Entomopathogenic fungi increases susceptibility to insecticides in highly resistant malaria mosquitoes .

BACKGROUND

spp. based mosquito control products are among the most investigated and could potentially serve as promising complements to chemical insecticides. However, limited knowledge exists on the implementation of this biocontrol tool in conjunction with primary insecticide-based strategies to achieve synergy.

METHODS

In laboratory bioassays, we combined 10 conidia/ml native strains with deltamethrin standard dose in three ways, before, after or simultaneously. These combinations were tested on laboratory insecticide resistant .

RESULTS

We found that and deltamethrin could be combined to achieve greater mortality against a highly insecticide resistance colony of . When mosquitoes were exposed to both simultaneously, no effect was observed, as expected for an insecticide resistant colony. However, when fungi were applied earlier than deltamethrin, mosquitoes became more sensitive to insecticide with a minimum Lethal Time to kill at least 50% of mosquito population (LT50) less than 8 days. In addition, when deltamethrin exposure was followed by infection, mosquito survival was similar to alone LT50 (LT50 ~11 days).

CONCLUSION

These findings suggest that early mosquito infection to followed by chemical insecticide exposure synergically improve mosquito control in the laboratory.