Thermal death kinetics of red flour beetle (Coleoptera: Tenebrionidae).
Authors:
Johnson, J.A. Valero, K.A. Wang, S. Tang, J. USDA, ARS
Source:
Journal of economic entomology. 2004 Dec., v. 97, no. 6, p. 1868-1873.
NALT Subjects:
Tribolium castaneum insect control heat treatment heat tolerance developmental stages mortality kinetics temperature duration dynamic models
Other Subjects:
lethal time heating block system kinetic model radio frequency heat treatment
Issue Date:
Dec-2004
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.
