Bluegrass Turf Research Articles

Exploring Natural Alternatives for Annual Bluegrass Control

A field experiment was conducted to identify and examine the effectiveness of potential non-traditional chemical products and alternatives for controlling annual bluegrass (Poa annua L.), a plant with increasing herbicide resistant problems. In managed turf systems annual bluegrass can be a difficult winter annual weed to control having negative impacts on turfgrass quality. This study included 12 different treatments [untreated check, baking soda, white vinegar + lemon juice, Suppress herbicide, superphosphate (0-20-0), clove oil, Weed Zap, Avenger Weed Killer, Fiesta Turf Weed Killer, Ecologic Weed & Grass Killer, Alcohol (43% ethanol), and Pool Time Algicide] applied to a TifEagle bermudagrass (Cynodon dactylon × C. traansvalensis) putting green where a natural infestation of annual bluegrass was present. Treatments were assessed visually for annual bluegrass control and turf phytotoxicity 1, 2, and 4 weeks after application. Overall, no treatment provided long-term control which was non-selective. Control was short-lived with annual bluegrass recovery beginning approximately two weeks after applying treatments. Greatest Poa burndown (~85%) was temporarily (1 to 2 weeks after application) with a combination of caprylic and capric acids (Suppress Herbicide) and a combination of clove oil and dishwashing detergent but plants fully recovered by three weeks after application. These products also produced similar temporary turf phytotoxicity. Bermudagrass turf phytotoxicity from selective treatments was most evident one week after applying treatments and turf had mostly fully recovered by four weeks after treatment. Suitable alternatives were not identified from products tested.

Quantitative and qualitative responses of an established Kentucky bluegrass (Poa pratensis L.) turf to N, P, and K additions

Kentucky bluegrass is a common turf species used on golf courses, sports fields, municipal parks, sod farms, road banks, as well as residential and school yards. Our objective was to determine the effects of N, P, K rates on turfgrass quantitative response (clipping yield and underground turf biomass) and qualitative response (shoot density and foliage colour) under a continuous clipping removal. A 3-yr field study was conducted on two sites, a sand that met the specifications of the United States Golf Association (USGA) and a loam. The factorial experiment was arranged in a randomized complete block design with four replicates and different levels of three nutrients, N (0 or 50 to 300 kg ha-1 yr-1), P (0 or 21.8 to 87.3 kg P ha-1 yr-1), and K (0 or 41.7 to 250 kg K ha-1 yr-1). The maximum clipping yield was produced at the rate of 200 kg N ha-1 yr-1 in the loam and 300 kg N ha-1 yr-1 in the sand. Increasing N rates linearly reduced underground turf biomass. Added P and K had no effect on clipping yield and underground turf biomass. Nitrogen significantly improved shoot density and foliage colour. However, equivalent shoot density and colour ratings required 40 to 80 kg more N ha-1 yr-1 in the sand compared to the loam. Phosphorus and K had no significant effect on shoot density and colour in the loam. Colour response to P and K depended on N rates in the sand. Fertilizer units needed to increase soil test P averaged 6 kg added P ha-1 mg-1 PM-III kg-1 across soil types. To replenish soil K, 7 kg K ha-1 per mg KM-III kg-1 were required in the sand, and 3 kg K ha-1 per mg KM-III kg-1 in the loam. Phosphorus and K fertilizer programmes should account for P and K removals to maintain low to medium fertility levels for P, and medium for K when conditions are similar to those in this research. Key words: Turfgrass clipping yield, underground turf biomass, turfgrass shoot density, turfgrass foliage colour, Kentucky bluegrass fertilization

Mass Balance of15N Applied to Kentucky Bluegrass Including Direct Measurement of Denitrification

