Cankerworms pose a threat to broad leaf trees. Early detection and control measures are necessary for proper control. Other species also are present, but are similar in biology, appearance and control. Cankerworms, in the family Geometridae, often are called inchworms or measuring worms after their walking habit. They move by forming a loop with the central part of the body and then extending the front to straighten out.
Adults are drab grey and green mottled moths.
The males are fragile with a wingspread of approximately 1 inch. Females are wingless, which means they can migrate only by walking. The females lay eggs in the spring or fall, giving them their common names. They crawl from the ground up tree trunks to lay eggs on the branches. Larvae or caterpillars of both species hatch from egg masses in the spring when trees are just reaching budbreak and new foliage is expanding.