Insecticide resistance in the houseflies of the third Yumenoshima, a new dumping-island of Tokyo (II)

Abstract

Affected by successive use of fenthion and dichlorvos houseflies inhabiting the third "Yumenoshima, " a dumping-island in Tokyo Bay have developed high multiresistance to organophosphorus compounds. In 1975-1977 maximum resistance ratios, R/S at LD50,were : fenthion, 428; dichlorvos, 79; fenitrothion, 2,224; diazinon, 1,042; malathion, 982. However, the cross-resistance to prothiophos was low with R/S 2 at LD50. The high OP pressure given in the field likely did not involve resistance to pyrethroids.