Grape vine disease - Ask Extension
Hello my grapes this year got some type of disease. There was like a white fuzzy think layer of mold maybe? They turned purple and then brown and wilt...
Knowledgebase
Grape vine disease #876611
Asked July 10, 2024, 8:35 AM EDT
Hello my grapes this year got some type of disease. There was like a white fuzzy think layer of mold maybe? They turned purple and then brown and wilted. How do I treat this so I don’t have the same problem next year.
Dakota County Minnesota
Expert Response
This likely is due to powdery mildew, which is the fuzzy layer you describe. As the infection progresses, browning and wilting can occur. Improve air circulation and sunlight exposure through proper pruning and training of vines. You might also consider a preventive fungicide in the spring. Here is an article about this condition: https://ohioline.osu.edu/factsheet/plpath-fru-37
What is the best treatment for powder mildew? I read through the article and looked up bulletin 708 but I still feel a little confused. Is there anything on the organic side to use? I did cut all the fruit off this year but we do eat and use these for cooking so I’m hoping to find something to use that is safe.
Thank you
Brooke
Sulfur is an organic option. It is commonly used for powdery mildew on grapes, and can be effective when applied early in the season.Here is an article from Michigan State University about using fungicides on grapes - https://www.canr.msu.edu/news/protecting_young_grape_clusters_from_powdery_and_downy_mildew
