Trish Hanson , Vermont Department of Forests, Parks and Recreation, Forest Biology Lab, Waterbury, Waterbury, VT E. Bradford Walker , Vermont Department of Forests, Parks and Recreation, Forest Biology Lab, Waterbury, VT a. Larva, pupa and adult stages of the Locust leafminer b. Adult Locust leafminers skeletonize leaves before seeking overwintering sites. Black locust is preferred, but apple, birch, beech, cherry, elm, hawthorn, and oak may also be attacked. Larval feeding results in blotch mines which eventually coalesce, causing leaves to turn brown. There are two generations per year.
Winter is spent as an adult in leaf litter under host trees or in bark crevices.
As new leaves develop, adults emerge and lay eggs in small clusters on the undersurfaces. Newly-hatched larvae form a common mine at first, but later separate and each larva mines several leaflets before pupating inside the last mine. Most trees can survive continued infestations with only minor setbacks. However reduced aesthetic values is a problem. Parasites and predators can cause significant reductions in leafminer populations .