Although the fate of fertilizer applied to turfgrass has been studied in the past, recovery of applied fertilizer N is typically low, and denitrification has been cited as the reason. The objectives of this research were twofold: (i) to examine the fate of 15 N applied to Kentucky bluegrass (Poa pratensis L.) turf as KNO 3, including direct measurement of denitrification; and (ii) to determine whether and how plants affect fertilizer-N recovery. Polyvinyl chloride (PVC) cylinders, modified to permit atmospheric sampling, were used throughout field experiments during the spring and summer 1999 and a greenhouse experiment in 2000. Potassium nitrate (98.5 atom % 15 N) was applied in solution at 49 kg N ha -1 to replicated plots, and atmospheric samples were collected three times a day from 0800 to 1100, 1100 to 1400, and 1400 to 1700 h during a 6-wk period in the spring and a 4-wk period during the summer of 1999. Emission of N 2 or N 2 O ranged from 3.3 to 21.3% and from 0.3 to 5.9% of labeled fertilizer N (LFN), respectively. Recovery of LFN in the soil or plant, plus that emitted as N 2 or N 2 O, ranged from 57.4 to 73.2%. A 4-wk greenhouse experiment comparing LFN recovery for bare soil and turf, including gas emission and leachate, was initiated in the summer of 2000. Total emission of LFN as N 2 or N 2 O was 19.0% for the turfgrass, as compared with 7.3% for the bare soil. Corresponding values for total recovery of LFN were 70.6 and 84.2%, respectively.

Kentucky Bluegrass Responses to Mowing Practice and Nitrogen Fertility Management

ABSTRACT The practice of leaving clippings on the lawn recycles nutrients and reduces yard-waste but the residue of unsightly clippings deters widespread adoption. An experiment was conducted on a Kentucky bluegrass (Poa pratensis L.) turf to evaluate mowing practice in combination with various fertilizer types and application rates. The main objective was to minimize clipping yield while achieving acceptable turfgrass quality. The return of clippings, as compared to clipping removal, was associated with fewer weeds and a darker green more luxuriant turf. Furthermore, the benefits of clipping return were achieved using half (97.6 kg ha□ 1 yr□ 1) as much N as is typically applied (195.2 kg ha□ 1 yr□ 1) for high maintenance turf. Slow-release N fertilizers were shown to reduce spring clipping yield and thereby make the practice of clipping return a more acceptable mowing practice.

Seasonal Factors Affecting the Control of Annual Bluegrass (Poa annua L.) with Xanthomonas campestris pv. poae (JT-P482)

Abstract To ascertain the optimum timing for the application of Xanthomonas campestris pv. poae to control annual bluegrass ( Poa annua ), the differences in the efficacy of treatments initiated in consecutive months were investigated. October treatment and February through April treatments produced acceptable levels of fresh weight (FW) loss in annual bluegrass the following spring in pot experiments set in the field. More than 75% cumulative seedhead suppression was achieved by the October, November, and February treatments. Bacterial populations in annual bluegrass plants increased to 10 9 CFU/g of FW in the case of all application timings but the best control was obtained when maximum bacterial numbers were reached within 1 month of treatment. The differences in efficacy caused by different application timings (fall or spring) were compared in different turf fields. In two Kohrai ( Zoysia matrella ) turfs and in Kentucky bluegrass ( Poa pratensis ) turf, the fall and spring treatments were highly effective. However, in bentgrass ( Agrostis palustris ) turf, control of annual bluegrass was slower. October and/or March treatments effectively inhibited seedhead production, but April treatment was too late to prevent seed scattering. Taking into account late-emerging annual bluegrass, the optimum strategy for timing of treatments is application in early fall to obtain significant fresh weight loss and seedhead suppression or application in early spring, just before seed ripening, to obtain seedhead suppression and to control late-emerging plants.

Fate of amended urea in turfgrass biosystems

Abstract The fate of nitrogen (N) has been studied under several agronomic crops and agricultural profiles, but relatively little information has been collected from areas managed as turfgrass. The turfgrass industry has become the focus of environmental concerns in recent years and is often identified as a source of ground water contaminate. The objectives of this study were to: i) investigate the hydrology of 20‐cm diameter by 50‐cm deep undisturbed soil columns covered with a Kentucky bluegrass (Poa pratensis L.) turf under a heavy (one 2.54‐cm application) and a light (four 0.64‐cm applications) irrigation regime, and to ii) quantify the fate of 15N‐labeled urea when it is applied to an undisturbed soil columns having intact macropores. Clipping, verdure, and thatch/mat samples were taken from each column, and the soil was excavated in 10‐cm layers at the end of the 7‐day test period. A glass collection chamber was used to collect volatilized N and a plastic bag for leachate collection. All samples we...

