German cockroaches are one of the most hated insects on earth. Nobody love roaches, especially when they are crawling around on our dishes and food, and that’s exactly where German cockroaches live, indoors in our kitchens and bathrooms. Although German cockroaches occur worldwide, they are unable to survive outdoors or in the absence of humans.
Adult German cockroaches are easy to recognize by those two dark brown stripes they have on their back, just behind the head. Although they are much smaller than some of our other roach species (about ½ inch long), they are much more important as pests. German cockroaches often occur in single-family homes, but they are an especially common problem in multi-family housing units, where frequent moving of tenants and variable sanitation practices make roach control an ongoing challenge.
Although German cockroaches have the potential to spread food born illnesses, such as Salmonella, their greatest health impact is as triggers of asthma-related health problems. Certainly, cockroaches are not the only triggers of asthma, but several studies have shown that people, especially children, living in buildings heavily infested with German cockroaches are much more likely to suffer asthma attacks. This has many negative health and economic consequences: missed days at work, missed days at school, increased hospitalizations and medical bills, missed fun and missed opportunities, and all too often, the cause of these problems goes unrecognized.
How do cockroaches trigger asthma attacks? Buildings with heavy infestations of cockroaches accumulate heavy loads of cockroach feces and broken dry body parts of dead cockroaches. Eventually, some of this feces and body parts become fine dust, which becomes airborne and is inhaled, along with other volatiles produced by cockroaches. Experienced pest control technicians can identify heavily roach-infested apartments by smell as they enter the door.
Control: German cockroach control can be challenging, especially in multi-family housing units. The key to successful control is to limit access to food and water through good sanitation practices. When used in combination with good sanitation, baits that are specifically designed to control German cockroaches are especially effective. Insecticide sprays are less effective against German cockroaches than for large roaches, such as American cockroaches, and total release aerosols or “bug bombs” are not recommended. The insecticide released by “bug bombs” is more likely to end up on surfaces that are exposed to humans than in the cracks and crevices where cockroaches hide. Often the best approach to controlling German cockroaches is to hire a professional pest control company and to assist the company by maintaining good sanitation practices.
See MSU Extension Publication 3346, Control Cockroaches in and around Your Home, for more detailed information on biology and control. See pages 5-9 for control information specifically for German cockroaches or pages 10-12 for information on how to control the larger roaches.
There is a big difference between control of German cockroaches and control of “large cockroaches,” such as American and smoky brown cockroaches. See Bug's Eye View Vol. 5, No. 25 for information on American cockroaches.
Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service.
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