title: Thermal death kinetics of red flour beetle (Coleoptera: Tenebrionidae).
abstract: While developing radio frequency heat treatments for dried fruits and nuts, we used a heating block system developed by Washington State University to identify the most heat-tolerant life stage of red flour beetle, Tribolium castaneum (Herbst), and to determine its thermal death kinetics. Using a heating rate of 15 degrees C/min to approximate the rapid heating of radio frequency treatments, the relative heat tolerance of red flour beetle stages was found to be older larvae > pupae and adults > eggs and younger larvae. Lethal exposure times for temperatures of 48, 50, and 52 degrees C for the most heat-tolerant larval stage were estimated using a 0.5th order kinetic model. Exposures needed for 95% mortality at 48 degrees C were too long to be practical (67 min), but increasing treatment temperatures to 50 and 52 degrees C resulted in more useful exposure times of 8 and 1.3 min, respectively. Red flour beetle was more sensitive to changes in treatment temperature than previously studied moth species, resulting in red flour beetle being the most heat-tolerant species at 48 degrees C, but navel orangeworm, Amyelois transitella (Walker), being most heat tolerant at 50 and 52 degrees C. Consequently, efficacious treatments for navel orangeworm at 50-52 degrees C also would control red flour beetle.
authors.affiliation: San Joaquin Valley Agricultural Sciences Center, USDA-ARS, 9611 South Riverbend Avenue, Parlier, CA 93648, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Johnson
authors.forename: K A
authors.initials: KA
authors.lastname: Valero
authors.forename: S
authors.initials: S
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Tang
mesh_terms: D000818:Animals; D005519:Food Preservation; D005638:Fruit; D006358:Hot Temperature; D007300:Insect Control / Q000379:methods*; D007700:Kinetics; D007814:Larva / Q000502:physiology; D009754:Nuts; D011679:Pupa / Q000502:physiology; D011846:Radio Waves; D013816:Thermodynamics; D014231:Tribolium / Q000254:growth & development / Q000502:physiology*