PMN Crop News Homepage   

Posted 10 April 2006. PMN Crop News.

Alternate Methods of Whitefly Control

Agricultural Research Service
United States Department of Agriculture


Having glued a whitefly to a leaf, the big-eyed bug can devour its prey.

Washington, D.C. (April 5, 2006) -
Donít bombard cotton pests with insecticide; supplementing chemical sprays with biological control methods is a better approach.

Thatís the advice of entomologists with the U.S. 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 Agricultureís 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 dollarsí worth of U.S. crops every year. ARS entomologists Steven Naranjo and James Hagler contributed to a national effort to reduce the whitefly population.

Now they advocate a combination of preventative action, biological control and selective insecticides as the most effective, environmentally-friendly response to whitefly invasions.

Entomologist James Hagler views results of an ELISA test. Bluish-colored wells indicate the presence of whitefly remains in the stomach of predator insects. ARS-USDA photos by Jack Dykinga.


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 control.

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 scientistsí 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.

Read more about the research in the April issue of Agricultural Research magazine.


Laura McGinnis
Public Affairs Specialist