Growth Characteristics of Fujian Cymbidium Blight Pathogen

Growth characteristics of Phytophthora palmivora that causes the cymbidium blight in Fujian were studied.The results showed that(a)the pathogen grew differently on different media,(b)the bacteria grew the fastest on V8 juice,and the slowest on water-agar among various media,(c)the bacterial colonies formed on different media differed in size in the order of V8juice>cymbidium leaf extract>tomato juice>PDA=PSA>corn flour>water-agar,(d)the averaged difference between the largest and the smallest colonies was 3.23 cm in diameter,(e)the morphology of the colonies grown on different media varied appreciably,(f)beef extract seemed to be the best nitrogen source for the bacterial growth,while mannitol the best for carbon,(g)the pathogen could grow in the range of 15-35℃ and pH 3-10,with the optimum temperature at 30℃and pH of 6,(h)the lethal temperature for the mycelia was 50℃,and(i)the bacteria seemed to thrive under alternated light and dark conditions.