Evaluation of the olfactory preferences of the allium leaf miner Phytomyza gymnostoma, an emerging pest in North America: comparison of three experimental bioassays

Authors: MENOUILLARD, MILLA - Université Jean-Monnet; BLANCHET, ARNAUD - European Biological Control Laboratory (EBCL); DESURMONT, GAYLORD - European Biological Control Laboratory (EBCL)

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2025
Publication Date: 9/13/2025
Citation: Menouillard, M., Blanchet, A., Desurmont, G. 2025. Evaluation of the olfactory preferences of the allium leaf miner Phytomyza gymnostoma, an emerging pest in North America: comparison of three experimental bioassays. Journal of Economic Entomology. 118,5:2301-2308. https://doi.org/10.1093/jee/toaf218.
DOI: https://doi.org/10.1093/jee/toaf218

Interpretive Summary: The allium leaf miner Phytomyza gymnostoma is an emerging insavie pest in the Northeast U.S., damaging allium crops such as onions, leeks, and chives. Monitoring tools that could reliably attract allium leaf miner adults do not exist yet and would be highly beneficial to improve early detection and management strategies. In this study, we investigated the odor preferences of the allium leaf miner with three different experimental setups (wind tunnel, olfactometer, and arena bioassay) and two different host plants (leek and chive). One of the objective of the study was to demonstrate that allium leaf miner adults are attracted by the odors of their host plants. A second objective was to compare the experimental setups and identify the most reliable and effective one. Results showed that there was a strong preference for host plants odors, with leek being more attractive than chive, compared to other plants in the wind tunnel bioassays. Moreover, previously infested leek plants were less appealing than healthy ones. In contrast, the olfactometer and arena bioassays did not show significant fly responses to host plant volatiles. These findings provide an initial foundation for developing attractants and monitoring tools for the allium leaf miner. Additionally, the study underscores the importance of using multiple bioassay approaches when investigating insect chemical ecology.

Technical Abstract: Evaluating the olfactory preferences of emerging insect pests is critical to develop monitoring tools and improve early detection and management strategies. Here the chemical ecology and olfactory preferences of the Allium leaf miner Phytomyza gymnostoma (Diptera: Agromyzidae), an invasive pest affecting crops like onions, garlic, and leeks in North America were investigated. Three bioassay methods were used under laboratory conditions: wind tunnel, Y-tube olfactometer, and an arena bioassay. All bioassays measured the responses of P. gymnostoma adults to odors of host and non-host plants, and two common allium crops, leek and chive, were used as host plants. Results of the wind tunnel bioassays showed a clear preference for host plants compared to non-host plants, with leek being more attractive than chive. Leek plants previously infested by P. gymnostoma were less attractive than healthy plants. Olfactometer and arenas bioassays failed to show any significant response of adult flies toward host plant volatiles. Overall, these results are a first promising step toward the development of attractants and monitoring tools against this pest and illustrate the value of comparing various types of bioassays when investigating the chemical ecology of insects.