2025-03-04 ミシガン大学
ミシガン大学の研究者たちは、除草剤ジカンバのドリフト（意図しない拡散）が、農地周辺の雑草に影響を及ぼし、結果として花粉媒介者（ポリネーター）の活動を妨げることを発見しました。 ジカンバは1950年代後半に開発され、1962年に使用が開始されましたが、その後、揮発性の高さから使用が減少していました。近年、グリホサート耐性雑草の増加に伴い、ジカンバ耐性作物が開発され、再び使用が拡大しています。研究では、ジカンバのドリフトが周辺の植物に及ぼす影響を調査し、曝露された植物周辺での花粉媒介者の減少や、一部の植物での訪花回数の減少が確認されました。この結果は、ジカンバの使用が非標的植物や花粉媒介者の健康に影響を及ぼす可能性を示唆しています。
＜関連情報＞
- https://news.umich.edu/dicamba-drift-new-use-of-an-old-herbicide-disrupts-pollinators/
- https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.20438
除草剤ジカンバのオフターゲット・ドリフトが新たな経路で植物と花粉媒介者の相互作用を阻害する Off-target drift of the herbicide dicamba disrupts plant–pollinator interactions via novel pathways
Regina S. Baucom, Veronica Iriart, Anah Soble, Matthew R. Armstrong, Tia-Lynn Ashman
New Phytologist Published: 31 January 2025
DOI:https://doi.org/10.1111/nph.20438
Summary
- While herbicide use in agriculture is expected to have many effects on surrounding weed communities, it is largely unknown how plant exposure to sublethal doses of herbicide may subsequently impact plant–pollinator interactions. We tested the hypothesis that sublethal herbicide exposure indirectly alters plant–pollinator interactions through changes in plant traits, and specifically through alterations in floral display.
- Using a common garden experiment, we exposed 11 weed species to the herbicide dicamba and examined the potential for changes in pollinator abundance and patterns of pollinator visitation as well as alterations to plant traits.
- We found variation among plant species in the extent of damage from dicamba drift, and variation in size, flowering time, and flower displays, with some plant species showing negative impacts and others showing little effect. Pollinator frequencies were reduced in dicamba-exposed plots, and pollinator visits were reduced for some weed species yet not for others. Structural equation modeling revealed that the relationship between flower display and pollinator visits was disrupted in the presence of dicamba.
- Our study provides the most comprehensive picture to date of the impacts of herbicide drift on plant–pollinator interactions, with findings that highlight an underappreciated role of services supplied by weedy communities.
