Biological characteristics of Cercospora zeae-maydis

In recent years gray leaf spot of corn caused by Cercospora zeae maydis Tehon and Doniels became more prevalent in the maize growing area of northern China. The biological characteristics of pathogen have been investigated. One of optimum media for Cercospora zeae maydis growth is peanut leaf disk medium, inferior PDA,V8 juice agar, V8 juice plus sugar and Richard's medium.Among the tested carbon and nitrogen resources, glucose, maltose, lactose and yeast extract, KNO 3 and beef extract are useful types, nutrition has no selective effect on conidial germination. For growth of the pathogen, the favorable pH is 4-12 with the optimum pH 6-8, the favorable temperature is between 20-25℃. The suitable temperature for conidial germination is between 20-30℃. The conidia germination has no strict pH requirement that conidia can germinate at RH 81%-98%, or have 100% germination rate in water.