Greenbug Control, 1992

Abstract Greenbug infested turf was treated with four insecticides in the right-of-way area between the sidewalk and street adjacent to a residential lawn in Urbana, IL on 23 Jul. The bluegrass turf was maintained at a mowed height of approximately 2-2.5 inches. Applications were made between 10:00 a.m. and 12:30 p.m. CDT at 85°F and 74% relative humidity. The experimental area consisted of turf areas under and near the canopies of two small Norway maple trees (Acer platanoides L.). The turf in these areas was somewhat uniformly infested with greenbugs as determined through visual observation, the turf generally orangish-brown with numerous green grassblades infested with greenbugs dispersed through the area. Each treatment plot was 25 ft2 with four replications in a RCB design, two replications per tree area. The two experimental plot areas were separated from each other by 14 ft. Applications were applied with a hand-pressurized portable sprayer at 5 gal/1000 ft2. Insecticide treatments were diluted with water; controls consisted of water only. No rainfall fell for 24 h after the application. Counts were made of surviving greenbugs 5 DAT in each plot. The number of greenbugs in a 4 inch square area (16 in2) in three locations in each plot were counted and then averaged.

Controlled-Release Preemergence Herbicide Formulations for Annual Grass Control in Kentucky Bluegrass (Poa pratensis) Turf

Field, greenhouse, and laboratory studies were conducted to evaluate the performance of starch xanthide (SX), sludge polymer (SP), and coventional formulations (CF) of benefin [N-butyl-N-ethyl-2,6-dinitro-4-(trifluoromethyl)benzenamine], oxadiazon {3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H-one}, and prosulfalin {N-[[4-dipropylamino)-3,5-dinitrophenyl] sulfonyl]-5,5-dimethylsulfilimine} for the control of large crabgrass [Digitaria sanguinalis(L.) Scop. # DIGSA] in Kentucky bluegrass (Poa pratensisL.) turf. Turf injury was greatest with SP oxadiazon and prosulfalin formulations, while SX formulations of oxadiazon and prosulfalin caused decreased and /or delayed injury and provided control comparable to conventional formulations. Coarse SX granules containing prosulfalin caused less turf injury than fine granules, while the opposite effect sometimes occurred with SX oxadiazon. Differences in control were observed in the greenhouse when SX benefin formulations which varied in cross-linking agent and/or degree of substitution were compared to the conventional formulation on sandy and silt loam soils. Benefin SX formulations also demonstrated controlled-release properties, which improved large crabgrass control when compared to the conventional formulation in the greenhouse. This effect was short lived on silt loam but persisted on sand. SX granules cross-linked with Fe3+extended benefin activity longer than H2O2cross-linked materials on sandy soil only. Release of14C-labeled benefin from SX matrices was altered by the extent of water imbibition, solvent characteristics, and granule size.

Fall Control of Japanese Beetle Larvae in Bluegrass Turf, 1982

Abstract The experiments were conducted in the left rough of No. 3 fairway at Blackhawk Golf Course, Westerville, OH. The turf was composed of approximately 90% Kentucky bluegrass and 10% crabgrass. Mowing height was 2.5-3 in. There was no measurable thatch at this site. The predominent soil type was Alexandria-Cardington, characterized as a greyish brown, strongly acid, friable silt loam 8-12 in thick. Environmental conditions at application time were as follows: air temperature, 70 F; relative humidity, 90%; wind from the NW at 0-4 mph; overcast skies; and dry soil. Nine treatments replicated 4 times were applied to 6ft × 8 ft (1.8m × 2.4m) experimental plots arranged in a RCB design. Liquid applications were made using a CO2 pressurized sprayer with 3 8020 nozzles mounted on a 4 ft aluminum boom, operating at 25 psi with a 4 gal/1000 ft spray rate. Granular materials were applied with a 2 ft Gandy drop spreader. All treatments were irrigated with 0.25 in of water immediately after application on Sep 15. Pretreatment counts showed a range of 16-30 grubs/ft. The experimental plots were evaluated at 40 DAT (Oct 25), by randomly sinking four 7.75 in diameter cylinders (ca. 0.33 ft) into the turf to a depth of 8-10 in and counting the number of viable larvae in the plugs of soil.

Degradation of Benefin and DCPA in Thatch and Soil from a Kentucky Bluegrass (Poa pratensis) Turf

The rates of degradation of14C-benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) and14C-DCPA (dimethyl tetrachloroterephthalate) were significantly faster in thatch than in soil from a Kentucky bluegrass (Poa pratensisL.) turf. These results suggest that herbicides applied preemergence in turf will persist for shorter periods of time because of the carbon-enriched medium (thatch) and that higher rates or more frequent applications may be required to maintain concentrations at effective levels.

