Abnormal chloranthy was observed on trees grown in an orchard in Uiseong, Gyeongbuk province,
Korea in 2015. Flower buds showing chloranthy were covered with numerous orange-colored sori, which were confirmed to
contain spermogonia and aeciospores by stereo microscopy and light microscopy. When observed using scanning electron
microscope, the aeciospores were globose, ellipsoid, or ovoid, and measured 22.8~35.6 × 19.8~36.8 μm, with a verrucae wall
ornamentation. To construct a phylogeny, the large and small subunit regions of rDNA were sequenced and compared with those
of allied species by the maximum likelihood method. The isolated fungus species showed high similarities with
(Teleomorph: ), which was previously isolated from in Japan. Therefore, we initially report this fungal
agent parasitic on as in Korea and name the disease it causes as “flower bud chloranthy disease”.