Comparative susceptibility of the eastern bat bug (Cimex adjunctus Barber) and the common bed bug (Cimex lectularius L.) to selected insecticides

The eastern bat bug, Cimex adjunctus Barber (Hemiptera: Cimicidae), is an ectoparasite of bats that can occasionally infest human dwellings, posing a potential public health concern. When found in homes, they are often treated with insecticides labeled for bed bugs (Cimex lectularius L.). However, there are no data available on the efficacy of these pesticides against bat bugs. This study assessed the efficacy of 3 commercial insecticide sprays containing pyrethroid or pyrethroid-neonicotinoid mixture and 2 insecticide dusts containing deltamethrin or diatomaceous earth (DE) against a field-collected strain of bat bugs. One susceptible and 2 resistant bed bug strains were included for comparison. Exposure to dry pyrethroid or a pyrethroid-neonicotinoid mixture residue for 5 min caused 90% to 100% mortality in bat bugs and the susceptible bed bug strain, whereas only 0% to 13% mortality in the 2 resistant bed bug strains. Brief (crossing a 2.5 cm treated band) or continuous exposure to 4.75% deltamethrin dust caused 100% mortality to bat bugs and the susceptible strain of bed bugs, but less than 20% mortality in the 2 resistant strains of bed bugs. DE dust caused 100% mortality to bat bugs and all bed bug strains, but the time to achieve this was much longer than with deltamethrin dust treatment (4 to 6 d compared to 4 h). Bat bugs showed similar susceptibility to the tested insecticides as the susceptible bed bug strain, except that a slower mortality occurred in the CrossFire (0.4% clothianidin, 0.01% metofluthrin, 1% piperonyl butoxide) spray treatment.