Potential Use of Benomyl for Control of Ergot (Claviceps africana) in Sorghum A-lines in Zimbabwe

In the absence of a successful practice for the control of ergot on sorghum A-lines (male-steriles) in Zimbabwe, two fungicides, Benlate and Thiram, were tested in greenhouse and field experiments. Fungicides were either applied to sorghum panicles singly, at concentrations of 0.1 or 0.2% a.i., or combined in mixtures at 0.1% a.i. each. Fungicides were applied before inoculation at heading or stigma exsertion, or after disease became visible. Treatment with either Benlate or Thiram was ineffective if applied when disease first became visible. A significant reduction in initial disease severity, rate of disease increase, and final disease severity was achieved with one application of Benlate at 0.2% a.i. at heading or stigma exsertion. At the concentrations tested Benlate and Thiram did not reduce seed-set in R- (restorer) lines.