Pest and Beneficials Search (search again)

Bitter rot

Greeneria uvicola

Bitter rot gives the berries a bitter taste that is detectable in wine. After flowering, the fungus infects the berry stem and remains latent until the berry is mature. Then the fungus rapidly invades the berry and sporulates in concentric circles, darkening and roughening the surface. Within a couple of days, the berries soften and easily detach. Berries that do not fall off shrivel up, similar to black rot-infected berries. The optimum temperature for infection is 82 to 86ºF (28 to 30ºC), but infection can occur at temperatures as low as 54ºF (12ºC). Fruit injury by insects, birds or cracking can cause bitter rot to spread rapidly throughout the cluster. The fungus invades wounds and overwinters in plant debris and bark of 1-year-old canes.


Bitter rot is common in southeastern growing regions.

Pest and Beneficials Search (search again)

The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.