Winter is coming!
As we head towards winter, one of the major challenges turfgrass managers in temperate climates face is infection by the pathogen Microdochium nivale. Commonly referred to as Fuzz, Fusarium patch or Microdochium patch, it infects most cool season turfgrass species with infection primarily occurring under moist conditions below 64°F (18°C). Optimum occurrence happens between 32°F-42°F (0°and 6°C) and under snow cover and it’s known as “Pink Snow” mold.
Controlling Microdochium nivale Infection
Integrated Pest Management (IPM) techniques are best employed, comprising of establishing disease threshold levels, intensive field monitoring, good record keeping, awareness of climatic conditions, and importantly, utilization of non-pesticidal disease control strategies. Fungicide use is the last step in the IPM process.
We can lessen Microdochium pressure by influencing environmental factors, not only weather conditions, but also the growth environment and how nutritional and maintenance programs can be used to reduce disease.
Nutritional programs play an important role in combating Microdochium infection and should be geared to providing growth and recovery through the autumn/winter season and building carbohydrate reserves.
Many elements and compounds have a direct effect on suppressing Microdochium.
While the above factors, individually, will have some effect on Microdochium, it’s only when you start combining them that you will see significant effects.
Influence all factors which reduce the microclimate conducive to Microdochium development.
- Dew removal is vital as leaf wetness is a key factor for infection.
- Late season aeration operations and topdressing can create the ideal microclimate for infection. If possible, try to complete prior to autumn. Bear in mind, however, that thatch reduction will help reduce inoculum sources.
- Raise height of cut. Turfgrass needs to generate and store energy for defenses.
- Incorporate rolling as much as feasible into the program.
- Nutritional programs to include compounds such as Phosphite, Manganese, Zinc, Sulfur, Salicylic acid, and Fe as part of balanced, sequentially applied, nutritional treatments.
Dr. John Dempsey
Independent Turfgrass Research