The locust leafminer is a destructive pest of black locust and honey
locust in both the adult and larval stages. It is found throughout the
range of these trees in the eastern half of North America. The adults
also feed on other species of trees.
The adult beetles overwinter in crevices in the bark of trees and under
litter on the forest floor. The beetles emerge and begin feeding in the
spring, usually after mid-April. After feeding for a short time they
deposit eggs on the undersides of leaves, piling them one upon another,
somewhat shingle-like. Eggs are covered with brownish fecal matter.
Larvae soon hatch and eat into the leaf tissue to form a mine. Newly
emerged larvae feed gregariously in a single mine for a short time. They
then construct new mines where the insects live singly. Several mines
are constructed before the larvae reach maturity. The larvae pupate in
the mines and emerge as adults in July to begin the second generation.
The adult beetles are foliage feeders, eating irregular holes in leaves.
When sufficient in number they may defoliate host trees.
[Illustration: Damage to black locust caused by the locust leaf
miner.]
Under forested conditions no control is recommended. Rarely do trees die
from attacks by this insect. Damage is objectionable mostly from an
aesthetic viewpoint.