Residual effectiveness of insecticidal deposits on various wall surfaces.

The effectiveness of three chemicals DDT, malathion and Dursban was evaluated against larvae and adults of C. p. fatigans. When larvae and adult mosquitoes were tested for susceptibility, they were susceptible to malathion and Dursban. These insecticides were sprayed onto various wall surfaces at a dose of 2 gm per square metre and the residual effect on C. p. fatigans were studied. Dursban residue was superior on all sufaces, giving effective kill for 10-30 weeks, malathion gave satisfactory result on thatch, plywood and galvanized iron while DDT residue failed to produce effective kills.