Safe Corn Pest Bait Expected to Slash U.S.
By Don Comis
January 16, 1997
The U.S. Department of Agriculture and
the Corn Belt states have targeted three regions for area-wide testing of a new
low-insecticide bait for corn rootworms, made from wild buffalo gourd roots.
Robert Faust of USDAs Agricultural
Research Service said the regions chosen are: Indiana-Illinois,
Iowa-Minnesota-South Dakota, and Kansas-Nebraska. If the bait--which is
commercially available--works in these states and expands to the entire Corn
Belt, it could reduce total corn pesticide use by half, Faust noted.
This test is part of an area-wide IPM (integrated pest management)
research program to support the departments goal of placing IPM on 75
percent of the nations cropland by 2000, Faust said. Mobile
pests such as the corn rootworm beetles dont respect farm fences let
alone county or state borders, making IPM most effective when applied over
Faust said this is USDAs second area-wide IPM project and the first to
target corn pests. In 1995, we began a program in the Pacific Northwest
to reduce numbers of codling moths, as a pest of apple and pear orchards,
Typical of IPM programs, the corn rootworm bait is only used when pests
reach a level at which they can significantly harm a farmer economically,
tentatively set at one female beetle per plant, said Faust. Based in
Beltsville, Md., he is ARS national program leader for field and horticultural
Corn rootworms have a fatal attraction to wild buffalo gourd roots, he said.
The roots are ground to a powder and laced with a low dose of carbaryl at
a rate equal to an ounce per acre. Thats 95 to 98 percent less than
active ingredients used in conventional insecticide sprays, he noted.
The bait is sprayed on corn leaves which the adult rootworm beetles eat.
Five years of field tests in the Corn Belt have proven the bait's
effectiveness, Faust said.
Corn rootworms are the target of almost half the insecticides used in row
crops in this country, requiring more insecticide than any other pest.
"About 25 million acres of corn are treated each year," Faust said.
"In some years, corn rootworms can cost farmers up to $1 billion in crop
losses and spraying expenses."
Richard Dunkle, co-chair of the corn rootworm area-wide management ad hoc
committee along with ARS entomologist Larry Chandler, said the areawide IPM
concept is that the new pest control technology that has been developed
will work best if all farmers in a given area use it. We will also target other
corn pests in these sites with similarly sound environmentally methods.
Dunkle is acting deputy administrator of ARS.
Since farmers can't tell how many larvae are in the soil, they apply soil
insecticides as a preventative measure. More than half of these treatments are
probably not needed, said Chandler.
Chandler is a research leader with ARS at Brookings, S.D., where the bait
was developed in 1989 by another ARS entomologist, Gerald Sutter. He has
further developed and tested the bait over the past two years. Buffalo gourd
roots contain bitter cucurbitacins that are unappealing to any insect except
rootworm beetles, making it safe for ladybugs, bees and other beneficial
Chandler said that in a South Dakota field test, the bait reduced beetle
numbers so low that soil insecticide was not needed in 1994. The
baits 'as needed' use combined with the low dose of carbaryl promise to
cut total corn insecticide use in half.
Scientific contact: Robert Faust,
National Program Staff,
Crop Production, Product Value and Safety, Agricultural Research Service, USDA,
Beltsville, MD 20705. Telephone: (301) 504-6918; fax (301) 504-6231; e-mail: email@example.com or Larry Chandler,
Northern Grain Insects Research
Laboratory, Agricultural Research Service, USDA, Brookings, SD 57006-9401.
Telephone: (605) 693-5239; fax (605) 693-5240; e-mail: