Biology and Management of Dollar Spot (Sclerotinia homoeocarpa); an Important Disease of Turfgrass

Walsh, Brenda; Ikeda, S. S.; Boland, G. J.

doi:10.21273/hortsci.34.1.13

Cited by 88 publications

(93 citation statements)

References 49 publications

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“…Sclerotinia homoeocarpa is the most economically important pathogen of turfgrass worldwide due to its wide host range, activity in a wide range of conditions, and its cosmopolitan distribution (Smiley et al, 2005;Vargas, 2005;Walsh et al, 1999). Management of dollar spot is becoming increasingly challenging partly due to the widespread development of fungicide-insensitive S. homoeocarpa populations (Jo et al, 2006;Koch et al, 2009;Putman et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Characterization and distribution of mating-type genes of the turfgrass pathogen Sclerotinia homoeocarpa on a global scale

Putman

Tredway

Carbone

2015

Fungal Genetics and Biology

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Section: Introductionmentioning

confidence: 99%

Characterization and distribution of mating-type genes of the turfgrass pathogen Sclerotinia homoeocarpa on a global scale

Putman

Tredway

Carbone

2015

Fungal Genetics and Biology

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“…Bennett), is one of the most serious and widespread diseases of turfgrasses (Bennett, 1937;Walsh et al, 1999;Allen et al, 2005), as well as other economically important plants including switchgrass (Vu et al, 2011) and perennial peanut (Hoover & Kucharek, 1995). On individual blades of grass, the disease manifests as bleached, hourglass-shaped to oblong lesions with reddish-brown borders (Allen et al, 2005;Smiley et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Development of a semi-selective medium for improved isolation of the turfgrass dollar spot pathogenSclerotinia homoeocarpafrom host tissues

Rioux

Ryzin

Kerns

2014

Canadian Journal of Plant Pathology

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Dollar spot, caused by Sclerotinia homoeocarpa, is one of the most economically devastating diseases of amenity turfgrasses worldwide. The pathogen is readily isolated from active lesions, but detection from seed, dormant host tissue and other plant debris that may serve as a source of primary inoculum is difficult. A semi-selective medium was developed to enhance isolation of S. homoeocarpa. Various fungicides used on turfgrass, the pH indicator dye bromophenol blue, and two pH levels, were assessed for their effects on, and in the case of bromophenol blue, response to growth of S. homoeocarpa and contaminant fungi frequently isolated from field and seed samples. Amendment of the medium to pH 4 promoted growth of S. homoeocarpa in the absence of fungicides and enhanced pathogen growth relative to contaminant isolates on medium amended with 0.1 μg mL −1 triticonazole or 5 μg mL −1 azoxystrobin. The growth rate of S. homoeocarpa on these three media, as determined by in vitro radial growth assays, was consistent for many isolates representing the majority of S. homoeocarpa vegetative compatibility groups. Isolation efficiency on the pH-amended media was tested against antibiotic-amended potato dextrose agar from field samples and artificially inoculated turfgrass seed. In both cases, the medium amended to pH 4 and containing 5 μg mL −1 azoxystrobin significantly decreased contaminant growth with no adverse effects on recovery of S. homoeocarpa in comparison with antibiotic-amended PDA. The enhanced specificity of this medium will be a useful tool for selective detection of S. homoeocarpa and identification of sources of initial inoculum for dollar spot development.Résumé: La brûlure en plaques, causée par Sclerotinia homoeocarpa, est une des maladies du gazon d'agrément dont les répercussions économiques sont des plus importantes à l'échelle mondiale. L'agent pathogène est facilement isolé à partir de lésions actives, mais la détection à partir de semences, de tissu dormant et d'autres débris végétaux qui peuvent servir de source primaire d'inoculum n'est pas aussi simple. On a développé un milieu semi-sélectif pour mettre en relief l'isolement de S. homoeocarpa. Divers fongicides utilisés sur le gazon, l'indicateur de pH bleu de bromophénol et deux niveaux de pH ont été évalués quant à leurs effets sur S. homoeocarpa et, dans le cas du bleu de bromophénol, quant à la réaction par rapport à sa croissance ainsi qu'aux champignons contaminants fréquemment isolés d'échantillons de sol et de semences. L'amendement du milieu pour obtenir un pH de 4 a stimulé la croissance de S. homoeocarpa en l'absence de fongicides et a favorisé la croissance de l'agent pathogène par rapport aux isolats contaminants se développant sur le milieu amendé avec 0.1 µg mL −1 de triticonazole ou 5 µg mL −1 d'azoxystrobine. Le taux de croissance de S. homoeocarpa sur ces trois milieux, comme défini pas les biotests de croissance radiale in vitro, était uniforme pour plusieurs isolats représentant la majorité des groupes de compatibilité végét...

