Sunshine disease occurred in high temperature grapes.

Harmful characteristics: when sunburn occurs, the fruit surface produces light brown nearly round spots, the edge is not obvious, the fruit surface shrinks at first and then gradually sinks, and the serious ear becomes dried fruit. The young parts of tendrils and new shoots that have not yet been lignified can also be damaged by sunburn, causing tip tips or tender leaves to wilt and turn brown. The cause of the disease: it is usually infected from mid-June to early July (ear coloring maturity), which mostly occurs on the ear exposed in the sun, due to the lack of water in the tree body and the lack of water supply to the fruit. Sunburn will occur when the root system does not absorb enough water, the leaf evaporation is large, and the osmotic pressure increases, resulting in the imbalance of fruit water. Sunburn also occurs when the root system retts or burns the root. Large grain varieties are prone to sunburn in production. Sometimes when the ear in the shade is moved due to pruning, topping, binding vines, or when the plant is unable to adapt to a sudden rise in temperature, sunburn will also occur in the new shoots and fruits. Prevention and control methods: strengthen cultivation management: appropriate deep fertilization to induce deep root group development, enhance tree potential, improve stress resistance; appropriate close planting, the use of scaffolding, so that the ear in the shade; prevent waterlogging or excessive fertilization root burning phenomenon; in the high temperature disease period, appropriate irrigation, evaporation should be timely watering to reduce plant temperature and avoid sunburn. Spraying fertilizer to reduce temperature: in the high temperature weather after overcast and rain, 0.2% potassium dihydrogen phosphate solution or 5% plant ash extract or 27% high fat film emulsion 80-100 times were sprayed on the leaves and ears for 2-3 times, which had a certain preventive effect on sunburn. The above is for reference only.