There are both Fall and Spring Cankerworms, which are often called inchworms or loopers. Cankerworms are easily identified because they only have feet at their front and rear, and they move by moving their rear portion forward in an arching motion. The cankerworms eat tree leaves for about five weeks, during the summer. Repeated defoliation on a mature tree severely weakens the tree to the point it may die or it becomes more susceptible to another fatal disease.
At the first sign of cankerworms, spray the tree with Garden Insect Spray with Spinosad or Bug Buster Pyrethrin Insect Spray, and repeat the spray every two to three weeks until the feeding period has ended. In the fall, remove any visible egg nests or spray them with Horticultural Oil Insect Spray. In the spring place a sticky TreeHelp Bug Bandon the trunk of the tree to prevent the cankerworm from migrating from the ground up towards the tree’s leaves.
In the early spring, treat trees that are too tall to spray with Once-A-Year Insecticidal Drench w/Merit, to provide insect protection throughout the growing season.