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Importance.
-- These leafminers occur over much of the East. They attack various
oaks, but prefer the white oak group. Heavy infestations cause browning
and premature dropping of foliage -- sometimes over large areas.
Identifying the
Insect. -- Adults and larvae of both species are similar. Young
larvae are flat and taper toward the rear, and are about .25 inch (6
mm) long at maturity. Adults are pale and silvery moths with bronze
patches on the wings.
Identifying the
Injury. -- Larvae of the solitary oak leafminer feed singly, forming
irregular, blotch-like mines just below the upper leaf surface; a single
leaf may contain several contiguous mines (figure 11). Larvae of the
gregarious oak leafminer feed together, forming large mines.
Biology.
-- The winter is spent in the larval stage in leaves on the ground.
Adult moths emerge during the spring and females lay eggs on the leaves.
There are two to several generations per year.
Control.
-- Rake fallen leaves promptly and burn them to destroy pupae in cocoons.
Natural enemies are helpful. Chemical control is occasionally needed.

Figure
11. -- Leafmines caused by the solitary oak leafminer.
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