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Abstract

Dollar spot is a destructive and widespread disease affecting most turfgrass species, but until recently it has been absent from the Scandinavian countries of northern Europe. In the fall of 2014, disease symptoms consistent with dollar spot were observed on a golf course fairway in Sweden. A fungus was isolated from symptomatic turf and identified as Sclerotinia homoeocarpa on the basis of ribosomal deoxyribonucleic acid (rDNA) internal transcribed spacer (ITS) sequences, morphology, and culture characteristics. The ITS sequence was identical to isolates of S. homoeocarpa from the eastern and midwestern United States. Koch’s postulates were fulfilled, confirming the S. homoeocarpa isolate as the causal agent. This is the first report of turfgrass dollar spot in Sweden and only the second report of the disease from Scandinavia. Because pesticides are rarely used in the cultivation of Scandinavian turfgrass, dollar spot disease may prove difficult to control through conventional means and potentially represents a major threat to the industry.

Abstract

Ice encasement (IE) is the most economically important winter stress in Scandinavia; however, little is known about the IE tolerance of different turfgrass species and subspecies except that creeping bentgrass (Agrostis stolonifera L.) is more tolerant than annual bluegrass (Poa annua L.). The objective of this study was to assess the impact of IE and two protective covers (plastic and plastic over a 10-mm woven mat) on the winter survival of six cool-season turfgrasses commonly used on golf greens. The experiment was conducted on a sand-based green at Apelsvoll, Norway (60°42′ N, 10°51′ E) during the winters of 2011–2012 and 2012–2013. Turfgrass samples (8 cm in diameter, 10 cm deep) were removed from the plots at the time of cover installation and throughout the winter. The samples were potted and percent live turfgrass cover assessed after 21 d of regrowth in a growth chamber. Percent turfgrass cover, percent disease, and turfgrass quality were also registered in the field plots in spring. Results indicated that velvet bentgrass (Agrostis canina L.) had superior tolerance to IE, surviving for 98 and 119 d of IE during the winters of 2011–2012 and 2012–2013, respectively. The order of IE tolerance in 2012–2013 was: velvet bentgrass > creeping bentgrass > Chewing’s fescue (Festuca. rubra L. ssp. commutata), slender creeping red fescue (F. rubra L. ssp. litoralis) ≥ colonial bentgrass (A. capillaris) > annual bluegrass. Colonial bentgrass responded negatively to both protective covers in 2012 due to the development of Microdocium nivale. None of the species benefited from the plastic cover alone, compared with natural snow conditions. Annual bluegrass was the only species that benefited from plastic over a woven mat.

Abstract

Ice encasement (IE) is the most economically important winter stress in Scandinavia; however, little is known about the IE tolerance of different turfgrass species and subspecies except that creeping bentgrass (Agrostis stolonifera L.) is more tolerant than annual bluegrass (Poa annua L.). The objective of this study was to assess the impact of IE and two protective covers (plastic and plastic over a 10-mm woven mat) on the winter survival of six cool-season turfgrasses commonly used on golf greens. The experiment was conducted on a sand-based green at Apelsvoll, Norway (60°42′ N, 10°51′ E) during the winters of 2011–2012 and 2012–2013. Turfgrass samples (8 cm in diameter, 10 cm deep) were removed from the plots at the time of cover installation and throughout the winter. The samples were potted and percent live turfgrass cover assessed after 21 d of regrowth in a growth chamber. Percent turfgrass cover, percent disease, and turfgrass quality were also registered in the field plots in spring. Results indicated that velvet bentgrass (Agrostis canina L.) had superior tolerance to IE, surviving for 98 and 119 d of IE during the winters of 2011–2012 and 2012–2013, respectively. The order of IE tolerance in 2012–2013 was: velvet bentgrass > creeping bentgrass > Chewing’s fescue (Festuca. rubra L. ssp. commutata), slender creeping red fescue (F. rubra L. ssp. litoralis) ≥ colonial bentgrass (A. capillaris) > annual bluegrass. Colonial bentgrass responded negatively to both protective covers in 2012 due to the development of Microdocium nivale. None of the species benefited from the plastic cover alone, compared with natural snow conditions. Annual bluegrass was the only species that benefited from plastic over a woven mat.

