Forest Tent Caterpillar

"Clump" of Forest Tent Caterpillars, Malacosoma disstria

Forest tent caterpillars are the most widely distributed native tent caterpillars that live throughout the United States and southern Canada. They can be found wherever hardwoods grow, especially broadleaved trees such as sugar maple, oaks, sweetgum, cottonwood, and aspen. Unlike other Malacosoma species, they do not actually construct tents, but rather silken mats on trunks and large branches. While the timing can vary depending on location, outbreaks are not uncommon. These high population periods of forest tent caterpillars can sometimes lead to mass defoliation and last an average of three years; however, unless the outbreak lasts far longer, few trees die from these outbreaks.