First Report of Summer Patch Caused by Magnaporthiopsis poae on Cool Season Grass

Ju Ho Han1,2   Chang Hyun Ahn1,3   Seung-Yeol Lee1   Chang-Gi Back1,4   In-Kyu Kang1   Hee-Young Jung1,*   

Abstract

Symptoms of summer patch were observed on Kentucky bluegrass (Poa pratensis L.) cv. “Midnight II” from mid-June in 2015 in Seoul, Korea. The symptoms appeared as leaf blight, root rot, and frog-eye patch, which are typical of summer patch. To identify the causal agent of these symptoms, a pathogen was isolated from diseased leaves and roots, and the cultural, morphological, and phylogenetic characteristics were analyzed. The isolate reached 50–60 mm on potato dextrose agar (PDA) after 10 days as a white-grey mycelium with septa, and became olive-green or brown from the center. Phialide-like structures were observed at the ends of hyphae, and conidia were rarely observed. A phylogenetic analysis was conducted based on large subunit (LSU) and RNA polymerase II large subunit (RPB1) sequences. According to this analysis, the isolated pathogen was confirmed to be Magnaporthiopsis poae. In a pathogenicity test, summer patch symptoms were observed at 20 days after inoculation using the same grass cultivar. This is the first report of summer patch disease caused by M. poae on cool season grass in Korea.

Acknowledgements

This research was supported by Cooperative Research Program for Agriculture Science & Technology Development (Project No. PJ010481032016) Rural Development Administration, Republic of Korea.

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