EFFECTS OF AZADIRACHTIN ON DIFFERENT STRAINS OF GERMAN-COCKROACH (DICTYOPTERA, BLATTELLIDAE)

Technical grade azadirachtin (11.46% [AI]) was tested for its toxicity to insecticide-resistant and -susceptible strains of German cockroach , Blattella germanica (L.), by injection and diet incorporation. The e ffect of azadirachitn was dose dependent. The LC(50) and LC(90) for 3 strains ranged between 2.49 and 2.56 mu g per insect and 6.49 and 6.92 mu g per insect, respectively. Incorporation of Azadirachtin in food pellets resulted in LT(50)s of 22, 23, d for D for Dursban-R, CSMA, an d Baygon-R strains, respectively. No significant differences were obse rved in toxicity of Azadirachtin to either insecticide-resistant or su sceptible strains. The body weight of German cockroaches varied with t ime depending upon the dose administered. The roaches injected with 2 and 3 mu g of Azadirachtin showed a continuous weight reduction. The t oxicity of Azadirachtin to German cockroaches may be associated with a n altered feeding behavior and a disruption of endocrinal events.