Chemical Alternatives to the Spray-Smother-Spray Method of Toxic Tall Fescue Replacement. (3804)
Authors:
J.G. Andrae* - University of Georgia N.S. Hill - University of Georgia T. Murphy - University of Georgia G. Durham - University of Georgia B. Kittle - University of Georgia
Abstract:
Novel endophyte-infected tall fescue is likely more competitive with toxic tall fescue than endophyte-free varieties. This may allow fall herbicide applications to replace the traditional spray-smother-spray renovation method. In this study, the effectiveness of multiple fall herbicide applications for replacing toxic tall fescue was examined. Wild-type 95% infected tall fescue was mowed during spring 2001 to prevent seedhead production. Single or double paraquat, glyphosate or
glufosinate applications were sprayed on September 10, 2001 and October 2, 2001 in six replicate 1.5 x 4.6 m plots. MaxQ tall fescue was no-till drilled (22.4 kg/ha) into all plots on October 17, 2001. Surviving plants were counted and plots were harvested over a three year period to quantify ergot alkaloid concentration. Single or double glyphosate applications had the lowest ergot alkaloid concentration in subsequent MaxQ harvests. Paraquat treatments had intermediate alkaloid levels, and escape plant counts indicated a large number of viable escape plants.
Glufosinate applications did not reduce sward alkaloids. Glyphosate plots had numerically higher alkaloid concentrations in 2003 than in 2002; however, this response may be due to decreased annual weed composition. A follow-up study examining various glyphosate application intervals versus spray-smother-spray is ongoing and will be reported.
Speaker Information: John Andrae, University of Georgia, 3111 Miller Plant Sciences, Athens, GA 30223; Phone: 706-542-1529; E-mail: [email protected]
Session Information: Monday, November 1, 2004, 1:10 PM-3:30 PM Presentation Start: 1:45 PM
Keywords: Tall Fescue; replacement; endophyte; herbicide
