There are two types of Snow Mold that can develop on residential lawns, Pink and Grey. Although all grasses are susceptible to the diseases, they are most common on bluegrass, ryegrass, bentgrass and fescues. Pink Snow Mold, also called Microdochium Patch and Gray Snow Mold, also called Typhula Blight.
Although they are both associated with snow cover, Gray Snow Mold requires at least 60 days of snow cover for it to develop. Both types of Snow Mold are most severe when snow falls on unfrozen turf, but Pink Snow Mold can occur without snow cover during cool (less than 60 degrees) weather that is wet and cloudy.
Identifying Pink and Gray Snow Mold
Gray Snow Mold
Symptoms develop under the snow and become evident as it melts. This lawn disease appears in circular to irregular-shaped patches that can grow as large as 3 feet in diameter. The grass is covered with a white or gray fungal growth and the grass blades appear matted together. In severe cases, large sections of grass blades can be damaged and will take a long time to recover.
Pink Snow Mold
This disease appears in roughly circular-shaped patch that can range from a couple of inches to about a foot in diameter. The disease presents as a white patch with a pinkish ring on the outer border of the patch. The grass blades appear matted and look is if they are glued together. As thee patches dry out, they will feel hard to the touch.
How to Control and Prevent Snow Mold
Both diseases overwinter as spores in the patch layer, so reducing thatch levels is very important. Fall core aerations will help to reduce the thatch levels and improve the health of the turf by developing better root systems and reducing compaction. Avoid excessive nitrogen fertilizer in the late fall and continue mowing if the grass continues to grow. Overly long grass that falls over on itself is more likely to develop snow mold.
If possible, grind up leaves with your mower in the fall to recycle the nutrients back in to the soil. If it becomes too cold to continue mowing, but there are still many leaves on the lawn, do your best to rake them up before the snow starts to fall. Leaves left lying on the lawn provide great conditions for this grass disease to develop.
In most cases, an application of a disease control material is not warranted on residential lawns. Snow mold is usually not severe enough to warrant an application of a disease control material. If small sections of either gray or pink snow mold does develop, lightly break up the fungal mats with a leaf rake or even your fingers if the spots are not very large. If large snow piles remain on the lawn near driveways or sidewalks, do you best to distribute the snow across the lawn so that it melts faster.
Usually this lawn disease is a sign that winter is ending as it is generally seen when temperatures start to warm up and snow quickly melts. If you have any questions or would like us to check it out, don’t hesitate to contact your local Spring-Green.