If wet humid conditions persist, a light gray, powdery mold develops on blighted tissue. In the second stage, conidia are produced on leaves and stems and blown onto flowers. Bees then transfer conidia to healthy flowers. If humidity remains high, germination will occur. The fungus grows through the style into the ovary of the developing berry.
Infected berries turn white or salmon in color as other berries ripen.
They shrivel, harden and fall to the ground prematurely. By spring they are pumpkin-shaped and a dark brown. Several cultural practices reduce the severity of this disease. Raking mummified berries just before bud break destroys ascospores as they are being produced. Covering the mummified berries with two inches of mulch before bud break will prevent light from reaching them and stop the formation of ascospores.