Insecticide Resistance of Alphitobius diaperinus (Coleoptera: Tenebrionidae) to β-Cyfluthrin And Associated Heat Tolerance
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The lesser mealworm Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) is an important economic pest to poultry producers globally that cause structural damage and spread pathogens to poultry. Adult lesser mealworms were collected from three farms in Mt. Pleasant, TX, USA (A-C) and three farms in Franklin, TX, USA (D-F) in order to assess insecticide resistance across populations, as well its relationship to heat tolerance. Filter papers were treated with a range of doses of the active ingredient (AI) β-Cyfluthrin. Farms B and E displayed much higher LD_(50) of 0.320 mg/mL and 0.627 mg/mL respectively compared to the remaining four farms, which ranged from 0.048-0.161mg/mL. In addition, a field bioassay was conducted to determine adult beetle susceptibility to label rates of formulated permethrin, Vector Ban Plus™ and a pyrethroid, Tempo SC Ultra™. These insecticides were applied to commonly found surfaces in poultry operations (concrete, wood chip particle board, and pressure treated wood). Adult beetles were exposed to the treated surfaces for 2 h and then placed in untreated sterile petri dishes. “Mortality” refers to mortality and morbidity recorded together at 2, 24, and 48 h post-exposure for both bioassays. Insecticide resistance varied greatly based on observation period and compound. The range of mean mortalities measured at 2 h regardless of surface type for Tempo SC Ultra™ was 58-100% and for Vector Ban Plus™ 17-100%. The mean mortality range at 24 h regardless of surface for Tempo SC Ultra™ (91-100%) had less than 10% variation, while Vector Ban Plus™ (0.00-49.73%) displayed almost 50% variation. The mean mortality range at 48 h regardless of surface for Tempo SC Ultra™ (72-100%) showed high knockdown and increased in variation by 30%, and Vector Ban Plus™ (0-29%) had a similar variation, but with low knockdown. Mortality was similar for Tempo SC Ultra™ for each substrate. β-Cyfluthrin (AI) had varying effectiveness depending on the population’s resistance levels, however all the farms tested had LD_(50) well above the equivalent formulation dosage of 0.02mg/mL. The β-Cyfluthrin formulation had high mortality on all the surfaces tested highlighting the importance of the other ingredients in a formulation. Heat tolerance experiments were conducted on the F_(1) progeny of populations B, D, and E (n=14). The heat shock results were inconclusive. Modification to the experimental design may be needed to yield comparable results.
Lyons, Brandon Nicholas (2014). Insecticide Resistance of Alphitobius diaperinus (Coleoptera: Tenebrionidae) to β-Cyfluthrin And Associated Heat Tolerance. Master's thesis, Texas A & M University. Available electronically from