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Abstract

Various rates of ethofumesate were evaluated for annual bluegrass (Poa annua L.) control in a perennial ryegrass (Lolium perenne L.) fairway. The tolerance of ‘Merion’, ‘Mystic’, and a blend of Kentucky bluegrasses (Poa pratensis L.) to ethofumesate also was assessed. Ethofumesate at 0.84, 1.1, and 0.84 + 0.84 kg·ha–1 provided poor annual bluegrass control; 2.2 and 1.1 + 1.1 kg·ha–1 provided good control; and 2.2 + 1.1 and 2.2 + 2.2 kg·ha–1 provided excellent control. Overall quality of Kentucky bluegrass was only slightly reduced by ethofumesate at 1.1 or 2.2 kg·ha–1; however, split applications at 2.2 + 1.1 and 2.2 + 2.2 kg·ha–1 severely reduced bluegrass cover and overall quality for 7 months. Foliar growth of sequentially treated Kentucky bluegrass appeared suppressed throughout fall and winter. Between January and April, Kentucky bluegrass plots treated with split applications of 2.2 + 1.1 or 2.2 + 2.2 kg·ha–1 had a dark-green color. No visual injury was observed in perennial ryegrass. Ethofumesate applied at 2.2 or 1.1 + 1.1 kg·ha–1 provided the best combination of safety to Kentucky bluegrass and control of annual bluegrass. Chemical names used: (±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate (ethofumesate).

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Abstract

Twenty well-watered Kentucky bluegrass (Poa pratensis L.) cultivars were evaluated for evapotranspiration (ET) under controlled environment, using the water-balance method. ET ranged from a low of 3.86 mm·day−1 for ‘Enoble’ to a high of 6.43 mm·day−1 for ‘Merton’, ‘Birka’, and ‘Sydsport’. Cultivars differed in shoot density, verdure, root density, stomatal density, and stomatal index. Only verdure was significantly correlated (r = 0.60) to ET for the 20 cultivars. Five cultivars were selected using cluster analysis to represent categories of high, medium, and low ET rates. ET for these cultivars increased from 1.1- to 1.7-fold when temperature was increased from 25° to 35°C, depending on cultivar. ET at 35° was positively correlated to vertical elongation rate (r = 0.96), and negatively correlated to shoot density (r = − 0.87) and verdure (r = − 0.83) under well-watered conditions.

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Abstract

In a 1983 study, ethofumesate at 1.1, 2.2, and 3.3 kg°ha−1; bensulide at kg°ha−1; and an untreated control were compared for annual bluegrass [Poa annua var. annua (L.) Timm] control and injury to ‘Park’ and ‘Touchdown’ Kentucky bluegrass (Poa pratensis L.). Ethofumesate at 1.1 to 3.3 kg°ha−1 reduced verdure and clipping yields of both cultivars, but gave significant P. annua control. Bensulide at 13.6 kg°ha−1 caused no injury and had unsatisfactory P. annua control. In 1984 ethofumesate was applied to ‘Touchdown’ at 1.1 and 2.2 kg°ha−1 and in repeat treatments of 1.1 + 1.1 kg°ha−1 and 2.2 + 1.1 kg°ha−1 with a 30-day interval between treatments, and was compared to bensulide at 13.6 kg°ha−1 and an untreated control. Ethofumesate caused injury at 7 and 15 days after treatment (DAT), but only the repeat treatments had significant injury at 60 DAT. No injury was detectable at 260 DAT. Excellent annual bluegrass control was obtained at 2.2 kg°ha−1 and 2.2 + 1.1 kg°ha−1. Good annual bluegrass reduction was noted for the other treatments with exception of bensulide, which only reduced the pest population by 50%. Lateral spread of ‘Touchdown’ increased with ethofumesate treatment (when compared to the untreated control) due to reduced annual bluegrass competition. Chemical names used: (±)-2-ethoxy-2,3-dihydro-3.3-dimethyl-5-benzofuranyl methanesulfonate (ethofumesate); and O,O-bis(l-methylethyl)S-[2[(phenylsufonyl) aminojethyl] phosphorodithioate (bensulide).

