Tuesday, November 14, 2006
172-4
Additives Improve Clumpy Ryegrass Control with Revolver when Applied During Winter.
Steve M. Borst1, J. Scott McElroy2, and Greg K. Breeden1. (1) University of Tennessee, Knoxville, TN 37996, (2) 2431 Joe Johnson Dr, University of Tennessee-Knoxville, University of Tennessee, Plant Sciences Dept./ 252 Plant Sciences Bldg, Knoxville, TN 37996-4561
Revolver (foramsulfuron) is utilized to control clumpy, volunteer perennial ryegrass (clumpy ryegrass; Lolium perenne) in warm-season grasses, such as bermudagrass (Cynodon dactylon). Control during cool conditions (≤18 C) is often less than under warmer conditions. Additives such as methylated seed oil (MSO) and ammonium sulfate (AMS) could potentially improve control of clumpy ryegrass with Revolver. Revolver was applied at 0.014 kg ai/ha and 0.028 kg ai/ha. Revolver was applied alone, with AMS at two rates (2.27 and 4.54 kg/ha) or MSO at 1% v/v, and a three-way mixture of Revolver, AMS, and MSO at the above rates. Applications were made on 23 February 2006 . Ratings discussed were taken 3 May 2006, 10 weeks after treatments. Revolver alone at 0.014 and 0.028 kg ai/ha controlled clumpy 11 and 21%, respectively. The addition of AMS or MSO to Revolver provided modest increases in clumpy ryegrass control. AMS at 2.27 and 4.54 kg/ha with Revolver at 0.028 kg ai/ha controlled clumpy ryegrass 28 and 45%, respectively. Revolver at 0.028 kg ai/ha + MSO controlled clumpy ryegrass 49%. The greatest increase in control was achieved when Revolver was applied with AMS and MSO. Revolver at 0.028 kg ai/ha + AMS at 4.54 kg/Ha + MSO controlled clumpy ryegrass 80%. These data indicate that AMS and MSO can improve clumpy ryegrass control with Revolver during relatively low temperature conditions.