The effect of nutrition on the susceptibility of larvae of Trogoderma granarium Everts (Coleoptera, Dermestidae) to certain fumigants

Abstract

The effect of ten natural powdered foods on the susceptibility of full-grown larvae of Trogoderma granarium Everts to four common fumigants was evaluated. In general, methyl bromide was found to be the most toxic fumigant against T. granarium from all foods, followed in a decreasing order of toxicity by ethylene dibromide, carbon disulphide and ethylene dichloride. The insects reared on pulses were, in general, less susceptible to the fumigants than those from cereals. Excepting methyl bromide, where insects from groundnuts were least susceptible, insects from Phaseolus mungo were, as a rule, the least susceptible to the fumigants as compared to those from other foods. The insects from Sorghum vulgare were nearly 3·3 times more susceptible to ethylene dichloride, and those from high extraction wheat flour 1·7 times more susceptible to carbon disulphide, than those from P. mungo. Insects from groundnuts were 4·9 times more susceptible to ethylene dibromide, while insects from wheat flour plus 5% brewer's yeast were nearly 1·5 times more susceptible to methyl bromide, than those from P. mungo. No correlation between the age or body weight of the insects and the ld 50 values of the fumigants could be established.