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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Stored Product Insect and Engineering Research » Research » Research Project #430316

Research Project: Modeling Distribution of Insecticidal Aerosols in Mills and Processing Facilities

Location: Stored Product Insect and Engineering Research

Project Number: 3020-43000-033-01-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2016
End Date: Sep 30, 2018

Objective:
Determine the factors that influence distribution of aerosols used to control stored product insects, model that distribution for different milling structures and configurations, and develop predictive models for field applications that can be utilized to improve efficacy of those aerosols.

Approach:
1. Model aerosol particle size distribution in a laboratory exposure chamber. Laboratory bioassays have been conducted to assess efficacy of pyrethrin aerosol dispensed at either 2 microns or 16 microns in a laboratory vertical-flow chamber at MRI Global in Kansas City, MO. Additional data will be collected on residual efficacy of a combination of pyrethrin + the insect growth regulator methoprene, using direct and indirect exposure of immature life stages of selected stored product insects. Data are also being collected regarding actual concentrations of the aerosol dispensed during those trials, which can be utilized to develop an initial model relating efficacy to particle size and concentration. Future trials will involve assessing impact of sanitation on residual efficacy. 2. Adapt the model for use in structures with different internal configurations. Data will also be used from completed field trials where aerosol distribution has been monitored, using TSI Aerodynamic Particle Sizers to determine particle size dispensed during field trials, and how that particle size changes during the application process. Aerosols are typically applied for short time intervals in a milling facility, but there is a waiting period or holding time, typically 2-6 hours, before the facility is vented and re-entry is allowed. Initial results show that particle size rapidly decreases after the aerosol application ceases and the particles settle to the floor area. Current and planned research assessing aerosol efficacy at different exposure times, utilizing forced air movement to improve distribution, examining impacts of structural barriers on aerosol efficacy, and impact of cleaning and sanitation on residual persistence of aerosols. Models will be developed for field sites that can be adapted for to account for potential variations in structural configuration.