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Grape black rot

Grape black rot is caused by a fungus in hot, humid summers.

recognize Grape black rot
Grape black rot, photo: Daniel Molitor - CC BY 2.0 de

Grape black rot (Guignardia bidwellii) is caused in hot, humid summers by a fungus. The fungus first affects the leaves of grapes (black edges, brown spots on the leaves), then the entire plant can be affected, including the ripening grapes.
The fungus survives via spores on dried and affected grapes, branches and leaves. Rain in spring disperses the spores, moist warm weather (15 – 32°C) activates them.

Where to find

Control

Difficult to control; once grapes are affected, recovery is not possible.

Prevention

Remove affected grapes, leaves and branches because spores of the fungus survive on them.