Cowpea powdery mildew is a common and destructive disease affecting leguminous vegetables, particularly in both northern and southern regions of China. During the peak season, it causes significant damage to the lower and middle leaves of the plant, leading to leaf death, reduced yield, and deterioration in product quality. This disease can result in substantial economic losses for farmers.
The symptoms of cowpea powdery mildew primarily affect the leaves, where white, powdery fungal growth appears on both the upper and lower surfaces, as well as on the stems and petioles. As the infection progresses, these patches merge into larger areas, eventually causing the leaves to wither and fall off. The disease is caused by *Erysiphe polygoni* DC., a fungus belonging to the Ascomycota division. The sexual stage produces dark, spherical ascocarps with mycelium-like appendages, while the asexual stage involves conidia formed on short conidiophores.
This pathogen has a broad host range, infecting various legumes, as well as vegetables such as cabbage, celery, rape, mustard, and tomatoes. It is a biotrophic parasite that cannot survive on dead plant material. In northern China, the fungus overwinters through ascospores, but in other regions, it may not form strong resting structures. The main source of infection comes from airborne conidia produced on nearby crops or weeds. These spores spread easily through wind and germinate under favorable conditions.
Powdery mildew thrives in dry environments and is less likely to develop in rainy weather. However, high humidity and poor air circulation still favor its occurrence. Plants suffering from drought or water stress are more susceptible. Overcrowded planting, excessive nitrogen fertilizer use, and poor field management also contribute to disease development.
To manage cowpea powdery mildew, farmers should choose resistant varieties, implement proper cultural practices, and apply timely fungicide sprays. Field ventilation and light exposure should be improved, and irrigation should be maintained to avoid water stress. After flowering, balanced fertilization with phosphorus and potassium is recommended to prevent early aging. Fungicides such as 70% thiophanate + 75% chlorothalonil (1:1), 30% copper oxychloride + 65% mancozeb (1:1), or 80% anthraquinone Fumei WP can be used. Spraying should begin before symptoms appear and continue every 7–15 days, with at least two to three applications. No chemicals should be applied within seven days of harvest to ensure safe consumption.
Indoor Power Wheelchair,Cheap Electric Wheelchair,Electric Wheelchair Outdoor Use,Low Price Electric Wheelchair
Suzhou Danyazhihe Technology Co., Ltd , https://www.autowheelchairs.com