COMPARATIVE SUSCEPTIBILITY OF PERIPLANETA AMERICANA (L) TO FIVE PYRETHROID INSECTICIDES

Five pyrethroids namely, lambda-cyhalothrin, permethrin, deltamethrin, cyfluthrin and alpha­ cypermethrin were evaluated using adult male and female cockroaches, Periplaneta americana (L). The American cockroaches were exposed for 10 minutes to glass jars treated with different concentrations of the five pyrethroids. The cockroaches were susceptible to all five pyrethroids and the susceptibility based on LC 50 and LC 90 were observed to be in the following order: lambda-cyhalothrin > permethrin > deltamethrin > cyfluthrin > alpha-cypermethrin. The results showed that lambda-cyhalothrin was the most effective and alpha-cyperme­ thrin was the least effective against Periplaneta americana (L ).