The Susceptibility to DDT Dust of Coleoptera infesting Stored Products

Abstract

The resistance to a 5 per cent. DDT powder of 36 species of adult and larval Coleoptera which infest stored products has been determined. The species are grouped according to the time required to effect 95 per cent. kill. In the data for adults, the slopes of the probit regression lines were not significantly correlated with the log-times for 50 per cent. kill. No obvious connection could be seen between the degree of resistance to the insecticide and size, activity, hairiness, etc., but larvae tended to be much more resistant than the corresponding adults.