1a. Objectives (from AD-416):
The overall goal of this project is to ensure strategic application of chemicals to control navel orangeworm (NOW) in almonds by mapping the environmental fate and transport of insecticides, particularly degradative pathways involving solar photolysis.
1b. Approach (from AD-416):
This research will integrate laboratory, model ecosystem, and field studies for the purpose of tracing the signature of organic agrochemicals through the environment. The specific approach involves: 1) developing methods of spectroscopic and mass spectrometric analysis of pyrethroids, 2) probing the direct and indirect sunlight-mediated photolysis of pyrethroids through a combination of kinetic modeling and byproduct analyses, 3) characterizing the chemical constituents of nut hulls as related to sun-light mediated degradation, and 4) relating sunlight-mediated degradation to the relative toxicity of pyrethroids and resulting products.
3. Progress Report:
This Assistance Type Cooperative Agreement was established to support objective 1 of the in-house project and is related to finding postharvest methyl bromide alternatives and techniques for improving methyl bromide fumigations. The specific goal of this project is to ensure strategic application of chemicals to control navel orangeworm in almonds by mapping the environmental fate and transport of insecticides, particularly degradative pathways involving solar photolysis. The approach will be to apply only those pyrethroids that resist indirect photolysis after hull split, as that is when the contribution of indirect photochemistry to pyrethroid degradation is at a maximum. The direct photolysis products of a suite of contemporary-use pyrethroids were chemically-characterized, including: bifenthrin, cypermethrin, deltamethrin, resmethrin, and phonethrin. Using benchmark photosentizers and transient oxidants, the products resulting from indirect photolysis were also characterized.