.................................................................................................................................. iii ACKNOWLEDGEMENTS ........................................................................................................... iv LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii CHAPTER 1. LITERATURE REVIEW ........................................................................................ 1 Sugarbeet history and development .................................................................................... 1 Rhizoctonia crown and root rot........................................................................................... 3 Description of Rhizoctonia solani ....................................................................................... 3 Distribution and host range ................................................................................................. 4 Disease symptoms ............................................................................................................... 5 Disease cycle and infection process .................................................................................... 6 Management ........................................................................................................................ 7 Genetic resistance ............................................................................................................... 7 Biological control................................................................................................................ 8 Cultural practices ................................................................................................................ 9 Chemical control ............................................................................................................... 11 Literature cited .................................................................................................................. 13 CHAPTER 2. EFFECT OF PENTHIOPYRAD AT DIFFERENT RATES AND USING DIFFERENT APPLICATION METHODOLOGIES ON RHIZOCTONIA SOLANI ON SUGARBEET ............................................................................................................................... 20 Introduction ....................................................................................................................... 20 Materials and methods ...................................................................................................... 22 Results ............................................................................................................................... 24 Discussion ......................................................................................................................... 28