Maple Bladder Gall Mites

Susceptible Plants

Silver Maple, Acer saccharinum L.

Description

  • Mites are tiny creatures, about 0.2 mm long, with two pairs of legs.
  • Dispersal is mainly through wind currents.
  • Fertilized females overwinter in bark crevices of their host.
  • In spring, they move onto the new foliage and inject their saliva into the leaf tissues.
  • This stimulates the formation of a gall (growth) on the upper side of the leaf. The galls are small raised bumps on the leaves. They are often bright red.
  • The mites move into the galls and lay their eggs inside to start the next generation.

Damage:

There is little damage to the tree. Sever infestations look unsightly, and may cause the leaf to appear deformed.

Control:

Control is not usually necessary for tree health. Treatment is done for appearance. It must be done in early spring when the new leaves are emerging. Root-drench with benomyl (Benlate) to control the mite population.

Compiled by: Dr. Bill Paton and Shauna Peters