Management of Okra Powdery Mildew Using Ampelomyces quisqualis

The fungus Ampelomyces quisqualis is a naturally occurring hyperparasite of powdery mildews. Stanes Bio-Dewcon is a talc- based biological fungicide that contains the spores and mycelial fragments (1 x 10 8 CFUs g -1 ) of A. quisqualis . Bio-Dewcon at three different concentrations, viz., 2.0, 2.5 and 3.0kg ha -1 significantly reduced the okra powdery mildew incidence. The product was applied to plants as preventive spray at 30 and 45 days after sowing. Among the three doses tested, 3.0kg ha -1 was found to be on par with wettable sulphur (0.4%). Even though both Bio-Dewcon and wettable sulphur were found to be equally effective in controlling powdery mildew, Bio-Dewcon may be preferred due to its non-residual and odourless properties, especially in vegetables.