Bioassay Systems for the Pyrethrins I. Water‐base Sprays Against Axdës Aegypti L. And Other Flying Insects

A bioassay system for the pyrethrins is discussed in which the quantity of toxicant that flying insects accumulate is measured, as well as the responses of the insects. The determination of spray pick‐up from water‐base sprays is described, and the use of primary responses, such as activation and paralysis, in biological assays is advocated. The test system is discussed in detail for Aëdes aegypti L. and the special characteristics of some other species of flying insects noted. It is considered that the location of the site of action of the pyrethrins under these conditions is at the peripheral nervous system of the test insects.