Leafminers Several Groups

From: Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold S., Jr.; Moore, Lincoln M. 1988. A guide to insect, disease, and animal pests of poplars. Agric. Handb. 677. Washington, DC: U.S. Department of Agriculture. 118 p.

Importance- The larvae, of several species of insects make irregular serpentine or blotch mines inside the leaves. Usually they are not a threat to Populus, although they occasionally cause some early leaf fall.

Look For: Leaves with serpentine mines or blotches of brown tissue where the leaf is hollowed out. Small larvae may be in the mined areas.

Blotch miner damage Photo by Steven Katovich, USDA Forest Service

Biology- The adult female lays eggs on the leaves; the larvae then enter the leaf tissues and feed on the parenchyma. When full-grown, they pupate within the leaf or on the leaf margin

Monitoring- Check trees for blotch leaf mines. Consider treatment only when more than 80 percent of the leaves are mined. Treat the next spring to get the new-generation insects. Most serpentine leafminers attack late in the season and cause little concern, even when conspicuous.

Control: Spray trees or apply a granular systemic insecticide in spring at dosages recommended for leafmining insects.

Serpentine leaf miner.