Phytophthora Rot of Strawberry in Kyushu, Japan

A new disease of strawberry caused by Phytophthora sp. was found in Saga and Fukuoka Prefecture on August 1978. The symptoms of the disease appeared on crown and leaves of strawberry grown in the nursery beds. Phytophthora sp. was isolated with high frequency from crown and leaves of infected young plants. Microscopic observations of fruit bodies of the isolated fungus revealed that zoosporangia had prominent apical papilla and antheridia were formed amphigynously. The optimum temperature for mycelial growth on a medium was at 30 C and the growth was slightly observed even at 35 C. Seedlings, mature fruits and petioles of strawberry, seedlings of egg plant, tomato and green pepper, fruits of egg plant and mature fruits of tomato were highly susceptible to the fungus by artificial inoculation. Fruits of green pepper and cucumber were slightly susceptible whereas seedlings of cucumber, melon, pumpkin and tabacco, and stem of tabacco were not susceptible. Based on these morphological and pathological properties, the fungus was identfied as Phytophthora nicotianae var. parasitica (Dastur) Waterhouse.