Lawn Fungus in Late Winter

Reduce thatch in the fall to help prevent lawn fungus from occurring in the late winter.

Two lawn diseases occur in the late winter to early spring: Typhula blight and Fusarium patch. Both lawn diseases can cause a number of health concerns of the lawn. It is important to employ proper Typhula blight and Fusarium patch prevention and treatment to ensure a healthy grass for the growing season.

Typhula Blight

Typhula blight, or gray snow mold, is caused by Typhula incarnata and Typhula ishikariensis fungal spores, according to the North Dakota State University. This fungal disease occurs in the late winter to early spring, or when the snow melts off the lawn. Gardeners may notice straw-colored patches of lawn that can reach 40 inches in diameter. Eventually, these patches will take on a matted appearance and gray fungal growth will appear growing on the surface. The mold stops growing when temperatures exceed 45 degrees Fahrenheit, according to North Dakota State University.

Fusarium Patch

Fusarium patch. or pink snow mold, is caused by Microdochium nivalis fungal spores. This lawn disease causes yellow patches of grass that enlarge when the air temperature warms in late winter to early spring. Also, these patchy, bleached-out areas appear pink when the grass is wet. The disease will continue to damage grass as long as the air temperatures remain between 32 and 60 degrees Fahrenheit, according to North Dakota State University. Grass can die out from Fusarium patch.

Treatment

Typically, fungicides are not used to treat Typhula blight or Fusarium patch, according to North Dakota State University. Gardeners may want to use a preventative fungicide on their lawns if their grass has a history of either one of the lawn diseases. Use a fungicide with a combination of fludioxonil and propiconazole if living in the northern part of the United States to prevent typhula blight. Those living in the southern part of the country can use a fungicide combination of fludioxonil and propiconazole, as suggested by the University of Massachusetts.

Prevention

Prevent your lawn from contracting a disease by mowing in the fall slightly shorter than you normally mow. By preventing a thick mat of grass, you can decrease the chances of the lawn contracting either Typhula blight or Fusarium patch, according to North Dakota State University. Avoid using a fertilizer high in nitrogen in the early spring , late summer of fall months. Refrain from fertilizing the lawn after Oct. 15, as recommended by the North Dakota State University.

References

• University of Massachusetts Extension; Protecting Turfgrass from Typhula Blight; Young-Ki Jo, et al.
• North Dakota State University Extension; Lawn Diseases; H. Arthur Lamey; July 1996