Anthracnose on the leaves and cane. Small, brown spots develop on the leaves, while gray, oval spots with dark margins develop on the cane. Fungal and Bacterial Diseases Anthracnose is frequently observed on the canes of black raspberry and susceptible cultivars of red raspberry. In late spring, red-purple oval lesions appear on the primocanes. The center of these lesions later turns pale brown to ash gray, while the margins become raised and purple.
Lesions usually girdle the cane causing it to die, dry, and crack.
Infected primocanes that survive winter usually produce irregular, lateral branching and irregular fruit. Surviving canes may also suffer tip dieback. Spores produced on infected canes during wet periods in the spring initiate new infections. Anthracnose also infects the leaves, flowers, and fruit. Small, purple-brown spots typically develop on infected leaves.