Leaf Miner is an appellation given to a variety of flying insects that, in their larval stage, feed inside the epidermis layers of leaves and needles. The leaves display blotches and dry patches as well as irregular trails on the damaged leaf where the larva has eaten the middle of the leaf. These hollow tubes or mines caused by the larva give them the name leaf miner. As the larva grows, the mines or trails become wider. These trails and blotches differ from marks left by fungi in that the blotchy part will be hollow when pulled apart. Elms, lilac, poplars and a number of other trees and shrubs are prone to leaf miner damage.
Symptoms: Leaf damage resembling hollow trails or blotches. Eggs laid on the underside of leaves.