A dynamic model for predicting survival of Tribolium castaneum adults to elevated temperatures during heat treatment of grain-processing facilities

Abstract. A dynamic model was developed to predict the survival of adults of the red flour beetle, Tribolium castaneum (Herbst), based on the logarithmic survival of adults as a function of time at nine constant temperatures between 42-60°C, and the logarithmic reduction of adult survival as a function of temperature. The developed model was validated using 10 datasets from a pilot feed mill, and two grain-processing facilities. Bioassays included bleached flour in plastic boxes containing 10 or 20 T. castaneum adults. Samples were collected at different intervals during the heat treatment of feed mills and grain-processing facilities and adults were sifted into plastic cups with bleached flour and placed in an environmental growth chamber at 28°C and 65% r.h. and assessed for mortality after 24 h. In the seven locations where 50°C was attained, the heating rate to 50°C from the initial ambient temperature ranged from 2.0°C/h to 15.4°C/h, and the time above 50°C until survival reached 0% was between 0.0-2.4 h. Three locations monitored did not reach 50°C before survival reached 0%. Mean absolute deviations between observed and predicted survival ranged from 5.7-39.5%. The dynamic model developed can be used to effectively predict survival of T. castaneum adults based only on time-dependent temperature.