The toxicity of formetanate and chlorphenamidine to resistant fruit tree red spider mite,Panonychus ulmi(Koch)

摘要

AbstractFormetanate was found to be somewhat less effective on three strains ofPanonychus ulmi(Koch) resistant to organophosphorus compounds (O.P.'s), and on two others multi‐resistant to O.P.'s and tetradifon, than on susceptible mites; the LC50's in tests on larvae or adult mites were two to three times greater. Chlorphenamidine was as effective on O.P.‐resistant mites as on susceptibles; but on the multi‐resistant strains it was more effective, the ratio of LC50's, R/S, in assays on larvae being ×0.37. However, it has not been shown that resistance to tetradifon confers true (pleiotropic) negative cross‐resistance to chlorphe