Horticulture : News
DATE: April 05, 2010
HARDIN COUNTY COOPERATIVE EXTENSION SERVICE
201 Peterson Drive
Elizabethtown, Kentucky 42701-9370
BY: Amy Aldenderfer
County Extension Agent for Horticulture
Tent Caterpillar Hatch
Eastern tent caterpillar egg hatch has started in Kentucky!
Questions about how soon egg hatch will be completed and when tent caterpillars will begin to feed will soon be answered by Kentucky's spring weather.
"When temperatures are in the upper 70s most of the eggs hatch in eight to ten days, however, highs in the 50s can spread hatch out over a month," said Lee Townsend, Extension entomologist in the University of Kentucky, College of Agriculture. "These caterpillars are basically inactive below 50 degrees so it's easy to see how great an effect temperature has on them."
The tent caterpillar, which gets its name from the silken tent it constructs in tree branches, prefers wild cherry but also feeds on peach, apple, crabapple and other trees.
This insect, which is common throughout the eastern United States, is a nuisance but poses no
health threat to humans.
Because the eastern tent caterpillar has been identified as one of the risk factors associated with Mare Reproductive Loss Syndrome, UK scientists are intensely monitoring its activity. As part of a comprehensive UK program this spring scientists also are watching other factors, including pasture
conditions and weather patterns.
A patient approach will allow any early natural control, such as heavy rains or freezes, to have an effect, and we need to keep in mind that treating too early can mean that additional applications may be needed. Spraying will be most effective when the nests are established and the caterpillars are actively feeding. Waiting until the nests are about the size of a baseball or softball should be about ideal.
Natural enemies play an important role in reducing eastern tent caterpillar numbers in most years. Caterpillars are frequently parasitized by various tiny braconid, ichneumonid, and chalcid wasps. Several predators and a few diseases also help to regulate their populations. This, in part, accounts for the fluctuating population levels from year to year.
Prevention and early control is important. Removal and destruction of the egg masses from ornamentals and fruit trees during winter greatly reduces the problem next spring. In the early spring, small tents can be removed and destroyed by hand. Larger tents may be pruned out and destroyed or removed by winding the nest upon the end of a stick. Burning the tents out with a torch is not recommended since this can easily damage the tree.
Young caterpillars can be killed by applying an insecticide containing Bacillus thuringiensis var kurstaki. Other insecticides include carbaryl, and methoxychlor. Larvae within the tents are protected beneath the webbing and are more difficult to kill with an insecticide.
Hardin County Extension Office (765-4121) www.hardinext.org is an excellent source of information on insect pest management, as well as the UK entomology department's web site at www.uky.edu/Agriculture/Entomology/enthp.htm.
NOTE: The nest session of the Gardeners’ Toolbox Series 2010 is “Gardening for the Butterflies”. Tuesday, April 27, 6:00 pm, Cost $5.00. Learn to build a garden around the “Flying Flowers of Nature”. Garden Design, host and nectar plants and garden accessories will be shown and given as door prizes. You must register and pay by the deadline, April 20, 2010. Class will be held at the Hardin County Extension Office, 201 Peterson Drive. Elizabethtown, KY 42701 270-765-4121
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