Field Sandbur (Cenchrus pauciflorus) Control in Pastures Using Gramxone, Roundup Ultra, or Touchdown

Abstract

Field studies were conducted during the 1997 and 1998 growing season to eval­ uate Gramoxone (paraquat), Roundup Ultra (glyphosate), or Touchdown (sulfosate) for field sandbur control, 'Coastal' bermudgrass tolerance, and effect on bermuda­ grass yield. All herbicides were applied within eight d of bermudagrass cut except in 1998 when herbicides were applied 17 d after cutting. Roundup Ultra at 0.5 and 1.0 pt/A controlled 90% field sandbur while Touchdown at 0.5 and 1.0 pt/A controlled 89%. Gramoxone control of field sandbur ranged from 61 to 94 %. Bermudagrass injury (stunting) was greater with the 1.0 pt/A rate of RoundupUltra or Touchdown. Injury was less than 10% in most instances when herbicides were applied within 8 d of bermudagrass cut.  When herbicides were applied 17 d after bermudagrass cut, bermudagrass injury varied from 11 to 93% and resulted in some bermudagrass death. Coastal bermudagrass yield was not affected by any herbicide treatments applied within 8 d of cutting when compared with the untreated check.