This looper is common in sugarbushes, but outbreaks are rare. Extensive maple defoliation occurred in Quebec during the early 1940s and 1950s and again in the 1960s. Damage was negligible.

The female moth has only rudimentary wings and cannot fly. It is 0.4 to 0.5 inch (10 to 12 mm) long and light gray with two distinct rows of black spots along the back. The light brown male has a wingspan of 1.4 to 1.8 inches (35 to 45 mm) long and has a rusty brown head and bright yellow underside (Fig. 48). The black usually is marked with 10 black wavy lines. Color intensity can vary to the point where some individuals appear uniformly yellow.