Open Access

Abstract

Three genetically diverse Kentucky bluegrasses (Poa pratensis L. cvs. Kenblue, Vantage, and Adelphi) and 6 other turfgrasses were evaluated for susceptibility to the greenbug, Schizaphis graminum Rondani. Nine common lawn weed species were also tested as potential alternative hosts. Heavy greenbug populations and feeding damage occurred on all 3 bluegrasses and on tall fescue (Festuca arundinacea Schreb. cv. Kentucky 31) and chewings fescue (Festuca rubra var. cummutata Guad. cv. Jamestown). Creeping bentgrass (Agrostis palustris Huds. cv. Penncross), bermudagrass (Cynodon dactylon L. cv. Midiron), perennial ryegrass (Lolium perenne L. cv. Derby), and zoysia grass (Zoysia japonica Steud. cv. Meyer) were not suitable hosts. No greenbugs survived on the 9 weed species tested.

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Abstract

Nitrogen uptake by two N-deficient turfgrass species was characterized by measuring N depletion from a complete nutrient solution. The uptake rate of both NO 3 and NH 4 + was enhanced up to 6-fold in N-deficient perennial ryegrass (Lolium perenne L.) compared to N-sufficient controls, reaching a maximum of about 0.3 and 0.4 g N/m2 per hr for NO 3 and NH 4 + , respectively. Deficiency-enhanced uptake exceeded uptake by controls for about 72 hr following resupply of N. Nitrogen uptake was enhanced to a similar degree by N deprivation in Kentucky bluegrass (Poa pratensis L.). Mowing had no effect on NO 3 uptake by N-deficient perennial ryegrass turf, whereas mowing inhibited uptake by N-sufficient turf by ≈60%. Deficiency-enhanced uptake was found to be the result of an increased capacity for N absorption (Imax) rather than an increased affinity for N (K m). Imax values increased from 0.24 and 0.73 mg N/g dry weight per hr for N-sufficient ryegrass turf for NO 3 and NH 4 + , respectively, to 1.44 and 2.68 mg N/g dry weight per hr for N-deficient turf. K m values increased slightly, from 14 μm for both N forms for N-sufficient turf to 24 and 39 μm for NO 3 and NH 4 + , respectively, for N-deficient turf.

Open Access

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The objective of this study was to determine the effect of several preemergence herbicides and of fenoxaprop, a postemergence herbicide, on establishment of Kentucky bluegrass (Poa pratensis L.) sod. Fenoxaprop was applied at 0.20 and 0.40 kg·ha-1 28 and 14 days before sod harvest and 14 and 28 days after sod laying. Three preemergence herbicides, bensulide at 8.43 kg·ha-1, DCPA at 11.80 kg·ha-1, and pendimethalin at 1.69 kg·ha-1, were applied over the top of the freshly laid sod. All applications of fenoxaprop at 0.40 kg·ha-1 were phytotoxic by 14 days after application 8 weeks after sod laying in 1986. Fenoxaprop at 0.28 (1987 only) and 0.40 kg·ha-1 caused phytotoxicity on three of the four application dates, and fenoxaprop at 0.20 kg·ha-1 discolored the turf when applied 14 days before sod harvest. None of the treatments affected rooting 4 or 8 weeks after sod laying in 1987. Chemical names used: 0,(0-bis(1-methylethyl)-S-[2-[(phenylsulfonyl)amino]ethyl]phosphorodithioate (bensulide); dimethyl tetrachloroterephthalate (DCPA); (±)-2-[4-[(6-chloro-2-benzoxazolyl) oxy]phenoxy] propanoic acid (fenoxaprop); N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin).

