Identification of Pathogen From Cucumber Target Leaf Spot and Research on Biological characteristics

Caused by Corynespora cassiicola(B.C.)Wei,Cucumber Target Leaf Spot is a serious disease in green house in Liaoning Province. The research results on biological characteristics showed: the optimum temperature for conidial germination is15～35℃,the optimum pH is pH5～8, water drop is necessary for conidial germination,the optimum temperature for hyphal growth is 15～35℃,the optimum pH is pH6～8.Hypha can grow well on PSA?PDA medium and light has no effect on its growth. The optimum temperature for sporulation is 25～30℃,the optimum pH is pH5～8.The fungi can sporulate a lot on PSA?PDA medium and light is in favor of sporulation.Under outside room condition, the conidium can't live through winter safely, but can live through summer safely in green house.The pathogen has a wide range of parasitifer,can infect more than 20 species of vegetable such as cucumber and tomato.