Early-season Application of Azoxystrobin to Sugarbeet for Control of Rhizoctonia solani AG 4 and AG 2-2

Abstract

Field trials were conducted in 1997-2003 to evaluate earlyseason application of azoxystrobin for control of R. solani AG 4 and AG 2-2. In furrow (IF) application of R. solani AG 4 and azoxystrobin resulted in an average of 14 plants m -1 at 30 days after planting (DAP) while the inoculated control averaged 4 plants m -1 . In furrow application of R. solani AG 2-2 with azoxystrobin or with two applications of azoxystrobin (IF + 4-leaf stage) averaged 15 and 16 plants m -1 at 30 DAP, respectively, while the inoculated control averaged 4 plants m -1 . At harvest, treatment with azoxystrobin IF + 4-leaf stage usually reduced disease caused by R. solani AG-2-2 and consistently increased yields (P < 0.05) compared to the inoculated control; single IF applications were less consistent in performance. Despite high inoculum densities of R. solani AG 4 and AG 2-2 and favorable temperatures and soil moisture for infection within 30 DAP, early-season application of azoxystrobin increased stands and sugarbeet yields compared to inoculated controls.