Bug FAQMaple Spindle Gall Mite
Vasates aceriscrumena · Order: Trombidiformes · Family: Eriophyidae
The maple spindle gall mite is microscopic and lives on maple leaves, making long, narrow galls that you can see the mite inside of. It spends winter under loose bark or near wounds, then in spring feeds on leaf buds to start gall formation, and new adults leave the galls in late June to mid-July. The mite is mainly found in the eastern United States and does not cause serious damage to the trees.
Source: Wikipedia
How to recognize it
Its galls are elongated rather than round, and the mite can be seen through the gall.
Source: Wikipedia
Size
The mite is microscopic.
Source: Wikipedia
Is it a pest in the house?
They do not cause major damage to maple trees and rarely distort the leaves.
Source: Wikipedia
Where it lives
It lives on maple trees, feeding on the leaves.
Source: Wikipedia
What it eats
In winter the mites live free-living under loosened bark and around wounds. In early spring they feed on leaf buds, which triggers gall formation.
Source: Wikipedia
Life cycle
Wintering occurs under bark or near wounds, then galls form in spring, and mature mites emerge from the galls from late June to mid-July.
Source: Wikipedia
When you see it
Gall induction happens in early spring, and after the galls dry the adults look for overwintering sites.
Source: Wikipedia
Where it comes from
It is primarily distributed across the eastern United States.
Source: Wikipedia
Lookalikes
Unlike the maple bladder-gall mite, its galls are not rounded but elongated.
Source: Wikipedia
Where it is found in the US
Recorded in 27 of 51 states and DC. Most records: Ohio, Pennsylvania, New York, Michigan, Indiana, Minnesota, Massachusetts, Vermont.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
How can I tell this mite apart from the maple bladder-gall mite?
The spindle gall mite makes long, narrow galls that you can see the mite inside, while the bladder-gall mite produces round galls.
Source: Wikipedia
Same family (Eriophyidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Vasates_aceriscrumena
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.