Insecticide Resistance of Cimex lectularius L. Populations and the Performance of Selected Neonicotinoid-Pyrethroid Mixture Sprays and an Inorganic Dust

SIMPLE SUMMARY: The common bed bug (Cimex lectularius L.) experienced a worldwide resurgence during the last two decades. Chemical control is one of the popular strategies to control bed bug infestations. Bed bugs developed resistance to insecticides, but the prevalence and levels of insecticide resistance among local bed bug populations and whether the commonly used insecticide products are effective on these populations, is unclear. This study tested 13 field populations of bed bugs collected in the United States and determined their insecticidal resistance levels. We found that seven populations developed very high level resistance to deltamethrin. Only one population exhibited high level resistance to neonicotinoids. The performance of three neonicotinoid-pyrethroid mixture sprays and an inorganic insecticide dust were evaluated using three field populations that exhibited high levels of resistance to deltamethrin. All three tested populations required much higher concentrations (55–2017 times higher) than the laboratory strain to induce 90% mortality. Exposure to silica gel dust caused >95% mortality after 72 h. These findings indicate most resistant bed bugs may not be effectively controlled by pyrethroids, neonicotinoid, or pyrethroid-neonicotinoid insecticide sprays. Insecticide dusts containing silica gel are an effective material for control of bed bug infestations. ABSTRACT: Insecticide resistance is one of the factors contributing to the resurgence of the common bed bug, Cimex lectularius L. This study aimed to profile the resistance levels of field-collected C. lectularius populations to two neonicotinoids and one pyrethroid insecticide and the performance of selected insecticide sprays and an inorganic dust. The susceptibility of 13 field-collected C. lectularius populations from the United States to acetamiprid, imidacloprid, and deltamethrin was assessed by topical application using a discriminating dose (10 × LD(90) of the respective chemical against a laboratory strain). The RR(50) based on KT(50) values for acetamiprid and imidacloprid ranged from 1.0–4.7 except for the Linden 2019 population which had RR(50) of ≥ 76.9. Seven populations had RR(50) values of > 160 for deltamethrin. The performance of three insecticide mixture sprays and an inorganic dust were evaluated against three C. lectularius field populations. The performance ratio of Transport GHP (acetamiprid + bifenthrin), Temprid SC (imidacloprid + β-cyfluthrin), and Tandem (thiamethoxam + λ-cyhalothrin) based on LC(90) were 900–2017, 55–129, and 100–196, respectively. Five minute exposure to CimeXa (92.1% amorphous silica) caused > 95% mortality to all populations at 72 h post-treatment.