
Wandering Gypsy Moths Get Nasty
SurpriseBy Jan Suszkiw April 13, 1999
A homeowners springtime battle against gypsy moths often comes down to
placing burlap skirts around tree trunks, where young caterpillars can be
easily removed. But Geoffrey White sees room for improvement. The
Agricultural Research Serviceentomologist has found that applying a latex coating of chlorpyrifos
insecticide beneath the skirts can kill more than 60 percent of the pests. He
works at the Insect
Biocontrol Laboratory, operated in Beltsville, by ARS, the
U.S. Department of Agricultures chief
scientific agency. The burlap skirt is among the few first-line defenses available to home or
property owners against the moth, Lymantria dispar, whose caterpillars
devour the leaves of hundreds of trees species, oak being a favorite. Combining the skirts and coating exploits the pests natural tendency
to seek daytime shelter before emerging at dusk to feed high in the trees
canopy. Property owners must ambush the pests well before then. Usually,
dropping them in a bucket of soapy water or bleach does the trick. But on large
properties this can become tedious and messy. To save time and ensure fewer caterpillars escape notice, Whites
approach calls for brushing the latex coating directly onto the bark beneath
the skirts. That way, instead of refuge, the pests get a small but lethal dose
of insecticide. In a 31-day experiment conducted last summer, a single,
six-hour exposure killed 64 percent of caterpillars hiding beneath the skirts.
On untreated, skirted trees, 95 percent survived. White hopes to replicate the results this spring. If follow-up studies are
successful, he may explore substituting chlorpyrifos with a biopesticide
containing beneficial fungi that kill by growing inside the moth. A longer
story appears in Agricultural
Research magazines April issue on the web at: http://www.ars.usda.gov/is/AR/archive/apr99/gypsy0499.htm Scientific contact: Geoffrey White, ARS Insect Biocontrol Laboratory,
Beltsville, Md., phone (301) 504-5869, fax (301) 504-8190,
[email protected]. Story contacts Insect Biocontrol Laboratory Jan R Suszkiw U.S. Department of Agriculture | |