Diseased Northern Spys
Hi. Is this last year’s fruit? This kind of damage indicates the plum curculio or possibly the apple curculio. It is a type of weevil. If you are a homeowner the best treatment is to make sure all the fruit is removed after it falls to the ground. Pick it up and destroy it since part of this insect’s life cycle happens in the soft fruit under the tree. It is very difficult for homeowners to use chemicals to treat this pest, timing is critical. If you grow apples commercially you can get in touch with a fruit extension agent through your extension office. There are a few charts of spray schedules for homeowners available on the web but be sure to use information published by universities. Always read and follow labels and instructions carefully.
What, then, do we do? Is there a way to treat the weevils?
Hi. When I did a search to try and find some helpful info for you there were 2 articles on the web targeted for homeowners. If you search for ‘plum circulio’ choose and read the ones published by Missouri Botanical Garden and the University of MN. Hopefully you will find them helpful.