Reversion of the Toxicity of Tricalcium Phosphate to Insects by Trehalose

Abstract

EARLIER we reported¹ data on the exceptional toxicity of tricalcium phosphate to insects. The symptoms of toxicity on larvae were supernumerary moulting, mottling of cuticle, reduction in growth, malformation and death. Further experiments were carried out to investigate the action of sugars on the toxicity of tricalcium phosphate. The sugars (A.R.) were incorporated into tricalcium phosphate at the 5 per cent level. These premixes were mixed with broken rice at the 0, 0.05, 0.1, 0.5, 1.0 and 2.0 per cent levels. The test insects, second instar larvae of Corcyra cephalonica drawn from laboratory cultures, were released on 10 g of the medium. There were ten replicates for each treatment. Observations were made on the growth, mortality and histological changes in the larvae during 15 days' incubation at 25° C and 65 per cent relative humidity. Staining for fat and tissues was carried out by the procedures described by Conn and Darrow². The results are given in Table 1.