The maple bladdergall mite is a tiny mite that feeds on the underside of leaves. The mites overwinter in cracks and under bark scales and begin feeding in spring. Infested leaves initially develop small depressions which soon grow into brilliant red galls 1/8" to 1/4" in length. Later in the season, the galls may turn green or black. Mite activity typically stops by around July. Silver and red maples are particularly susceptible to bladdergall mites. Severe infestations may cause leaves to become somewhat distorted. Although an aesthetic concern, bladdergalls are seldom harmful to the trees.

Management Options

Non-Chemical Management

Hand-pick severely infested or distorted leaves to improve appearance of small trees.

Select non-chemical management options as your first choice!

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

None recommended.

Images

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Caption: Maple bladder gall mite Photo by: A.L. Antonelli

WSU Extension

Hortsense