Improved strategy for control of Microdochium Nivale on golf courses

Project outcome by January 2009

The most important and widespread disease on golf courses is snow mould caused by Microdochium nivale. Attempts to control this disease mainly involve prophylactic spraying with fungicides in autumn. The aim of this project was to determine how inoculum of M. nivale survives from spring to autumn and to examine the efficiency of selected fungicides. 

Snow mould symptoms and the occurrence of Microdochium nivale in leaves and stems of grasses sampled from golf greens and foregreens declined during the growing season. Despite a low rate of occurrence in autumn, M. nivale was re-isolated in some of the original locations in the following spring. The M. nivale isolation rate was similar at sites located on greens and foregreens, and on greens at more sunny sites and more shady sites. We concluded that this fungus survives from year to year within the same locations on greens and foregreens.

A significant correlation was found between mycelial growth rate of M. nivale isolates at 2C and at 20C. At 20C, a greater variation in growth rate was observed between strains isolated immediately after snowmelt compared with strains isolated in spring, summer, autumn or prior to snowfall. No clear picture emerged in growth rate differences between groups of M. nivale strains isolated at different time points throughout the year.

A significant reduction in mycelial growth rate of M. nivale on agar was observed on addition of low concentrations of all the fungicides tested. The products were: Acanto Prima (cyprodinil, picoxystrobin), Amistar (azoxystrobin), Amistar duo (azoxystrobin, propiconazole), Baycor (bitertanol), Bumper (propiconazole), Comet (pyraclostrobin), Proline (prothioconazole), Rovral 75WG/Chipco Green 75WG (iprodion), Sportak EW (prochloraz), Stratego 250 EC (propiconazole, trifloxystrobin), Topsin WG (thiophanate methyl). 

Sportak, Stratego and Topsin were the most efficient products, with 90-100% reduction in mycelial growth rate on agar recorded for the 0.1% fungicide concentration recommended for disease control on golf greens. Acanto Prima, Bumper, Comet and Stratego were also field-tested for their effect to reduce snow mould damage on golf greens. Due to severe water damage on the greens in the second season, only the results from one season of the fungicide field trial could be used. Acanto Prima was ranked as the best product, significantly reducing winter damage on average from 21% in control plots to 6% in treated plots.