Occurrence of Stem Rot of Sunflower (Helianthus annuus) Caused by Sclerotium rolfsii

Kwon, Jin Hyeuk

Research in Plant Disease 2010;16(3):323-325.
Published online December 30, 2010.

Sclerotium rolfsii에 의한 해바라기 흰비단병 발생

권진혁

Occurrence of Stem Rot of Sunflower (Helianthus annuus) Caused by Sclerotium rolfsii

Jin Hyeuk Kwon

Abstract

The stem rot of sunflower (Helianthus annuus) occurred sporadically in the experimental field of Gyeongsangnam-do Agricultural Research and Extension Services, on September, 2009. The infected plants were wilted and water-soaked brown spots were formed on the stem, than infected stems were mostly died. White mycelial mats were spread over lesions, and then sclerotia were formed on stem and near soil line. The sclerotia were globoid in shape, 1~3 mm in size and white to brown in color. The optimum temperature for mycelial growth and sclerotia formation on PDA was 30oC and the hyphal width was 4~8 μm. The typical clamp connections were observed in the hyphae of the pathogenic fungus. On the basis of mycological characteristics and pathogenicity to host plants, this fungus was identified as Sclerotium rolfsii. This is the first report on the stem rot of sunflower by S. rolfsii in Korea.

Key Words: Helianthus annuus, Sclerotium rolfsii, Stem rot, Sunflower