story to find out more.
Having glued a whitefly to a leaf, the big-eyed
bug can devour its prey. Click the image for more information about
Alternate Methods of Whitefly Control
April 5, 2006
Dont bombard cotton pests with
insecticide; supplementing chemical sprays with biological control methods is a
Thats the advice of entomologists with the
Arid-Land Agricultural Research Center and the
University of Arizona. The center is a
new facility of the Agricultural Research Service (ARS), the U.S. Department of Agricultures primary
scientific research agency.
The silverleaf whitefly is a serious cotton pest. In the 1990s, at the peak
of their population explosion, whiteflies were destroying millions of
dollars worth of U.S. crops every year. ARS entomologists
Hagler contributed to a national effort to reduce the whitefly population.
Entomologist James Hagler views results of an
ELISA test. Bluish-colored wells indicate the presence of whitefly remains in
the stomach of predator insects. Click the image for more information about
Now they advocate a combination of preventative action, biological control
and selective insecticides as the most effective, environmentally-friendly
response to whitefly invasions.
Naranjo and University of Arizona researcher Peter Ellsworth analyzed the
factors contributing to whitefly mortality. They identified the most common
causes of death, including predatory insects and weather-induced dislodgment.
This led them to recommend conserving natural predators for effective whitefly
To discern which insects are natural whitefly predators, Hagler developed an
assay that tests insect gut contents for evidence of whitefly consumption.
Using this method, he and Naranjo quantified predation frequency for 18
whitefly predators, many of which had been unidentified previously.
The researchers recommend complementing biological control with commercial
insect growth regulators like buprofezin and pyriproxyfen. Their studies show
that growth regulators tend to conserve natural predators, while conventional
insecticides can be indiscriminate, eliminating predator and prey alike.
The scientists research has enabled them to make specific
recommendations for improving whitefly population management. Their work is
part of a growing knowledge base that has helped decrease insecticide use for
whitefly control by about 85 percent since 1995.
more about the research in the April issue of Agricultural Research