News and Reviews
USDA Bulletins on Biological Control
The USDA has produced several brochures on the biological control of specific pests.
Each of the three 12-page, half size publications summarized below describes the scope of the
pest problem, the biological control agents that have been utilized, how the USDA has been
involved in the project, and how you can help.
Biological Control of the Alfalfa Weevil, USDA-APHIS Program Aid No. 1321.
The alfalfa weevil is the most serious pest of the nation's leading crop for hay. In it's
native Europe several parasitic wasps hold it in check. From 1911 to 1953 limited numbers of
European parasites were introduced into the western United States, and in 1959 larger quantities
of wasps were imported into the East. An intensive program of survey, release, and evaluation
was conducted from 1980-1991 to help distribute the wasps to everywhere alfalfa is planted.
Today many growers do not need to apply insecticides for alfalfa weevil control because of
successful biological control.
Biological Control of Leafy Spurge, USDA-APHIS Program Aid No. 1435.
Leafy spurge is an aggressive perennial weed that displaces desirable native vegetation, is
avoided by cattle and horses because of irritating chemicals, and is difficult to control by
conventional means. The USDA coordinates a major biological control program that involves
importing and distributing the weed's natural enemies. Some of the beneficial insects being
utilized are a stem- and root-boring beetle, root-mining flea beetles, and a shoot-tip gall midge.
Numerous natural enemies were evaluated in test plots in Europe and in quarantine stations in the
US before six highly selective species were released in North America. Ranchers and land
managers need to be patient because it will take several years for the natural enemies to build up
to sufficient numbers at any specific location to provide benefit.
Biological Control of Euonymus Scale, USDA-APHIS Program Aid No. 1508.
Several types of ornamental Euonymus plants are susceptible to damage by the euonymus
scale, an insect pest that tends to be more severe in warmer climates. Both the pest and the
natural enemies imported to control it are from Asia. A species of lady beetle from Korea,
Chilocorus kuwanae, has been very effective in reducing or even
eliminating heavy scale populations in many locations. Other predators and parasitic wasps are
also being evaluated for introduction as part of a nationwide USDA biological control project.
These publications are available from the USDA and can be ordered through The NBCI Store.
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