scholarly journals Plant Growth Regulator Effects on Bacterial Etiolation of Creeping Bentgrass Putting Green Turf Caused by Acidovorax avenae

Plant Disease ◽  
2016 ◽  
Vol 100 (3) ◽  
pp. 577-582 ◽  
Author(s):  
Joseph A. Roberts ◽  
David F. Ritchie ◽  
James P. Kerns

Bacterial etiolation, caused by Acidovorax avenae, is a widespread problem in creeping bentgrass putting green turf. The symptoms normally appear as abnormally elongated turfgrass stems and leaves. Observations at multiple field sites suggest the involvement of plant growth regulators (i.e., GA-biosynthesis inhibitors) commonly applied to turf, alluding to a phytohormone imbalance caused by the bacterium. A 2-year field study examined the effects of trinexapac-ethyl, flurprimidol, and paclobutrazol on bacterial etiolation severity caused by A. avenae. Trinexapac-ethyl applied at 0.05 kg a.i. ha−1 every 7 days and 0.10 kg ha−1 every 14 days increased etiolation compared with all other treatments in both years. Flurprimidol and paclobutrazol were not different from the control but high-rate applications caused phytotoxicity that lowered turf quality early in 2014. When the etiolated turfgrass was removed with mowing, turfgrass treated with trinexapac-ethyl exhibited the highest turfgrass quality on most rating dates. Results from this work illustrate that using plant growth regulator materials with different modes of action is a solution to managing creeping bentgrass growth while limiting the potential for bacterial etiolation outbreaks.

1999 ◽  
Vol 13 (4) ◽  
pp. 829-834 ◽  
Author(s):  
Gregory E. Bell ◽  
Edward Odorizzi ◽  
T. Karl Danneberger

Two field studies, a seeded study and a golf course study, were conducted to compare competition among creeping bentgrass, annual bluegrass, and roughstalk bluegrass when subjected to common weed control practices and foliar applications of iron and magnesium. A research site was selected for the seeded study and divided into 10 whole plots receiving irrigation at either 50 or 100% evapotranspiration deficit. Each whole plot was further divided into subplots receiving one of seven treatments: bensulide, ethofumesate, trinexapac-ethyl, foliar Mg, foliar Fe, foliar Mg plus foliar Fe, and control. The site was seeded to a mixture of creeping bentgrass, annual bluegrass, and roughstalk bluegrass in September 1995, and treatments began in March 1996. Annual bluegrass was reduced 29% in plots treated with foliar Fe and 65% in plots treated with foliar Fe plus foliar Mg. Roughstalk bluegrass was significantly reduced in seeded plots treated with foliar iron (50%), plant growth regulator (75%), and foliar iron plus foliar magnesium (100%). Annual bluegrass and roughstalk bluegrass proportions were not affected by irrigation regime. In a second study, the most effective treatment, foliar magnesium plus foliar iron, was tested on a working golf course fairway and on a practice putting green beginning April 1997 and ending November 1997. Treatments on the golf course fairway and practice putting green were ineffective due to the established, perennial nature of the annual bluegrass biotypes on these sites. Further research is required to improve the efficacy of nutritional treatments on these perennials.


2000 ◽  
Vol 18 (1) ◽  
pp. 53-58
Author(s):  
John Stier ◽  
Zac Reicher ◽  
Glenn Hardebeck

Abstract Proxy is a newly-labeled plant growth regulator (PGR) for use on golf course and commercial turfgrass areas. Four rates of Proxy (ethephon), 2.3, 3.6, 4.6, and 9.1 kg ai/ha (2.0, 3.2, 4.1, and 8.2 lb ai/A,) were compared to Primo (trinexapac-ethyl) at 1.0 kg ai/ha (0.9 lb ai/A) and an untreated control for clipping reduction and effects on aesthetics of creeping bentgrass maintained as fairway turf. Treatments were applied three times at 28-day intervals during 1998 at locations in Indiana and Wisconsin. Proxy was as effective at reducing clipping yields as Primo, although the magnitude of effects varied between the two locations. In general, Proxy was more likely to reduce turf quality and color than Primo. All rates of Proxy reduced clipping weights similarly, but low rates were less likely to reduce color or quality ratings. Turf density was not affected by Proxy or Primo. Effects of Proxy on creeping bentgrass occurred within two weeks after application and generally dissipated within four weeks, whereas Primo effects occurred within one week after application and generally dissipated within three weeks. Turf quality was occasionally reduced following application of Proxy.


