Knowledgebase
Bugs attacking ash leaves #757210
Asked June 19, 2021, 3:45 PM EDT
Chittenden County Vermont
Expert Response
On Jun 21, 2021, at 10:31 AM, Ask Extension <<personal data hidden>> wrote:
Hello Ty,
Our Extension Entomologist writes the following:
This is called an ash bead gall. It is produced by Aceria fraxini, a tiny gall mite. It injects a growth hormone into the leaf cells while feeding which stimulates the leaf to produce these galls within which the mites live protected from predators. It is largely a cosmetic issue and does not have a major impact on the health of the tree.
Here is a website:
http://minnesotaseasons.com/Arachnids/ash bead gall mite.html
Thanks for using the Master Gardener site.
Kathy