Soft Rot of Rhizopus oryzae as a Postharvest Pathogen of Banana Fruit in Korea

Soft rot on banana fruit caused by Rhizopus oryzae was identified for the first time in Korea. Colonies were white to light brown and formed numerous sporangiospores. Optimum temperature for mycelial growth was 30degrees C. Sporangia were globose and 30~200 microm. Sporangiophores were usually straight, 8~20 microm, and rhizoids usually in groups of 3~5. Columella were globose to sub-globose and 90~110 microm. Sporangiospores were sub-globose or oval and 4~10 microm. Based on its mycological characteristics, molecular analysis, and pathogenicity to host plants, this fungus was identified as Rhizopus oryzae Went & Prisen Geerligs. This is the first report of soft rot on banana caused by Rhizopus oryzae in Korea.

Occurrence of Fruit Rot of Melon Caused by Sclerotium rolfsii in Korea

In 2007 to 2008, a fruit rot of Melon (Cucumis melo L.) caused by Sclerotium rolfsii occurred sporadically in a farmer's vinyl house in Jinju City. The symptoms started with watersoaking lesion and progressed into the rotting of the surface of fruit. White mycelial mats appeared on the lesion at the surface of the fruit and a number of sclerotia formed on the fruit near the soil line. The sclerotia were globoid in shape, 1~3 mm in size, and white to brown in color. The hyphal width was measured 3 to 8 microm. The optimum temperature for mycelial growth and sclerotia formation was 30 on PDA. Typical clamp connections were observed in hyphae of grown for 4 days on PDA. On the basis of symptoms, mycological characteristics and pathogenicity to the host plant, this fungus was identified as Sclerotium rolfsii Saccardo. This is the first report of the fruit rot of Melon caused by S. rolfsii in Korea.