Susceptibility to certain fumigants of male and female pupae of Trogoderma granarium Everts (Coleoptera, Dermestidae)

Abstract

Investigations were carried out on the differential sex susceptibility of 2–3 day old pupae of Trogoderma granarium Everts to four common fumigants. It was found that male pupae were more susceptible to the fumigants tested than the female pupae. Methyl bromide was the most toxic fumigant to both male and female pupae, followed in decreasing order of toxicity by ethylene oxide, carbon disulphide and ethylene dibromide. The effect of ten natural powdered larval foods on the susceptibility of male and female pupae of this insect to carbon disulphide was also evaluated. It was found that the pupae from Sorghum vulgare were four to five times more susceptible to carbon disulphide than those from Phaseolus mungo on which the insects were least susceptible. Irrespective of the nature of larval foods, male pupae were found to be more susceptible to this fumigant than the female pupae. Insects from oily foods were much less susceptible to carbon disulphide than those from other foods. No correlation between live-weight of the pupae from different foods and the corresponding ld 50 values of carbon disulphide could be established.