Boxwood Leafminer

This is the most serious insect pest of boxwoods. The leafminer is the larva of a very small fly. Adults emerge in April and lay eggs on new leaves for a day or so and then die. The eggs hatch in about three weeks and the small larvae feed inside the leaves throughout the summer and early fall. The insects overwinter as pupae within the leaves and emerge the following year as adults. Symptoms are not very obvious at first, but eventually yellow "puckered" areas develop on the leaves. Infected leaves may drop early.

Control: Light infestations can be pruned out and destroyed. Contact insecticides are available for controlling adults in mid-April to May. Systemic insecticides are available for controlling larvae inside the leaves.