This is on one of my mother’s maples. What is it and what should she do about it?
The silver maple capitate mite ( Vasates quadripedes ) is a herbivorous mite from the family Eriophyidae . Monophage, haloformer, damages North American maples: silver maple ( Acer saccharinum ), sugar maple ( Acer saccharum ), red maple ( Acer rubrum ). Induces the formation of small capitate galls on the leaves. Comes from North America. In the 20th century, with planting material, it was brought to Europe. Recorded in 1957 in Latvia, currently widespread in Europe on silver maple ( Acer saccharinum ).
Thank you. Can anything be done about it?
Insects that form galls like this are typically only causing cosmetic damage and don’t threaten the health of the tree. I wouldn’t worry about them unless they were really out of control or you started seeing leaves dying
You may not need to, but pesticides can work. Read up.
https://hort.extension.wisc.edu/articles/maple-gall-mites-eriophyidae/
Great! Thanks so much!
Hi, arborist here. I would advise against using pesticides to control this issue. The galls are completely harmless to the tree and the pesticides may cause harm both to you if you were accidentally exposed, and definitely to other invertebrates, many of which may be beneficial. Some may even help control the mites in future years.
Thanks. I think what my mother will do is just pick off the affected leaves that are really bad and leave the rest.
Great, that’s basically what I’d recommend. Disposing of any leaves you pull off the tree and those on the ground away from the tree should help reduce the intensity of the issue.
