Etiology and control measures of rotten grape fruit

Grape growers who have planted grapes usually encounter the phenomenon of grape rot, especially in the middle and late stages of grape planting. Once the fruit rot, it will seriously affect the yield and variety of grapes and bring great economic losses to farmers. This pro-farming network for everyone to bring the grape rotten fruit cause analysis and how to prevent and control the phenomenon of grape rotten fruit.

I. Causes of disease

1. Infection. White rot, anthracnose and black rot were the main diseases causing grape rot. White rot and black rot not only cause fruit rot and ear rot, but also infect grape branches and vines to form brown spots. In severe cases, branches and leaves die and tree vigor weakens, affecting fruit yield and quality in the current year and the next year.

2. Bad weather. Rainfall concentrates from July to August in Central Plains, which is the middle and late stage of grape fruit growth. At this time, the climate characteristics of high temperature, high humidity and much rain are easy to cause the epidemic of the above three diseases.

3. Orchard mismanagement. Most vineyards in the Central Plains adopt hedge arm. Although it is convenient to manage in summer, the luxuriant foliage inside and outside the whole frame easily leads to poor ventilation and light transmission, and most of the fruit clusters are exposed outside or crowded in the branches. In addition, there is much rain and stuffy air, and it is easy to form a microclimate of high temperature and humidity inside the frame. If mechanical damage is caused by storm, hail, sunburn, fruit cracking or bird insects, the epidemic of "fruit rot disease" will be aggravated and secondary diseases will be caused.

4. The tree is weak. The following factors will cause tree weakness and poor disease resistance: insufficient application of organic fertilizer, partial application of nitrogen fertilizer, neglect of phosphorus, potassium, calcium and other nutrients; unreasonable summer shearing, not timely binding vines, picking heads, thinning shoots, and following ears, resulting in poor nutrition supply during fruit growth; excessive ineffective branches and leaves, excessive ineffective consumption; excessive fruit hanging on trees, overgrown weeds under shelves; serious diseases and insect pests, etc.

II. Prevention and control measures

1. The fence arm frame was changed into a small trellis to create a microclimate unfavorable to the occurrence of diseases. Small trellises, single or double dragon trunks should be used for pruning, medium and short shoots should be pruned. It is necessary to ensure sufficient light on the shed surface, and the leaf area index should not exceed 1.5~2.0; the transmittance under the shelf should be adjusted at the near maturity stage of the fruit, generally requiring about 30%. In the growing season, summer shear, tie vines, thin shoots, pick cores and stretch clusters in time, so that clusters hang on the frame surface "under the shade of flowers", avoid sunburn or rainwater residue on the fruit surface, and avoid mechanical damage caused by storms and hail.

2. Strengthen soil, fertilizer and water management to enhance tree vigor. The decomposed organic manure, preferably chicken manure, combined with appropriate phosphorus and potassium fertilizer, was applied in alternate years and alternate rows. The higher temperature in this period is not only beneficial to the decomposition of organic fertilizer, but also has strong photosynthetic ability and can effectively utilize nutrients. At the later stage of grape growth, 2%~3% potassium dihydrogen phosphate solution can be sprayed in combination with drugs, which can obviously strengthen the tree vigor and reduce the occurrence of "rotten fruit". Plant growth regulators can be sprayed according to plant growth conditions to improve leaf function, enhance tree vigor and disease resistance.

After the rain, pay attention to removing the accumulated water in the garden, loosen the soil and weed in time to prevent the soil moisture from being too high, and pay attention to soil improvement to enhance the permeability of the root soil. Pay attention to improving the fruiting position, try not to leave ears at 40~50 cm on the ground to reduce the chance of infection by germs.

3. Remove bacteria. After autumn, before the vine is removed from the shelf, the sick and disabled body in the garden is removed and burned in a concentrated manner. Spray 50~100 times solution of Solibal or 300 times solution of 3~5 degree stone sulfur mixture of Baume + sodium pentachlorophenol before burying soil in autumn for cold protection and after coming out of soil in spring to eliminate bacteria source. In the growing season, we should timely remove the diseased leaves, diseased fruits and vines, and bury them deeply.

4. Strengthen shelf management. Pay attention to timely binding vines, picking cores, ventilation and light transmission in the cage. The yield should be controlled between 2 500 kg and 3 500 kg per 667 m2.

5. Chemical control. For infected vineyards, before the trees germinate, spray Baume 2 degree sulfur mixture + sodium pentachlorophenol 200 times solution and 50% Tuijunte WP 500 times solution to the trees or ground to play a protective and preventive role.

For seriously ill orchards, 1 part of thiram, 1 part of sulfur powder and 2 parts of lime can be mixed evenly at the early stage of disease occurrence and then sprinkled on the ground under grape racks, with 1~2 kg per 667 square meters. For the disease in growth period, spray 800 times solution of 50% Tuizong wettable powder or 600~800 times solution of 75% chlorothalonil wettable powder, spray once every 10~15 days in the whole growth season, but pay attention to alternate application.

For orchards with serious disease in the previous year, 500~600 times solution of thiram or 50% carbendazim 500~600 times solution should be sprayed under the rack before the disease occurs to eliminate the disease source overwintering in the soil; Bordeaux mixture of appropriate concentration should be sprayed every 10~15 days during the growing season to reduce the chance of disease infection. Once white rot, anthracnose and other diseases occur, symptomatic application should be applied, but attention should be paid to alternate application. After fruit coloring, in order to prevent pesticide pollution, 12% green milk copper 600~800 times solution spray can be used to control diseases.

The above is the reason for apple rot and related prevention and control methods collected and sorted out by pro-agricultural network for everyone. Fruit growers should remember not to panic after discovering the rotten fruit of grapes. They should effectively analyze the reasons for grape rot and then take relevant prevention and control measures.