scholarly journals Use of High-pressure Injection to Alleviate Type-I Fairy Ring Symptoms in Turfgrass

2005 ◽  
Vol 15 (1) ◽  
pp. 169-172 ◽  
Author(s):  
M.A. Fidanza ◽  
P.F. Colbaugh ◽  
M.C. Engelke ◽  
S.D. Davis ◽  
K.E. Kenworthy
Keyword(s):  
High Pressure ◽  
Root Zone ◽  
Creeping Bentgrass ◽  
Golf Course ◽  
Type I ◽  
Putting Greens ◽  
Pressure Injection ◽  
Spray Method ◽  
Putting Green ◽  
High Pressure Injection

Fairy ring is a common and troublesome disease of turfgrasses maintained on golf course putting greens. Type-I fairy ring is especially destructive due to the development of hydrophobic conditions in the thatch and root zone, thus contributing to turfgrass injury and loss. The objective of this 2-year field study was to evaluate the application and novel delivery method of two fungicides and a soil surfactant for curative control of type-I fairy ring in a 20-year-old creeping bentgrass [Agrostis palustris (synonym A. stolonifera)] putting green. In both years, all treatments were applied twice on a 28-day interval. In 1998, flutolanil and azoxystrobin fungicides were applied alone and in combination with Primer soil surfactant by a conventional topical spray method, and fungicides without Primer applied via high-pressure injection (HPI). Acceptable type-I fairy ring control was observed in plots treated with flutolanil plus Primer, HPI flutolanil, azoxystrobin alone, azoxystrobin plus Primer, or HPI azoxystrobin. In 1999, treatments were HPI flutolanil, HPI flutolanil plus Primer, HPI azoxystrobin, HPI water only, and aeration only. Acceptable type-I fairy ring control was observed in plots treated with HPI flutolanil plus Primer or HPI azoxystrobin. HPI of fungicides alone or in combination with a soil surfactant may be a viable option for alleviating type-I fairy ring symptoms on golf course putting greens.

scholarly journals Effects of Flutolanil Fungicide and Primer Wetting Agent on Water-repellent Soil

2001 ◽  
Vol 11 (3) ◽  
pp. 437-440 ◽  
Author(s):  
Keith J. Karnok ◽  
Kevin A. Tucker
Keyword(s):  
Root Zone ◽  
Water Repellency ◽  
Creeping Bentgrass ◽  
Wetting Agent ◽  
Golf Course ◽  
Water Repellent ◽  
Agrostis Palustris ◽  
Putting Greens ◽  
Soil Hydrophobicity ◽  
Dry Spot

Localized dry spot (LDS) caused by water repellent soil is a common problem on golf course putting greens having a predominately sand root zone. Fairy ring often causes LDS by developing hydrophobic soil. Although the fungicide flutolanil is labeled for the control of fairy ring, golf course superintendents often apply flutolanil to all LDS caused by hydrophobic soil and other conditions. The objective of this study was to determine the effect of flutolanil on an existing hydrophobic soil. The study was conducted on a creeping bentgrass [Agrostis palustris (synonym A. stolonifera)] experimental golf green in which the top 4 inches (10.2 cm) of the root zone was a moderately hydrophobic sand. Six treatments were used: uncored, cored, flutolanil (two applications.), flutolanil + Primer wetting agent (two applications.), Primer (two applications.) and Primer (three applications.). Plots receiving the fungicide and wetting agent treatments were cored before application. Each treatment containing the wetting agent significantly reduced soil water repellency. Flutolanil without wetting agent had no effect on soil hydrophobicity.

Creeping Bentgrass (Agrostis stolonifera) Golf Green Tolerance to Bispyribac-Sodium Tank-Mixed with Paclobutrazol

2012 ◽  
Vol 26 (1) ◽  
pp. 145-150 ◽  
Author(s):  
Justin Q. Moss ◽  
Xi Xiong ◽  
Kemin Su ◽  
Bishow P. Poudel ◽  
John B. Haguewood
Keyword(s):  
Creeping Bentgrass ◽  
Field Trials ◽  
Agrostis Stolonifera ◽  
Golf Course ◽  
Putting Greens ◽  
Annual Bluegrass ◽  
Turf Quality ◽  
Putting Green ◽  
Zone Field ◽  
Weekly Application

Annual bluegrass is a troublesome weed in golf course putting greens. The objective of this research was to evaluate creeping bentgrass putting green tolerance to bispyribac-sodium tank-mixed with paclobutrazol in the transition zone. Field trials with four replications were conducted in Oklahoma during 2009 and 2010 and in Missouri during 2010. The results of this study suggest that tank-mixing bispyribac-sodium with paclobutrazol may discolor creeping bentgrass putting greens but will not reduce turf quality below acceptable levels. Normalized vegetative difference index readings indicated no treatment differences in turf greenness at 4 and 8 wk after initial treatment. Weekly application of bispyribac-sodium at 12.4 g ha−1 or biweekly application at 24.8 g ha−1 alone or with monthly applications of paclobutrazol at 224 g ha−1 did not cause unacceptable injury to creeping bentgrass putting greens during the spring.

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

2021 ◽  
pp. 1-11
Author(s):  
Paweł Petelewicz ◽  
Paweł M. Orliński ◽  
James H. Baird
Keyword(s):  
Los Angeles ◽  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Creeping Bentgrass ◽  
Golf Course ◽  
Putting Greens ◽  
Annual Bluegrass ◽  
Putting Green ◽  
Effective Treatments

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.

A Numerical Investigation on Mixing Characteristics of Natural Gas Jets With High-Pressure Injection

2021 ◽  
Author(s):  
Long Liu ◽  
Tianyang Dai ◽  
Qian Xiong ◽  
Yuehua Qian ◽  
Bo Liu
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Air Entrainment ◽  
Gas Jet ◽  
Swirl Ratio ◽  
Marine Engine ◽  
Low Speed ◽  
Pressure Injection ◽  
Mixing Characteristics ◽  
High Pressure Injection

Abstract With increasingly stringent emissions limitation of greenhouse gas and atmospheric pollutants for ship, the direct injection of natural gas on the cylinder head with high-pressure injection is an effective method to make a high power output and decrease harmful gas emissions in marine natural gas dual fuel engines. However, the effects on mixing characteristics of high-pressure natural gas underexpanded jet have not been fully understood. Especially, the injection pressure is up to 30 MPa with large injection quantity and critical surrounding gas conditions for the low-speed two-stroke marine engine. Therefore, this research is focused on the flow and mixing process of the natural gas jet with high-pressure injection under the in-cylinder conditions of low-speed two-stroke marine engine. The gas jet penetration, the distribution of velocity and density, the equivalence ratio and air entrainment have been analyzed under different nozzle hole diameters by numerical simulation. The effects of surrounding gas conditions including pressure, temperature and swirl ratio on air entrainment and equivalence ratio distribution were studied in detail. From the numerical simulation, it is found that the mixing characteristics of natural gas jet can be improved under in-cylinder conditions of higher ambient temperature and swirl ratio, which is relevant to the low-speed two-stroke marine engine.

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