The efficacy of high temperature and diatomaceous earth combinations against adults of the red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae) and the grain weevil Sitophilus granarius (Coleoptera: Curculionidae)

摘要

Recent research has shown that diatomaceous earth (DE) can be used to augment the effect of high temperature (48°C) to control stored product invertebrate pests in flour mills. Laboratory bioassays were set up against adult Sitophilus granarius and Tribolium castaneum under conditions simulating stages of heating from 25°C / 70% r.h. to 40°C / 30% r.h.. Humidity was decreased for each step-wise increase in temperature, as calculated using a psychrometric chart. The DE formulation was applied as adry dust to glass Petri dishes at doses of 1 - 10 g/m~2, and the insects exposed for 48 hrs, followed by a 7-day recovery period on whole wheat. All doses achieved 100% mortality against both species at or above 35°C, with 89% of S. granarius survivingin untreated controls at 35°C, and the more heat tolerant T. castaneum all surviving 35°C and 40°C. At the lower temperatures there was no significance difference in efficacy for doses at or above 5 g/m~2, suggesting this to be a threshold for maximum DE pickup. It is proposed that DE is used to treat crevices and voids as part of an integrated pest management (EPM) strategy for flour mills.