Abbreviations: BS, bare soil; FRLD, fine-root length density; KS, killed K-31 tall fesuce sod; LRLD, large-root length density; LS, living K-31 tail fescue sod; PT, living Poa trivialis sod. 1 Soil Scientist. 2 Weed Scientist. Mention of a
Roughstalk bluegrass ( Poa trivialis L.; RSBG) is a problematic weed throughout much of the northeastern quarter of the United States. Roughstalk bluegrass performs poorly under summer stresses, including high temperature, drought, and disease
Roughstalk bluegrass ( Poa trivialis L.; RBG) contamination is problematic on creeping bentgrass ( Agrostis stolonifera L.; CBG) fairways from the Midwest to the mid-Atlantic regions of the United States. Roughstalk bluegrass has poor drought
.J. 2007 Effect of certainty and velocity on cultivars of Poa trivialis . 2006 Purdue turfgrass research summary < http://www.agry.purdue.edu/turf/report/2006/18.pdf > Olson, B.L.S. Al-Khatib, K. Stahlman, P
of anthocyanin pigments to osmotic adjustment during leaf reddening J. Plant Physiol. 170 230 233 Hurley, R. 2010 Rough bluegrass ( Poa trivialis L.), p. 67–73. In: M.D. Casler and R.R. Duncan (eds.). Turfgrass biology, genetics, and breeding. Wiley
Annual bluegrass (Poa annua L.) continues to be a problem in bermudagrass golf greens overseeded with roughstalk bluegrass (Poa trivialis L. `Sabre) due to weed encroachment from adjacent fairways, lack of selective herbicide options, and weed diversity. A 2-year study was conducted on an overseeded `Tifgreen bermudagrass putting green to evaluate effects of herbicide treatments on overseeding and annual bluegrass control. Excellent annual bluegrass control (≥90%) and acceptable turfgrass cover (§70%) was achieved with oxadiazon at 2.2 kg·ha-1 a.i. applied 60 days before overseeding (DBO). Fenarimol (AS) at 4.1 kg·ha-1 a.i. (30 + 15 DBO) followed by 1.4 kg·ha-1 a.i. 60 days after overseeding (DAO) and dithiopyr at 0.6 kg·ha-1 a.i. (60 DBO + 120 DAO) also provided acceptable results. Dithiopyr at 0.4 kg·ha-1 a.i. (30 DBO + 120 DAO), dithiopyr at 0.3 kg·ha-1 a.i. (30 DBO + 30 + 120 DAO), and fenarimol (G) at 2.0 kg·ha-1 a.i. (45 + 30 DBO) followed by 0.8 kg·ha-1 a.i. 60 DAO provided inconsistent annual bluegrass control (55% to 75% in 1999 and 87% to 95% in 2000), but offered acceptable turfgrass cover (§70%) each year. The remaining treatments were generally ineffective and provided <50% annual bluegrass control one or both years. Oxadiazon applied 60 DBO at 2.2 kg·ha-1 a.i. provides an excellent option for annual bluegrass control in overseeded bermudagrass putting greens.
Rough bluegrass (Poa trivialis L.) is being utilized more frequently to overseed bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] putting greens and rapid seed germination is necessary for successful establishment. Cultivar and seed lot differences in germination rate and sensitivity to cold may exist. Germination of 10 rough bluegrass cultivars/seed lots was examined in growth chambers at 12-hour day/12-hour night temperatures of 25/15, 20/10, 15/5, and 10/0 °C, and on a bermudagrass putting green at three overseeding dates. Differences in germination among cultivars and seed lots were minimal at 25/15 or 20/10 °C, but substantial at lower temperatures. When seeded on the bermudagrass putting green, differences in germination among cultivars/seed lots were greater at the last seeding date (average daily max./min. of 16/2.7 °C), than at the first seeding dates (average daily max./min. of 21/6.1 °C). Use of blends of several cultivars or seed lots is suggested to ensure the successful establishment of rough bluegrass when overseeding at low temperatures.
