General research methods on pathogen of potato late blight (Phytophthora infestans)

It's known that Phytophthora infestans is very difficult to be isolated and purified. According to the working experience in the past 8 years,the general research methods of potato late blight were summerized in this paper,which includes the method of sample collection of Phytophthora infestans ,the methods of isolation and purification of P. infestans,evaluation of late blight resistance in potato germplasm.