Pathogen and characteristics of pumpkin powdery mildew

The pathogen belongs to Oidium sp. In South China, the pathogen takes asexual conidia as primary and re-invasive inoculum, spreads infection among field host crops through airflow, and completes the annual cycle of the disease, with no obvious overwintering period. Pathogens often produce sexual capsules (small black particles as big as needles in powder) around the end of crop growth period to spend summer or winter, but in the south, especially in Guangdong, there are few sexual stages of pathogens, and even if they exist, their role in disease cycle is not important. Warm, humid or dry hot weather is conducive to the occurrence of this disease. At present, there is still a lack of comprehensive investigation on interspecific resistance. At present, only Phoenix pumpkin bred in Taiwan Province Province has strong resistance, while Tanzi pumpkin in Shashi, Hubei Province and Jinpumpkin No.3 in Taigu, Shanxi Province are also resistant to powdery mildew. Other varieties with strong resistance or disease resistance, such as Ding Jiao Pumpkin (Jinggangshan, Jiangxi), Duolun Pumpkin and Pumpkin (Inner Mongolia), Meizao Pumpkin (Xianning, Hubei), Goose-necked Pumpkin (Hebei), Box Pumpkin (Jiangsu) and Papaya Pumpkin (introduced from Taiwan Province Province), are also resistant to powdery mildew, which needs further observation and identification.