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Bitter rot - Greeneria uvicola
Annemiek Schilder, MSU Plant Pathology
Home > Scouting guide> bitter rot
Bitter rot is common in southeastern growing regions. It 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 82º to 86ºF (28º 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 one-year-old canes.
Bitter rot Bitter rot
Fruiting bodies.
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Funding for this web site provided by Project GREEEN, American Farmland Trust, EPA Region 5's Strategic Agricultural Initiative program, The National Foundation for IPM Education, the Center for Agricultural Partnerships and the MSU Integrated Pest Management Program in collaboration with MSU Extension and the Michigan Agricultural Experiment Station. Partially support from NC-IPM Center.

05/24/11 Contact: E. Haney
     
Michigan Agricultural Experiment Station Michigan State University Extension