Marssonina coronaria associated with apple blotch disease causes severe premature defoliation, and is widely distributed in Korea. Thirteen isolates were collected from orchards located in Gyeongbuk Province from 2005~2007. All isolates displayed over 99.6% and 99.2% sequence similarity to each other in internal transcribed spacer regions and partial sequences of 28S rDNA, respectively. The isolates were phylogenetically closely related to Chinese isolates. Selected isolates did not differ in their pathogenicity. The optimum conditions for fungal growth were 20℃ and pH 6 on peptone potato dextrose agar (PPDA). Peptone and mannose were the best nitrogen and carbon source, respectively. Fungal growth was better on PPDA than on common potato dextrose agar. This study provides valuable information for integrated disease management program and facilitates the routine culturing of M. coronaria.

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To examine the duration of post-infectional activity of ergosterol biosynthesis-inhibiting fungicides (EBIs) against Botryosphaeria dothidea, the cause of apple white rot, a series of experiments was conducted for 3 years at different times during the apple-growing season using apples infected through artificial inoculation or natural infection. Disease incidence at harvest was gradually reduced as the time of chemical application was delayed until early or mid-August, regardless of the time of infection. Latent infections, detected after storing the fruit at 26C for 4 weeks were also reduced by late season applications, but the reduction was less than that observed on the fruit at harvest. From these results, apple white rot can be effectively controlled by a single application of EBIs around mid-August, after which time, infections no longer occur in Korea.