If a decision is made to destroy an infested stand, then it is essential to get 100% kill and to prevent emergence of volunteer seedlings from long-living buried seeds and/or regrowth from crowns or rhizomes. In no-till situations, the herbicides paraquat (1,1'-dimethyl-4,4'-bipyridinium) and glyphosate [n-(phosphonomethyl)glycine] are effective for the initial kill and must be followed with a second spraying at or shortly before reseeding. Experience by several agronomists has shown that glyphosate is much more effective than paraquat for spring applications and that paraquat is satisfactory, usually in late summer only.
To obtain the latest information on formulations, rates and methods of application, label restrictions and cautions, the appropriate web pages for herbicide manufacturers and distributors should be consulted. Currently, information on paraquat can be obtained at http://www.syngenta.com/ (verified 23 Feb. 2009) and information on glyphosate can be obtained at http://www.monsanto.com/ (verified 23 Feb. 2009).