Evaluation of the susceptibility of An. gambiae s.l. to deltamethrin, chlorfenapyr and clothianidin in four agricultural areas of Benin

Abstract

This study evaluates the susceptibility of vectors to deltamethrin, chlorfenapyr (CFP) and clothianidin (CTD) in different agro-ecological zones of the country. Populations of An. gambiae s.l. derived from larvae collected between April and September 2022 in 04 cropping zones: vegetable, cereal, rice and cotton were exposed to deltamethrin, chlorfenapyr and clothianidin. Biochemical and target-modification resistance mechanisms were detected in a sample of each mosquito population. All populations of An. gambiae s.l. tested with deltamethrin showed mortality that varied between 9 and 60%. Overall, the mean frequency of the kdr L1014F mutation across all localities was 86% followed by overproduction of detoxification enzymes. As for the new insecticides, the mortality rate was 98%-100% for the CFP and for the CTD regardless of the locality and the agro-ecological zone tested. Chlorfenapyr and clothianidin are viable alternatives that could be used for improved control of pyrethroid-resistant populations of An gambiae s.l.