For many decades, Botswana has been engaged in various malaria control activities that involved programmes that focused on the elimination of the malaria vector Anopheles arabiensis, by using DDT and pyrethroids. Despite the numerous and continuous application of these insecticides, studies have shown that there is susceptibility of this vector to DDT and pyrethroids in Botswana. Natural insecticides such as Bacillus thuringiensis and Spinosad, as alternatives to the use of chemicals, have shown to be effective against the eggs and larvae of DBM. Insect-resistant crop varieties were also found as alternatives in order to minimise insecticide resistance through the application of insecticides on insect infesting crops. The appearance of esterases B1 and A2–B2 in the Gaborone and Molepolole strains of Culex, respectively, indicates dispersion of these esterases through human migration.
Part of the book: Insecticides Resistance