MANAGEMENT OF MAJOR PEANUT (Arachis hypogaea L.) DISEASES USING BAHIAGRASS (Paspalum notatum Fluegge) ROTATION BY FRANCIS KODJO TSIGBEY A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2007 1 © 2007 Francis Kodjo Tsigbey 2 To my children and entire family 3 ACKNOWLEDGMENTS I am highly indebted to Dr. Jim Marois for the opportunity to work with him and for his invaluable mentoring and patience. I thank the rest of my supervisory committee, Dr. Lawrence Datnoff, Dr. David Wright, Dr. Jeffery Jones, and Dr. Jimmy Rich for their support, insight, and constructive critique of this work. My thanks go to all the staff at the Extension Agronomy section, NFREC Quincy for their time and assistance in conducting this research. I thank the staff of Dept. of Plant Pathology, Univ. of Florida especially Gail Harris for taking time to sort out my complex paper work during my study. My gratitude goes to all my friends Dr. and Mrs Clottey, Enoch Osekre, Jennifer McGriff, Dr. Tawainga Katsvairo, Mary Arhinful, Ernest Ankrah, Dr. Daniel Mailhot, Dr. Susan Bambo, Loraine Gibson, Cynthia Holloway and all others for their encouragement throughout all these years. To my family Grace Dikro, Peace Amoako, Rev. Dr. Kofi Asimpi, Linda Dzah, Kwaku Bansah, Mr. Aigboviobsia and many others, I say thank you for standing with me and supporting me in unimaginable ways. I thank my siblings (Amy Acolatse, Dora Boso, and Emmanuel Tsigbey among others) for their prayers and sacrifices. I also thank my beloved parents Bertha Afare and the late Tefe Tsigbe. I am proud to be their son and I thank them for the suffering they endured in bringing me up. I also thank my children (Akpedonu Kodzo Tsigbey Jr., Edem Tsigbey, and Mawuena Tsigbey). Nothing I can do could pay for their sacrifice, for they have paid the price for my pride. It has been a long journey, and I thank all whose name I am not able to mention here. I thank them for allowing God to use them in bringing me this far. Finally, I thank the Lord God Almighty for His guidance, wisdom and protection. For unto God belong the glory and honor of my life. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...............................................................................................................4 LIST OF FIGURES .........................................................................................................................9 ABSTRACT...................................................................................................................................11 CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW ..............................................................13 Importance of Peanut in the United States (US) Economy .............................................13 Overview of Peanut Diseases and their Management .....................................................14 Peanut Diseases Caused by Nematodes ..........................................................................19 Impact of Crop Rotations on Diseases ............................................................................19 Cover Crops and Crop Disease Management..................................................................20 Influence of Organic Amendments on Plant Diseases ....................................................20 Role of Root Exudates in Rhizosphere Interactions........................................................22 Allelopathic Properties of Bahiagrass .............................................................................23 2 EFFECT OF BAHIAGRASS (Paspalum notatum fluegge) AND CONVENTIONAL ROTATION ON EARLY LEAF SPOT (Cercospora arachidicola s. hori), LATE LEAF SPOT (Cercosporidium personatum (Berk. & M.A. Curtis) Deighton), AND RUST (Puccinia arachidis Speg.) DISEASES ON PEANUT IN NORTH FLORIDA.........25 Introduction.............................................................................................................................25 Importance of Peanut Diseases and their Management...................................................25 Epidemiology of ELS and LLS .......................................................................................26 Peanut Rust (Puccinia arachidis Speg.)..........................................................................27 Management of Peanut Leaf Spots..................................................................................28 Materials and Methods ...........................................................................................................30 Rotations and Field Practices ..........................................................................................30 Field Practices in 2003 and 2004.....................................................................................31 Field Practices in 2005 and 2006.....................................................................................32 Disease Assessments .......................................................................................................33 Pod Yield and Grade .......................................................................................................34 Statistical Analysis ..........................................................................................................34 Results.....................................................................................................................................35 Rust (Puccinia arachidis)................................................................................................37 Influence of Rotations on Peanut Pod Yield and Quality................................................37 Discussion...............................................................................................................................37 5 3 SUPPRESSION OF TOMATO SPOTTED WILT (TSW) OF PEANUT IN A BAHIAGRASS (Paspalum notatum Fluegge) ROTATION..................................................49 Introduction.............................................................................................................................49 Materials and Methods ...........................................................................................................52 Rotation and Cultural Practices.......................................................................................52 Field Practices in 2003 and 2004.....................................................................................52 Field Practices in 2005 and 2006.....................................................................................53 Tomato Spotted Wilt Assessment ...................................................................................53 Thrips Infestation Studies................................................................................................54 Statistical Analysis ..........................................................................................................55 Results.....................................................................................................................................55 Monitoring of Thrips Activity.........................................................................................57 Pod Yield and Grade .......................................................................................................59 Discussion...............................................................................................................................59 4 EFFECT OF ROTATIONS ON SOUTHERN STEM ROT (SSR) (Sclerotium rolfsii sacc) AND SURVIVAL OF SCLEROTIA IN FIELD SOIL AMENDED WITH BAHIAGRASS CUTTINGS UNDER GREENHOUSE CONDITIONS. .............................70 Introduction.............................................................................................................................70 Material and methods .............................................................................................................73 Field Studies ....................................................................................................................73 Isolation and Maintenance of Micro-organisms..............................................................74 Soil Treatment .................................................................................................................74 Determination of Sclerotia Survival in Soils...................................................................75 Data Analyses..................................................................................................................75 Results.....................................................................................................................................76 Field Results ....................................................................................................................76 Greenhouse Results .........................................................................................................76 Discussion...............................................................................................................................77 5 EFFECT OF BAHIAGRASS ON NEMATODE POPULATION, REPRODUCTION AND MOVEMENT IN THE FIELD, GREENHOUSE AND LABORATORY CONDITIONS........................................................................................................................81 Introduction.............................................................................................................................81