Abstract:

      We employed floating leaf disc test to determine the control effects of antagonistic Paenibacillus polymyxa PB-2 against grape downy mildew. Results show that when PB-2 is 10⁸ cfu/mL,the fermentation broth and  aseptic fermentation filtrate both have better inhibitory effects on grape downy mildew. Their inhibitory rates are 77.21% and 60.24%. We also prepared wettable powder (WP) of PB-2. Field tests indicate that the relative control effects of 50 and 100 times dilution PB-2 WP against grape downy mildew are 46.91% and 36.99% after 1 week and 46.44% and 42.10% after 2 weeks. This demonstrates that PB-2 WP has better field application prospect for controlling grape downy mildew.

Key words: grape downy mildew, Paenibacillus polymyxa, field evaluation