Occurrence of White Smut Caused by Entyloma cosmi on Cosmos bipinnatus in Korea

Research in Plant Disease 2012;18(3):250-254.
Published online September 30, 2012.

Entyloma cosmi에 의한 코스모스 흰깜부기병 발생

박지현 ( Ji Hyun Park ) , 조성은 ( Sung Eun Cho ) , 박미정 ( Mi Jeong Park ) , 홍선희 ( Sun Hee Hong ) , 신현동 ( Hyeon Dong Shin )

Occurrence of White Smut Caused by Entyloma cosmi on Cosmos bipinnatus in Korea

Ji-Hyun Park, Sung-Eun Cho, Mi-Jeong Park, Sun-Hee Hong1 and Hyeon-Dong Shin*

Division of Environmental Science and Ecological Engineering, Korea University, Seoul 136-701, Korea
¹Institute of Environment and Ecology, Korea University, Seoul 136-701, Korea

Received: March 08, 2012 Revised: June 16, 2012 Accepted: June 18, 2012

Abstract

In July 2011, hundreds of garden cosmos (Cosmos bipinnatus) were found to be infected with a white smut in Namyangju. Further surveys in central Korea showed that the disease occurred in all the nine localities visited, with disease incidence rate of >50%. Symptoms manifested as pale-green to chlorotic areas on the leaves, followed by white mildew development on lesions. The lesions usually coalesced and became necrotic, considerably reducing the aesthetic value. Caespituli were initially hypophyllous but later epiphyllous as well. Conidiophores were 10?40 in moderately dense fascicles, hyaline throughout, mostly guttulate, 20?45 × 2?4 μm, obtuse at the apex, and had inconspicuous conidial scars. Conidia were solitary, botuliform, hyaline, aseptate, mostly guttulate, apex rounded, base rounded to truncate, 17?24 × 3.5?5 μm, hilum inconspicuous, unthickened, and not darkened. Sori were rounded to elongated, resulting in first white and later brown leaf spots. Teliospores embedded in the leaf tissue were subglobose to ellipsoidal, subhyaline to pale yellowishbrown, 12.5?20 × 10?15 μm. These morphological characteristics corresponded with those of Entyloma cosmi V?nky, Horita & Jage. This is the first report of white smut disease of garden cosmos due to infection of E. cosmi in Korea.

Key Words: Garden cosmos, Teliospore