Insecticide resistance in the currant-lettuce aphid, Nasonovia ribisnigri (Hemiptera : Aphididae) in the UK

Bioassay data for a reference strain of Nasonovia ribisnigri (Mosely), exhi biting similar responses to proven susceptible strains of Myzus persicae (S ulzer) and Aphis gossypii Glover, were used to assess insecticide resistanc e in two suspected resistant strains and nine field strains of N, ribisnigr i originating from lettuce in the UK. Results showed widespread but varied levels of resistance to pirimicarb, lower and also varied resistance to pyr ethroids and organophosphates, and no significant differences in response t o imidacloprid, In some strains, resistance was associated with an intensel y-staining esterase band disclosed by polyacrylamide gel electrophoresis (P AGE). However, no direct relationship between esterases and resistance has yet been established. There was no biochemical evidence of an altered acety lcholinesterase contributing to pirimicarb resistance in these strains.