The most important and widespread disease on golf courses is Microdochium nivale. Attempts to control the disease mainly involve prophylactic spraying with fungicides in autumn. Preventive application of fungicides against snow mould is independent of the actual risk of infection and disease development, and probably often unnecessary. The aim of the project is to understand how M. nivale inoculum survives from spring to autumn, how climatic conditions affect the potential inoculum and how the aggressiveness of strains varies. The project will also clarify whether the fungicides used for control of snow mould in the Nordic countries are effective against M. nivale.
SOURCE OF PRIMARY INOCULUM
Occurrence of M. nivale on grass leaves and stems in spots on greens and foregreens was observed from spring to autumn during two growth seasons. Immediately after snow melt and in late spring, M. nivale was isolated from leaves and stems in most of the spots. The occurrence of M. nivale was reduced during summer, so that in autumn M. nivale was hardly isolated from any of the selected spots. Preliminary results indicate that the fungus does not occur in the same spots in successive years. There may be several explanations for this, and it needs further investigation.
IN VITRO TESTS OF FUNGICIDES
Fungicides used for control of snow mould in Scandinavia were selected and tested in vitro for their efficiency to reduce mycelial growth of M. nivale. The products were: Acanto Prima (cyprodinil, pikoxystrobin), Amistar (azoxystrobin), Amistar Duo (azoxystrobin, propiconazole), Baycor (bitertanol), Bumper (propiconazole), Comet (pyraclostrobin), Proline (protioconazole), Rovral 75WG/Chipco Green 75WG (iprodione), Sportak EW (prochloraz), Stratego 250 EC (propiconazole, trifloxsystrobin), Topsin WG (thiofanatmethyl). A clear reduction in fungal growth was recorded at low concentrations of fungicides. Acanto Prima, Sportak and Stratego were the most efficient compounds, with a clear reduction in mycelial growth recorded even at 0.01% of the concentration recommended for disease control on golf greens.
TEST OF FUNGICIDES IN THE FIELD
The products Acanto Prima, Bumper, Comet and Stratego were tested for their effect in reducing snow mould damage on golf greens. The greens were sprayed with fungicides in late autumn and percentage winter injury was recorded on two occasions in the following spring: immediately after snow melt and after a period of spring regrowth. In the first season Acanto Prima was the most effective of the products tested.
