Effects of propoxur treatment on populations containing susceptible and resistant German cockroaches (Orthoptera: Blattellidae).

Abstract

Three experiments on the effects of propoxur treatment on German cockroach, Blattella germanica (L.), populations were conducted on an inactive ship. In one, all members of the population except adult males were from a resistant field strain; in the others, populations were equally divided between genetically marked susceptible and resistant cockroaches. Each population was established at a known site. Treatment with propoxur caused immediate dispersal. Most movement was into nearby untreated locations. The majority of cockroaches in each population returned to their original site in 1–2 weeks. However, small groups appeared and remained in previously uninhabited harborages. Some of the new spot infestations were near the original site; others were in relatively distant locations. No difference in pre- or posttreatment distribution of susceptible and resistant cockroaches was found. Kill of resistant cockroaches did not appear to vary greatly with age or sexclass. In the susceptible strain, mortality for adults was considerably higher than nymphal mortality. The experiments demonstrated that a 7- to 8-fold resistance to propoxur reduced mortality of adults and nymphs compared with that of susceptible cockroaches under conditions where the cockroaches were free to escape from the insecticide treatment.