maple bladdergall mite

Maple bladdergal mite is about 1 ⁄500″ to 1 ⁄125″ long and invisible to the naked eye. It is most easily identified by the shape of the gall it produces and the plant species on which it is found. This mite is found exclusively on silver maple, red maple, and sugar maple.

The pouch-type galls first appear on the upper side of a leaf in late spring. They are solitary, though there are usually many galls on a single leaf. They are hollow and globe-shaped with a hairy opening on the underside of the leaf. They vary in size but may be up to 1 ⁄10″ in height. They are green when they first appear, turning pinkish or red, and then finally black. The galls are unsightly but the tree is otherwise undamaged.

Microscopic, about 1 ⁄125″

Maple bladdergal mite is the only mite that causes bladder galls on these host species. It is not found on other plant species.

Silver maple, red maple, and sugar maple

Several generations each year. The first galls develop late spring.

The adult overwinters in a crevice of the trunk or a branch. As leaf buds begin to swell in the spring the female emerges and begins feeding on a leaf bud. This causes the leaf to produce excess cells that rises above the leaf surface like a blister. The female then enters the hollow gall and deposits eggs. When the eggs hatch the young feed on the interior of the gall. In the summer the gall dries out. In fall the gall opens on the underside of the leaf. The adult emerges and searches for a site to overwinter.

Unsightly but not harmful to humans or host trees

Sources

Order
The family Eriophyidae was formerly classified within the order Trombidiformes, specifically in the suborder Prostigmata. However, molecular phylogenetic analyses, beginning in the early 2010s, have strongly challenged this placement. Current research indicates that Eriophyidae represents a very ancient and basal lineage within the order Acariformes. While Acariformes was historically treated as a superorder by some classifications, it is now widely recognized as one of the two major orders of mites (along with Parasitiformes). Due to ongoing debates about their precise relationships with other mite groups, Eriophyidae is currently placed directly under Acariformes without being assigned to a specific suborder.

Leaf with bladder galls

Bladder galls

Bladdergall Mite (Eriophyidae) Damage to Maple Leaf
Carl Barrentine

Maple Gall Bladder and Mulberries
shootsandvines