Relation Among Efficacy of Insecticides, Resistance Levels, and Sanitation in the Control of the German Cockroach (Dictyoptera: Blattellidae)

The efficacy of several insecticides for controlling the German cockroach, Blattella germanica (L.), was compared in field and laboratory tests. Based on trap catch before and after treatment in a multiunit public housing complex, 0.2% cypermethrin was more effective than 0.5% chlorpyrifos or 1.1% propoxur. Up to 3 mo of residual activity was achieved with cypermethrin. A positive correlation was confirmed between poor sanitation and higher cockroach populations. Improved sanitary conditions increased the efficacy of some insecticide treatments. Cockroaches collected from apartments where these tests were done were > 100 times as resistant to propoxur and bendiocarb, and 4.51, 1.34, and 1.84 times as resistant to cypermethrin, chlorpyrifos, and diazinon, respectively (continuous exposure surface contact test).