Different species of leafminers feed upon different plants. Leafminers may be either a wasp, fly, moth or beetle species.
Adult leafminers are often confused with shore flies. However, leafminer adults are often brightly colored.. Adult leafminers puncture holes in the leaves as they lay eggs. Look for white specks from these egg laying punctures in the photo. As the larvae feed, winding (serpentine) mines develop. Leafminer larvae are protected as they feed between the upper and lower leaves making control difficult. In this photo a mine was opened up to expose the burrowing larva. If only a few plants are affected, remove infested plants. Once larvae are inside the mines, insecticides with systemic or slightly systemic (translaminar) activity work best.
For more information on management see: New England Greenhouse Pest Management Guide
