UK Research Leads to New and Safer Eastern Tent Caterpillar Insecticide

LEXINGTON, Ky. (April 7, 2006) Experts predict that Eastern Tent Caterpillars will begin showing up in greater numbers around central Kentucky during the next few weeks, making this an especially important time for area horse farms to be implementing control strategies. One such strategy might be a product just released on the market.
 
Based on data from a 2004 University of Kentucky College of Agriculture study on managing Eastern Tent Caterpillars to prevent Mare Reproductive Loss Syndrome (MRLS), the J.J. Mauget Company, which manufactures injectable formulations of insecticides, fungicides, fertilizers and antibiotics for tree care, has released a new formulation of a compound called abamectin. The product, Abacide 2 (2 percent abamectin in 4-milliliter capsules) showed 100 percent control of Eastern Tent Caterpillars in trials done by UK researchers.
 
Abamectin is the first effective non-spray caterpillar insecticide on the market where the active ingredient has low toxicity to people and livestock. It is in the same insecticide class of anti-parasite medication already in use on pets and livestock. Farm managers can inject the product directly into the tree, eliminating the logistical problems of spraying and containing any resulting drift.
 
According to Daniel Potter, professor of entomology in the UK College of Agriculture, this new formulation shows good promise as a long term control strategy for Eastern Tent Caterpillars. He does caution, however, that the UK study was limited to one year and one site and recommends that farms start with a few trees in lower priority areas to see if this approach works well for them.
 
One of the product’s biggest strengths is its ease of application. “It’s neat and clean,” explained Potter. “You’re essentially giving an IV to the tree. Once you gain experience injecting the capsules, you can finish a tree in five minutes. And because Abacide 2 is not classified as a restricted use pesticide, farm mangers can apply it themselves. Ask for the 4 milliliter capsules, though, as lower dosages may not be as effective.”
 
“This research provides a new and effective option for farm managers concerned with controlling Eastern Tent Caterpillars. We expect it to be highly beneficial for horse farms,” said Nancy Cox, UK College of Agriculture Associate Dean for Research. “Dr. Potter has worked closely with professional arborists and Mauget, not only to test efficacy, but also to assure approval and labeling of the new compound.”
 
The research resulting in this new product was funded by the Grayson Jockey Club Research Foundation with the support of the Kentucky Thoroughbred Association /Kentucky Thoroughbred Owners and Breeders Association. Consulting arborist Larry Hanks also donated time and equipment to assist with the study.
 
Controlling Eastern Tent Caterpillars is important to area horse farms, as UK research has strongly linked the caterpillars with outbreaks of MRLS, which can cause late-term abortions, early-term fetal losses and weak foals. During the 2001-2002 season, when MRLS hit central Kentucky particularly hard, an estimated 30 percent of the 2002 Thoroughbred foal crop was lost and the state suffered an economic cost of approximately $336 million due to losses suffered by all horse breeds.
 
With three cases of MRLS now suspected in Florida, area farms may be wondering about caterpillar levels in central Kentucky this season.
 
“Our collective sense is that Eastern Tent Caterpillar populations are well below the densities seen from 2000 to 2003, but there are nonetheless some farms and areas of central Kentucky with fairly high localized infestations,” said Potter. “The Eastern Tent Caterpillars have hatched but are still small.
 
“While I imagine most of the local horse farms already have a control plan in place for this year, they might want to experiment with this new option themselves this year and use that information to plan ahead for 2007 and beyond,” he continued.
 
He recommends that each farm scout for the telltale white tents, which will start showing up in cherry and crabapple trees in the next few weeks, and err on the side of caution by keeping mares away from any caterpillar locations.

 
Writer: Holly Wiemers, 859-257-4883, holly.wiemers@uky.edu
Contact: Dr. Lee Townsend, 859-257-7455, ltownsen@uky.edu