Japanese Beetle Control on Bluegrass Turf, 1978

Abstract Candidate insecticides were compared with two registered insecticides commonly used on turf in Connecticut. The test was laid out in a randomized complete block design with 100 ft2 plots. Treatments were replicated 4 times. The test site was a commercial turf farm near Windsor. Insecticides were applied on September 7 with granular materials mixed in sand to increase bulk and applied with a hand spreader. Liquid formulations were applied with a watering can at 1.5 gal/100 ft2 rate. All plots were irrigated with 0.5 inches of water one hour after treatment. The grub population consisted of 15 second and third stage larvae per ft2. The soil was a silty loam with an analysis of: pH 5.2, organic matter 4.1%, sand 72.4%, silt 22.6% and clay 5.0%. The thatch layer was 0.50 inches. Rainfall from the start of the test to September 28-29, when the test was evaluated, was 1.30 inches. The sampling technique consisted of taking six, 0.23 ft cores from each test plot and counting the grubs in each core.

Effect of Nitrogen Sources in Complete Fertilizers on Bluegrass Turf1

SynopsisA single spring application of fertilizer containing both quickly and slowly available nitrogen produced a greater summer weight of grass than either regular fertilizer or sewage sludge with equivalent nitrogen contents. The advantage was more pronounced when clippings were removed than when they were retained. Summer grass yields were greatest when a spring fertilizer‐application was supplemented by additional summer treatments.

Herbicidal Properties of 2,4-Dichlorophenoxyacetic Acid Applied in Dusts Containing Hygroscopic Agents

1. 2,4-Dichlorophenoxyacetic acid was applied in different concentrations (0.5, 1.0, 2.5, 5.0, and 10.0%) in dust carriers, at the rate of 4 pounds per 1000 square feet, to Kentucky bluegrass (Poa pratensis) and white clover (Trifolium repens) growing in a mixed stand in greenhouse flats. The 10.0% dusts were also tested on heal-all (Prunella vulgaris) and lawn pennywort (Hydrocotyle rotundifolia) in flats and on narrow-leaved plantain (Plantago lanceolata) growing in 3-inch clay pots in a greenhouse. 2. Comparison of Pyrax, fuller's earth, and Cherokee Clay as diluents or dust carriers at each of the concentrations indicated that there was no marked difference among them on the basis of the plant responses observed. 3. Complete eradication of clover from bluegrass turf was obtained by applications of dust containing 10.0% of the acid, but the bluegrass was severely injured and recovered only slowly. Almost complete eradication (99%) was obtained by application of dust containing 5.0% of the acid, and the grass recovered quickly from the slight injury that developed. A minimum concentration of 2.5% of the acid was necessary to kill an appreciable amount (85%) of clover. No bluegrass injury was observed at this concentration. 4. Heal-all, lawn pennywort, and plantain were likewise killed by application of dusts containing 10% of the acid. 5. Addition of hygroscopic agents, such as Carbowax 1500 or glycerin, at the rate of 3% markedly increased the effects of the growth-regulating substance in dust mixtures. Addition of calcium chloride to the regular dusts resulted in only a slight increase in effectiveness of the acid. Plants of morning-glory (Ipomea lacunosa) were killed by dusts containing 0.05% concentration of acid plus 3% Carbowax 1500, while comparable plants were but slightly affected and recovered from treatment with the same kind of dust having an equal concentration but no hygroscopic agent added. 6. Plants of ragweed (Ambrosia bidentata) were not evidently affected by the application of dusts containing 0.5% of the acid. Comparable plants exhibited severe epinasty and failed to grow following treatment with a 0.5% acid dust to which either Carbowax 1500 or glycerin had been added. 7. Similar results were obtained with plants of lamb's-quarters (Chenopodium album), which were killed after 4 weeks by application of dust containing 0.5% of acid and 3% of Carbowax 1500 or dust containing the same amount of the acid but with glycerin added. The plants were but slightly affected by comparable dusts that did not include the hygroscopic agents. 8. Caution should be exercised in applying 2,4-dichlorophenoxyacetic acid by the dust method, first to avoid accidental treatment of adjacent plants by drifting of the dust particles, and second to avoid breathing the dust mixtures during application until definite information is available on the nontoxicity of the acid.