Posted on Sat, May. 10, 2008

Tent caterpillars worst since 2001

SO FAR, NO FOAL DEATHS FROM MRLS

By Janet Patton

JPATTON1@HERALD-LEADER.COM

Eastern tent caterpillars, which have been linked to mare reproductive loss syndrome, covered a a fence post outside of Paris. Photo by David Stephenson | Staff

Eastern tent caterpillars are at the highest levels seen in the Bluegrass since 2001 but there have been no reports of foal deaths linked to the caterpillars, as there were that year.

The University of Kentucky College of Agriculture has issued an alert that caterpillars are on the move and warns farms to keep pregnant mares out of fields bordered by cherry trees or other potential hosts for the next several weeks.

In 2001, Kentucky was hit by waves of foal losses. Hundreds of foals were born dead or dying, and thousands of mares aborted in the early stages of pregnancies. About 30 percent of the state's Thoroughbred crop from 2001-02 was lost, and all breeds suffered an estimated $336 million in economic damage.

The mysterious epidemic of what came to be known as mare reproductive loss syndrome has been strongly tied, through UK research, to massive infestations of eastern tent caterpillars. Scientists found that mares could inadvertently ingest the hairy caterpillars; the hairs can cause tiny punctures in the digestive tract that let in bacteria that compromise the foals.

UK's Livestock Disease and Diagnostic Lab has not seen any MRLS cases this year.

But in a news release, UK entomology professor Dan Potter said, "The eastern tent caterpillar populations are dramatically up this year -- the highest I've seen since the MRLS crisis."

Barry Robinette, farm manager of Glennwood Farm in Versailles and president of the Kentucky Thoroughbred Farm Managers Club, said his group sent an e-mail warning to members Thursday.

"I don't think it's as bad as '01 and '02, but it's also a little later in the year," he said Friday. "It's certainly a rise in what we've seen in the last few years. I think it's a concern, so right now is the time to treat them."

He recommends injecting trees with an insecticide, but that can be more expensive than general spraying.

Because of the cool spring, the caterpillars are a few weeks behind in hatching, so many mares have safely foaled. But, Robinette said, farms also have a lot of mares who are in critical early months of gestation. After 2001, many horse farms removed black cherry trees from pastures and fence rows.

UK entomologist Lee Townsend said this year's infestation is spotty. "Where we're seeing them is in highway right-of-ways and where cherry trees are left intact," Townsend said.