My grapes are being infected by a disease or insects what can I do to prevent...

Asked July 13, 2015, 8:01 PM EDT

My grapes are being infected by a disease or insects what can I do to prevent this from happening again? Please see attached picture

Rockingham County New Hampshire trees and shrubs viticulture horticulture

1 Response

It's difficult to tell if the disease is only affecting the fruit or if it is in the leaves as well One common problem that looks like this is Elsinoe ampelina, or Grape Black Spot. This is a fungal disease. To treat, remove vine canes or shoots that have small amounts of black spot on them. Vines that are heavy infected should be sprayed with copper or Mancozeb at bud burst and 10-14 days later. A follow up application 14 days later may be needed if the weather is cool and damp. Conditions have been excellent this year for all kinds of fungal problems. I would take a sample to your local Extension office for confirmation of this diagnosis.