A rust on Asiatic dayflower plant (Commelina communis L.) was found in Geoje, Korea, in August 2010. Uredia are mostly produced on abaxial leaf surface or elongated on stem, early naked, surrounded by the ruptured epidermis, cinnamon-brown. Uredospores are globose, ellipsoid or ovate, echinulate, yellowish brown or brown, 20-30 × 20-25 ㎛. On the basis of mycological characteristics and molecular data, the fungus was identified as Uromyces commelinae Cooke. The phylogenetic position of U. commelinae is separate from the other rusts where the economically important rusts of the Poaceae are situated. Although host ranges of the rust caused by U. commelinae were previously recorded, full descriptions and illustrations, including symptoms and signs have not been described. This is the first description of rust disease on C. communis plant with molecular identification, symptoms, and signs.

Recently, ambrosia beetles have become very important pest of 2~5 year old apple trees with M9 dwarf rootstocks in South Korea. The beetles have killed the branches and stems of the young trees, especially, frozen damage trees in winter or drought stressed tree in spring. By the increase in planting area and weaken property in winter of M9 dwarf rootstock, ambrosia beetles are becoming a key pest in Korean apple orchards using M9 rootstock. According to the survey of damaged apple trees by ambrosia beetles, Xylosandrus germanus Blandford, Xyleborus apicalis Blandford and Xyleborinus saxeseni (Ratzeburg). These insects are hosts of the ambrosia fungi. ITS region of rDNA has shown to be a useful source for phylogenetic studies and identifying speices in previous published articles. We analyzed the nucleotide sequences of ITS1, 5.8S and ITS2 region of ambrosia fungi isolated from three ambrosia beetles, in order to observe molecular variation among the fungi strains and to reveal phylogenetic relationships.