Leafminers form tunnels by burrowing in the leaf between the epidermal layers consuming the green tissue as they go. Irregular grayish-green tracks remain in the leaves. In severe cases, the leaves may cease to function and abscise. The adult insect is a small, yellow-bodied fly about 1/8 inch in length. The larvae are small (about 1/8 inch long) white maggots.
Consult the Vegetable IPM Web Site for recommended controls of this pest.