Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2001
Publication Date: 3/30/2003
Citation: ARTHUR,F.H., DOWDY,A.K., EFFECTS OF EXTREME TEMPERATURES ON EFFICACY OF CYFLUTHRIN AND HYDROPRENE APPLIED TO CONCRETE, JOURNAL OF STORED PRODUCTS RESEARCH 39: 193-204. 2003.
Interpretive Summary: Heat treatments are being used as an alternative to methyl bromide for controlling stored-product insects inside flour mills, and there are concerns as to whether the temperatures attained during a heat treatment would cause degradation of residual insecticides. Several tests were conducted to determine if high temperatures would affect residual control of cyfluthrin (Tempo) and hydroprene (Gentrol), two products commonly used as surface treatments in storage facilities. In laboratory studies, temperatures of 120 to 130 F did not effect the toxicity of either cyfluthrin or Gentrol. Results from a field trial show that cyfluthrin toxicity was actually greater on concrete that had been heated compared to unheated concrete. Combination treatments with heat and residual insecticides show potential for practical use inside flour mills, and could be used in combination to selectively treat areas within a mill, instead of heat-treating the entire structure.
Technical Abstract: Studies were conducted to determine if temperatures commonly attained during a flour mill heat treatment would have a negative impact on efficacy of cyfluthrin wettable powder (WP) or hydroprene. In laboratory trials, concrete was treated with cyfluthrin WP at the high label rate, then heated 45 or 55 C. Survival of Tribolium castaneum Herbst, the red flour beetle, was generally greater on unheated concrete treated with cyfluthrin compared to the heating treatments, and there appeared to be a slight pattern of decreased survival as the heating time increased at both 45 and 55 C. In a second laboratory trial, concrete was treated with the label rate of hydroprene (Gentrol), and bioassayed by exposing late-instar T. castaneum larvae on the treated surface. There were significant differences between untreated controls and the heat treatment regimes with respect to the percentage of live emerged adults, the percentage of those adults with deformities, and the percentage of dead adults, but no differences among treatments. In a field trial, concrete was treated with cyfluthrin at a low rate and placed either in a flour mill undergoing an experimental heat treatment and or in an unheated office. The percentage of beetle survival on unheated concrete was generally greater than survival on concrete that had been heated in the mill. Results of these studies show that short-term exposures to high temperatures may not have an appreciable effect on efficacy of either cyfluthrin WP or hydroprene, and combination treatments of heat plus either of these insecticides may be an alternative to methyl bromide for disinfestation of milling facilities.