May 3, 2002 | By: Haven Miller

As University of Kentucky scientists continue their examination of the possible association between eastern tent caterpillar (ETC) and Mare Reproductive Loss Syndrome, the insect continues to generate curiosity.

"People in Kentucky are interested in this hairy caterpillar because they have seen so many of them in both rural and urban areas the past few years, but the eastern tent caterpillar is not unique to this state," said Lee Townsend, UK Extension entomologist. "True to its name, this native species known as Malacosoma americanum is found throughout the eastern half of the United States."

Townsend said eastern tent caterpillars are active as far south as northern Florida, and as far north as southern Canada. They are found in the first tier of states west of the Mississippi River and extend into New England. Heavy populations can be expected this year in other states.

"Numbers of these insects fluctuate from year to year, with larger outbreaks happening on roughly 10 year cycles," Townsend said.

Eastern tent caterpillars have been observed in the U.S. since colonial times. After spending much of their life in and around their silken tents, ETC larvae begin to leave the nest in search of a protected area to spin a cocoon. The adult moth will emerge from the cocoon about three weeks later.

"ETC moths are reddish brown with pale stripes on their wings, but since they fly at night few people see them," Townsend said. "After mating, females will lay eggs on small branches of wild cherry and related trees, and the following spring the eggs will begin to hatch and the cycle begins again."

Natural enemies, such as certain kinds of wasps, play an important role in reducing ETC numbers in most years. Recommendations on chemical and mechanical controls can be found at