Comparison of slow and fast action gel baits for pest management of Blattella germanica (German cockroach) infestation in housing

Background: Gel baits are important for integrated pest management (IPM). The relative efficacy of various baits is unknown. Objectives: To evaluate the efficacy of different gel belts (hydramethylnon 2%, fipronil 0.05%, and imidacloprid 2.15%) for control of Blattella germanica (German cockroach) infestation. Methods: All the tested (field) strains were collected from housing in Yasuj city, Iran. Ten German cockroaches for each developmental stage were placed in separate labeled glass rearing jars of the same size. Mortality was observed at 12 h intervals after exposure to baits. Each study was conducted in triplicate. Results: All gel baits produced 100% mortality of cockroaches within 1 to 5 days. However, imidacloprid killed cockroaches more rapidly (LT50 = 13.3 h) than fipronil (LT50 = 32.5 h) or hydramethylnon (LT50 = 61.6 h). The results showed rapid, quick, and slow action for the three baits respectively. Comparison between the baits showed that the slow action bait is more compatible with IPM, being the most effective in 3 or more days; increased potential for secondary mortality through horizontal transmission of lethal dose and also via residue; decreased risk of food contamination by dead cockroaches; will decrease the chance of behavioral resistance, and it had higher feeding stimulation potential than the others. Conclusions: Hydramethylnon is preferred for IPM. Fipronil is a plausible alternative. Keywords: Cockroach infestation, fast action bait, IPM, slow action bait