As the infection progresses, the leaves curl up and expose the powdery fungus. Eventually, leaves fall from plants, exposing developing fruit to direct sunlight. Sunburned fruit can be a secondary problem. The disease problem also is likely to be more devastating earlier in the growing season when favorable conditions occur. A few good thunderstorms, and the disease begins to appear.
Powdery mildew is very difficult to manage once infection is noticeable.
Protective fungicide sprays with sulfur can be effective, Goldberg said. Unfortunately, conditions in New Mexico make practical use of this material difficult. Sulfur can cause damage to the plants if temperatures rise above 90 degrees in the three days following application. In addition to proper timing of sulfur applications, thorough coverage is vital for successful treatment. In chile, the fungus first attacks the underside of the older leaves, then spreads throughout the plant.