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United States Department of Agriculture

Agricultural Research Service

Research Project: Circumventing Ovicidal Deficiencies of Sulfuryl Fluoride and Other Postharvest Fumigants Project Number: 5302-43000-037-26
Project Type: Reimbursable

Start Date: Feb 17, 2013
End Date: Feb 16, 2014

Objective:
Complete normal atmospheric pressure testing and then scale vacuum and normal atmospheric pressure fumigation toward commercial scale applications with validation. Specific objectives of the research include: 1) Conduct insecticidal efficacy trials at temperature < 70ºF (i.e., 50 & 60ºF), 2) Begin scaling fumigations toward commercial scenarios, and 3) Determine the environmental factors (e.g., temp, air flushes, etc.) that minimize chemical residues associated with ovicide-sulfuryl fluoride pairings, particularly those resulting from the propylene oxide-sulfuryl fluoride mixture. Tailor fumigant-ovicide application to minimize residue formation.

Approach:
At 70ºF, the optimized ratio for the sulfuryl fluoride-propylene oxide mixture has been identified under vacuum as well as normal atmospheric pressure. We will follow the same experimental procedure and process at 50 and 60ºF. At 70ºF, efficacy studies will transition from 1 cubic foot chambers into nine cubic foot chambers and commodity will be included in the testing. To facilitate the detection of biomolecular conjugates, mass-labeled propylene oxide will be synthesized via the method of Beckman. The mass-labeled propylene oxide will then be used to fumigate inshell walnuts; a mass balance will be generated. Mass-labeled residues that are likely to be formed during walnut fumigations will be characterized in studies on surrogate biomolecules such as: oleic acid, bovine serum albumen, and glutathione. We will expose eggs to fumigants, ovicides, and other physiologically active gases to observe any morphological change that results. Once mechanistic details are gathered, we will tailor chemical and physical approaches to exploit weakness in egg shells. Approaches will only be explored that are amenable to existing infrastructure of the walnut industry.

Last Modified: 12/20/2014
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