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“…High quality turf grown for golf course greens and fairways is highly susceptible to foliar diseases such as dollar spot caused by Sclerotinia homoeocarpa which requires regular fungicide applications for management throughout the growing season (Vargas, 1994;Walsh et al, 1999). Suppression of dollar spot on creeping bentgrass/annual bluegrass turf in the field with various microbial antagonists has been shown, raising the possibility of eventually including biological control for managing this disease (Goodman and Burpee, 1991;Walsh et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

“…Suppression of dollar spot on creeping bentgrass/annual bluegrass turf in the field with various microbial antagonists has been shown, raising the possibility of eventually including biological control for managing this disease (Goodman and Burpee, 1991;Walsh et al, 1999). For example, some strains of Enterobacter cloacae significantly reduced dollar spot severity in the field for at least 32 days after a single application as a top-dressing of a sand-cornmeal mixture (Nelson and Craft, 1991).…”

Section: Introductionmentioning

confidence: 99%

“…Biocontrol of other foliar turf diseases under field conditions was also reported, such as leaf spot by Stenotrophomonas maltophilia (Zhang and Yuen, 1999) and gray snow mold by Typhula phacorrhiza (Burpee et al, 1987). However, in most experiments, biological agents applied to turf rarely equaled the level of control obtained with chemical fungicides (Walsh et al, 1999). For instance, we need to know how to achieve and maintain suppressive antagonistic populations that would provide reliable control of turf diseases.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of Foliage and Thatch Populations of Introduced Pseudomonas fluorescens and Streptomyces sp. on a Fairway Turf

Mercier

2006

Biocontrol

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Populations of bacteria (Pseudomonas fluorescens A506 and Streptomyces sp. strain 93) applied to a creeping bentgrass/annual bluegrass fairway turf were followed over time on leaves and thatch. While introduced populations remained at detectable levels over a period of 11-25 days, they usually declined gradually and did not increase after their application to turf. Streptomyces rapidly disappeared from leaves while P. fluorescens was able to maintain similar population sizes on both thatch and leaves, after an initial decline of about 1-log unit, showing that it was actively colonizing the foliage despite loss of biomass from lawn mowing. Throughout these experiments, populations of indigenous microbes on foliage and thatch remained stable, about 10 6 and 10 8 cfu g )1 for fungi and bacteria, respectively, and were not affected by the application of bacterial antagonists. Niche-clearing with hydrogen peroxide, which temporarily reduced the population size of indigenous microorganisms two-fold, caused population size of P. fluorescens to increase approximately ten-fold within 24 h, while it declined by about one log unit on untreated turf. It is concluded that the indigenous microflora competes with introduced bacterial antagonists and interferes with their establishment and persistence on turf. Additional studies with P. fluorescens revealed that its population size was inoculum dose-dependent and that solid top dressing was slightly more efficient than spraying liquid suspension in establishing the antagonist. It was possible to maintain P. fluorescens populations above 10 5 cfu/g of thatch and leaves for 2 weeks or more with both top-dressing or spraying with about 1 to 3 Â 10 10 cfu m )2 .

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Biology and Management of Dollar Spot (Sclerotinia homoeocarpa); an Important Disease of Turfgrass

Cited by 88 publications

References 49 publications

Characterization and distribution of mating-type genes of the turfgrass pathogen Sclerotinia homoeocarpa on a global scale

Characterization and distribution of mating-type genes of the turfgrass pathogen Sclerotinia homoeocarpa on a global scale

Development of a semi-selective medium for improved isolation of the turfgrass dollar spot pathogenSclerotinia homoeocarpafrom host tissues

Dynamics of Foliage and Thatch Populations of Introduced Pseudomonas fluorescens and Streptomyces sp. on a Fairway Turf

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