Also called inchworms for their looping motion, these 1 inch long pests are found in all but the southernmost parts of the country. Spring cankerworm moths show up in spring, fall cankerworm moths in autumn when weather turns cold. The caterpillars of both types feed in spring, moving from tree to tree on silken strands. Spring canker-worms are green, brown, or black with colored stripes, while the fall type is brown on top and green below, with three slender white stripes.