIST OF T A B L E S ......................................................vii LIST OF FIGURES ........................................................xi INTRODUCTION ........................................................ 1 CHAPTER ....................................... PAGE I. STUDIES ON MAIZE STREAK VIRUS AND CICADULINA LEAFHOPPERS IN NIGERIA ..................................... 7 Introduction ...................................... 7 Materials and Methods ........... '....................9 R e s u l t s ............................................. 15 D i s c u s s i o n ......................................... 47 II. DISPERSAL OF CICADULINA STOREYI IN MAIZE FIELD AND ITS BEHAVIOR IN RELATION TO MAIZE VARIETY, MAIZE GROWTH STAGE AND PRESENCE OF MAIZE STREAK VIRUS ........................................ 54 Introduction .................. 54 Materials and Methods .......... 56 R e s u l t s ......................... 62 D i s c u s s i o n ......................................... 79 III. CICADULINA BIOLOGY AND ITS TRANSMISSION OF MAIZE STREAK V I R U S ..................................... 87 Introduction ...................................... 87 Materials and Methods ........................... 89 R e s u l t s .......... 92 D i s c u s s i o n ............................... 102 vi VI. TRANSMISSION OF MAIZE STREAK VIRUS ISOLATES BY CICADULIA STOREYI ................................... Ill Introduction ............................. Ill Materials and Methods ........................... 112 R e s u l t s ............................................ 118 D i s c u s s i o n ........................................ 130 V. MAIZE STREAK VIRUS DISEASE PROGRESSION CURVE AND PATTERN OF SPREAD UNDER FIELD CONDITIONS IN A TROPICAL RAIN FOREST LOCATION ......................................135 Introduction .......... 135 Materials and Methods . ......................... 136 R e s u l t s ................ 139 Discussion ...................................... 150 EPILOGUE .......................................................153 LIST OF R E F E R E N C E S ............................................ 157 vii LIST OF TABLES TABLE ................................................................ PAGE 1. Maize streak virus (MSV) incidence and severity in October 1989 planting at Ikenne .............. 24 2. Maize streak virus (MSV) incindence and severity in July 1989 planting at Mokwa ....................... 25 3. Maize streak virus (MSV) incidence and severity in August 1989 planting at Mokwa .............................26 4. Maize streak virus (MSV) incidence and severity in September 1989 planting at M o k w a ...........................27 5. Maize streak virus (MSV) incidence and severity in June 1989 planting at Funtua . ........................... 29 6. Maize streak virus (MSV) incidence and severity in July 1989 planting at F u n t u a ......................... 30 7. Maize streak virus (MSV) incidence and severity in August 1989 planting at F u n t u a .............................31 8. Maize streak virus (MSV) incidence on maize varieties at 14 and 28 days after inoculation with different numbers of MSV-exposed leafhoppers following a 24 hr inoculation access period (IAP).................................42 9. Maize streak virus (MSV) severity on maize varieties at 28 and 56 days after inoculation with different numbers of MSV-exposed leafhoppers following a 24 hr inoculation access period (IAP). ............ 43 10. Maize streak virus (MSV) incidence on maize varieties at 14 and 28 days after inoculation with different numbers of MSV-exposed leafhoppers at various time periods following a 24 hr inoculation access period (IAP)............. 4 5 11. Maize streak virus (MSV) severity on maize varieties at 28 and 56 days after inoculation with different numbers of MSV-exposed leafhoppers at various time periods following 24 hr inoculation access period (IAP)................. 47 viii 12. Effect of fluorescent dye on survival of C. storeyi............ 63 13. Effect of fluorescent dye on Cicadilina storeyi flight activity and its virus transmission efficiency. .... 64 14. Cicadulina population density in maize field with different growth s t a g e s .......... 75 15. Numbers of Clcadulina storeyi settling on healthy maize varieties......................................... 76 16. Numbers of Cicadulina storeyi settling on maize varieties infected with maize streak virus (MSV) ............. 76 17. Number of eggs laid by female Cicadulina storeyi on three maize varieties over 7 day oviposition period (free choice test)............................. 80 18. Number of eggs laid by female Cicadulina storeyi on three maize varieties
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