Biological Characteristics of Phytophthora infestans on Tomato

The study of biological characteristics of Phytophthora infestans showed that the mycelium could grow better on the most of culture media,but RSA was the best one.The light held up the growth of mycelium and sporangium,and the dark generated the promoting effect.The pathogen could make full use many kinds of carbohydrates.The sucrose was the best C source and mannose was the worst C source.Alanine was the best N source while cystine was the worst one.The temperature for mycelial growth and sporulation was from 10℃ to 30℃,and the optimum temperature was 20℃.The proper pH values ranged from 5 to 9.For sporangium germination of the pathogen,the optimum temperature was 15℃.The sporangium failed to germinate at temperature higher than 35℃.The light had no effect on the sporangium germination,and the proper pH value was 7.All kinds of nutrients were suitable for sporangium germination.The sporangia lethal temperature was 57℃,10min.