First report of strawberry fruit rot caused by Alternaria tenuissima in Korea

Abstract

A strawberry (Fragaria × ananassa Duch.) fruit rot disease has been observed in several vinyl-house fields at Nonsan and Taejon, Chungnam district, Korea, especially following moist and cool conditions in the spring and again in September. Over the past 7 years, incidence of the disease has ranged from 0.2 to 2.0%. Early symptoms on fruits were characterized by small, irregular lesions, which were slightly sunken and appeared light green to black in color as sporulation began. Conidia were 25 to 55 μm long by 10 to 17 μm wide; beaks, when present, were 2 to 3 μm wide and up to 40 μm long; and conidiophores were 20 to 110 μm long by 3 to 5 μm wide. Older lesions were circular, largely sunken, firm, and dark-green to almost black because of abundant sporulation. The fungus isolated from infected fruit tissues was identified as Alternaria tenuissima (Fries) Wiltshire, based on the morphological characteristics of the conidia and conidiophores. Pathogenicity tests were conducted by inoculating slightly wounde...