Causes of fruit cracking of facility grapes and preventive measures

Causes of fruit cracking of facility grapes and preventive measures

Characteristics of ① varieties. The varieties with close arrangement of grains and thin and brittle pericarp are easy to crack, such as Zhana, Xiangfei, Zhengzhou early jade, Victoria, Jufeng and so on. Preventive measures: select anti-cracking fruit varieties, such as red, summer black, beauty finger, autumn black and so on.

The change of soil moisture in ② is too great. The fruit was dry in the early stage of fruit growth, and the fruit was irrigated by heavy rain or flood during the coloring period. due to the high sugar content and high osmotic pressure of the fruit, the pulp moisture suddenly increased, and with the increase of fruit swelling pressure, it broke the pericarp and split the fruit. Preventive measures: adjust soil moisture to ensure that there is no shortage of water in drought and no stagnant water in waterlogging. Reduce the difference between soil dryness and humidity. When the soil is dry in the later stage of fruit growth, it should be watered in time and not flooded. In case of drought after the fruit begins to color, it can be watered every 7 to 10 days to prevent the fruit from cracking caused by long drought and rain. The soil water content is maintained at 60%-70%, which can effectively prevent the occurrence of fruit cracking.

③ fruit is squeezed. The amount of fruit left in the large ear is too much, and the fruit grains are too tight. In the process of fruit expansion, the fruit grains squeeze and deform each other, resulting in fruit cracking. Preventive measures: thinning flowers and fruits, adjusting fruit density, maintaining suitable fruit yield, generally loading 2500~3000kg per 666.7m2. The amount of fruit left is too much, the nutrient supply is insufficient, the fruit is dysplastic, the flesh is soft and the skin is thin; the amount of fruit is too little, it is easy to crack fruit in case of rain.

④ fruit diseases or improper use of drugs. During the occurrence of powdery mildew and downy mildew, continuous spraying of pesticides such as bacteria and other pesticides will weaken leaf transpiration, and a large amount of water in the tree will flow to the fruit, which will increase the swelling and pressure of the fruit and cause fruit cracking. The use of ethephon and abscisic acid to accelerate ripening, too high concentration or spraying too early often lead to fruit cracking. Preventive measures: at the initial stage of the disease, when it is found that the fruit is sick, first cut off the diseased fruit, and then spray to prevent and cure it. In the growing season, no more than 3 times a year, ethephon is suitable for 500mg/kg, abscisic acid 100mg/kg, and must be applied when the fruit is 5% ~ 10% colored to prevent fruit cracking.

The ⑤ shelf is closed. The plant has too many branches, large total leaf area, poor ventilation and light transmission, unbalanced water metabolism between leaves and fruit grains, thin and brittle skin after fruit ripening, and easy to crack fruit. Preventive measures: adjust the load by thinning branches and ears, keep the distance between branches and shoots about 10cm, the ratio of leaf to fruit is 15: 20 ∶ 1, leave 2 ears in strong branches, 1 ear in middle branches, and no weak branches. Go to the accessory ear in time, pinch the ear tip, so that the ear size is moderate.

⑥ fruit was sprayed with 500 mg/kg rare earth at the second expansion stage, spraying the ear once every 7 ~ 10 days, twice in a row to prevent fruit cracking. Rare earth liquid preparation, adjust the water to slightly acidic with vinegar (pH value 5: 6), add rare earth to mix well. Spray on a cool sunny day.