title: Root Rot of Balloon Flower (Platycodon grandiflorum) Caused by Fusarium solani and Fusarium oxysporum.
abstract: Balloon flower (Platycodon grandiflorum) is a kind of mountain herbs whose roots have restorative properties and the cultivating acreage of balloon flower has been steadily increasing in Korea. More frequent rain and high amount of rainfalls as a result of climate changes predisposed balloon flower to the outbreaks of root rot at high-density cultivation area in recent years. Root crowns were usually discolored into brown to blackish brown at first and the infected plants showed slight wilting symptom at early infection stage. Severely infected roots were entirely rotted and whole plants eventually died at late infection stage. The overall disease severities of root rot of balloon flower were quite variable according to the surveyed fields in Jeonnam, Gyeongnam and Jeju Provinces, which ranged from 0.1% to 40%. The root rot occurred more severely at the paddy or clay soils than the sandy soils and their severities were much higher at lowland than upland in the same localty. The disease increased with aging of the balloon flower. The causal fungi were identified as Fusarium solani and F. oxysporum on the basis of their mycological characteristics. The optimum temperature ranges of their mycelial growths was found to be 24°C. The pathogenic characters of F. solani and F. oxysporum treated by artificial wounding inoculation on healthy roots of balloon flower revealed that F. solani was more virulent than F. oxysporum. This study identified the causal agents of root rot of balloon flower as Fusarium solani and F. oxysporum, probably for the first time.
authors.affiliation: Department of Plant Medicine, College of Life Science and Natural Resources, Sunchon National University, Suncheon 540-950, Korea.
authors.forename: Chi Sung
authors.initials: CS
authors.lastname: Jeon
authors.affiliation: Department of Plant Medicine, College of Life Science and Natural Resources, Sunchon National University, Suncheon 540-950, Korea.
authors.forename: Gyoung Hee
authors.initials: GH
authors.lastname: Kim
authors.affiliation: Department of Plant Medicine, College of Life Science and Natural Resources, Sunchon National University, Suncheon 540-950, Korea.
authors.forename: Kyeong In
authors.initials: KI
authors.lastname: Son
authors.affiliation: Department of Environment Education, College of Education, Sunchon National University, Suncheon 540-950, Korea.
authors.forename: Jae-Seoun
authors.initials: JS
authors.lastname: Hur
authors.affiliation: Southern Forest Resources Research Center, Korea Forest Research Institute, Jinju 660-300, Korea.
authors.forename: Kwon-Seok
authors.initials: KS
authors.lastname: Jeon
authors.affiliation: Southern Forest Resources Research Center, Korea Forest Research Institute, Jinju 660-300, Korea.
authors.forename: Jun-Hyuck
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of Plant Medicine, College of Life Science and Natural Resources, Sunchon National University, Suncheon 540-950, Korea.
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Koh
keywords: F. oxysporum; Fusarium solani; balloon flower; root rot