Symptoms: The fruit is damaged. First, a layer of gray-white powdery mildew is formed on the surface of the fruit. The white powder is wiped off, the epidermis has a brown pattern, and finally the epidermal cells become dark brown. The leaves are damaged, and a layer of gray-white powdery mildew is formed on the surface of the leaves, which gradually spreads to the entire blade. In severe cases, the diseased leaves are curled and withered. The new vines are damaged, and initially appear grayish white spots, and then spread and spread to make the whole vines onset. The diseased vines turn from grayish white to gray, and finally black.

Pathogenic bacteria and pathogenesis: the pathogen is a genus of the genus Ascomycetes. Asexual generations are of the genus Aspergillus. The pathogens overwinter the mycelium on the damaged tissue or in the bud scales. In the next spring, conidia are produced in the spring, and the wind is transmitted to the surface hyphae of the host to produce aspirator, which directly penetrates into the host cell to absorb nutrients, and the hyphae spread on the host surface. The fruit surface, the branches and the leaves are dark brown, mainly affected by the suction device. Diseases generally occur in July, mid-July and September-October.

Control methods: 1 Strengthen cultivation management, increase organic fertilizer, strengthen tree potential, improve disease resistance; timely picking hearts, thinning branches and vines, keeping ventilation and light transmission, can reduce the occurrence of diseases. 2 Pay attention to the health of the orchard, remove the sick body, concentrate on burning or deep burial, and reduce the source of bacteria. 3 Spray 3~5 wave of sulphur sulphur mixture before germination, spray 0.2~0.5 wave of sulphur sulphur mixture after germination, or 50% thiophanate 500 times solution, or 70% thiophanate 1000 times solution , or 25% triazolone wettable powder 1000 times solution.