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Screening new herbicides to manage herbicide-resistant weeds in Christmas tree

• Project Objectives. The long-term goal of this study was to develop new practical, economical, and environmentally sound weed management options for Christmas trees that enable growers to deliver high-quality trees to market. This project was initiated in 2021-22. The fluridone project is now completed and the manufacturer has the data in hands to support future registrations.
• All five studies confirmed Christmas tree tolerance to fluridone in Douglas fir, Grand fir, Noble fir, and Nordman fir. Application over the top did not affect tree growth.
• The season-long studies conducted on commercial farms have shown that Cleantraxx does not effectively control cats’ ears and rattail fescue. Fluridone, in combination with Goaltender plus Simazine, improved control of these weeds as well.
• Tiafenacil was safe for Christmas trees when applied to dormant plants, even if foliage was exposed. It also temporarily controlled the cat’s ear.
• Florpyrauxifen was safe for Christmas trees in winter and summer when the foliage was not exposed.
• These data will support the registration of new herbicides in Christmas trees.

  • Project ID22-01-OSU
  • CategoriesWeed Management
  • Growing Region(s)Pacific Northwest
  • Tree SpeciesFir
  • Investigator(s)Moretti
  • Institution(s)Oregon State University
  • Research Year2021
  • Publication Year2024
  • ReportDownload 📁