by Larry Williams, UF/IFAS Extension Agent
When people first see the Asian cockroach, they may think they are seeing little flying
moths. Or they may believe they are seeing the German cockroach, because the two species look similar. Both German and Asian cockroach adults are about 5/8-inch long and are brown with two darker parallel bands running lengthwise just behind their head. But unlike German cockroaches, Asian cockroaches are strong fliers with sustained flights of at least 120 feet. As a person hand-waters a mulched plant bed, the roaches quickly fly out of the mulch, resembling little moths. German cockroaches prefer to live indoors and are major household pests as a result. Asian cockroaches prefer to live outside in shaded mulched beds, compost piles and in lawns. Their populations are high, with 30,000 to 250,000 thousand roaches per acre reported.
Asian cockroaches become active at night and are attracted to lights. They often fly inside through any opening in a house, such as a lighted doorway or window. Once inside, they fly to and crawl on illuminated television or computer screens and on walls while lights are on during the evening. This is when many people believe they are seeing a German cockroach invasion. But German cockroaches do not fly.
Most people become upset when they see Asian roaches inside their home. But indoor infestations are rare occurrences, as this roach species requires more humid outdoor conditions to survive and breed. Once indoors, they usually die within hours.
Even though they are susceptible to insecticides, Asian cockroaches are difficult to control because of their abundant population and ability to fly great distances. Because they can fly 120 feet or more in a single flight, large areas around a home require treatment. And roaches in nearby, untreated areas may result in re-infestation. Residual sprays around the perimeter of structures are usually unsuccessful because of numerous infested areas in adjacent lawns, mulched and wooded areas. Adults that enter homes immediately fly to walls, avoiding baseboards and other typical areas that are normally treated for German cockroaches. Best control has been attained by using insecticide baits (labeled for roach control) in infested areas outdoors.
Additional information is available at the University of Florida’s institute of Food and Agricultural Science Extension Office in Crestview, or at http://edis.ifas.ufl.edu/in277.