Population densities of cockroaches from human dwellings in urban areas in the Republic of Korea.

Studies on the population and infestation rates of domestic cockroaches were conducted from September 1999 to October 2000 in 154 residences in 21 districts (dong) in Busan and 170 residences in 12 districts in Seoul, Republic of Korea, using sticky traps. Blattella germanica, Periplaneta americana and Periplaneta fuliginosa were collected from three different types of houses, apartments, single dwelling houses and multi-union houses (villa). B. germanica was the dominant species collected from all residences. P. fuliginosa was collected more frequently (0.2 and 0.7/trap) than P. americana (0.1 and 0.2/trap) in Busan and Seoul, respectively. Population indices for B. germanica in Busan were nearly twice as high (mean 6.4/trap) when compared to Seoul (mean 3.6/trap). Mean numbers of B. germanica (6.4/trap), P. americana (0.1/trap) and P. fuliginosa (0.2/trap) in Busan were not significantly different among the three residential types sampled. In Seoul, mean numbers of P. americana (0.2/trap) and P. fuliginosa (0.7/trap) were not significantly different among the residential types whereas B. germanica (3.6/trap) indices were significantly greater for houses (11.4/trap) than for apartments (2.0/trap). Except for single dwelling houses in Seoul, seasonal mean indices for B. germanica were not significantly different for these cities. Residential infestation rates of P. americana (8.2% and 0.6%) and P. fuliginosa (13.7% and 2.8%) were very low compared to the infestation rates of B. germanica (56.9% and 76.2%) throughout the study period in Busan and Seoul, respectively. Houses were most commonly infested with B. germanica (72.9% in Busan and 93.8% in Seoul), followed by apartments (54.2% in Busan and 68.3% in Seoul) and villas (43.6% in Busan and avg. 66.4% in Seoul). The infestation rates of the cockroaches were related to the residential types (P < 0.05).