Insecticidal effects of activated charcoal and clays.

Abstract

BRISCOE1, Kitchner et al. 2, Wigglesworth3, and Parkin4 have studied the ‘inert’ dusts for their insecticidal action. Reports on the insecticidal properties of ‘inert’ dusts, particularly of silica, coal ash, diamond, ‘Carborundum’, dusts from blast furnaces, flint, felspar, magnesite and dolomite are available1,2,4. While screening samples of various clays, decolourizing carbon, gas absorbing carbon, silica gel and commercial soil conditioners for insecticidal effects, it was observed that most of the dusts passing through a 300-mesh had various degrees of insecticidal effects on Tribolium casteneum Hbst. adults; but activated charcoal and decolourizing clays exhibited, in general, quicker effects on insects than unactivated dusts. Samples of wood shavings, sawdusts, coconut shells and kaolinic clays were activated therefore, for further studies on their insecticidal properties. Activated charcoals were prepared by the zinc chloride activation method5 and kaolinic clays were activated by acid treatment6.