Identity of ectotrophic black runner hyphae on roots of Poa annua. Canadian Plant Disease Survey 78:116-117. Turfgrass / Gazon CROP: Turfgrass LOCATION: Ontario NAME AND AGENCY:

INTRODUCTION: Summer patch is a destructive disease of Poa species including Kentucky bluegrass (P. pratensis) and annual bluegrass (P. annua). It has only been found in the northeast and the northern mid-west of the USA Ring-patch symptoms are most commonly observed in summer, under conditions of sustained high temperatures and heavy rainfall (Jackson, 1993). In southern Ontario and Quebec, there are claims that this disease is present, but no confirmed microscopic or molecular diagnosis has been reported. Interestingly, there is even a fungicide registered for control of this disease in Canada. In our previous screening of ring patches on Kentucky bluegrass (Hsiang et al. 1992), we only found Leptosphaeria korrae, and did not find the causal agent of summer patch, Magnaporthe poae, in any of the samples. Since then, we have continued to attempt to confirm the presence of this fungus in Canada.