Mano76answered grow question 4 years ago Just got the same problem, and another grower helped me out. White Powdery Mildew, also known as White Powdery Mold or just “WPM” to cannabis growers.
Solution spray with :
Milk (1:9 ratio of milk to water)
Baking soda (2 tablespoons per gallon of water)
Neem Oil (4 teaspoons per gallon of water)
Hydrogen Peroxide (1 teaspoon of 35% H202 per gallon of water)
SM-90 (1:5 ratio of SM-90 to water