Submitted to: Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2007
Publication Date: 3/30/2008
Citation: Arthur, F.H. 2008. Aerosol distribution and efficacy in a commercial food warehouse. Insect Science. 15(2): 133-140. Doi: http://dx.doi.org/10.1111/j.1744-7917.2008.00193.x. Interpretive Summary: There is little published information regarding the effectiveness of insecticidal aerosols in commercial facilities, and results of laboratory trials may not always be an indication of effectiveness in field applications. Tests were done by exposing adult red flour beetles and confused flour beetles, along with pupae and larvae, to pyrethrin insecticide inside a commercial warehouse. In addition, larvae of the beetles and eggs of the Indianmeal moth were also exposed to the insect growth regulator methoprene. Although the aerosol system effectively distributed the insecticide throughout the test facility, the red flour beetle was more susceptible than the confused flour beetle to the pyrethrin insecticide. Methoprene was effective against larvae of both beetle species, but eggs of the Indianmeal moth were difficult to kill. Results show that the effectiveness of aerosols will depend on several related factors, including how well the application system distributes the insecticide, the toxicity of that insecticide, differences in susceptibility between target insect species, and variation in susceptibility of individual life stages.
Technical Abstract: A series of field trials were conducted in a commercial field storage facility to evaluate exposure of stored-product insects to aerosol formulations of pyrethrin and the insect growth regulator methoprene. When adults of Tribolium castaneum (Herbst), the red flour beetle, and Tribolium confusum (Jacqueline DuVal), the confused flour beetle were exposed to pyrethrin aerosol with and without a flour food source, there was no difference in mortality at 7 and 14 days after exposure (P > 0.05). The percentage mortality was lower in T. confusum (40.4 and 79.3% with flour at 7 and 14 days, 38.9 and 84.8% without flour at 7 and 14 days) compared to T. castaneum (96.5 and 99.8% with flour at 7 and 14 days, 91.0 and 98.7% without flour at 7 and 14 days). Few late-stage larvae and pupae of either species exposed to the aerosol emerged as adults. In tests with methoprene aerosol, adult emergence of exposed 3- and 4-week-old larvae of T. confusum was less than 2%. Only 0.3% of 4-week-old larvae of T. castaneum exposed in open and obstructed areas emerged as adults, while adult emergence was 13.2 ± 3.5% from eggs of Plodia interpunctella (Hübner), the Indianmeal moth, embedded in culture media. Results show that the aerosols evaluated in our study would give effective control of some of the major stored-product insect pests in commercial food storage facilities, and offer an alternative to methyl bromide fumigation.