2000 年 66 巻 3 号 p. 242-245
Gray mold was found on petioles and stems of Mitsuba (Cryptotaenia japonica Hassk.) growing in hydroponics in the summer of 1998. A Botrytis species was isolated from the infected plants. Based on the morphology and the growth temperature, this fungus was identified as Botrytis cinerea Persoon: Fries. Because a cooled nutrient solution was circulated in the hydroponic system in summer, temperature at the base of the Mitsuba plants was kept on rather lower temperature in this season. Cool weather, therefore, is required for this disease to occur during the season.