Laboratory Experiments With Non‐arsenical Insecticides for Biting Insects

Abstract

Summary. A convenient technique for experiments with insecticides for biting insects is described. The silicofluorides of sodium, potassium, aluminium and calcium, used in the form of spray‐fluids, showed considerable toxicity to young larvae of several species of moths. The degree of resistance varies with different species and is greater with older larvae. Considerable, but irregular, injury to foliage was noted, and much further work is required to establish the conditions under which these compounds could be safely used. Foliage sprayed with extracts of certain tropical plants is extremely repellent to young larvae. Even with high dilutions of the extracts, the foliage remained uneaten and the larvae eventually died of starvation. A short review of some recent work on laboratory experiments with non‐arsenical insecticides for biting insects is given.