HEAT PLUS DIATOMACEOUS EARTH TREATMENT EFFECTS ON RED FLOUR BEETLE (COLEOPTERA: TENEBRIONIDAE) MORTALITY IN A FLOUR MILL ENVIRONMENT

Authors: Dowdy, Alan

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2000
Publication Date: 3/15/2001
Citation: DOWDY, A.K. HEAT PLUS DIATOMACEOUS EARTH TREATMENT EFFECTS ON RED FLOUR BEETLE (COLEOPTERA: TENEBRIONIDAE) MORTALITY IN A FLOUR MILL ENVIRONMENT. JOURNAL OF STORED PRODUCTS RESEARCH, 11-22. 2001.

Interpretive Summary: Methyl bromide is used to fumigate food-processing facilities for controlling stored product insects. The fumigant will be banned in the United States in 2005 under the terms of the Montreal Protocol, thus an alternative must be identified to maintain adequate food protection. An alternative control is to heat part or all of the processing facility to 50 0C. for 20 to 30 hours. Some equipment or structures, however, cannot tolerate these conditions, or it is difficult or expensive to attain the required temperature. A combined treatment of heat with the desiccating dust, diatomaceous earth, resulted in insect mortality below 47 C. An application of DE may be advantageous in areas that are difficult to heat or where it is desirable to heat to lower temperatures due to the presence of temperature sensitive equipment.

Technical Abstract: 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 to 60 C. for 20 to 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 requirements necessary for effective control by using a desiccating dust, diatomaceous earth (DE), in combination with the heat treatment. The objectives of this study were to examine the combined impact of high temperature and DE on the mortality of Tribolium confusum in a flour mill environment 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 temperatures were in excess of 47 D. for at least 25 h, DE applications of 0.3 g/m2 in combination with the heat were no more effective than the heat treatment alone. At higher application rates, the DE was more effective. In cooler areas, adult beetles exposed to DE died sooner than insects not exposed to the insecticidal dust. These results indicate that the application of DE in areas that cannot be heated to 47 C. is effective for controlling T. confusum in a flour mill. A comparison is made to a parallel study conducted in Canada.