Why snow mold prevention is important

Now’s the time to think about snow mold prevention. Ken Hutto, Ph.D., product development manager for herbicides and fungicides for FMC, sat down with Landscape Management to help contractors understand how snow mold symptoms can start and why snow mold preventative applications are important.

LM: What snow mold symptoms would LCOs see first?

KH: For Typhula snow molds (gray and speckled), initial symptoms can begin as small as 1-2 inch diameter patches that are pale green/yellow. Once under snow cover, the mycelial growth of the fungi increases creating, larger patches (6 to 12 inches) that are gray to white. These patches can’t be seen until the snow has subsided.

During snowmelt you can see white mycelium, fungal threads that carry the pathogen, at the edges of the patches. Smaller patches of blighted leaf tissue can become larger ones by mating together. Speckled and gray snow molds produce different sclerotia, which are larger groups of mycelium. The sclerotia of gray snow mold are reddish brown, while the sclerotia of speckled snow mould are smaller and more black. These sclerotia are found on dead leaf blades.

The symptoms of pink snow mold/microdochium patches are small, circular spots 2 to 3 inches wide with gray to white colors. Pink mycelium can sometimes be seen around individual patches’ borders in cool and moist conditions. Blighted or matted-down turf can lead to larger gray patches. As the snow melts, you can see white to pink mycelium around the patches.

Patches that form in an area with a high amount of Poa Annua may develop rusty borders.

LM: Is there anything else an LCO might mistake snow mold symptoms for?

KH: Once snow cover breaks, gray snow mold symptoms may be mistaken for winter desiccation of turfgrass.

LM: What are some mistakes LCOs might make when dealing with a lawn with snow mold?

KH: Fertilizing too late in the fall with soluble nitrogen fertilizers. This causes an excessive amount of growth at a time when the environment favors disease development.

LM: How can LCOs work with homeowners to understand the benefit of snow mold preventative treatments as opposed to curative treatments?

KH: Preventative control using fungicides is the most effective way to control snow mold. Preventative treatments should be applied before the first snowfall. This is usually between late October and early November depending on the geographic location. Snow mold control programs that include both systemic and contact fungicides are the most effective. A second application of fungicide may be necessary in certain areas where cold, humid conditions persist late into the year.

LM: Is there anything else an LCO might want to know/think about snow mold?

KH: Mowing turfgrass until dormancy will maintain a consistent height of cut and reduce the potential for matted down areas where disease can develop. For areas that have suffered severe damage, you can help turfgrass recover by raking them away and applying normal fertilizer. LCOs may also employ cultural practices to reduce thatch accumulation. Snow mold infestation can be reduced by reducing the time an area is covered with snow.

Christina Herrick

About the Author: Christina Herrick

Christina Herrick is the editor of Landscape Management magazine. Herrick is known for her unique approach to traveling from coast to coast as the senior editor at American Fruit Grower Magazine. She uses social media (Twitter/Instagram @EditorHerrick), to share her travel experiences with her audience. Herrick holds a journalism degree from Ohio Northern University. She has been involved in B2B publishing since 2007. She can be reached at cherrick@northcoastmedia.net.

Christina Herrick
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