A Farewell Party for Corn Earworm Pests

By Linda McGraw
February 11, 1999

Like catnip that tantalizes cats, scents from plant flowers lure corn earworm or bollworm moths into a partying mood. The moths are attracted to their favorite foods by zeroing in on plant scents. In the South, the feast begins with corn but soon the moths move into cotton. Each year, these pests cost farmers nearly $2 billion in losses and chemical control expenses.

Now scientists are throwing a farewell party for the moths. In a field study, entomologist Juan Lopez and agricultural engineer Kenneth R. Beerwinkle at College Station, Texas, gave the insects a lethal dish that killed 730 moths in a 54-foot row of corn. Lopez and Beerwinkle work for the Agricultural Research Service, chief research agency of the U.S. Department of Agriculture.

In search of food, the insects were drawn to the artificial smell of the night-blooming Gaura plant. The moths feasted at sunset for a few hours and ate a fatal dose of carbaryl, a commonly used household insecticide. More dead moths were found on the second night after treatment.

Not all the insects that died were found intact. On the morning after treatment, the researchers found wings without bodies, which they estimated to represent another 150 moths. These insects were likely eaten by predators. The second night after treatment, the researchers found more dead moths.

Females ready to lay eggs in the silks of sweet corn or in cotton are especially attracted to the aroma. But in this study, both sexes of several insect species were attracted. Other ARS researchers at Charleston, S.C., and Ames, Iowa, have tested the attractant against melonworm, pickleworm, cabbage and soybean looper, and European corn borer.

ARS has applied for a patent on the attractant, which can be used optionally with a feeding stimulant and insecticide. The researchers are developing a cooperative research and development agreement with an industry partner to commercialize the technology.

Scientific contact: Juan D. Lopez, Jr., ARS Areawide Pest Management Research Unit, College Station, Texas, phone (409) 260-9530, fax (409) 260-9386, j-lopez@tamu.edu.