Studies on Pathogen Identification and Biological Characteristic of Tomato Cercospora Leaf Mold

The tomato Cercospora leaf mold broke out in Xinxiang, Henan province in 2003. The symptom of the disease was observed and described, the pathogen and the biological characteristics were studied.The results show that the disease is caused by fungal pathogen of Cercospora fuligena Roldan.The symptom of the disease in leaf is regular or irregular spot and the color is black and brown.The optimal temperature for spore germination is 25-27 ℃.The optimal pH value for spore germination is 6-7.The lethal temperature of conidia is 53 ℃ for 10 minutes.The water drop is essential for the spore germination. The conidia of the pathogen can be killed by ultraviolet-ray.