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United States Department of Agriculture

Agricultural Research Service

Research Project: Retaining Export and Food Security of U.S. Specialty Crops: Low-Emission Methyl Bromide Fumigations for Quarantine and Pre-Shipment Uses

Location: Commodity Protection and Quality

Project Number: 2034-43000-037-21
Project Type: General Cooperative Agreement

Start Date: Feb 17, 2011
End Date: Feb 14, 2014

Objective:
Ensure pest-free security and food safety of walnuts in postharvest marketing channels via the development of efficient, economical, and environmentally benign chemical treatments. Evaluate ovicides, such as propylene oxide, to use in concert with sulfuryl flouride fumigations.

Approach:
Phase 1. The LD 50 of sulfuryl fluoride has already been determined in our lab at 60 - 80 F for the eggs of the following target species: navel orangeworm, codling moth, and dried fruit beetle. Using these mortalities as benchmark indices, we will quantify how mortality changes as a function of increasing the molar proportion of ovicide to sulfuryl fluoride over the range: 1:100, 1:10, 1:1, and 10:1. Propylene oxide will be the first ovicide examined. Phase 2. To facilitate the detection of biomolecular conjugates, mass-labeled propylene oxide will be synthesized via the method of Beckman. The mass-labeled PPO 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. Phase 3. Using core microscopy facilities at SJVASC, we will comparatively evaluate the egg physiology of stored product insect pests including, dried fruit beetle, codling moth, indianmeal moth, and navel orangeworm. We will then expose eggs to fumigants and ovicides to observe any physiological 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: 10/25/2014
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