栃木県で発生した Colletotrichum acutatum Simmonds によるイチゴ炭そ病

抄録

A new causal fungus of strawberry anthracnose was found in Tochigi Prefecture in 1991. The symptoms of the disease appeared on leaves, petioles and runners in nurseries. The lesions are dark brown to nearly black and occur on the margins and tips of leaflets. Mycelia of the fungus are white, becoming pinkish grey, and conidial masses are salmon pink on PDA medium. Sclerotia and setae are absent. Conidia are hyaline, single-celled and fusiform with the dimensions of 8.9-16.2×3.2-4.9 (15.5×4.4)μm. Appressoria are dark brown, clavate and 5.9-8.9×4.1-8.1 (7.8×5.7)μm in dimensions. The fungus is pathogenic to tomato, sweet pepper and rocket larkspur. Optimum temperature for mycelial growth on PDA medium was about 25°C. Based on these morphological and pathological characteristics, the causal fungus was identified as Colletotrichum acutatum Simmonds.