Cottony Snow Mold or LTB

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Coprinus psychromorbidus

Disease description
Cottony Snow Mold or LTB (non-sclerotial low-temperature basidiomycete) and SLTB (sclerotial LTB) Snow Molds (Coprinus psychromorbidus ). Large patches,
occasionally with dense, white cottony mycelial growth at edges (LTB); or small (1-3 mm) brownish-black, irregular sclerotia on leaves and stem bases (SLTB). Often, LTB patches do not coalesce.

Predisposing factors
  • shallow to deep snow covers
  • slow melting of drifts in spring
  • unbalanced, late nitrogenous fertilization
  • previous attacks
  • most common tuff grass species, e.g., Flyking, Nugget, Sydsport, Merion, and Newport Kentucky blue grasses are susceptible
Cultural control
Control snow cover with fences and spread snow drifts or encourage rapid melting with soot or fine ashes. Control thatch. Tests suggest that unbalanced phosphate applied when turf is dormant in late fall in the Prairies will favour LTB snow mold. Dormie and Park are more resistant than other Kentucky blue grass cultivars. Arctared was most resistant of the red rescue cultivars in Saskatchewan tests. Poa annua turf re-establishes well from seed lying at the turf surface.
For information about other diseases that affect turf grasses, go to Major Diseases of Turf Grasses in Western Canada.
This document is maintained by Shelley Barkley.
This information published to the web on November 20, 2001.
Last Reviewed/Revised on November 27, 2012.