The first symptom is sunken, water-soaked spots on leaves, either yellowish or grayish in color. Spots later become covered with a downy purplish mold growth which may eventually be blackened by a second fungus. Infected leaves become covered with a grayish-white powdery fungus growth. Unopened flower buds may be white with mildew and never open. Leaves will become brown and shrivel when mildew is extensive.
Fruits ripen prematurely and have poor texture and flavor.
Wash both upper and under surfaces of the leaves. Do in early afternoon because that is when spores are most likely to be moving on air currents. Be certain to cover the tops and underside of leaves, paying special attention to the growing tips. It is best to begin applications early in the season, since sulfur is more effective at preventing disease than at curing it. If the temperature exceeds 85 o F, do not apply sulfur since it may burn the leaves.