Grape – Black Rot Disease
Q: What’s wring with my grapes? This is the second year in a row. They get about 1/4 inch in diameter, turn black and fall off.
A: Your grapes have a disease called black rot. Its first symptom is small yellow spots on the leaves. The spots shed spores which infect the fruit. Unfortunately, the fruit doesn’t show much damage until it is half mature…too late to prevent further damage.
You can slow the spread of the disease by destroying all infected fruit as they are seen. Rake fallen leaves in the fall and remove them from your property.
To really have a chance at harvesting grapes, though, you’ll need to begin an insect and disease spray program.
Black Rot on Grapes
Predicting Black Rot
Fruit – 2020 Homeowner Spray Guide
Black rot on bunch grapes