Maple Gall Mite

Vasates quadripedes

Ronald S. Kelley, Vermont Department of Forests, Parks and Recreation

Maple Gall Mites are tiny cousins of spiders which make galls on maple leaves. These galls are sometimes called "bladder galls."

The bladder galls are green at first, turning red and then black. Sometimes there are so many galls on one leaf that nearly the entire surface is covered.

 

Canadian Forest Service

Canadian Forest Service

Bladder galls form when adult mites start feeding in early Spring. The mites munch on newly-forming leaves, and as the leaves grow, leaf tissue grows out and forms a gall around each mite. The gall help protects mites from predators.

Once a leaf is full size, each mite lays eggs and dies. Eggs hatch quickly, with hundreds of tiny nymphs inside each bladder gall. Nymphs are carrot-shaped and worm-like. They are whitish-orange with two pairs of legs.

Once the nymphs have grown into adults, they leave their gall and crawl to new leaves. The cycle continues until late Summer when the tree stops new leaf growth for the year. These parasites cause very little damage to the tree.

Adult mites overwinter beneath bark on the host tree.

Canadian Forest Service

Minnesota Department of Natural Resources Archives

Predators of Maple Gall Mites include insects, such as Green Lacewings and Ladybugs.

Maple Gall Mites live on all maple trees, including Red Maple, Silver Maple, and Sugar Maple.

The picture to the right is a drawing of a cross-section of a bladder gall. It shows how the leaf tissue will grow around the mite, closing it inside. As the mite eats and grows, the gall grows too. Galls are hollow inside.

British Plant Gall Society

Relationships in Nature:

FOOD
PREDATORS
SHELTER
OTHER

Red Maple

Green Lacewing

Red Maple

Red Maple H

Silver Maple

Convergent Ladybug Beetle

Silver Maple

Silver Maple H

Sugar Maple

Sugar Maple

Sugar Maple H

Relationship to Humans:

Maple Gall Mites do not harm people or our trees. Some people do not like the way galls look on their trees, so they spray to get rid of bladder galls.

SCIENTIFIC CLASSIFICATION

KINGDOM
Animal
PHYLUM
Arthropod
CLASS
Arachnid
ORDER
Trombidiformes
FAMILY
Eriophyidae
GENUS
Vasates
SPECIES
Vasates quadripedes

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