Tree Fruit Disease - Alternaria Rot

Alternaria rot, Alternaria alternata, is a common fungus found on stone and pome fruit. The disease can occur during preharvest and postharvest.
Tree Fruit Disease - Alternaria Rot - Articles


Photo by K. Peter.


Alternaria rot is characterized by circular, dry, firm, shallow lesions covered with dark, olive green to black surface mycleial growth. The infected tissue is brown, like that caused by brown rot. The disease typically develops near insect feeding injuries, when fruit is overripe, in split pits of fruit, around skin breaks, or at the calyx or stem insertion.

Disease management

Preventing skin injury is key to managing this disease. The strobilurin class of fungicides (FRAC Group Code 11) are most effective for managing Alternaria rot on both pome and stone fruit. Captan and EBDCs are ineffective.