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Abstract

There has long been a claim that winter injuries of grass are a significant economic burden for golf courses in the Nordic countries. To confirm this claim, in 2015 the Norwegian Institute of Bioeconomy Research and the Norwegian Golf Federation, with support of the Scandinavian Turfgrass and Environment Research Foundation, conducted a net-based survey about winter injury in the five Nordic countries (Denmark, Finland, Iceland, Norway, and Sweden). This comprehensive survey showed that total costs of repair of winter-injured greens and fairways together with lost revenue on golf courses in the Nordic countries can be at least €14 million. In a year with significant winter injuries, the average cost to repair the turf was between €3000 and €12,000 on 88% of the courses. The revenue loss after a winter with considerable injuries was less than €6000 at 50% of the courses, and 25% of the courses reported a loss between €6000 and €12,000 for these years. The causes of winter injuries varied depending on geography and grass species used on the greens. Biotic factors played a major role in the southern part of Scandinavia, and ice and water injuries were most devastating north of 60°N. This paper summarizes some of the answers from the respondents, including information about the dominating grass species on Nordic golf greens.

Abstract

Microdochium nivale (Fries) Samuels & Hallett is an important turfgrass pathogen on golf courses. Our objective was to evaluate Gliocladium catenulatum Gilman & Abbott and/or Streptomyces species for biological control of M. nivale on golf greens. The microbial agents were tested relative to fungicides and an untreated control in vitro and in five field trials from 2011 to 2014. G. catenulatum (Turf G+/WPG, Verdera OY, Finland) was applied from October to December and in March–April, while Streptomyces species (Turf S+/WPS, same manufacturer) was applied from May to October, both at four week intervals. In vitro, Streptomyces species suppressed the growth of M. nivale at 6 and 16°C, while G. catenulatum suppressed growth of M. nivale at 16°C only. In contrast, neither product, nor their combination, had any consistent effect in the field trials. A statistically significant reduction in Microdochium patch (from 3 to 2% of plot area) was seen in a trial on a green dominated by Festuca rubra L., but this reduction was deemed to be of little practical interest to the greenkeeper. Despite multiple applications over 3 yr to build up an antagonistic microflora, only fungicides reduced M. nivale significantly on greens dominated by Poa annua L. or Agrostis capillaris L., which generally had more disease. In conclusion, this research showed no potential of G. catenulatum or Streptomyces species to replace fungicides for control of M. nivale on northern-latitude golf greens.

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Abstract

Red fescue (RF, Festuca rubra L.) is used on golf putting greens in the Nordic region due to its high disease resistance and low requirements for nitrogen (N) and water, but low density and growth rate makes RF susceptible to annual bluegrass (AB, Poa annua L.) invasion. Putting greens seeded with RF + bentgrass (Agrostis sp.) may be more competitive with AB but also have different playing characteristics. Our objective was to compare RF, RF + colonial bentgrass (CB, Agrostis capillaris L.), and RF + velvet bentgrass (VB, Agrostis canina L.) putting greens at two mowing heights (4.0 or 5.5 mm), three N rates (5, 10, or 15 g N m−2 yr−1), and three phosphorus (P)–arbuscular mycorrhizal fungi treatments (0 and 1.8 g P m−2yr−1 without inoculation and 0 g P m−2yr−1 with inoculation). The four-factorial experiment was conducted in 2011 and 2012 at Landvik, Norway. Red fescue provided lower visual quality and density and less competition against AB than RF + bentgrass combinations. Increasing the N rate from 5 to 15 g N m−2yr−1 increased the proportion of bentgrass tillers from 53 to 64% in RF + CB and from 86 to 92% in RF + VB. Surface hardness increased in the order RF + VB < RF + CB < RF turfs. Ballroll distance decreased with increasing N rate and was longer with RF and RF + VB than with RF + CB. The main effects of N and mowing height on AB invasion were not significant, but lower mowing increased AB competition in RF. Mycorrhiza colonization of roots was not significantly affected by any practice, and neither P nor arbuscular mycorrhizal fungi influenced the competition against AB.

