Isolates of Bacillus thuringiensis from Maranhão biomes with potential insecticidal action against Aedes aegypti larvae (Diptera, Culicidae)

Abstract Entomopathogenic agents are viable and effective options due to their selective action against insects but benign effects on humans the environment. The most promising entomopathogens include subspecies of Bacillus thuringiensis (Bt), which widely used for biological control insects, including mosquito vectors human pathogens. efficacy B. toxicity has led search new potentially toxic isolates in different regions world. Therefore, soil samples from Amazon, Cerrado Caatinga biomes state Maranhão were evaluated potential larvicidal Aedes aegypti. with high larvae, as detected by bioassays, subjected histological evaluation under a light microscope identify genes responsible toxicity. Additionally, these intestinal epithelium assessed. In A. aegypti cry cyt amplified at frequencies, cry4, cyt1, cry32, cry10 cry11 being frequent (33-55%) among those investigated. These encode specific proteins dipterans may explain severe morphological changes intestine larvae caused toxins isolates.