Effect of Typhula Phacorrhiza on Winter Injury in Field Trials across Canada

An isolate of the fungus Typhula phacorrhiza (Reich:Fr.) Fr. was evaluated in field tests across Canada for suppression of winter injury which was rated based on combined abiotic and biotic symptoms after snowmelt. This isolate, TP94671, has been identified in previous tests as being suppressive to gray snow mold, and a specific purpose of these trials was to evaluate the effect on pink snow mold. Out of 11 trials across Canada, six did not show significant differences in winter injury among the treatments (untreated control, fungicide treatment, or T. phacorrhiza treatment). In these locations, abiotic winter injury may have confounded the results or disease pressure was so low such that the effects on winter injury, including pink and gray snow molds, could not be assessed. In two trials at Montreal, Quebec (1999) and Waskeiu, Saskatchewan (1999), the -treated plots showed more winter injury than the fungicide-treated plots, but less than the untreated control plots. In three trials at Guelph, Ontario (1999), Barrie, Ontario (1999) and Panorama, British Columbia (2000), there were significant differences among treatments, with the T. phacorrhiza treatment suppressing winter injury as much as or even more than the fungicide control. In these trials, both pink snow mold and gray snow mold were commonly observed on the untreated plots and surrounding areas, and the T. phacorrhiza treatment was able to suppress winter injury in all three locations to an acceptable level (<10% affected area).