Pest description and crop damage Adults of this insect are tiny moths. Early instar larvae are flat. The larvae produce blotched mines, which may be more visible on one side of the leaf. Miners spin silk across the leaf surface, which dries and shrinks to create a ridge over the mine. The larvae feed initially on sap, then feed inside the leaves on tissue during summer. There may be more than one generation per year.
Aspen and cottonwood are very susceptible. Plant resistant trees where serious problems exist. Remove affected leaves as they are seen.