Ash flower gall mite
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.
No treatments are necessary, but galls may be pruned off to improve the tree’s appearance.
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