Natural Enemies of Russian Wheat Aphid Established in 6
States By Hank
May 17, 2000
Ten years after scientists released millions of exotic wasp
parasites in small grain fields in eastern Colorado to control the Russian
wheat aphid, they've found that four wasp species have become established in
Since invading the United States in 1986, the green,
1/16-inch-long aphids have caused more than $1 billion in insecticide costs and
related losses. Conventional breeding has produced aphid-resistant wheat
varieties. But these varieties aren't yet available to producers.
In 1988, to screen natural controls for the Russian wheat aphid,
Agricultural Research Service scientists
worked with a consortium of federal and state scientists to release 11 species
of wasps. These imported, exotic enemies of the pest were released in the wheat
and barley growing areas of the western United States. The 11.8 million
parasitic wasps released represented more than 80 geographic strains collected
from 25 different Eurasian countries where the aphid originated.
From 1991 through 1993, ARS scientist John D. Burd at the
Plant Sciences and Water
Conservation Research Laboratory in Stillwater, Okla., working with USDA's
Animal and Plant Health Inspection
Service, the Colorado State
Agricultural Experiment Station and the
Colorado Department of Agriculture
conducted an intensive biological control release program. Its purpose: to
establish natural enemies of the aphid in small grains in eastern Colorado.
Burd's group released seven wasp species into Russian wheat aphid
infested wheat fields.
Now, seven years later, Burd reports that four of the seven wasp
species have become established throughout a six-state area--Colorado, Kansas,
Montana, Nebraska, Oklahoma and Wyoming. Three species were found parasitizing
greenbugs, an aphid relative, on sorghum. Two species successfully parasitized
the Russian wheat aphid on wild grasses that aphids used as host plants over
It's important to establish natural enemies as part of integrated
pest management systems because they do not cost anything, are highly
compatible with plant resistance, and can contribute considerably to the
overall reduction in the reliance on insecticides to control aphid cereal
ARS is the chief research arm of the
U.S. Department of Agriculture.
Scientific contact: John D. Burd, ARS
Plant Sciences and Water
Conservation Research Laboratory, Stillwater, Okla., phone (405) 624-4141,
ext. 223, fax (405) 624-4142, email@example.com.