Location: Stored Product Insect and Engineering Research
Project Number: 3020-43440-010-011-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2024
End Date: Sep 1, 2025
Objective:
Stored product insect pests are cosmopolitan and can be found in food facilities, mills, processing plants, storage warehouses, and during transportation in railcars, ships, and shipping containers. Fumigation has been the primary method for treating grain and grain-based commodities, with the major fumigants being methyl bromide and phosphine. Methyl bromide use is extremely restricted and there is a need to improve the use of alternative fumigants. Phosphine and sulfuryl fluoride are two alternatives that are routinely used to fumigate warehouses and food facilities, but the distribution patterns of these gases in other structures, such as shipping containers used for shipping grain and finished products for trade and humanitarian aid, are much less well understood. In addition, the efficacy of these methods combined with other pest management tactics, such as the treatment of surfaces with contact insecticides and the use of insecticide treated packaging is unknown. The objective of this agreement will be to optimize fumigant application methods for phosphine and sulfuryl fluoride based on experiments in shipping containers, and develop and validate a computational fluid dynamics (CFD) model to simulate phosphine distribution in shipping containers filed with bagged commodities using gas concentrations collected from shipping containers for training and validation.
Approach:
To address this question, we will develop a lab-scale CFD model for phosphine in a 0.2 m3 stainless steel vessel loaded with bagged rice. Parameters such as gas tightness, spatial and temporal distribution of phosphine gas concentration, and spatial distribution of insect mortality from bioassays will be collected from this laboratory steel container and used to refine the CFD model and also test its validity. Data will be collected over four seasons to understand the impact that temperature and humidity have on gas distribution. The model will be scaled up and applied to shipping containers (20 feet in length). Data on gas-tightness and spatial and temporal distribution of fumigant gas concentration and spatial distribution of insect mortality from bioassays during fumigation will also be collected on this container. Likewise, experiments will be conducted over multiple seasons to understand the impact that temperature and weather have on gas distribution and efficacy. Additionally, the impact of leakage on fumigation efficacy, which is common in shipping containers, will be assessed.
