Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2017
Publication Date: 9/1/2017
Publication URL: http://handle.nal.usda.gov/10113/5733376
Citation: Tilley, D.R., Casada, M.E., Subramanyam, B., Arthur, F.H. 2017. Temporal changes in stored-product insect populations associated with boot, pit, and load-out areas of grain elevators and feed mills. Journal of Stored Products Research. 73:62-73. http://dx.doi.org/10.1016/j.jspr.2017.07.002.
Interpretive Summary: Stored grain insect infestations in elevator boot pits areas can spread throughout grain storage and processing facilities, reducing grain quality, contaminating the grain, and causing economic losses. The effect of time of year on insect infestations in elevator boot pit areas has not been studied before. We determined the types and numbers of stored-grain insect species found in the boot (pit) area and in grain stored in silos of commercial elevator and feed mill facilities. The number of insects found in residual grain samples was low in the cool winter months and peaked during the warm summer months. These results showed regular boot and pit cleaning is critical in preventing pest population outbreaks during the warm summer months. New facility pest management sanitation guidelines were developed including boot residual grain clean-out every 30 days, removal of grain spillage and floor sweepings from the pit area, and proper disposal of boot and pit residual grain. Grain handling facilities following the frequent clean-out of the boot residual grain and general sanitation of the pit area should reduce the number of insects that are picked-up in the boot area and transferred to other locations of a facility, which will reduce the damage and losses that would occur if insects are allowed to proliferate in the boot area and spread elsewhere.
Technical Abstract: Commercial grain elevator and feed mill facilities can quickly become infested with stored-product insect pests, compromising the protection of the raw and processed cereal products stored at each facility type. Grain facilities of each type were sampled monthly for adults of stored-product insects in grain residues from the boot (pit) areas and bulk load-out samples during 2009-2010. Grain samples collected from the boot, pit and load-out areas was either corn, soybeans, or a mixture of the two grains. Impact of boot (pit) cleaning and insecticide spray treatments on insect densities in each location was determined, by correlating insect density between the boot (pit) areas and grain storage bins. Low insect densities were recorded from the boot (pit) area during the cool winter months. Insect counts increased in the spring and peaked during the warm summer months before declining in the fall. The rice weevil, Sitophilus oryzae (L.) was the most prevalent species collected in all grain residues sampled and comprised 69.2 and 35.8% of total insects collected during 2009 and was commonly collected during 2010. Other commonly collected insect species included: Tribolium castaneum (Herbst), Cryptolestes ferrugineus (Stephens) , and Oryzaephilus surinamensis (Linnaeus). Our results show monthly boot and pit cleaning is critical in preventing pest population out breaks during the warm summer months. We conclude with new facility pest management sanitation guidelines of the boot and pit area would include (1) boot residual grain clean-out every 30 days, (2) removal of grain spillage and floor sweepings from the pit area, and (3) proper disposal of boot and pit residual grain. These boot and pit sanitation guidelines could be used to improve elevator and feed mill insect pest management programs.