2009 Annual Report
1a.Objectives (from AD-416)
Evaluate efficacy of potential alternatives to the use of methyl bromide as a structural treatment and improve Integrated Pest Management (IPM) programs for stored-product insect pests in food facilities such as wheat flour mills, rice mills, pet food facilities, and their associated warehouses with the goal of reducing the number of methyl bromide critical use exemptions (CUEs) requested or the amount of methyl bromide used.
1b.Approach (from AD-416)
A four part approach, based on priorities identified by stakeholders at the NP308 program review, will be used to meet this objective. (1) Obtain information on the field efficacy of alternative structural treatments, such as sulfuryl fluoride or heat, compared with methyl bromide. (2) Evaluate the impact of some alternative tactics, such as reduced-risk aerosol insecticides or targeted treatment with residual contact insecticides, as part of an IPM or systems approach to eliminate the need for, or reduce the frequency of, fumigations or other structural treatments. (3) Develop improved monitoring tools and strategies to evaluate the need for and effectiveness of different management tactics to improve the implementation of an IPM program (in association with Gainesville). (4) Develop models using the above information with which to determine optimal management strategies using methyl bromide alternatives.
Monitoring programs at commercial food processing facilities around the U.S. were conducted to evaluate seasonal patterns in stored-product insect populations and the impact of structural treatments and other management tactics on pest populations. Long-term monitoring projects were conducted in two wheat flour mills and one rice mill that received methyl bromide and sulfuryl fluoride fumigations and short-term monitoring projects were conducted in a wheat mill and pasta plant that both received methyl bromide fumigations. In all locations pheromone traps and temperature monitoring using data-loggers attached to some traps were used to obtain information on the pest population and environmental conditions, and information on fumigation treatments was obtained from cooperators. Red flour beetle movement patterns inside a pilot scale flour mill were measured to determine their ability to disperse among floors in a flour mill and if heat treatments applied to the mill increased their movement between floors. At four fumigations, traps were placed outside before, during, and after treatment to determine if insect emigration from facilities during treatment could be detected. Evaluations of the efficacy of reduced-risk insecticides such as pyrethrins, pyrethroids, and insect growth regulators were conducted using different stored-product pest species, including Indianmeal moth and red and confused flour beetles. Experiments were conducted in simulated warehouses to evaluate the long-term impact of pyrethroid aerosol applications, using two- and four-week treatment intervals, on red flour beetle populations. Experiments were designed, cooperators identified, and initial studies conducted to evaluate residual activity of different aerosol insecticides applied in commercial food facilities. Developed a population dynamics model for the red flour beetle in flour mills that includes structural treatments such as methyl bromide and alternatives such as heat and sulfuryl fluoride. Currently adding treatment algorithms and validating the model.
Monitoring stored-product insect populations in food processing facilities. Ongoing research in commercial food facilities conducted by ARS scientists at the Grain Marketing and Production Research Center in Manhattan, Kansas, and industry cooperators is providing not only some of the first information on pest population dynamics in different types of facilities and geographic locations, but also the first in depth evaluation of structural treatment efficacy, in terms of both initial reduction and long-term population rebound. Results to date indicate considerable variation in efficacy against the target pest species, differences in seasonal patterns in pest activity, and geographic variation in species abundance and diversity. The specific information being generated from this project is currently being used by industry cooperators to help guide their management programs, and the combined information from multiple locations will be used to determine average impact of treatments.
Simulation model for red flour beetle in flour mills. Insect contamination of flour has many negative impacts on the industry including damage to brand identity, failure to pass inspections, and the cost of product returns. With the phase-out of methyl bromide for fumigation, the milling industry needs new alternatives and treatment strategies. ARS scientists at the Grain Marketing and Production Research Center in Manhattan, Kansas, developed a computer model for the red flour beetle in flour mills. The model was used to investigate several fumigation strategies. Insect population rebound following fumigation was much longer in mills that were fumigated in the fall compared to spring fumigations. Findings from this study will be used to develop optimal treatment programs for flour mills using alternative methods such as heat and sulfuryl fluoride.
Insecticide combination to control Indianmeal moth eggs and larvae. Aerosol insecticides are used to control beetle pests inside flour mills and other facilities, but there is little published information regarding control of the Indianmeal moth, a primary pest of stored foods. ARS scientists at the Grain Marketing and Production Research Center in Manhattan, Kansas, evaluated two registered insecticides for their ability to control eggs and late-stage larvae of the Indianmeal moth. Methoprene, an insect growth regulator, was effective on larvae but not as effective on eggs. Esfenvalerate, a pyrethroid, was not effective on larvae but gave some control on eggs. Using both insecticides in combination gave more complete control of eggs and larvae, and the combination treatment was also supported by an economic analysis.
Red flour beetle ability to move among floors in flour mill. Understanding the dispersal ability of an insect pest in a food facility is important in terms of interpretation of monitoring programs, understanding the rate at which an infestation can spread, and determining population structure. Red flour beetles typically disperse by walking or in short flights so they may have limited ability to move among floors in multistory structures. ARS scientists at the Grain Marketing and Production Research Center in Manhattan, Kansas, and cooperators from Kansas State University used self-mark and recapture techniques to show that beetles were able to move among floors, typically downward, even in a mill that is relatively tightly sealed between floors. Heat treatments applied for insect control drove insects from hidden refugia, but did not increase movement among floors. These results suggest that red flour beetles may be more mobile within flour mills then was originally suspected and will be useful in determining sources of insects captured in traps and in modeling population dynamics.
Field trials show effectiveness of aerosols. Small-scale tests have shown the potential of combination treatments with the insect growth regulator methoprene to control the Indianmeal moth. ARS scientists at Grain Marketing and Production Research Center in Manhattan, Kansas, conducted several field trials by exposing eggs of the Indianmeal moth in different foods and on different packaging materials treated with synergized pyrethrins applied alone and in combination with the insect growth regulator methoprene. Results of the field trials show the aerosols penetrated underneath pallets, and the combination of pyrethrin and methoprene was optimal for both best control of eggs and lowest economic cost. There was some variation depending on the specific diet or package exposed, but overall results show that the aerosols could be used to control the eggs of the Indianmeal moth in a commercial facility.