Control methods of Apple Tree Diseases

In recent years, there are many diseases in apple orchards, such as early defoliation disease, rot disease, ring disease, viral fruit shrinkage disease, mosaic disease and so on. Generally speaking, apple trees enter the initial fruit stage 3-5 years after planting, the full fruit period 6-8 years later, and the senescence period of 20 years or so, but now the trees of about 15 years in many places have shown weakness, why is this the case? In our investigation, we found that there are three main reasons for the weakness of the tree.

Poor nutritional condition

The problems of low content of soil organic matter and insufficient application of organic fertilizer are common in many orchards. Although the income and enthusiasm of fruit farmers have increased in the past two years, and the application of organic fertilizer has gradually increased, it still does not meet the due standard and organic nutrition is still lacking. In addition, many fruit growers still attach importance to the application of base fertilizer, but topdressing is occasional, so that fruit trees can not get timely and adequate nutrient supply in each critical growth period.

Overload

Some fruit growers still have the idea of using yield to increase their income, leaving too much fruit has become a "predatory" production, so that the tree is overloaded, the fruit is too small, the number of flowers decreases in the next year, the fruit of the year is formed, the tree decays prematurely, and the disease resistance decreases.

Improper application of ring peeling technology

In order to promote the formation of flower buds, some fruit growers peel around all levels of backbone branches and lateral branches of the tree year after year, resulting in poor wound healing, seriously affecting the transport of nutrients produced by leaf photosynthesis to the roots, resulting in poor accumulation of organic nutrients and extremely weak tree potential, which is easy to cause various diseases.

In addition to the above three main reasons, improper application of shaping and pruning technology, ineffective prevention and control of diseases and insect pests, drought and freezing injury will also affect the tree potential.

In view of the main reasons for the weakness of the tree, the following measures need to be taken to strengthen the tree:

① increased the application of organic fertilizer and topdressing in time to improve the nutrition level of the tree. The application of farm manure such as rotten chicken manure, cow and sheep manure and human manure in autumn and winter can fertilize the soil, enhance the tree potential and improve the disease resistance of the tree. The application amount of organic fertilizer is based on "jin fruit fertilizer" as the standard.

② hanging fruit in the right amount. Determine the right amount of fruit in order to ensure stable and high yield, balance the tree potential and enhance the disease resistance of the tree. The amount of fruit retained can be determined by distance flower thinning method or dry week method.

③ implements ring-cutting technology instead of ring-peeling technology. In order to promote the formation of flower buds in apple trees, some fruit growers peel around the backbone branches at all levels of the tree year after year, resulting in poor wound healing, seriously affecting the transport of nutrient roots, leading to tree weakness and early defoliation. In order to enhance the tree potential and improve the disease resistance, girdling on the central trunk was prohibited, and multi-channel ring cutting was carried out on the main branch, side branch and branch group, and the circle was cut through laterally with a ring cutter at the 15cm above the base of the branch. According to the branch potential, each ring cut 1-2 channels, spacing 10cm, every 7-10 days ring cut once. When cutting, the distance between incisions should not be less than 3cm, and the orchard with large and stable flower yield should not adopt the circumferential cutting technique.