What are the symptoms, causes and control methods of dry rot of planted apple trees?

With the continuous expansion of apple planting area in recent years, more and more diseases have been produced. Apple tree dry rot is one of the diseases that apple often produces. This disease has already occurred in most regions of China 4- 5 years ago, and it also contains objectivity. Once apple tree dry rot is obtained, it will immediately seriously harm the production and quality of apples, and cause great damage to growers. What are the symptoms of apple tree dry rot? What's wrong with that? How to prevent?

1. The key position of apple tree dry rot is on the main stem, because the development trend of disease is different, some only in the upper epidermis, some have already achieved phloem in the deep epidermis. The symptoms are dark brown ulcerated spots of different sizes and uncertain appearance caused by the injured branches. At the beginning of the disease, the main performance is dark brown, the edge is not neat, the surface is wet, and the tea-brown mucus overflows. Then the diseased part is depressed and withered, the intersection of diseased and healthy organs is cracked, small protruding spots appear on the diseased spot, and the diseased part can be separated. Declining trees or weak trees can cause some branches to wither because of rapid disease development.

2. Reasons Apple tree dry rot disease can invade through root wounds and leather holes. Its occurrence is closely related to the climate and natural environment standards. Water stress is one of the key reasons for the disease, especially in dry years and sand areas with poor water solubility. Hillside orchards, insufficient soil water supply will cause the disease. * The disease was more serious in orchards with poor soil and easy outflow of water. The average temperature in winter and spring fluctuates greatly, the freeze-thaw cycle changes, the tree body cells just start the theme activity in broad daylight, the sudden temperature reduction tissue cells freeze at night, the tree body organs are more likely to cause damage to the tree body, and the dry rot bacteria are very easy to invade. The disease incidence of orchard with high fertilizer level was significantly lower than that of orchard with poor soil, especially the orchard with organic fertilizer and biological fertilizer had fewer diseases. The orchard adopting preventive measures in winter and spring has remarkable practical effect.

Dry rot disease can not only lead to branch disease, but also can infect fruit and cause ring disease. Therefore, for the prevention of dry rot, in addition to all normal prevention of normal spraying, we must do a good job in basic prevention work. 1. Improve the management method of liquid fertilizer, cultivate strong fruit type, and improve the working ability of tree disease resistance, which is the root of disease prevention. Topdressing organic fertilizer, biological fertilizer (such as Mumei * li), effective pruning, dealing with natural ventilation and light transmission problems of orchards, clear effective load, and immediately prevent diseases. 2. Pay attention to the water management method of orchard, moderately carry out agricultural water-saving irrigation in areas with standards, and implement integrated liquid fertilizer application. 3. Grass in orchard covers solid soil, clover, hairy vetch, rape seed, etc. are planted, and the grass is cut immediately to cover tree stems after growing. Rape seeds must be cut immediately before spring bloom to cover tree stems, or implement straw cover, which can improve soil structure, enhance soil organic matter, store water and solid soil, and conduct heat insulation. 4. Clean up idyllic scenery and reduce bacterial source. In autumn and winter, immediately remove dry branches and dead leaves from orchards, centralize damage or bury, dig out rotten plants, remove orchards immediately and damage them, shave off pachyderms on tree stems, and immediately apply medicine to tree stems for maintenance. 5. Improve agricultural and animal husbandry prevention countermeasures. After fruit picking, before the dead leaves are cleared, the leaves are sprayed with pesticides, fungicides and liquid fertilizer with high concentration, which not only kill all kinds of winter pests, but also supplement vitamins to slow down the decline of leaves, enrich flower buds, improve the nutrient content stored in the tree body and improve drought resistance. Branch sprayer with 48% chlorpyrifos 500 times solution peach microbial shield or anti-corrosion shield 300 times Baihefeng (fulvic acid)300 times sprayer. 6, chemical control coating dry drug secret recipe: tree stem smeared fertilizer with 1.8% cyclamid 5-10 times solution or Guo Kangbao 5 times solution Baihefeng 5 times solution to carry out tree body coating dry. Or dry it with rot wheel number four. It's good for cold and sterilization. Sprayer must be the whole tree washing spray complete, the most important is the main stem branches. It must be noted here that before drying, it should be scraped with a scraper to remove the skin of the scar position (just scrape the skin, no need to be too deep), or with a sharp knife to cross the scar horizontally and vertically, deep into the phloem, and then apply fertilizer, in order to obtain significant results.

The disease, cause and prevention of apple tree dry rot disease are mentioned above. Apple tree dry rot disease is generally produced in orchards with the following crown diameters for ten years, and the incidence of orchards with crown diameters above ten years is light. Close to the village warmer orchard disease light, winter tree stem painted white orchard disease light, winter tree stem to prevent rot disease coated orchard disease light, fruit type strong disease light, fruit type decline, management methods extensive orchard disease heavy, growers should pay attention to.