Volatile profiles of almonds and pistachios and their sex-specific detection by navel orangeworm moths

Authors: Gee, Wai; REYNOLDS, BETHANY - Former ARS Employee; MAHONEY, NOREEN - Former ARS Employee; Haff, Ronald; Shilman, Mikhail

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2025
Publication Date: 1/6/2026
Citation: Gee, W.S., Reynolds, B., Mahoney, N., Haff, R.P., Shilman, M.M. 2026. Volatile profiles of almonds and pistachios and their sex-specific detection by navel orangeworm moths. Journal of Agricultural and Food Chemistry. 74, 2637-2654. https://doi.org/10.1021/acs.jafc.5c12232.
DOI: https://doi.org/10.1021/acs.jafc.5c12232

Interpretive Summary: The navel orangeworm is a significant insect pest that causes severe damage to almond and pistachio crops in California. It feeds on the nuts and spreads harmful fungi that can make the food unsafe for consumption. In this study, researchers collected and analyzed smells (called volatiles) released from various parts of almond and pistachio plants, including the nuts, shells, and leftover fruit from previous seasons. They identified 88 volatile chemicals, many of which had never been associated with these crops. The researchers then tested how the moths’ antennae (their "noses") reacted to these smells and found that male and female moths respond strongly to different odors. This research identifies the specific smells that the navel orangeworm can detect, paving the way for the development of more effective traps and repellents. Farmers may soon have access to safer and more environmentally friendly tools to monitor and control this costly pest, helping to protect crops and reduce food contamination.

Technical Abstract: The navel orangeworm (Amyelois transitella) is a major pest of almonds and pistachios in California, causing crop damage and facilitating fungal and mycotoxin contaminations. This study characterized volatile compounds emitted from almond- and pistachio-derived materials, including kernels, shells, hulls, and mummies, and evaluated their ability to elicit antennal responses in male and female moths using electroantennography. Volatiles were collected using solid-phase microextraction, Tenax adsorption, and solvent or steam distillation, and analyzed by gas chromatography–mass spectrometry. Eighty-eight volatile compounds were identified, including 50 not previously reported from almond or pistachio emissions, and 80 compounds were tested for antennal activity. Male antennae responded significantly stronger to alkenes and carboxylic acids, particularly C8–C14 carbon-chain compounds. Notably, the strongest antennal responses were elicited by low-abundance components of the volatilome, indicating heightened sensitivity to minor odorants. These findings provide a chemical basis for developing improved semiochemical-based tools for navel orangeworm monitoring and management.