Occurrence of Brown Patch on Kentucky Bluegrass Caused by Rhizoctonia solani AG-1 IB

Abstract

ABSTRACT. Brown patch caused by Rhizoctonia solani AG-1 IB occurred on Kentucky bluegrass during late May through early October 2010 at golf course in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass for spring season were leaf blights dying from the leaf tip, which appeared patches of brown color in the field. However, it appeared patches of dark brown color or gray brown color in fall. The fungus (B-7 isolate) of brown patch was isolated from the diseased leaf tissue and cultured on potato-dextrose agar (PDA) for identification. The young hyphae had acute angular branching and few septa and mature hyphal branches showed about 90-degree angles and development of monilioid cells, which were morphologically identical to Rhizoctonia solani AG-1 IB reported previously. DNA sequences of ribosomal RNA gene (internal transcribed spacer) of the fungus were homologous with similarity of 99% to those of Rhizoctonia solani AG-1 IB isolates in GenBank database, confirming the identity of the causal agent of the disease. Pathogenicity of the fungus was also confirmed on the creeping bentgrass and Kentucky bluegrass by Koch's postulates. This is the first report of brown patch on Kentucky bluegrass caused by Rhizoctonia solani AG-1 IB in Korea.

Occurrence of Pythium Blight Caused by Pythium aphanidermatum on Chewing Fescue

“…병원성 검정 병원성을 검정하기 위하여 포장에서 병이 발생한 chewing fescue 품종인 "Jamestowm II", Kentucky bluegrass 혼용 품 종(Midnight 33%, Moonlight 33%, prosperity 33%) 및 creeping bentgrass 품종인 "Penn Cross" 에서 병원성 시험 을 실시하였다. 잔디는 관행 관리에 의해 1년 이상 자란 시험포장 잔디를 홀 컷터로 잘라내어 화분에 옮긴 후 온실 에서 20일간 관리한 잔디에 병원균을 접종하였다 (Chang, 2011;Chang and Lee, 2013 (Fig. 6).…”