The latest apple tree disease control methods

In recent years, many apple orchards have appeared early leaf disease, rot disease, ring disease and viral fruit shrinkage disease, flower face disease, mosaic disease and other diseases. Generally speaking, apple trees enter the early fruit stage 3-5 years after planting, 6-8 years after entering the peak fruit stage, about 20 years into the senescence stage, and now many places about 15 years old trees have shown weakness, why does this happen? In our investigation, we found that there are three main reasons for tree weakness.

Poor nutritional conditions

Many orchards generally have the problems of low soil organic matter content and insufficient organic fertilizer application. Although the income of fruit growers increased in recent 2 years, their enthusiasm increased, and the application amount of organic fertilizer gradually increased, but it still did not reach the due standard, and organic nutrition was still lacking. In addition, many fruit growers pay attention to basal fertilizer, but sometimes there is no topdressing, so that fruit trees cannot get timely and adequate nutrient supply in each critical period of growth.

heavy load

Some fruit growers still have the idea of increasing income by yield, leaving too many fruits, becoming "predatory" production, making the tree body overloaded, the fruit small, the flower quantity of the next year reduced, forming the phenomenon of big and small annual fruit, premature aging of the tree, disease resistance reduced.

Improper application of girdling technique

In order to promote the formation of flower buds, some fruit growers have been girdling the trunk branches and lateral branches at all levels of the tree for years, and the stripping band is wider, resulting in poor wound healing, seriously affecting the transportation of nutrients produced by leaf photosynthesis to the roots, resulting in poor accumulation of organic nutrients in the tree body, extreme weakness of the tree, easy to cause various diseases.

In addition to the above three main reasons, improper application of pruning techniques, poor pest control, drought, freezing damage and so on will also affect tree vigor.

For the main causes of tree weakness, the following measures need to be taken to strengthen the tree:

① Increase the application of organic fertilizer, timely topdressing, improve the nutritional level of trees. In autumn and winter season to apply decomposed chicken manure, cattle manure, human manure and other farm manure, can fertilize the soil, enhance tree vigor, improve tree disease resistance. Organic fertilizer application rate to "jin fruit jin fertilizer" as the standard.

2. Appropriate amount of fruit hanging. To ensure stable and high yield, balance tree vigor and enhance tree disease resistance, a proper amount of fruit can be determined. The distance thinning method or the dry cycle method can be used to determine the amount of fruit retained.

(3) ring cutting technique is applied instead of ring stripping technique. In order to promote the formation of flower buds on apple trees, some fruit growers have been girdling the trunk branches at all levels for years, and the peeling mouth is wider, resulting in poor wound healing, seriously affecting the transportation of nutrients at the roots, resulting in tree weakness and causing early leaf blight. In order to strengthen tree vigor and improve disease resistance, girdling on the central trunk is prohibited, and multi-channel girdling is carried out on the main branch, lateral branch and branch group, and the circular cutting knife is used to cut the circle horizontally 15cm above the base of the branch. According to branch potential, circumscribe 1-2 channels at a time, with a spacing of 10cm, and circumscribe once at an interval of 7-10 days. The distance between incisions should not be less than 3cm, and the technique of circumcision should not be adopted for orchards with large and stable flower yield.