Laboratory Evaluation of a Novel Insecticide, Isocycloseram, Against the Common Bed Bug (Cimex lectularius L.) (Hemiptera: Cimicidae)

Isocycloseram is a novel insecticide belonging to the class of isoxazoline (IRAC MoA Group 30) that exhibits excellent efficacy and selectivity against invertebrate pests. We evaluated the efficacy of two 0.1% isocycloseram formulations against a laboratory and four insecticide-resistant field strains of common bed bugs (<i>Cimex lectularius</i> L.) (Hemiptera: Cimicidae) by direct spray and forced exposure on three surfaces (fabric, vinyl tiles, and unpainted pinewood). Their efficacy was compared with that of five commercial insecticides including Demand CS (0.03% λ-cyhalothrin), Temprid FX (0.05% imidacloprid and 0.025% β-cyfluthrin), Crossfire (0.4% clothianidin, 0.01% metofluthrin, and 1.0% piperonyl butoxide), Bedlam Plus (0.4% d-phenothrin, 1.0% MGK 264, and 0.05% imidacloprid), and PT Phantom II (0.5% chlorfenapyr). Both isocycloseram 45 SC and 400 SC formulations were the most effective among the tested insecticides. The isocycloseram 45 SC formulation caused faster mortality than the 400 SC formulation. Four hours of exposure to 0.025, 0.05, and 0.1% isocycloseram 45 SC residue on porous and non-porous surfaces caused 100% bed bug mortality after 3-4 days. Exposure to 30-day-aged 0.1% isocycloseram 45 SC residue for 4 h still caused 100% mortality, compared to 0-73% mortality by the five commercial insecticides. Isocycloseram is a highly effective compound for controlling resistant <i>C. lectularius</i> populations.