Some laboratory investigations relevant to the possible use of new pyrethroids in control of mosquitoes and tsetse flies

Cypermethrin, fenvalerate, permethrin, (S)‐α‐cyano‐3‐phenoxybenzyl (1R,cis)‐3‐(2, 2‐dibromovinyl)‐2, 2‐dimethylcyclopropanecarboxylate (NRDC 161) and (R,S)‐α‐cyano‐3‐phenoxybenzyl 2, 2,3, 3‐tetramethylcyclopropanecarboxylate (S‐3206; WL 41706) have been tested against adult mosquitoes (Anopheles stephensi) and tsetse flies (Glossina austeni). They possess many of the necessary characteristics such as high intrinsic toxicity, low volatility, and high stability but vary considerably in the contact action of their spray residues.