Most controls are directed towards trapping the wingless females or spraying the active larvae after they start feeding on the tree leaves. Trapped females may remain attractive to the males which also get stuck in the sticky band. Be sure to thoroughly wet the trunk bark if spring cankerworms are present. Reduce the oil rate, especially on maples, if the trees seem to be active in the spring. Wait until all the eggs have hatched but spray before the larvae get to be over inch long.
Most common insecticides are effective for control of cankerworms and loopers.
Best results are obtained if the spray is applied after all the eggs have hatched and the larvae are still small. See Bulletin 504 for currently registered insecticides. Disclaimer - This publication may contain pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used.