Studies on Bacillus thuringiensis H‐14 strains isolated in Egypt. VII. Toxicity to insecticide resistant and susceptible strains of mosquitoes

Two strains of Bacillus thuringiensis H-14 (M1 and S128) isolated in Egypt were bioassayed in the laboratory against various insecticide-susceptible and -resistant mosquito species and strains. The results for both bacterial strains tested against Aedes (4 strains), Culex (4 strains), and Anopheles (7 strains) larvae indicate a wide spectrum of larvicidal activity within the Culicidae. Generally, fourth instar larvae of the Aedes and Culex strains were found to be more susceptible than third instar larvae of Anopheles strains. In addition, mosquito strains within the same species that have different geographical origins and/or resistance patterns to residual insecticides were found to have different susceptibilites to the tested preparations. No apparent relationship was found between resistance to insecticides in these mosquito strains and their susceptibility to the tested preparations of B. thuringiensis H-14. These data indicate that B. thuringiensis H-14 could be of potential use against insecticide-resistant vector populations in integrated disease-control programs. © 1994 by John Wiley & Sons, Inc..