2003 Volume 69 Issue 3 Pages 198-204
A new disease of European pear (Pyrus communis L. var. sativa de Candolle), causing small black spots on the fruits, was found in Sannohe district, Aomori Prefecture in 1990. A fungus with Cylindrosporium-type conidia was isolated at a high rate from the spots. In 1998, small brown flecks were noticed on leaves of European pear in the same orchard. The affected leaves, which had overwintered on the ground, yielded a fungus with pseudothecia of the Mycosphaerella type in May 1999. Singleascospore isolates from the pseudothecia produced the Cylindrosporium anamorph on plates of potato dextrose agar. Inoculations with conidia of the fungus reproduced the typical fruit spots on unwounded fruits of European pear. Also, inoculations of unwounded fruits of apple (Males pumila Mill. var. domestica Schneid.) with the fungus produced typical symptoms of Brooks fruit spot disease. On the other hand, inoculations of unwounded fruits of European pear with conidia of M. pomi from apple produced typical symptoms of the new fruit spot disease. Based on morphological and cultural characteristics, the causal fungus of the diseases on fruits and leaves of European pear was identified as Mycosphaerella pomi (Passerini) Lindau (anamorph: Cylindrosporium pomi Brooks). This is the first report of M. pomi on European pear. The disease is named “Mycosphaerella fruit spot” (kokuten-byo in Japanese) of European pear.