Insecticide resistance in Phthorimaea oper-culella (Zell.) with particular reference to DDT

Abstract

Strains of Phthorimaea operculella (Zell.) from tobacco-growing and potato-growing areas of Queensland have been found resistant to DDT and endrin. No completely susceptible strains of P. operculella have been found in Queensland even in areas where little or no insecticide has been used and tolerance of local strains has been referred to a susceptible strain from Victoria. The compound N,N-di-n-butyl-p-chlorobenzene sulfonamide had no influence on DDT-resistant strains. Removal of insecticide pressure did not lower DDT tolerances significantly after 16 generations in culture.