Heat combined with diatomaceous earth to control the confused flour beetle(Coleoptera : Tenebrionidae) in a flour mill

An alternative to methyl bromide fumigation for controlling stored-product insects in food processing facilities is to heat part or all of a facility to 50-60 degreesC for 20-30 h. However, some equipment or structures cannot tolerate these conditions, or it is difficult or expensive to attain these high temperatures. It may be possible to reduce the temperature requiremen ts necessary for effective control by using a desiccating dust, such as dia tomaceous earth (DE), in combination with the heat treatment. The objective s of this study were to examine the combined impact of high temperature and DE on the mortality of Tribolium confusum (du Val) in a flour mill environ ment and to evaluate the effects of DE application rate on insect mortality in a mill environment during heat treatment. In areas of the mill where te mperatures were in excess of 47 degreesC, DE applications of 0.3 g/m(2) in combination with heat were no more effective than the heat treatment alone. At higher application rates, the DE was more effective. In cooler areas, a dult beetles exposed to DE died sooner than insects not exposed to the inse cticidal dust. These results indicate that application of DE in areas that cannot be heated to 47 degreesC is effective for controlling T. confusum in a flour mill. A comparison is made with a parallel study conducted in Cana da. Crown Copyright (C) 2001 Published by Elsevier Science Ltd. All rights reserved.