However, when environmental conditions are cool and wet, infected berries may become covered by a mass of gray or brown fungal material. This mass of fungal material gives fruit a moldy appearance. Physical damage, bruising, or wounding causes an increase in the number of fruit infections and post harvest rot. Cool, wet weather prior to and during harvest also increases the chance for rot. Spur blight on the cane.
Lesions initially appear dark purple to brown, but later turn silver to gray.
Phytophthora root rot is caused by a soilborne fungus that commonly infects the roots of red raspberries. This disease causes the leaf margin to appear yellow, wilted, or scorched. Infected canes may wilt and die rapidly or remain symptomless until the following year. Phytophthora can persist in the soil for many years and is stimulated by wet, saturated soils. Verticillium wilt is a soilborne fungus that infects the vascular tissue of raspberries.