The last stage larva appears a couple of days later, and skeletonizes foliage for about a week. The pupal stage lasts 1-2 weeks. A second generation occurs in late summer and fall. Winter coccons are often heavily parasitized. Larvae are preyed upon by spiders.
Young larvae create narrow winding mines.
Larger larvae skeletonize foliage. The second generation can cause heavy injuyry in outbreak conditions. White, ribbed cocoons may be conspicuous in the winter. Because of the sporadic nature of this pest, neither formal sampling procedures nor thresholds have been established.