Eriophyid Galls

I'm an unabashed fan of willows. Of course, no tree is perfect and willows have a few pests. Thankfully, the depth of their vital spark means willows are capable of handling the depredations of most pests. However, the pests I'm highlighting can make trees look bad.

Making a correct tree identification is the critical first step in correctly diagnosing a tree problem. Of course, sometimes the diagnosis identifies the tree. Insect galls are often so host-specific, they can give you six-legs up on tree identification.

The irregular, wart‑like light green to reddish-green bladder galls now rising from the upper leaf surfaces of poison ivy are produced by the eriophyid mite, Aculops rhois (= A. toxicophagus) (family Eriophyidae).