Fusarium patch (Microdochium patch or pink snow mold)
Microdochium nivale
Also Known As - Microdochium patch (Fusarium patch or pink snow mold),Pink snow mold (Microdochium patch or Fusarium patch)What is Fusarium patch, pink snow mold (Microdochium nivale)?
Microdochium patch, also known as pink snow mold or Fusarium patch, is a fungal disease caused by Microdochium nivale. It commonly occurs in regions with extended periods of wet, cool weather and affects cool season turfgrasses such as bentgrass, Kentucky bluegrass, ryegrasses, and more. Symptoms include small, circular dead spots with a pinkish color. In the early morning, affected areas may show white to pink mycelia. Under snow cover or in wet conditions, visible white fungal growth may be present.
How does Fusarium patch, pink snow mold (Microdochium nivale) occur?
Microdochium patch reproduces through spore dispersal. The fungal spores are found in infected plant debris or soil. When the weather is wet and cool, the spores germinate and infect the turfgrass. The fungus grows and spreads through fungal threads called mycelium within the turfgrass. In snowy or wet conditions, the fungus produces white to pink spore masses (sporodochia). These spore masses help the fungus spread and infect other susceptible turfgrass plants, completing its reproductive cycle.
Symptoms
1 - Effect on Soil Health
This disease can affect soil health by accumulating plant debris, thatch, and fungal mycelium on the soil surface. This can lead to increased thatch layers, poor soil aeration, altered nutrient availability, water infiltration, and overall soil quality
2 - Plant Growth and Vigor
Turfgrass plants infected with mold may experience weakened growth, reduced vigor, and thinning. Patches of blighted and discolored grass can diminish the aesthetic appeal and functional quality of lawns, athletic fields, and golf courses.
Solutions
1 - Cultural Practices
• Ensure proper soil aeration and water drainage. • Reduce shade and improve sunlight exposure. • Maintain good turfgrass health through regular mowing, fertilization, and overseeding with resistant varieties. • Remove excessive thatch and fallen leaves.
2 - Fertilization and pH Management
• Follow recommended fertilization practices for your turfgrass species to avoid excessive nitrogen. • Avoid late-season nitrogen applications that promote lush growth before winter. • Time fertilizer application to avoid nitrogen close to a killing frost or snowfall. • Maintain soil pH around 6.5 to 6.7 to suppress the pathogen.
5 - Fungicide Application
• In high-risk areas or severe cases, consider preventive fungicide applications following the manufacturer's instructions. • Common fungicides used for the control of pink snow mold (Microdochium nivale) disease include azoxystrobin, chlorothalonil, fludioxonil, propiconazole, thiophanate-methyl, and trifloxystrobin. • Use fungicides with different modes of action to minimize resistance. • Follow label instructions and repeat applications during high disease pressure.
