Ash flower gall mite, Michigan trees, shrubs

Integrated pest management resources for Michigan

IPM Scouting in Woody Landscape Plants

Christmas trees
Field crops
Fruit
Home and yard
Nursery and landscape
Turfgrass
Vegetable

Diagnostic Services
Soil/Plant Nutrient Lab
Enviro-weather
Regional IPM Center
Pesticide safety
Organic: New Ag Network
Invasive species
Sustainable ag & food systems

MSU ANR departments
MSU Extension

Site index
Contacts/permissions

Ash flower gall mite - Eriophyes fraxiniflora

This cigar-shaped mite is one of a group of eriophyid mites that cause galls to form on plants. It affects only male ash trees, causing a proliferation of flower buds to form, which results in unattractive galls. Although the galls are unsightly, they aren’t harmful to the tree since they only affect the flowers. Galls start out green, then turn brown to black and persist over the winter. The size of the mite is less than 0.5 mm.

Management: No treatments are necessary, but galls may be pruned off to improve the tree’s appearance.

Ash flower gall affects only male flowers.

Additional information

MSU Diagnostic Services for assistance in pest identification.
MSU Landscape Alert newsletters for information about the current growing season, pest concerns and plant advice.

This information was developed from A Pocket IPM Scouting Guide for Woody Landscape Plants by Diane Brown-Rytlewski. Purchase this in a pocket-sized guide for reference in the orchard from MSU Extension (publication E-2839).

The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the Michigan Agricultural Experiment Station, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.
Email the web developer.

Updated 7/05/07