Mortality of red flour beetle, Tribolium castaneum (Coleoptera : Tenebrionidae) exposed to high temperature and diatomaceous earth combinations

Four diatomaceous earth formulations and one calcium carbonate formulation were evaluated in combination with high temperature as a control method for the adult stage of the red flour beetle, Tribolium castaneum (Herbst). At 34 degrees C, exposure to the insecticidal dusts for 15 or 30min did not in crease mortality relative to beetles not exposed to the dusts, However, at 50 degrees C, exposure increased mortality by 8-100%. Exposure to the Prote ct-It(R) formulation caused greater beetle mortality than exposure to any o f the other materials. The calcium carbonate formulation exhibited no insec ticidal activity. Withholding food from the beetles after exposure to heat plus diatomaceous earth increased mortality 2-4 times beyond the level for beetles that were not denied food. A combination treatment of heat with an effective diatomaceous earth formulation may be useful for managing this pe st in cereal-grain processing facilities. Published by Elsevier Science Ltd .