Performance of Commercial Insecticide Formulations Against Different Developmental Stages of Insecticide-Resistant Tropical Bed Bugs (Hemiptera: Cimicidae)

This study examined the presence of insecticide resistance in different developmental stages (adults, first instars, and eggs) of the tropical bed bug, Cimex hemipterus (F.) using several insecticide formulations. Adults and first instars of five strains (Queensland, Kuala Lumpur, Bukit Mertajam, Saujana, and Krystal Point) were evaluated using the surface contact method and compared with a susceptible strain (Monheim) of the common bed bug Cimex lectularius L. The insecticide formulations were used at their label rates in this study: Tandem (thiamethoxam 11.6%, lambda-cyhalothrin 3.5%) at 183.96 mg/m2; Temprid SC (imidacloprid 21%, beta-cyfluthrin 10.5%) at 106.13 mg/m2; Sumithion 20CS (fenitrothion 20%) at 250 mg/m2; Pesguard FG161 (d-tetramethrin 4.4%, cyphenothrin 13.2%) at 110 mg/m2; and Sumithrin 10SEC (d-phenothrin 10%) at 100 mg/m2. Results showed a very high level of resistance to Pesguard FG161 (388.3 to >605.0 times) and Sumithrin (302.9 to >365.5 times) in all adults of the strains tested, whereas low to high levels of resistance were registered for Tandem (1.4-4.7 times), Temprid (7.3-16.7 times), and Sumithion (1.2-14.6 times) for adults of all bed bug strains. For first instars, resistance to the former two formulations were high to very high (31.4-118.1 times). In contrast, they showed lower resistance to Tandem, Temprid, and Sumithion (1.0-10.2 times). An immersion method used to test on bed bug eggs found high to very high resistance toward all tested formulations. Results demonstrate that the resistance level varies between bed bug developmental stages.