Cause Alternaria spp., a fungus. This disease has caused severe losses in some Oregon and Washington fields, although it is not as common as ripe rot. The fungus overwinters as mycelium and spores in old, dried-up berries, dead twigs from the previous season's crop and on other plant debris. Infections can occur any time between late bloom through fruit maturity. Infections remain quiescent (latent) until fruit ripens.
