Corn blotch leafminer larvae tunnel within corn leaves, consuming all the green tissue between the upper and lower leaf surface. Mines widen as the larva grows, resulting in a broad blotch in the last third to half of the mine.

June 15, 2006

Corn blotch leafminers in central Nebraska

There are several generations per year in Nebraska, but typically the first generation on corn does the most injury. Field reports indicate that the first generation larvae are actively feeding, and tunneling can be observed. The corn blotch leafminer will be active the rest of the summer. As corn matures the leaves thicken and the maggot tunnels in only the lower or upper half of the leaf, causing less damage. Also, on larger plants the injury is spread out over a greater total leaf area.

Foliar insecticides are not recommended for these insects. The adult flies emerge over several weeks and would be difficult to economically control with insecticides. The egg and immature stages are inside the leaf and protected from insecticides.

Bob Wright
Extension Entomologist

Copyright 2006 by the University of Nebraska Board of Regents. All rights reserved.

Published by University of Nebraska-Lincoln Extension in the Institute of Agriculture and Natural Resources Cooperating with the counties and the U.S. Department of Agriculture.

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