Field Insights Blog | GreenCast | Syngenta
Field Insights Blog | GreenCast | Syngenta

Somethings don’t change: Need for a snow mold treatment

Years ago when I when I was a plant pathology graduate student at Michigan State University, the most important fungicide spray of the year occurred in late fall, normally around Thanksgiving. It was the preventive snow mold application. Little has changed since that time.

Photograph 1.  A close-up of Typhula blight symptoms on an annual bluegrass green.

Throughout the northern United States this is the time that golf courses plan the most important fungicide application of the year.  The two most common are Typhula blight and Microdochium patch. 

Typhula blight (Typhula incarnata) occurs under snow cover.  Although the spores begin to germinate in late fall it takes a snow cover for infection to take off.  Disease symptoms do not appear until spring snow melt.  Symptoms appear as circular areas of straw to grayish brown turf. The turf may also appear matted with the appearance of a grayish-white mycelium at time of snowmelt. The mycelium often dries and becomes encrusted over the patch.

Photograph 2.  Typhula blight symptoms appearing after spring snow melt on an annual bluegrass green.

Microdochium patch (synonyms: Pink snow mold, fusarium patch) is often associated with Typhula blight.  However, the disease pathogen Microdochium nivale does not require snow cover to infect and cause symptoms.  

Initially, Microdochium patch symptoms appear as small patches, maybe 1 to 2 inches in diameter that eventually reach 12-inches in diameter.  Leaves become water soaked, turn reddish-brown then turn a bleach color.  In cool wet weather, the leaves are matted together, which is especially true on high cut turf, and covered with a whitish pink mycelial growth that is slimy when wet.  The pink mycelium is often observed in the early morning.  The circular patches may exhibit a pink coloration when exposed to light.  Mature Microdochium patch symptoms appear as circular patches of pinkish-orange to brown infected turf.

pinkish border
​​​​​​​Photograph 3.  Microdochium patch on an annual bluegrass green

Although both Typhula blight and Microdochium patch infect most cool season turfgrasses, it is annual bluegrass that is especially susceptible to the diseases in the northern United States.

Fungicide treatments are the most effective management means for snow molds. Cultural practices can help reduce the severity of the snow molds, specifically Microdochium patch.  Cultural practices include:

  1. Continue to mow through the fall until the turf ceases growth.
  2. Mulch or remove leaves from the turf. Leaf removal helps reduce the severity of a wet moist environment for disease development. 

Microdochium patch on higher cut turf​​​​​​​
​​​​​​​Photograph 4. Microdochium patch on an annual bluegrass turf.

Syngenta offers a Snow Mold Assurance program to protect your course for up to 130 days of control with Instrata® fungicide and up to 110 days of control with Contend® fungicide.

For more information on Gray Snow Mold, Microdochium Patch, or other diseases, you can check out the Syngenta Disease ID Guide.

About the author

Dr. Karl Danneberger is a professor of Turfgrass Science at The Ohio State University. Dr. Danneberger's contact information can be found here. You may also follow Dr. Danneberger on Twitter:

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