Development of Chlordane and Malathion Resistance in the German Cockroach

Abstract

Resistance de-veloped more rapidly to malathion, and slightly more rapidly to chlor-dane, in strains of German cockroaches (Blattella germanica) exposed only to 1 insecticide in each generation than in strains exposed to both insecticides, either in combination with each generation or alone in alternate generations. A small, degree of cross-resistance to chlor-dane was evident in the later generations of the colony subjected to malathion.