Cucumber powdery mildew is also called "white hair" disease. It is a common occurrence in all parts of the country and is a serious hazard. One of the three major diseases. From seedlings to adults can be harmed. ã€symptom】 The main damage leaves, petioles, stems, does not harm the fruit. At the beginning of the disease, white small spots were produced on the front and back sides of the leaves, and then expanded and contiguous with a layer of white mold. White mold edge is not neat, later turned gray. Sometimes there is a small black spot on the lesion. Leaves yellow, brittle and dry. It usually starts from the bottom leaves and gradually develops upwards. Incidence conditions The disease is a fungal disease. The pathogenic bacteria overwintered in the field with the diseased plant residues or overwintered in the protected area. Hunchun is spread by air currents and rain. The suitable temperature for disease onset is above 25-30°C, and the viability is lost below 30°C. Appropriate air relative humidity is 75%, and it can also be caused by drought. When conidia germinate, they do not need water droplets, they do not circulate in the air, they are managed extensively, nitrogenous fertilizers are applied in some places, the plants are long and the leaves and branches are too dense, and the diseases are easy to occur when the light is insufficient. 1, select the appropriate species: As far as possible, Jinyan 4th, Jinyan 6th, Jinza 1st, Jinza 2nd, Jinchun 3rd, Zhongnong 5th and other disease-resistant varieties were selected. 2, field management: Pay attention to ventilation and light transmission, remove yellow, old and diseased leaves in a timely manner; rationally apply water, lay plastic film, and reduce air humidity; apply organic fertilizer and increase phosphorus and potassium fertilizers. 3, pharmaceutical control: In the protected area, chlorothalonil smoke agents were used to treat the disease. 30% Teflon 2000 times; 40% DuPont Fuxing 5000 times; 47% Garinong 600-800 times, one of the above drugs, once every 7-10 days, even spray 3-4 times. Baking soda 500 times, or 300 times salt spray, every 3 days, even spray 4-5 times; Generally, the ground full of plastic film, or afraid of watering the air is relatively dry, the incidence of serious greenhouse, as long as the spray of the above-mentioned agents, while pouring a large water cucumber, stop the air for 3-5 days, the condition can be subsided. Ningbo Siny Medical Technology Co., Ltd , https://www.sinymedical.com