Crop Science ◽  
2014 ◽  
Vol 54 (6) ◽  
pp. 2815-2826 ◽  
Author(s):  
Marco Schiavon ◽  
Bernd Leinauer ◽  
Matteo Serena ◽  
Bernd Maier ◽  
Rossana Sallenave

2021 ◽  
pp. 1-11
Author(s):  
Jonathan Ebba ◽  
Ryan W. Dickson ◽  
Paul R. Fisher ◽  
Crysta N. Harris ◽  
Todd Guerdat ◽  
...  

The overall goal was to evaluate fertilizer options for greenhouse producers, with or without a plant growth regulator (PGR) application, to improve subsequent performance of container-grown annuals. Petunia (Petunia × hybrida) was the model container-grown crop in simulated production and consumer environments. The first experiment at two locations (New Hampshire and Florida) compared strategies using water-soluble fertilizer [WSF (17N–1.8P–14.1K)], controlled-release fertilizers (CRF), and slow-release fertilizers (SRF) that were either applied throughout or at the end of the 8-week production phase [point of shipping (POS)] for petunia rooted cuttings grown in 8-inch azalea containers. In the subsequent simulated “consumer” phase, container plants were irrigated with clear water (no fertilizer) for 6 weeks. Plant performance [number of flowers, SPAD chlorophyll index, dry weight, and tissue nitrogen (N)] at the end of the consumer phase was improved by top-dressing at POS with either CRF or granular organic fertilizer (both at 2.74 g/container N), or preplant incorporation of either a typical CRF at 4.12 g/container N or a CRF with an additional prill coating to delay initial release (DCT) at 2.74 g/container. There was no carry-over benefit from applying a liquid urea-chain product (1.37 or 2.74 g/container N) or top dressing with granular methylene di-urea (2.74 g/container N), or 400 mg·L–1 N (0.2 g/container N) from a liquid organic fertilizer at POS. The consumer benefit of applying 400 mg·L–1 N (0.2 g/container N) from a WSF at POS was increased by supplementing with 235 mg·L–1 magnesium (Mg) and 10 mg·L–1 iron (Fe). A second experiment in 10-inch-diameter pots evaluated the effect on consumer performance from providing 200 or 400 mg·L–1 N of WSF with the PGR paclobutrazol, at the final 1 L/pot irrigation at POS. Application of 3 mg·L–1 paclobutrazol delayed leaf yellowing and reduced plant height, width, and shoot dry weight during the consumer phase, resulting in a more compact growth habit and higher plant quality compared with plants that received no PGR, regardless of WSF treatment. Addition of supplemental 235 mg·L–1 Mg and 10 mg·L–1 Fe to the high rate of WSF and PGR did not improve consumer performance compared with other treatments that included a PGR. Overall, the first experiment demonstrated that the most effective fertilizer strategies require a CRF or SRF that will release nutrients throughout the consumer phase, and that impact of liquid fertilizer options is limited because of lower N supply per container. A single application at POS of a high rate of WSF with supplemental Mg and Fe may have short-term benefits, for example while plants are in a retail environment. Growers should consider combining a residual fertilizer with a PGR application for premium, value-added container annuals.


