Annual Bluegrass (Poa Annua) Control in Creeping Bentgrass (Agrostis Stolonifera) Putting Greens with Bispyribac-sodium

Abstract

Annual bluegrass is one of the most difficult-to-control weeds in creeping bentgrass putting greens. Field trials were conducted in 2003 and 2005 to evaluate bispyribac-sodium for annual bluegrass management in creeping bentgrass greens maintained at a 3 mm mowing height. Bispyribac-sodium applied weekly at 12 or 24 g ai/ha controlled annual bluegrass 86% 12 wk after initial treatment (WAIT). In 2003, bispyribac-sodium applied at 12 and 24 g/ha/wk injured creeping bentgrass approximately 15 and 50% by 4 WAIT, respectively. However, injury was transient and was not evident by 12 WAIT. In 2005, the 12 and 24 g/ha/wk injured creeping bentgrass 15 and 85% by 8 WAIT, respectively, and was still evident throughout the trial. Putting green quality was reduced when compared to nontreated creeping bentgrass by the same treatments. The removal of annual bluegrass caused soil exposure until creeping bentgrass grew over the bare areas, contributing to decreased quality evaluations. Management of annual bluegrass in creeping bentgrass putting greens is possible with bispyribac-sodium. However, these results indicate bispyribac-sodium can cause excessive injury when applied to creeping bentgrass mowed at 3 mm.

Annual Bluegrass Control in Perennial Ryegrass and Tall Fescue with Bispyribac-sodium

“…Bispyribac-sodium efficacy for annual bluegrass control in both turfgrasses was greater in 2006 than 2007. Bispyribac-sodium activity for annual bluegrass control is highly affected by application timing, temperature, and soil properties which may influence efficacy over years (6,8,11,12,23). Lower rates (37 to 148 g/ha) of bispyribac-sodium provided inconsistent levels of annual bluegrass control over years but higher rates (222 and 296 g/ha) provided ≥ 90% control in both years.…”

Annual Bluegrass Control on Putting Greens from Three or Four Years of Season‐long Applications of Herbicides or Plant Growth Regulators in Three States

“…In this same study, season‐long applications of the commercially available combination of flurprimidol + trinexapac‐ethyl provided marginal to no control of ABG depending on rate and location. There are currently no postemergence herbicides labeled for ABG control on putting greens, but bispyribac has reduced ABG in putting greens–height turf in research trials, albeit with varying levels of discoloration or injury (McCullough and Hart, 2010; Teuton et al, 2007).…”

Fall Applications of Mesotrione For Annual Bluegrass Control in Kentucky Bluegrass

“…Though mesotrione has potential for controlling annual bluegrass in Kentucky bluegrass, the inconsistency in control between years and/or locations in this study would be considered commercially unacceptable. However, this inconsistency is typical among other herbicides labeled for annual bluegrass control including ethofumesate (7,9,26) or bispyribac-sodium (11,21,31). Mesotrione is highly effective on creeping bentgrass (5,11,17) and a number of broadleaf weeds (12), thus fall applications could target these weeds primarily with Poa annua as a secondary target.…”