Susceptible Strawberry Cultivars to Alternaria Black Spot of Strawberry (Alternaria alternata Strawberry Pathotype) in Japan

The purpose of this paper is to report susceptible strawberry cultivars and strains to Alternaria black spot of strawberry (Alternaria alternata strawberry pathotype) in Japan. The test for susceptible strawberry cultivars and strains to the pathogen was carried out by artificial inoculation with the spores (isolate OH-5) in June and September, 1988 and 1989. Natural infections under field conditions were also recorded.Among sixty Japanese and foreign strawberry cultivars and strains tested, only two cultivars, ‘Morioka-16’ previously known as susceptible cultivar in Japan and ‘Robinson’ from the United States of America, were susceptible to the pathogen in Japan. The other cultivars including ‘Chiyoda’ and ‘Fairfax’, used as crossing parents of ‘Morioka-16’, were completely resistant.