Snow Mold, Gray or Speckled

Typhula spp.

Disease description
Gray Snow Mold is patches of damaged grass sometimes with superficial gray mycelium -- sclerotia in or on plant tissues:

Typhula incarnata - British Columbia and eastern Canada, rare in Prairies -- orange to brown sclerotia up to 2 mm.
T. ishikariensis var. canadensis -- the most common T. ishikariensis var. of the deep snowfall areas of western Canada, known as far east as Ottawa. Abundant gray, superficial mycelium--sclerotia brown-black, less than 1 mm. Often occurs with F. n/vale on Prairies.
T. ishikariensis var. ishikariensis- distribution not fully known -- deep snowfall areas in western and eastern Canada --less abundant gray mycelium than var. canadensis, sclerotia about 1 mm. Complexes of Typhula spp. with each other and with other snow molds are common

Predisposing factors

forced fall growth
most commercially available Kentucky blue grass cultivars are susceptible to T. incarnata
most Agrostis cultivars seem to be susceptible to T. i. var. canadensis
little information on varietal resistance. T. incarnata does not require long duration snow cover to cause damage

Cultural control
Allow turf to "harden off" in fall in prairie region, as for fusarium patch and LTB. Insufficient information on culti-var resistance for reliable recommendations on Agrostis cultivars. Adorno and Monopoly Kentucky blue grasses are reported to be resistant. Applications of soot, fly ash or other finely ground, dark materials to hasten melting of snow in late winter may reduce severity of snow molds in general.

For information about other diseases that affect turf grasses, go to Major Diseases of Turf Grasses in Western Canada.

For more information about the content of this document, contact Ron Howard.
This document is maintained by Shelley Barkley.
This information published to the web on November 20, 2001.
Last Reviewed/Revised on November 7, 2007.