Ash Flower Gall Mites infest ash trees. Eriophyid mites are less than 1 mm long, have eight legs, and vary from yellowish to greenish to orangish to reddish to red. Each species causes a characteristic gall.
Under favorable conditions, these mites can develop from egg to adult in 10 to 14 days; therefore, many generations may occur throughout the growing season.
Ash flower gall mites feed in male flower clusters. Infested clusters become irregularly branched and fringed. They initially are green, and turn black as they dry. The clusters persist until the following spring. This damage is unsightly but does not affect tree vigor.