Control Powdery mildew is a fungal disease that affects plant leaves, pods, and stems. This problem looks alot like whitish spots that spread. They eventually look like white splotches with black speckles. This disease can reduce the yield of your prize plants.
Mildew likes warm days, cool nights, and lots of humidity or rainfall.
Infected seeds will look slightly hairy, kind of like a furry brown patch or something on it. It also overwinters on plant debris. Avoid planting in heavy shade. Deep and infrequent is best and water in the mornings. Fall crops seem to be more susceptible.