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 fungal metabolism.
1b. Approach (from AD-416):
Utilizing a cooperative effort between USDA-ARS, industry, and University of California at Davis, research will be conducted in the context of enhancing production of California almonds via development of efficient, economical, and environmentally benign chemical strategies to reduce pest pressure, including those of synthetic and natural product origin. This research will integrate laboratory, model ecosystem, and field studies for the purpose of tracing the signature of organic chemicals through the environment and particularly fungi-mediated processes. Unique and complementary features of this research team include 1) daily access to almond orchards to gain seasonal insight, 2) utilization of world-class mass spectrometry and irradiation facilities, 3) and pre-existing infrastructure for sampling and anlysis of runoff from almond orchards.
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 goal of this project is to ensure strategic application of chemicals to control NOW in almonds by mapping the environmental fate and transport of insecticides, particularly degradative pathways involving fungal metabolism. University of California collaborator has conducted experiments related to the metabolic profiling of pyrethroids in fungi. In addition, the potential for fungal colonization over the course of a growing season has been enumerated and evaluated relative to other degradative processes, including abiotic factors (e.g., absolute humidity, sunlight, etc.) and chemical constituents of nut hulls (e.g., total phenolics, transient oxidant flux), which participate in indirect photochemcial degradation. Due to these abiotic and degradative factors, the potential for colonization of nut hulls by fungi increased as the season progressed. In particular, a marked increase in colonization potential occurred at the onset of hull split, which is also when navel orangeworm oviposition on nut hulls is at a maximum.