Knowledgebase
Apple Trease Disease White Powdery leaves #868538
Asked May 15, 2024, 12:34 PM EDT
I have three apple trees that have diseases. From Left to right they are Red Delicious, Yellow Delicious and Red rome. The leaves have a white powdered appearance and are curling. I sprayed the trees once a week ago with Captain Jacks Fruit Tree Spray (70% Neem Oil, and 30% other ingredients. Could you please tell me how to treat the problem seen on the photos I sent. Could you also outline a seasonal spray plan.
Muskegon County Michigan
Expert Response
Hi Daniel,
Yes, this is powdery mildew. While the neem product is listed as effective against fungal diseases, there are more effective controls for this disease. I would recommend a sulphur based fungicide for this disease. Here's an article with more in depth information on this issue:
https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/ApplePowderyMildew.aspx.
It is most important to note that it will continue to reinfect all available tissue throughout this season and future seasons if it is not treated thoroughly.
I can't really recommend a specific spray plan. It depends upon your specific conditions and pest pressures. However, I have a couple resources to share. One is on apple pest management and the other is on general fruit production.
https://ulster.cce.cornell.edu/resources/apple-ipm-for-beginners
https://ecommons.cornell.edu/items/ce4a3ab3-a2cb-4787-a21d-190d6e6bfbf5
Best wishes,
