Herbicide Programs for Annual Bluegrass (Poa annua L.) Control in Nebraska

Abstract

Core Ideas Research done on annual bluegrass (ABG) control in other areas of the US are likely applicable to Nebraska. However, extreme weather can dramatically affect short‐term annual bluegrass cover and emphasize the need for long‐term control studies. Three fall POST applications of mesotrione plus prodiamine applied preemergence in August and/or November were effective for ABG control in Kentucky bluegrass fairways. Replacing mesotrione with ethofumesate was also effective when combined with prodiamine in August and November. June applications of bispyribac‐sodium at 4 oz/ac was highly effective for controlling ABG in creeping bentgrass fairways, and adding two more fall applications at the same rate improved control slightly, but there was no benefit to raising the rate to 6 oz/ac. Annual bluegrass (Poa annua L.) (ABG) is common in golf courses, and its control has been thoroughly researched in cool‐season turf east of the Mississippi River in the United States. However, ABG response to herbicides varies widely among environments and/or biotypes, and little ABG control research has been done in the northern Great Plains. Therefore, our objective was to validate ABG herbicide control systems in golf course fairways of Kentucky bluegrass (Poa pratensis L.) (KBG) or creeping bentgrass (Agrostis stolonifera L.) (CBG) in Nebraska. Preemergence (PRE) treatments of prodiamine or mesotrione were applied in late summer over 3 yr with or without fall postemergence (POST) treatments of mesotrione or ethofumesate for ABG control in a low‐mow KBG fairway. We also evaluated rate and frequency of bispyribac‐sodium applications with or without a late summer–applied PRE (dithiopyr) in early September for ABG control over 3 yr in a CBG fairway. Our research indicates that ABG control work done in other areas are likely applicable to Nebraska. Three fall POST applications of mesotrione plus prodiamine applied as a PRE in August and/or November was effective for ABG control in KBG fairways. Replacing mesotrione with ethofumesate was also effective when combined with prodiamine in August and November. June applications of bispyribac‐sodium at 4 oz/ac were highly effective for controlling ABG in CBG fairways, and adding two more fall applications at the same rate improved control slightly, but there was no benefit to raising the rate to 6 oz/ac. Lastly, extreme weather in one summer and one winter dramatically affected short‐term ABG cover and emphasized the need for long‐term control studies in areas with dramatic weather cycles.

Annual bluegrass weevil, paclobutrazol, and overseeding for annual bluegrass control in cool‐season turfgrass

“…Previous field studies have shown that 1 yr of similar paclobutrazol regimen eliminated 85% of annual bluegrass on creeping bentgrass fairways (Woosley et al, 2003). The efficacy of sequential paclobutrazol applications for annual bluegrass control is also demonstrated on putting greens through the work of Patton et al (2019) and Reicher and Sousek (2017). In our research, effects of paclobutrazol were less dramatic at Forest Hill than at Hort Farm 2.…”

Using Herbicides and Perennial Ryegrass to Renovate Turf Dominated by Annual Bluegrass

“…Investigating multi-year herbicide programming for ABG suppression following PRYE seeding is warranted. While it is unclear why greater success was achieved in our research following 2015 applications compared with 2016 applications, inconsistent suppression of ABG using mesotrione has been previously reported (Patton et al, 2011;Reicher et al, 2011;Skelton et al, 2012;Reicher et al, 2017).…”

“…However, ABG control with these herbicides is often poor or inconsistent (Reicher et al, 2011). Mesotrione is registered for preemergence ABG suppression (Anonymous, 2011); research evaluating postemergence efficacy demonstrates that while sequential applications can provide ABG control, efficacy is often inconsistent across experiments (Patton et al, 2011; Reicher et al, 2011; Skelton et al, 2012; Reicher et al, 2017). Ethofumesate is registered for ABG control in cool‐season turfgrass and provides more consistent ABG control than mesotrione in cool‐season turf as well as bermudagrass ( Cynodon dactylon [L] Pers.)…”

“…Ethofumesate is registered for ABG control in cool‐season turfgrass and provides more consistent ABG control than mesotrione in cool‐season turf as well as bermudagrass ( Cynodon dactylon [L] Pers.) overseeded with PRYE (Dernoeden and Turner, 1988; Rossi, 2001; Reicher et al, 2011; Reicher et al, 2017; Kopec et al, 2016). Amicarbazone is another herbicide registered for selective ABG control in cool‐season turfgrasses; tank mixtures with mesotrione can be synergistic (Anonymous, 2012; Branham, 2012; Elmore et al, 2013a).…”

Hydroseeding with mesotrione in tankmix for establishment of perennial ryegrass

“…Many herbicides are labeled for use on established turfgrass but few are labeled for use before or at seeding. Mesotrione (2-[4-(methylsulfonyl)-2-nitrobenzoyl]-1,3-cyclohexanedione, sold as "Tenacity") is an effective preemergence and postemergence herbicide that controls common turfgrass weeds and is labeled for use both during 2008; Golob, Johnston, Proctor, & Williams, 2013;Jones & Christians, 2007), annual bluegrass (Poa annua L.; Elmore, Brosnan, & Kopsell, 2013;Reicher, Sousek, & Giese, 2017;Reicher, Weisenberger, Morton, Branham, & Sharp, 2011) and other weeds (Beck et al, 2015;Brewer, Willis, Rana, & Askew, 2017;Brosnan, Breeden, & Elmore, 2010a, 2010b.…”