Submitted to: Washington Mint Drops
Publication Type: Popular Publication
Publication Acceptance Date: November 1, 2005
Publication Date: November 1, 2005
Citation: Boydston, R.A. 2005. Emerging weed problems in mint. Washington Mint Drops. Washington Mint Growers Association, p. 1-2, Fall 2005. Interpretive Summary: Weeds lower mint oil quality and oil yield when present in mint production. Several winter annual weeds and biennial weeds that are often difficult for growers to control are discussed. Shifting from a spring applied herbicide program to fall applied herbicides may improve control of some of these difficult to control weeds. Herbicide resistant weed populations have been confirmed in mint production. Weed resistance to the herbicide terbacil is the most common. Growers should identify and confirm herbicide resistant weed populations and alter weed management practices to prevent weed resistance. Diverse crop rotations, utilizing several or methods of weed control, and altering herbicides with different mode of actions will help delay development of herbicide resistant biotypes.
Technical Abstract: New weed problems continue to evolve in mint production. Common groundsel, western salsify, white cockle, rattail fescue are four weeds that are difficult to control and often escape weed management programs in mint production. All four of these weeds have the ability to germinate in fall and spring. Fall germinated seedlings are often too large to control well with spring applied herbicides. Fall tillage and/or fall applied herbicides can often improve control of these and other winter annual weeds. Specific herbicide treatments that effectively control these weeds are discussed. Herbicide resistant weed biotypes have been confirmed in mint production in the Pacific Northwest, with resistance to terbacil being the most common. Altering weed management practices and crop rotations and avoiding using the same weed management strategies and herbicides year after year facilitate the prevention of herbicide resistant biotypes.