Destructive Moths

California Oak Moth - photo by Donald Hobern
California Oak Moth – photo by Donald Hobern

The damage caused by destructive moths to the leaves of trees can be tremendous.

The California Oak Moth is primarily found in Coastal regions of our beautiful state. The moths are a tan brown color, and can be regularly seen in the afternoon which is a prime feeding time for these parasites. Oak Moths primary goal is to find mates, and lay eggs to repopulate for the future population of caterpillars. The moths themselves is not what causes the initial damage, it is the existence of the caterpillars that descend on the leaves.

The larvae feed on the leaves of oak between veins on the lower leaf surface. Although the upper leaf surface is left intact, it dries out and turns brown. Some chew completely through the leaf blade, often leaving only major leaf veins. Small frass pellets drop from the canopy as larvae feed. In outbreak years, individual trees or groups of trees may be almost entirely defoliated, typically by late summer or early fall.