Musky Lure Proves Fatal Attraction for Major Corn PestBy
Manna from heaven it wasn't. But the powder drifting down from the
sky--as part of a research study--was an appetizing surprise to
western corn rootworm beetles. They immediately switched to it from
the corn leaves they'd been munching. Then they died.
The "manna" was powdered roots of wild buffalo gourds. It
was sprayed from crop-dusting airplanes on thousands of acres across
the Corn Belt this summer. Cucurbitacins in the gourd roots--compounds
partly responsible for the musky smell of cantaloupes--stimulated the
beetles to feed on the powder. Unfortunately for them, it was laced
with a tiny dose of insecticide.
This summer's spraying marked the first year in a large-scale,
five-year test of this alternative to conventional insecticide use
against the rootworms. The new technique uses up to 98 percent less
carbaryl insecticide than conventional applications. Most of the 20
million acres of U.S. cropland threatened by the corn rootworm is
treated with much higher doses of insecticide.
Scientists with the Agricultural
Research Service say the new approach lowered beetle numbers.
Some fields had to be re-sprayed with the powder because of heavy
infestations--up to 30 adult beetles per plant.
The true test will come next spring, when offspring of this year's
adult beetles start hatching, according to entomologist Larry
Chandler. He's at ARS' Northern
Grain Insects Research Laboratory, Brookings, S.D.
Chandler is technical coordinator of the five-year corn rootworm
areawide management program. The program, funded by the
U.S. Department of Agriculture and
several universities, supports USDA's goal of having farmers use
integrated pest management (IPM) on 75 percent of the nation's
cropland by 2000. IPM combines many control strategies--including
nature-based tactics such as gourd root powder--instead of relying on
An article on the rootworm program appears in the October issue of
ARS' Agricultural Research magazine. The article also is on
the World Wide Web at:
Scientific contact: Laurence D. Chandler, ARS
Northern Grain Insects
Research Laboratory, Brookings, S.D., phone (605) 693-5239, fax