Suppression of Annual Bluegrass in Creeping Bentgrass Putting Greens Using Plant Growth Regulators

Abstract

Decreased stand uniformity together with reduced aesthetics and playability caused by annual bluegrass (Poa annua) intrusion in creeping bentgrass (Agrostis stolonifera) putting greens is one of the major problems that golf course superintendents face with managing newer playing surfaces. Few herbicides are registered for selective control of annual bluegrass in creeping bentgrass greens, and the risk of herbicide resistance remains an issue, thus use of plant growth regulators (PGRs) is still the primary method of annual bluegrass suppression. This study was conducted to evaluate eight PGR treatments, employed as a series of 15 consecutive, biweekly applications to suppress annual bluegrass encroachment in ‘Pure Distinction’ creeping bentgrass maintained as a golf course putting green in Los Angeles, CA. Best annual bluegrass suppression was observed with products containing flurprimidol (FP) at 0.256 lb/acre, paclobutrazol (PB) at 0.119 lb/acre, or three-way mixture of FP, trinexapac-ethyl (TE), and PB (FP+PB+TE) at 0.055, 0.014, and 0.055 lb/acre, respectively. Although all treatments caused some significant creeping bentgrass injury, which increased over time, PB at 0.119 lb/acre and FP+PB+TE at 0.055, 0.014, and 0.055 lb/acre, respectively, appeared to be safest among effective treatments. Additionally, those treatments caused significantly darker green turf, which may be desirable on putting greens. This research confirms the potential of PGR use to limit annual bluegrass infestation on creeping bentgrass greens in a Mediterranean climate and reveals the most effective treatments that could be used in a putting green maintenance program.

Plant growth regulators differentially suppress goosegrass and smooth crabgrass in creeping bentgrass turf

“…Conversely, flurprimidol and paclobutrazol are often avoided due to perceived injury risks to creeping bentgrass in warmer, transition zone summers as was observed by Baldwin and Brede (2011). However, neither paclobutrazol nor flurprimidol unacceptably injured creeping bentgrass in this research, which is consistent with previous literature (Koski 1994;Petelewicz 2021;Reicher et al 2015). Many turfgrass managers include early-GA-inhibiting PGRs with trinexapac-ethyl applications to prolong creeping bentgrass growth suppression while maintaining the physiological benefits associated with trinexapac-ethyl applications (Kreuser et al 2018) a Area under the progress curve d -1 (AUPCD) was calculated by assuming linear changes in smooth crabgrass coverage between rating assessments.…”

Response of creeping bentgrass (Agrostis stolonifera) and weed species to plant growth regulators

“…Turfgrass managers often apply plant growth regulators (PGRs) for the improvement of putting green quality through the inhibition of uneven leaf canopy growth, suppression of annual bluegrass seedhead production, and increasing surface uniformity (Haguewood et al., 2013; Petelewicz et al., 2021). Additional benefits may include enhanced turfgrass color and tolerance to environmental stresses like drought and reduced light conditions (Burgess & Huang, 2014; Tegg & Lane, 2004).…”

Are prohexadione calcium and Pseudomonas fluorescens a solution to limit the spread of annual bluegrass (Poa annua L.) on football pitches?

“…PGRs can be divided into several groups, i.e. compounds related to auxins, gibberellins and inhibitors of gibberellin biosynthesis, cytokinins, and abscisic acid, as well as compounds affecting ethylene status (Glab et al, 2020;Petelewitz et al, 2021). Prohexadione calcium (Pc), one of the PGRs used in our study, inhibits gibberellin production in turfgrass and is mainly used to reduce the number of mowings and to suppress the seed heads of annual bluegrass (Rademacher, 2016).…”