Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2005
Publication Date: 8/1/2006
Citation: Toews, M.D., Campbell, J.F., Arthur, F.H. 2006. Temporal dynamics and response to fumigation of stored-product Coleoptera in a grain processing facility. Journal of Stored Products Research 42:480-498. Interpretive Summary: Spray insecticides and fumigants are regularly used to control insects in food processing facilities, but more information is needed about which insect species are found in these facilities and efficacy of pest management practices. During a 22-month study in an operating mill and adjacent distribution warehouse, the red flour beetle was found throughout the year in the mill, but not in the warehouse. Warehouse beetles were a serious problem during the summer months in the warehouse, but not during cooler months. Neither methyl bromide nor aerosols consistently eliminated insect populations in the facilities suggesting either that some insects survived the treatments or that they were able to immigrate into the facility soon after treatment. These data will be used to develop novel pest management and control strategies.
Technical Abstract: Stored-product Coleoptera were monitored continuously over 22 months using pitfall traps at an operating food mill and adjacent warehouse in Kansas. Mill management practiced conventional pest management, including monthly crack and crevice applications of a residual insecticide and bi-annual fumigation with methyl bromide in the mill, and application of dichlorvos + pyrethrin in the warehouse. The dynamic temporal changes in insect populations and effect of the global interventions were analyzed. Data show that more Trogoderma variabile were captured in the warehouse than any other species, but Tribolium castaneum was captured with greater frequency. Trogoderma variabile captures inside the warehouse tended to mirror outside captures suggesting immigration from the outside. The mill was infested year round with T. castaneum but developed substantial populations of Typhaea stercorea during the warm months from May through October. Neither methyl bromide nor dichlorvos + pyrethrins consistently eliminated insect populations. Insects were nearly always captured in the first trapping interval following methyl bromide or dichlorvos + pyrethrin applications, but it was not clear if the insects were surviving inside the structure or if they were rapidly recolonizing after treatment. Fungus-feeders had a tendency to be captured in greater numbers immediately after fumigation suggesting that they were reentering the facility while the fumigant was being vented. The most successful fumigation was conducted late in the autumn when environmental conditions prohibited insect activity outside. Information contained in this study provides data that could be used to improve insect management programs for milling and processing facilities.