Location:2013 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.
3. Progress Report:
This report documents progress for the parent Project 5430-43000-028-00D, Development of Integrated Pest Management Programs to Reduce Methyl Bromide Fumigations for Control of Insects in Postharvest Structures, which started May 2008. Under Objective 1, data collection on the impact of structural treatments with methyl bromide (MB) and alternatives such as sulfuryl fluoride (SF), high temperature, or Integrated Pest Management (IPM) programs was completed. A meta-analysis dataset was compiled and analyzed to determine overall patterns in effectiveness. Because pest dispersal behavior contributes to avoiding treatments and recolonizing after treatment, movement behavior of the red flour beetle was evaluated, and the impact of a heat treatment on movement was measured. Research under this objective is supplying critical information to food facilities managers and pest control industry on fumigation efficacy and factors that impact efficacy. Under Objective 2, significant progress has been made on determining the impact of reduced-risk insecticides on pest insect populations. Studies were completed evaluating the spatial pattern of aerosol insecticide deposition using bioassay insects and equipment to measure the size and number of aerosol droplets. Experiments were conducted to evaluate the relationship between droplet size and exposure time on aerosol insecticide efficacy. The potential for treated insects to transfer insecticide to untreated insects in hidden areas within a food facility was evaluated. Tests were conducted to evaluate several new neo-nicotenoid insecticides for efficacy against stored product beetles and psocids. Several laboratory and field studies were also done to evaluate residual efficacy of pyrethrin alone and combined with methoprene for residual control of flour beetles. Research was conducted to determine the susceptibility of the life stages of warehouse beetle and sawtoothed grain beetle to the high temperatures used to disinfest structures as a replacement for MB fumigation. More effective use of these MB alternatives as part of an IPM program could reduce the need to conduct structural fumigations, facilitating the phase-out of MB. Under Objective 4, to better understand how different alternatives to MB affect populations, a simulation model for red flour beetle population dynamics in mills was further refined, and a simulation model for warehouse beetle populations was developed. These models will provide important information to guide pest management strategies for food facilities. The research conducted in this project will contribute to the development of more effective pest management programs, with the potential benefit of reducing the number of MB critical use exemptions requested and the amount of MB used.
1. Aerosols control flour beetles in mills. Pyrethroid insecticides are used as aerosols to control insect pest populations in flour mills, but the information on how aerosols impact resident populations is limited. Scientists at ARS in Manhattan conducted studies by placing food patches with different life stages of the red flour beetle underneath metal shelves inside small sheds. The sheds were either untreated or sprayed every 2 or 4 weeks with the labeled rate of the pesticide esfenvalerate, trade name Conquer. The aerosol treatments did not affect the population development in the food patches. However, there were more dead beetles in the treatments compared to the controls, and more live beetles in pheromone traps in the controls compared to the treatments. Results show that although the aerosol applications reduced overall insect numbers, the presence of available food material allowed for continued population development.
2. Uneven coverage by aerosol insecticides can lead to gaps in efficacy. Aerosol insecticide applications involve applying insecticide as small droplets in a mist or fog, and use of this method is increasing with the decline in structural fumigation. As droplets settle, horizontal features in the facility can block movement of droplets and reduce the amount of insecticide deposited under covered areas. Vertical features in facilities can also impact the dispersion of droplets from the point of release. Scientists with ARS in Manhattan KS and cooperators at Kansas State University using three different insecticide formulations found differences among treatments in how evenly the aerosol insecticide settled and also identified how temperature and horizontal and vertical features in a building impact this deposition. This information will be useful for improving application strategies to obtain a more even coverage and increase treatment efficacy.
Opit, G.P., Arthur, F.H., Throne, J.E., Payton, M.E. 2012. Susceptibility of stored-product psocids to aerosol insecticides. Journal of Insect Science. 12(139): 1-14. Available: http://www.insectscience.org/12.139.