Assessment of yield losses in sunflower due to powdery mildew Erysiphe cichoracearum DC.

Erysiphe cichoracearum DC. is a widely distributed pathogen of sunflower (Helianthus annuus L.) In hybrid KBSH 44 the reduction in the disease severity was found to be from 90.92 to 97.53 per cent, when the crop was sprayed 3 to 4 times with difenoconazole @ 0.05 per cent. While it was 71.34 and 82.92 per cent with one and two sprays, respectively. Maximum per cent increase in yield over control was recorded in the plots receiving four sprays (27.50%) and three sprays (14.43%). while, it was 9.24 per cent when the plots were given two sprays and 6.67 per cent when plots were sprayed only one time. Hence, two sprays of difenoconazole @ 0.05% was found to be effective in reducing severity of powdery mildew on sunflower.