Resistance of the Bulb Mite, Rhizoglyphus robini CLAPARÉDE (Acarina: Acaridae), to Insecticides

I. Resistance Patterns to Organophosphorus Insecticides

Abstract

Toxicity of 41 organophosphorus insecticides to adult females of the bulb mite was examined by using the filter paper method. Field-collected strains showed a high level of resistance to a wide range of organophosphorus insecticides, especially to aromatic phosphorothionate, aliphatic phosphorothiolothionate, phosphoramidothiolate, aliphatic derivatives of phosphate, phosphonate and phosphorothiolate. However, the resistance ratio to heterocyclic phosphorothionate, aromatic phosphonothionate, phosphorothiolothionate and phosphate forming an ester bond with aliphatic thioalcohol substituted with the heterocyclic compound and enol, S-propyl phosphorothiolothionate and phosphorothiolate was less than five times as that of the susceptible strain. These strains also showed similar resistance patterns to various organophosphates. These results indicate that there is a cross-resistance to organophosphates, and suggest that major resistance factors are involved in organophosphate resistance in the bulb mite.