lambda-Cyhalothrin resistance detection in the German cockroach (Blattodea: Blattellidae)

lambda-Cyhalothrin resistance levels of 13 recently collected field strains of German cockroach, Blattella germanica (L.), were determined by topical insecticide bioassay. The resistance levels ranged from 21- to 67-fold. Res idual bioassays were conducted simultaneously against the Orlando insectici de-susceptible strain, the HRDC strain (carbamate resistant), the Village G reen strain (pyrethroid resistant), and the Marietta strain (pyrethroid, ca rbamate, and organophosphorus resistant) to determine a diagnostic concentr ation for use in resistance detection bioassays. The LC99 of the Orlando su sceptible strain (0.9 mu g per jar) and 5 times the Orlando LC99 (4.5 mu g per jar) were chosen for use in lambda-cyhalothrin resistance detection bio assays. A highly significant relationship was observed between mortality at 5 times the LC99 of Orlando (4.5 mu g per jar) and resistance ratio (LD50 in topical bioassays). The relevance of this relationship to lambda-cyhalot hrin resistance detection is discussed.