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Research Project: Sensitizing Navel Orangeworm to Radiation for Sterile Insect Technique Programs

Location: Healthy Processed Foods Research

Project Number: 2030-41430-001-03-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Oct 1, 2016
End Date: Jun 30, 2019

Navel Orangeworm (NOW) is a major pest of specialty crops and the top factor in infestation by A flavus and subsequent aflatoxin contamination. Stakeholders have initiated a collaborative Sterile Insect Technique program (SIT) to replace the discontinued APHIS Boll Weevil program. Currently, gamma sources are the only practical means for insect sterilization on the required level. WRRC scientists have reported that x-ray is a suitable substitute, but can’t practically meet the throughput required. WRRC scientists have also shown that natural products can sensitize fungus and bacteria to existing treatments, reducing required doses. It is known that insects can be sensitized to radiation under certain controlled atmosphere conditions. We propose to investigate sensitizing NOW through application of natural compounds, atmospheric conditions, and EM pretreatments, with the goal of reducing required doses to the point that x-ray can replace radioisotopes for a large scale SIT program.

Natural Compounds: Certain natural compounds that have been shown at WRRC to have antimicrobial and/or antifungal properties have also been shown to act as insect repellants. Of these compounds, salicylaldehyde in particular has demonstrated promising characteristics in terms of affecting insects. Salicylaldehyde is one of the most potent antimicrobial (antifungal) natural compounds tested in our lab. It is highly volatile and thus is easily spread into the target site. Most importantly, it also functions as an insect repellent. We propose to examine the effect of this compound alone on the behavior/activity of target insects, using containers to examine different concentrations and doses, then, investigate potential the synergetic relationship between NOW exposure to salicylaldehyde and sensitivity to irradiation. Other natural compounds will also be tested for ability to sensitize NOW to irradiation. 2. Atmospheric conditions: We propose to irradiate NOW in various modified atmospheric conditions, varying levels of component gasses to test for the ability to sensitize insects. 3. EM pretreatments: We propose to investigate pretreatment with microwave, UV, and infrared energies for the ability to reduce required sterilization doses for the NOW.