Abstract

Control strategies of the German cockroach, Blattella germanica (L.) populations in residential environments have shifted from predominant use of insecticide sprays to the inclusion of baits in management programmes. The change has been facilitated by the general perception that baits were safer and therefore appeal to the public's concern about risks associated with pesticides in domestic environments. Current active ingredients are toxic enough to deliver a lethal dose in one meal. However, they act slowly enough to allow time for the cockroach to return to their harbourage after feeding. The objective of this study was to investigate whether Mohlolo insecticide bait (MIB) would reduce populations of B. germanica in various environments within the residential areas. A completely randomized design (CRD) was used in the study with the four treatments. Approximately 1 g of MIB was placed in 6 cm3 container, with two containers placed in the kitchen, lodge, bathroom and bedroom. In the kitchen, MIB containers were placed behind the cooking stove and refrigerator, in the lodge next to the table which was used for eating and studying. At least 50% reduction in B. germanica numbers was achieved within 7 and 10 days after the cockroaches were exposed to the MIB, while 100% mortality was attained within 12 and 14 days. Cockroach mortality over exposure time attributed 99.8, 99.34, 99.84, 99.35, 98.73, 99.31, 99.92, 97.31, 98.08 and 98.51% to the variation in mortality percentage in Apartments.