• Research in Plant Disease
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• v.9 no.1
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• pp.28-31
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• 2003

A sclerotinia rot was occurred on the stems of Obedient plant (Physostegia virginiaqna) grown in the exhibition field of Gyeongsangnam-do Agricultural Research and Extension Services, Korea in 2002. The typical symptoms of the disease were that the infected leaves and stems, at first, became dark green, then watery and soft rotted, later, White fluffy mycelia formed on the lesion developed black sclerotia, later, Sclerotia formed on the plants and PDA medium were globose to cylindrical or irregular in shape and 1.0~10.3$\times$1.0~8.4 mm in size. Aphothecia were cup-shape with numerous asci and 0.8~1.8 cm in diameter, Asci were cylindrical in shape and 84~286$\times$4.7~26.3 ${\mu}{\textrm}{m}$ in size. Ascospores were one cell hyaline, ellipsoid to ovoid in shape, and 7.6~12.8$\times$3.4~6.2 ${\mu}{\textrm}{m}$ in size. The optimum temperature far mycelial growth was $25^{\circ}C$. This is the first report on the sclerotinia rot of Physostegia virginiaqna caused by Sclerotinia sclerotiorum in Korea.