Pathology of Winter Injured Grasses and Legumes In Western Canada1
- J. B. Lebeau
Winter killing of turfgrass and forage crops is seldom due to subzero temperatures alone but is also caused by desiccation or attack by psychrophilic fungi. In Western Canada snow mold is caused by an unidentified basidiomycete. Cold-hardy varieties of turfgrass and forage crops were more resistant to this pathogen than non-hardy varieties. Investigations on snow mold in Alberta showed that damage on turfgrass and alfalfa was consistently associated with accumulation of HCN in the host tissues. The effect of low temperature on cell permeability appears to be the important factor making a cyanogenic glycoside from the host available to beta-glycosidase secreted by the fungus. Snow mold on turfgrass was controlled in southern Alberta by raising the temperature of the soil a few degrees during cold periods in the winter. Minimum temperatures were maintained in experimental plots by soil-heating cables controlled by thermostats. The temperature required for control was critical. No snow mold was found in plots with minimum controlled temperature of 0 C. The grass grew slowly during the winter in these heated plots and was lush and green in the early spring. Regulation of temperature in conjunction with the application of fungicides should ensure complete protection of turfgrass from damage caused by psychrophilic pathogens. The extended use of this method will depend largely on the future cost of supplying heat energy.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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