Phostrol Agricultural Fungicide (phosphorous acid), EPA#55146-83, READ THE LABEL
Phostrol provides moderate protectant, post-infection, and antisporulant control of downy mildew, with moderate risk of resistance development. Apply at 2.5 to 5 pints per acre per application. Protective activity infections against infections is limited to 3 to 5 days after application, with significant post-infection and antisporulant activity; spray intervals should not exceed 10 days during periods of wet weather. Downy mildew resistance is known to occur in many growing regions. Do not apply Phostrol in more than 2 consecutive applications before rotating with another downy mildew fungicide, and do not apply more than 4 times per season. Some varieties are susceptible to leaf burn, test for sensitivity prior to use. 4 hour reentry interval, 0 days to harvest.
2.5 gallon