Laboratory efficacy of insect growth regulators on the mortality rate of tropical bed bugs, Cimex hemipterus (F.)

Abstract

Cimicidae are blood feed ectoparasites of mammals and birds. The Cimex hemipterus has been pestering humans since before globalisation and urbanisation. Till today, this pest has shown resilience and resurgence in infestation cases as documented in North and South America, Africa, Asia, and Europe. Hence, research on the efficacy of insect growth regulators was conducted using surface contact bioassay on a plastic surface using six insecticides at four concentrations (100ppm, 500ppm, 1000ppm, and 10 000ppm). Bioassay was performed in triplicates comprising of five-bed bugs (an adult male, two adult females, and two nymphs) per replicate. Six exposure times were designed; 1hr, 2hr, 3hr, 24hr, 48hr, 72hr and continuous exposure until mortality was achieved. The mean mortality of bed bugs within the first week of exposure demonstrated significant difference (P=0.004) while when evaluated for continuous exposure of 13 weeks tropical bed bugs showed no significant interaction (P=0.126) with zero knockdown rate. Treated bed bugs indicate significant difference between the mean egg deposited and hatched (P<0.001). During the exposure, chlorfluazuron resulted in the fastest mortality rate, followed by beta-cyfluthrin+imidacloprid, tebufenozide, methoprene, chlorfluazuron, and pyriproxyfen. Better killing efficacy was observed in insecticide at high concentrations, followed by lower concentrations with a slightly slower mortality assessment interval. The mortality of bed bugs proves that insect growth regulators do work on bed bugs. Further studies should be done before better control measures could be proposed to curb the infestation of bed bug populations.