Control of mosquito vectors of tropical infectious diseases: (1) bioefficacy of mosquito coils containing several pyrethroids and a synergist.

ABSTRACT

The bioefficacy of mosquito coils containing several pyrethroids were tested in a 25 m3 room against Culex pipiens quinquefasciatus, Aedes aegypti and Anopheles dirus. The test results were compared with tests against Culex pipiens pallens in Japan. Based on the KT50 values (the 50% knockdown time) of mosquito coils containing dl, d-T80-allethrin, d, d-T-prallethrin and methoxymethyl-tetrafluorobenzyl tetramethyl-cyclopropanecarboxylate (K-3050) at doses of 0.05-0.5% (w/w) with or without a synergist, the pyrethroid susceptibility of the four mosquito species was as follows Cx. p. quinquefasciatus was several times more tolerant to pyrethroids than Cx. p. pallens, Ae. aegypti was a further several times more tolerant than Cx. p. quinquefasciatus, and An. dirus was more susceptible than Cx. p. pallens (KT50 value about half of Cx. p. pallens). The order of their susceptibilities is common for pyrethroids. Mosquito coils containing d, d-T-prallethrin and K-3050 at doses of 0.05-0.2% (w/w) and N-(2-ethylhexyl)bicycle-[2,2,1]-hept-5-ene-2,3-dicarboxyimide as a synergist at a ratio of 2 times the active ingredient were highly effective against Ae. aegypti, the most important mosquito vector for dengue fever.