First Report of Waitea circinata from Turfgrass in British Columbia, Canada

Abstract

In Canada, Waitea circinata was first identified from buckwheat (Fagopyrum sp.) in 1965 in Ontario (4). In 2004, the fungus was found on diseased putting greens of Poa annua and Agrostis stolonifera near Toronto, Ontario (2). In late July 2009, symptoms on A. stolonifera resembling those of brown ring patch were seen at a golf course in Kelowna, British Columbia. Brown rings with light-colored, cottony growth were observed on a putting green with mixed P. annua and A. stolonifera, originally seeded with A. stolonifera cv. Penncross. Following a short incubation of the diseased grass at 25°C, hyphae of a Rhizoctonia-like fungus, not matching the characteristics of R. cerealis or R. solani, were seen. Symptomatic leaves were surface sterilized in 1% hypochlorite and plated onto potato dextrose agar (PDA) amended with streptomycin. After 1 week at 23°C, the plates contained white colonies that were 5 cm across. DNA was extracted and amplified with primers ITS1/ITS4 and sequenced with ITS1. The 600-bp sequence (deposited in GenBank as GU176409) from the internal transcribed spacer (ITS) region of ribosomal DNA showed a 100% match in the overlapping range with sequence FJ755879 from GenBank, which is annotated as W. circinata var. circinata. Pathogenicity was tested at 23°C by inoculating 3-week-old A. stolonifera 'Penncross' plants grown in Magenta boxes and incubated for 15 days after inoculation with ground wheat seed inoculum of W. circinata. Within 1 week, significant blighting of leaves and sheaths was observed as well as spherical orange brown sclerotia that were 2 to 5 mm in diameter on sheaths. These sclerotial features match characteristics of W. circinata var. circinata (1). Symptomatic leaves were plated on PDA and fungal growth characteristic of W. circinata was recovered. W. circinata was previously reported as the causal agent of brown ring patch on A. stolonifera in Japan (3), as a pathogen of P. annua in the United States (1), and as a pathogen of both species in Ontario, Canada (2). To our knowledge, this is the first report of W. circinata from turfgrass in western Canada.