Open Access

Drain tile installation into a native-soil athletic field and subsequent sand topdressing applications are cost-effective alternatives to complete field renovation. However, if cumulative topdressing rates exceed root system development, surface stability may be compromised. The objective of this research was to evaluate the effects of cumulative topdressing, over a compacted sandy loam soil, on the fall wear tolerance and surface shear strength of a kentucky bluegrass (Poa pratensis)–perennial ryegrass (Lolium perenne) stand. Research was initiated in East Lansing, MI, on 10 Apr. 2007. A well-graded, high-sand-content root zone (90.0% sand, 7.0% silt, and 3.0% clay) was topdressed at a 0.25-inch depth [2.0 lb/ft2 (dry weight)] per application, providing cumulative topdressing depths of 0.0, 0.5, 1.0, 1.5, or 2.0 inches applied from 11 July to 15 Aug. 2007. Fall traffic was applied twice weekly to all treatments from 10 Oct. to 3 Nov. 2007. In 2008, topdressing applications and traffic, as described earlier, were repeated on the same experimental plots. Results obtained from this research suggest that the 0.5-inch topdressing depth applied over a 5-week period in the summer will provide improved shoot density and surface shear strength in the subsequent fall. Results also suggest that topdressing rates as thick as 4.0 inches accumulated over a 2-year period will provide increased shoot density, but diminished surface shear strength.

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Abstract

The systemic fungicides benomyl and carboxin were evaluated in controlled environment chambers as ozone protectants on annual bluegrass (Poa annua L.), Kentucky bluegrass (Poa pratensis L. cv. Merion) and creeping bentgrass (Agrostis palustris Huds. cv. Penncross); and in open-top outdoor chambers on creeping bent-grass. Benomyl sprays were effective in reducing ozone-induced injury in controlled environments on all grasses at all rates used. Carboxin was not a satisfactory ozone protectant and had direct toxic effects on leaves of all 3 species. Growth retardation due to ozone or carboxin was generally proportional to leaf injury. Benomyl sprays in the outdoor situation limited ozone injury on creeping bentgrass for several weeks in the summer but for a much shorter time in the fall.

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Abstract

The freezing resistance of leaf, crown, and root tissues was determined for nonhardened and cold-hardened cultivars of perennial rye (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and red and chewings fescues (Festuca rubra L. and F. rubra var. commutata Gaud.). The nonhardened leaf and crown tissues of all the cultivars studied survived temperatures below –9.8°C. After acclimating at 5° under short days for 6 weeks or longer, the maximum increase in hardiness was in ‘Wintergreen’ (chewings fescue) which survived –27°. The cold-acclimation behavior of ‘Wintergreen’ was studied at acclimating temperatures of 0° and 5°. Both the leaf and crown tissues had at least 2 stages of acclimation, in which an acclimating temperature of 5° was conducive to the initial stage, followed by a lower acclimating temperature (0°) for the second stage.

Open Access

Abstract

Small weighing lysimeters were used to determine potential evapotranspiration (ET) (i.e., ET when soil water is not limiting) rates of turf weeds and ground-covers. When ET was monitored during two consecutive summers, white clover (Trifolium repens L.) had the highest mean water use rate (7.4 mm·day-1). Dichondra (Dichondra repens J.R. Forst. and G. Forst.), a low-growing C4 dicot, and barnyardgrass [Echinochloa crusgalli (L.) Beauv.], a C4 monocot, used the least water (3.9 and 4.1 mm·day-1, respectively). ‘Merion’ Kentucky bluegrass (Poa pratensis L.), a C3 species, and yellow foxtail [Setaria glauca (L.) Beauv.] and smooth crabgrass [Digitaria ischaemum (Schreb.) Muhl.], C4 species, exhibited intermediate ET rates. Water use rates of these ground-covers should be considered when using them in landscapes. Eradication of some weeds, such as white clover, in well-watered turf areas may be an effective means of reducing ET.

Open Access