Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2015
Publication Date: 10/1/2015
Publication URL: http://handle.nal.usda.gov/10113/62146
Citation: Arthur, F.H. 2015. Food source and residual efficacy of chlorfenapyr on sealed and unsealed concrete. Journal of Stored Products Research. 64A:65-71. doi: 10.106/j.jspr.2015.08.007.
Interpretive Summary: Residual insecticides are used to treat floors inside flour mills and food warehouses for the control insect pests. Floors are usually concrete and are sometimes treated with sealants that might impact insecticide absorption. Evaluation of residual efficacy of the insecticide Phantom® against adult red flour beetles indicated that sealing concrete did not improve efficacy, but that the presence of food material on the concrete, whether sealed or not, greatly decreased residual efficacy. Managers can use this information to emphasize the importance of sanitation before using a residual insecticide, and to make decisions about whether or not sealing concrete is necessary for this particular insecticide.
Technical Abstract: Adult Tribolium castaneum (Herbst), the red flour beetle, were exposed at 1 day, and 2, 4, and 6 weeks post-treatment on sealed and unsealed concrete arenas treated with chlorfenapyr at rates of 2.8, 6.9, 13.5, 20.6, 27.5 mg active ingredient/m2. Beetles were held either with or without flour, and assessments were done of the percentage of active beetles after 24 hr and after 1 wk, and the percentage of beetles knocked down and dead after 1-wk. Although the percentage of active individuals after 24-hr of exposure increased on sealed and unsealed concrete with increasing post-treatment interval, generally there were less active beetles on the arenas without flour compared to those with flour. At the one week assessments, there were usually more beetles remaining active and more beetles knocked down on arenas with flour compared to those without flour, and more dead beetles on arenas without flour compared to those with flour. Sealing had mixed effects. The presence of the flour food source greatly decreased efficacy of the insecticide, regardless of concentration.