Each country has its own lists of registered herbicides that can be used on tall fescue or grass seed crops. Data from herbicide trials are summarized in Appendix 23-1.

Seedling Stands

Broadleaf weed control can be achieved using herbicide programs that are similar to those used for ryegrass.

Grass Weeds

Commonly used herbicide programs include:

Ethofumesate [Nortron, Bayer CropScience, Research Triangle Park, NC; (RS)-2-ethoxy-2,3-dihydro-3,3-dimethylbenzofuran-5-yl methanesulfonate]. Tall fescue is tolerant to rates of up to 1.5 kg ai/ha (3 L/ha of Nortron).

Wild Oat Control. Wild oat can be controlled in seedling tall fescue with difenzoquat (Avenge, American Cyanamid Company, Parsippany, NJ; 1,2-dimethyl-3,5-diphenylpyrazolium) at a rate of 640 kg ai/ha. In late winter, control is achieved with fenoxaprop-p-ethyl {Puma 500, Bayer CropScience, Research Triangle Park, NC; ethyl (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionate} at a rate of 500 g ai/ha with no surfactant or with L-flamprop-isopropyl (isopropyl N-benzoyl-N-(3-chloro-4-fluorophenyl)-dl-alaninate; Commando) at a rate of 1.0 kg ai/ha after closing. Mediterranean-type tall fescue cultivars are not tolerant of fenoxaprop-p-ethyl.

Volunteer Ryegrass. Volunteer ryegrass is perhaps the most serious weed in second- and multi-year crops. Volunteer plants should be rogued out by hand or by spot spraying with glyphosate [N-(phosphonomethyl)glycine]. Atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) at 4 L/ha plus roguing three times has been used successfully to reduce ryegrass levels from 31% seedlot contamination to 0.8% (H. Ritchie, at Otane, New Zealand, personal communication, 2006). Atrazine + diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] mixes resulted in higher levels of ryegrass control than either atrazine or diuron alone (Rolston and Archie, 2002).


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