My very mature 3 vines (common grape. I've called them Concord) in the back yard have been diagnosed having black rot. The most noticeable sign is spots on some of the green grapes. These turn into mummified grapes. The local agricultural agency made the diagnosis based on submitted photos. I've made wine from these in the past but now have been advised to destroy all fruit. The cure is to remove all of the fruit, clean up any fruit that has dropped & spray fungicide ( been advised to use "Mancozeb") in the spring. Wondering if anyone else has experienced this diagnosis and what their actions were and results? If I do nothing will my vines grow resistant to this fungi?
Black Rot
- Thread starter Dewbie
- Start date
Help Support Winemaking Talk - Winemaking Forum:
* native grapes are resistant to black rot. It is worse/ I can get no crop with hybrid vinifera grape genetics.
* two treatments of Mancozeb will help a lot. Ex after bud break with new shoots and at flowering. Black rot mainly attacks the new growth. You should not use Mancozeb closer than 60 days to your harvest period. It has residual toxicity.
* fungal spores are worse with high humidity. In a dry California climate less spraying is required and also not legal every two weeks. The midwest had drought conditions in May and June, I didn’t spray a lot this year. Yes diseased plant material carries the fungus. I burn canes.
* two treatments of Mancozeb will help a lot. Ex after bud break with new shoots and at flowering. Black rot mainly attacks the new growth. You should not use Mancozeb closer than 60 days to your harvest period. It has residual toxicity.
* fungal spores are worse with high humidity. In a dry California climate less spraying is required and also not legal every two weeks. The midwest had drought conditions in May and June, I didn’t spray a lot this year. Yes diseased plant material carries the fungus. I burn canes.
