A five-component plant-derived pesticide blend targeting insect pests, fungal pathogens, and mycotoxin contamination in tree nuts

Authors: Shilman, Mikhail; Davis, Thomas; Gee, Wai; Henderson Ii, Thomas; Gomez, Joseph; Kim, Jong Heon; Chan, Kathleen; Palumbo, Jeffrey; Sarreal, Siov Bouy; Haff, Ronald; Hougardy, Evelyne; Rivas, Somanette; Hogg, Brian; Bansal, Raman; GHIMIRE, MAHESH - University Of California - Cooperative Extension Service; RIJAL, JHALENDRA - University Of California - Cooperative Extension Service

Submitted to: ACS Agricultural Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2026
Publication Date: 6/15/2026
Citation: Shilman, M.M., Davis, T.Z., Gee, W.S., Henderson II, T.D., Gomez, J., Kim, J., Chan, K.L., Palumbo, J.D., Sarreal, S.L., Haff, R.P., Hougardy, E.H., Rivas, S.O., Hogg, B.N., Bansal, R., Ghimire, M., Rijal, J. 2026. A five-component plant-derived pesticide blend targeting insect pests, fungal pathogens, and mycotoxin contamination in tree nuts. ACS Agricultural Science and Technology. 6(7):1368-1379. https://doi.org/10.1021/acsagscitech.6c00209.
DOI: https://doi.org/10.1021/acsagscitech.6c00209

Interpretive Summary: California’s almond, pistachio, and walnut industries generate billions of dollars annually. However, farmers are suffering significant losses due to three destructive insect pests: the navel orangeworm, the carob moth, and the Carpophilus truncatus beetle. Although current pest management methods, including the use of insecticides, have been somewhat effective, their efficacy is declining as these pests develop resistance. Furthermore, when these insects feed on the nuts, they create openings for fungi that produce aflatoxins—poisonous compounds that can contaminate entire shipments and pose a threat to food safety. In this study, researchers discovered a blend of five natural plant-based compounds that work together to effectively eliminate all three of these major pests. In addition to controlling insects, three of the compounds also inhibited the growth of harmful fungi, while one of them reducing the production of aflatoxins. This breakthrough provides more than just an additional pest control solution; it highlights a safer, natural strategy for protecting California’s most valuable nut crops from insect damage, reducing the risk of fungal contamination, and ensuring food safety for consumers around the world.

Technical Abstract: Tree nuts (almonds, pistachios, and walnuts) are highly vulnerable to insect pests and mycotoxin-producing fungi, resulting in significant economic losses and food safety concerns. We evaluated plant-derived compounds, previously identified as semiochemicals in tree nut systems, as candidates for pesticidal development. Screening of analogs of 1-octen-3-ol and 2-phenylethanol identified sulcatone, phenylacetate, and acetophenone, while eucalyptol and pogostone were independently identified and incorporated into further studies. These compounds exhibited rapid, dose-dependent insecticidal activity against adult navel orangeworm (Amyelois transitella), causing mortality within minutes at 0.1–2.2%, and were also effective against carob moth and Carpophilus truncatus. A five-component blend demonstrated insecticidal efficacy comparable to that of its most active constituents. Acetophenone, phenylacetate, and pogostone inhibited the growth of mycotoxin-associated fungi, and pogostone reduced aflatoxin production in Aspergillus flavus at =400 µM. Together, these results demonstrate a multicomponent strategy for simultaneous control of pests and mycotoxin risk.