Abstract
Seven colonies of Aedes albopictus larvae collected on 7 islands (Okinawajima, Agunijima, Miyakojima, Ishigakijima, Iriomotejima, Yonagunijima and Minamidaitojima) in Okinawa Prefecture in 1988 were tested for susceptibility levels to 11 insecticides. The (LC)_<50> values of these colonies were 0.057-0.855ppm to p, p'-DDT, 0.046-0.211ppm to malathion, 0.0035-0.0319ppm to fenitrothion, 0.029-0.044ppm to dichlorvos, 0.232-0.516ppm to trichlorfon, 0.163ppm to diazinon, 0.0055ppm to fenthion, 0.011ppm to temefos, 0.019-0.036ppm to bromofos, 2.563-4.922ppm to propoxur and 0.0039-0.0092ppm to permethrin. (LC)_<50>tto p, p'-DDT against the larvae in Iriomotejima was the highest value in Japan, being 50.6 times the lowest value (0.017ppm) obtained in Nagasaki, 1960 (Suzuki and Mizutani, 1962). Against fenitrothion, larvae in Minamidaitojima, Ishigakijima and Miyakojima showed 0.0319,0.0236 and 0.0220ppm respectively in (LC)_<50> value. In general, Ae. albopictus in Okinawa Prefecture was susceptible to all insecticides tested except p, p'-DDT.
