The cause of death The disease of watermelon is also called Phytophthora, commonly known as "death," and it is a kind of soil fax fungus disease. It can occur in the watermelon seedlings and adult plants, especially in the late growth period, high temperature and rainy conditions of watermelon. And serious; the general rainy season comes early, long time for precipitation, rainfall is large, then the onset is early, serious illness, loss. The peak incidence in the field is often immediately after the peak rainfall. Leaf disease, resulting in dark green water spots round or irregular shaped lesions, rotten or boiled like hot water when the humidity is too large, dry spots, light brown, easy to break. The basal part of the vine spreads, and a spindle-shaped water-immersed dark green spot appears, enveloping the stem and rot, and all the diseased parts are dead. Onset of fruit, the formation of dark green round water-immersed depression spots, rapid expansion after the whole fruit, resulting in fruit rot, the smell of silage, dense white mycelium diseased surface. Prevention and control methods From the early stage of disease occurrence, use 50% methicone wettable powder 700 to 800 times liquid, 72.2% Preclosure 800 times liquid, 64% antivirus WP 500 times or 58% metalaxyl Mn Zinc wettable powder 500 times, spray once every 7~10 days, even spray 3~4 times. When necessary, the above liquid can also be used to irrigate the roots, and 0.4 to 0.5 liters per plant. If the spray and irrigation are performed at the same time, the effect is better. HEBEI PINGLE FLOUR MACHINERY GROUP CO., LTD , http://www.plrollermill.com