1990 ◽  
Vol 115 (3) ◽  
pp. 412-416 ◽  
Author(s):  
Billy J. Johnson

Two separate experiments (one and two applications and dates of treatment) were conducted on plant growth regulator (PGR) injury and seedhead suppression of centipedegrass [Eremochloa ophiuroides (Munro) Hack.]. Mefluidide caused less injury to centipedegrass than either imazethapyr or flurprimidol + mefluidide. Mefluidide applied at 0.56 kg·ha-1 in each of two applications at 2-week intervals suppressed seedheads of centipedegrass for 10 weeks. A single 0.56-kg·ha-1 application of the mefluidide failed to suppress seedheads when applied any time from mid-June until late July. A single treatment with flurprimidol + mefluidide severely injured centipedegrass, and seedhead suppression was poor regardless of date of treatment. Centipedegrass was severely injured when flurprimidol + mefluidide was applied at 1.68 + 0.28 kg·ha-1 in each of two applications, but seedheads were suppressed for 10 weeks. Imazethapyr applied at 0.30 and followed by 0.15 kg·ha-1 suppressed seedheads 10 weeks after treatment in 1987 and 6 weeks after treatment in 1988 without reducing turf density. When this PGR was applied as a single treatment at 0.30 kg·ha-1, seedhead suppression was generally greater for 8 weeks when applied mid- to late July than mid- to late June. Chemical names used: N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide (mefluidide); α -(1-methylethyl)- α -[4-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol (flurprimidol); and (±)-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-ethyl-3-pyridinecarboxlic acid (imazethapyr).


HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 471-474 ◽  
Author(s):  
Patrick E. McCullough ◽  
Haibo Liu ◽  
Lambert B. McCarty

Plant growth regulators (PGRs) are commonly used to enhance putting green quality and ball roll distances but their effects with various mowing operations have not been reported. Three experiments were conducted and repeated at Clemson University, Clemson, SC, on an `L-93' creeping bentgrass putting green to evaluate the effects of mowing operations and PGRs on diurnal ball roll distances. The PGRs tested included ethephon at (a.i.) 3.8 kg·ha-1, flurprimidol at (a.i.) 0.28 kg·ha-1, paclobutrazol at (a.i.) 0.28 kg·ha-1, and trinexapac-ethyl at (a.i.) 0.05 kg·ha-1. Mowing operations tested included rolling vs. mowing, morning mowing vs. morning plus afternoon mowing, and single vs. double morning mowing, all with and without PGRs. PGR by mowing operation interactions did not occur in any experiments. Ball roll distances decreased from 12:00 hr to evening observations in all experiments. In Experiment 1, rolling the green without mowing reduced ball roll distance 4% (5 cm) compared to mowing. Turf rolled without mowing in the morning and treated with flurprimidol, paclobutrazol, and trinexapac-ethyl produced similar ball roll at 12:00, 15:00, and 18:00 hr to mowed untreated turf. In Experiment 2, all plots were mowed at 08:00 hr and half of each plot was remowed at 12:30 hr. The second mowing at 12:30 hr enhanced ball roll distances 6% (8 cm) over the day. Turf mowed only at 08:00 and treated with paclobutrazol and trinexapac-ethyl had greater or equal ball roll distances at 12:30, 15:30, and 18:30 hr to untreated turf that had a second mowing at 12:30 hr. Turf receiving ethephon and 08:00 hr mowing had 4% to 12% (4 to 17 cm) shorter ball roll distances throughout the day compared to untreated turf mowed at 8:00 and 08:00+12:30 hr, respectively. In the third experiment, mowing twice in the morning increased ball roll 3% (4 cm) compared to mowing once. Trinexapac-ethyl and paclobutrazol treated turf mowed once in the morning had greater or equal ball roll distances throughout the day to untreated turf mowed twice in the morning. Overall, PGR use may provide putting green ball roll distances similar to or greater than untreated turf despite additional mowing; however, ethephon reduced ball roll distances regardless of mowing operations. Chemical names used: [4-(cyclopropyl-[α]-hydroxymethylene)-3,5-dioxo-cyclohexane carboxylic acid ethyl ester] (trinexapac-ethyl); {α-(1-methylethyl)-α-[4-(trifluoro-methoxy) phenyl] 5-pyrimidine-methanol} (flurprimidol); (+/-)-(R*,R*)-β-[(4-chlorophenyl) methyl]-α-(1, 1-dimethyl)-1H-1,2,4,-triazole-1-ethanol (paclobutrazol); [(2-chloroethyl)phosphonic acid] (ethephon).


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