Alabama’s Newest Invader: The Asian Cockroach

The rogue’s gallery of invasive species just got larger. Along with German cockroaches, dog and cat fleas, red imported fire ants and Formosan termites, Alabamians must now contend with Asian cockroaches.

At first glance, the roaches look a lot like German cockroaches. However, unlike German cockroaches, Asian cockroaches fly off and hide when approached. Raefield Vestor, a trained entomologist and retired Houston County Extension agent, first noticed the cockroaches at a Dothan church. Vestor sent samples to Auburn entomology professors Drs. Arthur Appel and Xing Ping Hu.

After closely scrutinizing the samples, the two entomologists’ worst fears were confirmed: The cockroaches weren’t German at all but their highly mobile Asian cousins. Follow-up visits to the region confirmed yet another fear: The cockroaches already are well-established in the Dothan area in parks and homes. They have also been spotted as far north as Abbeville.

Native to Japan, the Asian cockroach was first discovered in Florida in 1985. It is believed they were introduced to the United States via the Port of Tampa several years earlier.

“Since then, they’ve spread steadily into virtually every county in Florida and northward to Georgia and South Carolina,” says Hu, an Alabama Cooperative Extension System entomologist and Auburn University assistant professor of entomology.

Populations of about 250,000 per acre are common about five years after establishment in an area.

Even though the cockroaches bear a striking resemblance to their German counterparts, they exhibit several notable behavioral differences.

“German cockroaches are active only at night and run and hide when exposed to light, preferring crawling to flying,” Hu says. “They are also predominantly indoor pests.”

Asian cockroaches, on the other hand, become most active at dusk and for a few hours thereafter, though they also can be active and take flight during the day, if disturbed.

Asian cockroaches are strong fliers and can travel for distances of up to 150 feet. Their activity at dusk and beyond is typically very frenzied, Hu says.

“That’s the big difference,” Hu says. “German cockroaches are rarely seen, but because of their frenetic behavior, Asian cockroaches are seen all the time.”

They’re also more versatile than German cockroaches, able to survive in both indoor and outdoor habitats.

In wild habitats and areas around the home, they prefer to infest shaded and moist areas as well as grassy areas and groundcovers, Hu says. Lights and other bright surfaces within homes act like beacons for the pests.

“People mistakenly believe the cockroaches are attacking them,” she says. “But the cockroaches are merely following people from room to room as they flip on light switches.”

Once inside, they’ll crawl or rest on illuminated TV and computer screens or any other light-colored surface.

The new arrivals, Hu fears, likely will create all sorts of economic and health problems for Alabamians.

Like their German counterparts, Asian cockroaches carry pathogenic organisms and are a major source of allergens, including the ones that cause allergic asthma common in children.

“Their ability to reproduce coupled with their mobility and adaptability to a variety of habitats virtually ensure these pathogens will be spread by the cockroaches whenever they enter a home,” Hu says.

Unfortunately, she says, the cockroach’s unique biology and mobility will render control efforts difficult. Due to the pest’s close resemblance to German cockroaches, hybrids not only will be hard to identity but much more resistant to control efforts.

To minimize problems associated with Asian cockroaches, Hu recommends cleaning up litter and other debris around the home --- natural habitats for roaches. Also make sure to seal door and window screens tightly, and make sure they are in good order.

Replace white porch lights with yellow lights; Asian cockroaches can’t see yellow.

If necessary, control outdoor infestations by using a solid or gel cockroach bait such as Combat, Maxfore granular, Niban or by spraying with a general use insecticide, Hu says.

[Source: Dr. Xing Ping Hu, Alabama Cooperative Extension System Entomologist and Auburn University Assistant Professor of Entomology and Plant Pathology, (334) 844-6392.]

Posted by Jim Langcuster at October 1, 2004 04:22 PM | TrackBack