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The residual performance of two pyrethroid-neonicotinoid mixture formulations: Temprid SC (10.5% beta-cyfluthrin and 21% imidacloprid) and Tandem (3.5% lambda-cyhalothrin and 11.6% thiamethoxam) on two substrates (glass and filter paper) against eight pyrethroid-resistant strains (BM-MY, BP-MY, CH-MY, GL-MY, KL-MY, SAJ-MY, TT-MY, and QLD-AU) of the tropical bed bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae) collected from Malaysia, and Australia were evaluated. The aging effect of treatment residues on glass was also investigated. A susceptible C. lectularius L. strain (Monheim) was used for comparison. Temprid SC showed varying levels of performance against all C. hemipterus strains: TT-MY (PR50 = 6.5-fold, high performance), BM-MY, GL-MY, SAJ-MY, and QLD-AU (12.8–21.6-fold, moderate performance), BP-MY, and KL-MY (48.2–49-fold, poor performance), CH-MY (128.2-fold, very poor performance). On the other hand, Tandem displayed high performance against all C. hemipterus strains (1.8–8.3-fold). Tandem caused faster mortality than Temprid SC for all strains. Temprid SC and Tandem residues killed C. hemipterus significantly faster on glass than filter paper. Compared with fresh residues, the efficacy of Temprid SC residues significantly declined after one week of aging, while the effectiveness of Tandem residues declined after two weeks of aging. Further investigations using the topical assay method with a diagnostic dose of imidacloprid found two strains (CH-MY and GL-MY) resistant to imidacloprid. The six other strains (BM-MY, BP-MY, KL-MY, SAJ-MY, TT-MY, and QLD-AU) were susceptible. [ABSTRACT FROM AUTHOR]

Insecticide resistance in the common bed bug, C imex lectularius Linnaeus has been suspected in Australia with anecdotal reports of poor product performance. To investigate this possibility, LD50 values were determined via topical application of technical grade permethrin, deltamethrin, bendiocarb, pirimiphos-methyl and imidacloprid serially diluted in acetone to a suspected resistant field-collected strain and a susceptible laboratory strain. All compounds tested against the susceptible strain were efficacious. However, for the field strain, only pirimiphos-methyl and imidacloprid showed high levels of activity. Resistance was confirmed in the field-collected strain to the pyrethroids and bendiocarb, but not to pirimiphos-methyl or imidacloprid. Resistance factors ('resistant' LD50/susceptible LD50) for each compound were: permethrin ≈ 1.235 million, deltamethrin ≈ 370 000, bendiocarb ≈ 250, pirimiphos-methyl = 2.6, imidacloprid = 2.6. Bendiocarb, permethrin and deltamethrin all failed to return greater than 60% mortality at the maximum dose of 100 μg/μ L. This research has significant operational implications for bed bug control and the registration process of new products in Australia. [ABSTRACT FROM AUTHOR]