Loathed by homeowner and restaurateur, the lowly cockroach is gaining some respect in the agricultural community.Researchers in South Texas are beginning to sing the praises of a flying cockroach from Asia that has shown a voracious appetite for pests that plague farmers. They concede, however, that most people would still be revolted at the sight of the helpful predator. "It just brings out this visceral reaction in people," said Bob Pfannenstiel, an entomologist with the U.S. Department of Agriculture (web|news) . "There's too much cultural antipathy just because of the other cockroaches."

The other cockroaches include the German variety, a common breed that doesn't fly and is often seen scattering from countertops when kitchen lights are flicked on.



The Asian cockroach, Blattella asahinai, is almost identical in appearance to the German variety and is also active at night. But instead of leftover pizza, it feasts on insects harmful to crops.

They first appeared in Florida in 1986, and the species has expanded its range ever since. They've migrated to southern Georgia, Alabama and up the East Coast.

They ventured west into Texas in 2006, and became the most common predator of bollworm eggs in the state's Rio Grande Valley region. The bollworm threatens cotton, soybean, corn and tomato crops.

Pfannenstiel has counted as many as 100 roaches per square meter in soybean fields. In one instance, he found 14 cockroaches on a single leaf. None damaged the plants.

About 86 percent of the pests' eggs — which Pfannenstiel and colleagues placed out in fields to conduct research — were gone within 24 hours.

"I saw them feeding more than any other predator," Pfannenstiel said. "It was truly a spectacle. It was unbelievable, and I'm sure they were feeding on more than eggs."

The cockroach also eats the eggs of the beet armyworm — a pest to cotton, cabbage and a variety of other crops.

South Texas cotton producer Jimmy Dodson said he's thankful the Asian cockroach is helping reduce pests in the region's cotton fields.

"The enemy of my enemy is a friend," said Dodson, whose family farms 9,000 acres of cotton. "When you have an ally in (reducing pests) you're not going to run them off. We need all the help we can get."

Scientists have studied predator insects in agriculture for years but not much research has been done at night. Pfannenstiel, who researches beneficial insects, plans a long-term study to determine whether the cockroach remains a predator all its life.

"Without studying what goes on at night, we would never have observed some of our most important predators in cotton and soybeans," he said. "It's interesting that the cockroach could be a benefit to farmers."

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On the Net:

South Texas Cotton and Grain Association, http://www.stcga.org

Agricultural Research Service, http://www.ars.usda.gov/main/main.htm

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