At present, it has entered the Meiyu period, with high temperature and high humidity, which is conducive to the occurrence of diseases such as watermelon blight and anthracnose. Recent investigations have found that some watermelon fields have been infected with blight, and the symptoms are obvious when the weather is fine after the rain.

Watermelon blight is a fungal disease that mainly damages the vines and also harms the leaves and fruits. On the onset of melon, the oily fading cracks in the initial section and the secretion of gelatin. When the condition is serious, the crack on the vine will burst, and the crack at the base of the main vine will flow out of gray or red gel, and the side vine will crack and produce a white oil. The diseased plants grow slowly or stop, and the whole whole plant dies. The vines are russet after drying. The stems of the seedlings were damaged, and the water spots were spotted, and then expanded rapidly, causing the seedlings to die. The incidence of leaf parts starts from the leaf margin and produces a "V" shape or a semi-circular brown large lesion with many wheel patterns. The fruit is diseased, initially with a small oily spot, and then becomes a dark brown round large concave spot. The surface is dry and star-shaped, and the small black spots are dense. Watermelon blight does not harm the roots and vascular bundles. A large number of small black spots and secreted amber gums can be produced on the lesions, which can be distinguished from anthracnose, blight and disease.

The pathogens overwinter in the soil and on the shelf with mycelium, conidia and ascus. When the weather changes greatly, especially under high temperature and high humidity conditions, the disease is easy to be popular. Protected cultivation, low-lying terrain, poor ventilation, and weak plant growth are serious.

To prevent watermelon blight, pay attention to balanced fertilization, and open the "three ditch" to facilitate drainage and dehumidification. The diseased field is sprayed with anti-virus cockroach 64% mold, manganese-zinc wettable powder 500 times liquid, or 50% iprodione wettable powder 1500 times liquid, etc., every 5 to 7 days, continuous control 3~ 4 times, pay attention to alternating medication. In order to avoid affecting pollination, watermelon should be applied after 4 pm after flowering. For a few diseased plants, it is also possible to combine the treatment with the stems, and mix 2 parts of 50% carbendazim wettable powder, 1 part of 15% triazolone wettable powder (cannot be used in the emulsion preparation), add water to make a thin paste and spread the diseased stem. Use a knife to remove the decayed part of the lesion before applying. In addition, the diseased fields should pay attention to controlling watering, remove the sick plants in time and concentrate on destruction.