University of Maryland Extension

Leafminers - Trees and Shrubs

Leafminer damage

Leafminers feed on leaf tissue between the upper and lower surfaces of a leaf. They may be the immature stages of moths (caterpillars), beetles, flies, or sawflies. Most cause little damage. Several are pests of shade trees. These include the holly leafminers, locust leafminer, birch leaf- miner, and oak blotch leafminer.

Birch leafminer is a primarily a pest of gray and river birch. This pest is a sawfly. The feeding activity of the larvae results in irregular, brownish, blotch mines. These mines may coalesce in heavy infestations, causing leaves and entire trees to turn brown by late spring. The best control is prevention. Try to plant or replace susceptible birches with resistant species. If the infestation must be controlled, use a foliar absorbed insecticide to kill larvae in newly developing mines.
Oak blotch leafminer (native moth) attacks scrub, post, black, red and white oaks. The larvae (caterpillars) feed just below the upper surface of the leaf, causing irregular brown blotch mines. This is a minor pest and control is usually unnecessary.

birch leafminer damage on leaves

birch leafminer adult

Birch leafminer damageBirch leafminer adult
larval stage of birch leafmineroakblotch leaminer
Close-up of birch leafminer larvaOak blotch leafminer damage
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