Abstract:

The paper aims to solve the resistance of grape downy mildew to conventional fungicides. The control effects of fluopimomide, cyazofamid, oxathiapiprolin, fluopimomide + cyazofamid and fluopimomide + oxathiapiprolin on grape downy mildew were tested using the field inhibition and control methods. The results showed that the three fungicides and their combinations had certain effects on grape downy mildew, the protective effect of them was higher than the curative effect, seven days after 3 times’ application, the disease leaf prevention rate of the three fungicides and their combinations was 87.23%-100%, the disease index prevention effect was 96.47%-100%; and fourteen days after 3 times’ application, the disease leaf prevention rate was 54.39%-89.66%, and the disease index prevention effect was 78.40%-97.33%. Among the three fungicides and their combinations, fluopimomide (50%, WDG diluted by 7500 times)+ oxathiapiprolin (10%, OD diluted by 5000 times) showed the best control effect seven days after 3 times’ application, the disease leaf prevention rate and disease index prevention effect was 75.17% and 81.77% respectively; cyazofamid (100 g/L, SC diluted by 2500 times) showed the best control effect fourteen days after 3 times’ application, the disease leaf prevention rate and disease index prevention effect was 64.30% and 73.42%, respectively. According to the protective effect and the curative effect in field, we suggest that fluopimomide (50%, WDG diluted by 7500 times)+ oxathiapiprolin (10%, OD diluted by 5000 times) should be recommended as a fungicide applied on grape downy mildew.

Key words: Grape, Downy Mildew, Fluopimomide, Oxathiapiprolin, Control Effect