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Abstract

This report presents results from a project testing Turf G+/WPG (fungal products containing Gliocladium catenulatum) and Turf S+/WPS (bacterial products containing Streptomyces spp.), both from Interagro BIOS AB, and Vacciplant (seaweed product containing laminarine) from Nordisk Alkali AB, for the control of Microdochium nivale and other diseases on golf greens. Five field trials were carried out in Denmark, Sweden and Norway from October 2011 to September 2014, and Turf G+/WPG and Turf S+ were tested also in vitro. None of the test-products gave any consistent disease control in the field trials. A significant reduction in Microdochium nivale from 3 % of plot area on untreated plots to 2 % on treated plots was seen in one trial, but this was considered to be of little practical relevance. In all other trials with more severe attacks of Microdochium nivale, only the fungicide control treatment showed a significant reduction in disease compared with the untreated control. On average for all field trials over three years, the higher rate of Vacciplant, the combination of Turf G+/WPG and Turf S+/WPS, and the fungicide treatment gave, in turn, 22, 24 and 87 % less microdochium patch in the fall, but among these, only the effect of fungicide was significant. The effects of the biological products on pink or gray (Typhula incarnata) snow mold after snow melt were even smaller. In the in vitro trials, Turf S+ provided good control of Microdochium nivale at 6 and 16 ̊C, but Turf G+/WPG was effective only at the higher temperature. However, since these results could not be repeated under field conditions, we have to conclude that none of the test products represent any real alternative to fungicides for control of M. nivale or other diseases on Scandinavian golf courses.

Abstract

Syngenta’s GREENCAST model was used to predict timing of fungicide application against microdochium patch and pink snow mold caused by Microdochium nivale on an experimental golf green with annual bluegrass (Poa annua) at Bioforsk Landvik, Southern Norway from 5 Oct. 2012 until 1 June 2013. From 5 Oct. until snow covered the green on 2 Dec. 2012, application of the fungicides Headway (azoxystrobin + propiconazole) or Medallion (fludioxonil) only at GREENCAST high risk warnings resulted in equal control of microdohium patch with one less fungicide application than prophylactic application every third week, application at first sign of disease or application at GREENCAST medium risk warnings. The consequences for pinks snow mold in spring could not be evaluated as the turf was killed by the combination of ice encasement and low freezing temperatures during winter.

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Abstract

This progress report presents preliminary results from a project providing data for potential registration of Turf S+ (bacterial product containing Streptomyces) and Turf G+/WPG (fungal product containing Gliocladium catenulatum), both from Interagro BIOS AB, and Vacciplant (seaweed product containing laminarine) from Nordisk Alkali AB, for the control of Microdochium nivale and other diseases on golf greens. Field trials with all three products are carried out on greens in Denmark, Sweden and Norway from 2011 to 2014, and Turf S+ og Turf G+/WPG are also tested in vitro. Half way through the project, none of the test-products have shown any consistent control of M. nivale or any other disease. In the trials at Bioforsk Landvik and Arendal GK, Norway, there was little attack of M. nivale and no significant effect of any treatment, while in the trials at Rungsted GC, Denmark and Kävlinge GC, Sweden, there were massive attacks, but a significant reduction in disease only in the fungicide control treatments. The fifth trial, at Sydsjælland GC, Denmark, had more healthy turf just before snow cover in late November 2012 on plots that had been sprayed the test products, especially with Turf S+ or Vacciplant than on unsprayed control plots, although the turf quality was not as good as in the fungicide control treatment. The first in vitro trial with the microbial agents suggested better effect of both G. catenulatum and Streptomyces sp. on M. nivale at 16 than at 6°C. Possible implications of this for the protocol will be discussed with the manufacturer. The experimental work continues until the summer of 2014.

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Abstract

This is a progress report from the second experimental year of the project ‘VELVET GREEN - Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments’. The report is divided into four main chapters, the first giving results from evaluation of winter hardiness of velvet bentgrass under controlled conditions, the second describing experimental layout and preliminary results from two field trials with fertilizer levels, thatch control methods and topdressing levels; the third describing experimental layout and preliminary results from a lysimeter study on irrigation stategies for velvet bentgrass on greens varying in rootzone composition; and the fourth describing a supplemental experiment evaluating the biological product ‘Thatch-less’ for thatch decomposition.

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Abstract

This is a report from the first experimental year of the project ‘VELVET GREEN - Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments’. The report is divided into three parts, the first giving results from evaluation of winter hardiness of velvet bentgrass under controlled conditions, the second describing experimental layout and preliminary results from two field trials with fertilizer levels, thatch control methods and topdressing levels; and the third describing experimental layout and preliminary results from a lysimeter study on irrigation stategies for velvet bentgrass on greens varying in rootzone composition.