Stem Rot of Tomato Caused by Sclerotium rolfsii in Korea

ABSTRACT

A destructive stem rot of tomato (Lycopersicon esculentum) occurred sporadically some farmers' fields in Jinju City, Gyeongnam province in Korea. The infected plants also showed stem, crown rot or whole plant blight. White mycelium spread over stems of infected plants and formed sclerotia on the old lesions nearby soil surface. The fungus showed maximum mycelial growth around 30degrees C. The fungus formed white colony on PDA, usually with many narrow mycelial strands in the aerial mycelium and the width were 4.0~9.8 microm. The typical clamp connections were formed on the mycelium. Numerous sclerotia was formed on PDA at 30degrees C. The shape of sclerotia was globoid and 1.0~3.0 mm in size. The fungus was isolated repeatedly from the infected tissues and the pathogenicity was confirmed to tomato and identified as Sclerotium rolfsii. This is the first report on the stem rot of tomato caused by S. rolfsii in Korea.