March 19, 2003

Horse farm managers trying to reduce potential problems from eastern tent caterpillars (ETC) this spring likely will get help from nature.

Entomologists with the University of Kentucky College of Agriculture have been carefully examining wild cherry trees, the caterpillar’s favorite host.  Signs so far indicate significantly fewer numbers of ETC for 2003 than in recent outbreak years.

“Relatively small numbers of fresh egg masses can be found at most sites checked in central Kentucky,” said Lee Townsend, UK Extension entomologist.  “As you would expect, there is some site-to site variation, but all still remain in the ‘low’ category.”

Presence of eastern tent caterpillars has been strongly associated with Mare Reproductive Loss Syndrome.  The insect gets its name from the silken nests, or “tents,” it builds in the crotches of trees. 

It appears that tents this year will likely be few and scattered.

There is no preventative control of eastern tent caterpillar prior to egg hatch.  However, foliar sprays and injected insecticides may be applied after hatch is complete and small tents are visible in trees.

“Careful watching and directed spot sprays can be used to control the caterpillars in cases where mares will be pastured near cherry trees,” Townsend said.

The start of egg hatch for ETC generally coincides with 50 percent forsythia bloom.  However, the first signs of egg hatch this year were observed in central Kentucky March 17. 

“Don’t spray or inject until small tents are seen,” he said.

Information on eastern tent caterpillar can be found on the UK Department of Entomology’s web, or the Department of Veterinary Science’s MRLS web page at:


Lee Townsend, 859-257-7455