Laboratory bioassay on efficacy of dual mode of action insecticides (beta-cyfluthrin and imidacloprid) towards tropical bed bugs, Cimex hemipterus (Hemiptera: Cimicidae)

Abstract

In testing the efficacy of insecticides, bed bugs were exposed to the dual-action mode insecticides (beta-cyfluthrin and imidacloprid) on a plywood surface. The mortality rate was recorded at 1, 3, 6, 12, 24 hours of each day for seven days until a duration of six weeks post-treatment which showed a decrease in total survival of insect especially the nymphs. The percentage of mortality of bed bugs within the first day of application showed that nymphs were more susceptible than adults at high concentration of insecticide (630 ppm). Varying the concentrations of insecticide and age of bed bugs statistically showed no significant difference. However, both nymphs and adult bed bugs were killed by insecticides of high concentration (0.0.63%). Results showed that there were no statistically significant interactions between the effect of concentration of insecticide and stages of bed bugs, F (1,108) = 0.051, p = 0.822. However, there were significant difference within concentrations (p = 0.005) against different stages of bed bugs (p = 0.0005). Survival of bed bugs after the application of insecticide proved that the pest cannot be eliminated easily probably due to their modified mechanisms or development of resistance. As such, more studies should be implemented to investigate the real reasons for their resilience.