Planting sod beneath peach trees (Prunus persica) to control excessive vegetative growth was evaluated from 1987 to 1993 in three field studies. Peach trees were established and maintained in 2.5-m-wide vegetation-free strips for 3 years, and then sod was planted beneath the trees and maintained for 5 to 7 years. Reducing the vegetation-free area beneath established peach trees to a 30- or 60-cm-wide herbicide strip with three grass species (Festuca arundinacae, Festuca rubra, Poa trivialis), reduced total pruning weight/tree in 5 of 16 study-years and weight of canopy suckers in 6 of 7 study-years, while increasing light penetration into the canopy. Fruit yield was reduced by planting sod beneath peach trees in 5 of 18 study-years; however, yield efficiency of total fruit and large fruit (kg yield/cm2 trunk area) were not reduced in one study and in only 1 year in the other two studies. Planting sod beneath peach trees increased available soil water content in all years, and yield efficiency based on evapotranspiration (kg yield/cm soil water use plus precipitation) was the same or greater for trees with sod compared to the 2.5-m-wide herbicide strip. Planting sod beneath peach trees has the potential to increase light penetration into the canopy and may be appropriate for high-density peach production systems where small, efficient trees are needed.
In 1992, a cultivar trial was initiated in Columbus, Ohio to evaluate differences in establishment and long-term performance of cultivars of tall fescue (Festuca arundinacea), creeping red fescue (F. rubra), chewings fescue (F. rubra ssp. fallax), hard fescue (F. brevipila), kentucky bluegrass (Poa pratensis), rough bluegrass (P. trivialis), and perennial ryegrass (Lolium perenne) under low maintenance conditions in a shaded environment. Fertilizer and supplemental irrigation were applied until 1994 to establish the grasses, after which no supplemental irrigation, or pesticides were applied and fertilizer rates were reduced to 48.8 kg·ha-1 (1 lb/1000 ft2) of N per year. Percentage cover and overall quality data were collected in 2000 and compared with data collected in 1994. Initial establishment success does not appear to be a good predictor of long-term success of a cultivar in a shaded environment. There was some variability in cultivar performance under shade within a given turfgrass species. The tall fescue cultivars, as a group, had the highest overall quality and percentage cover under shade, followed by the fine fescues, kentucky bluegrass, rough bluegrass, and perennial ryegrass cultivars.
Previous research on the potential of the gibberellin inhibiting growth regulator trinexapac-ethyl (TE) [4-(cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid ethyl ester] to improve quality and density of shaded turfgrass has been conducted under neutral-density shade. However, some phytochrome-mediated growth responses of turfgrass, such as tillering, are different under deciduous shade versus neutral-density shade. The objectives of this study were to investigate 1) whether TE would result in improved stand density and quality of turfgrass grown under deciduous shade as has been observed under neutral-density shade and 2) the shade tolerance of sheep fescue (Festuca ovina L. `Quatro') compared to tall fescue (Festuca arundinacea Schreb. `Plantation'), and rough bluegrass (Poa trivialis L.). Trinexapac-ethyl at either 0 or 29 kg·ha–1 a.i. and nitrogen at 12 or 36 kg·ha–1 were applied on 23 May, 3 July, and 15 Aug. 2003 and 21 May 2004 to each species in a randomized complete block design under deciduous shade (about 9% of full sun). Clipping yield, color, and density data were collected for 6 weeks after the May applications in each year. Visual quality was assessed for 6 weeks after application in 2004 only. In 2003, TE significantly reduced clipping yields by 35% to 50% on sheep fescue, 58% to 76% on tall fescue and 55% to 80% on rough bluegrass. However, in 2004, yield reduction was 0% to 50% for all three species and there was no interaction between week, TE, and species. `Plantation' tall fescue had the highest overall visual quality and density. Sheep fescue also provided an acceptable quality turf stand. TE application did not significantly impact the quality of these species. Rough bluegrass performance was unacceptable, and high rate applications of TE to this species in shade resulted in significant (P < 0.05) losses in density. Trinexapac-ethyl application, based on the results of this study, may not enhance turf quality of cool season grasses grown under dense tree shade.