Why is the recurrence rate of apple rot disease so high? Every year, every year, there is.

Apple rot disease is also called carcass rot, commonly known as black plaster disease. Primary damage to main, lateral branches and young trees near the grafting joint.

1. Strengthening cultivation management, strengthening tree potential, and improving tree disease resistance are the fundamental measures for disease prevention, and the specific practices are the same as apple tree rot disease. In order to avoid the disease of young trees, it is necessary to strengthen the management of nursery land to cultivate strong seedlings. The sprout seedlings should be cut 15 to 20 days before germination, the wound should be disinfected with 1 copper sulfate, and then coated with Bordeaux solution for protection.

When seedlings are planted, it is advisable to be flat with the ground at the grafting joint, avoid planting deep, and water enough to shorten the seedling delay time.

2 Scrape off the lesions. The initial damage of dry rot is usually limited to the surface layer, and the lesions should be scraped and treated in time. After scraping, the sick part is coated with Fumei arsenic and other agents for disinfection. The method is the same as that of apple tree rot. It can also be used to scrape the skin to eradicate the ground germs carried by the tree.

3 Pharmaceutical prophylaxis**. Before germination, combined with other pest and disease prevention**, spray 40 Fumei arsenic 100 times solution or Baumé 3 5 degree stone sulfur mixture plus 0·3 sodium pentachlorophenol mixture to protect the trunk. 5 and 6 months again spray two more times in a row 1:

2: 200 240 Bordeaux liquid or 50 antibacterial special wettable powder 800 times liquid.

Hello, the pathogenesis of rot disease is latent in winter, onset in spring, infected in summer, and expanded in autumn. Rot disease is a weak parasitic bacteria, in the winter low temperature stage mostly lurking in the dead tissue or semi-dead tissue in the cortex, such as warped skin, frost damage, insect mouth, wound, cut saw mouth, the germ secretes virus again to kill the living cell tissue with poor physiological activity, and incubates in it until the spring of the following year, and begins to spread and expand when the temperature rises to more than 5 degrees, and the impact on the tree will become more and more serious. Due to the different climatic conditions, the performance is also different in different places, and in the Loess Plateau, that is, the arid and semi-arid fruit areas in the northwest, the symptoms of dry branches are the majority. In humid and semi-humid areas such as Bohai Bay, i.e., the Yellow River Ancient Road, ulcerative symptoms are more common. When the ambient humidity is high, small black dots appear on the tissues of the diseased area, and sometimes there is a reddish-brown liquid flowing out, accompanied by the smell of sake lees.

In general, before the tree bears fruit, it is not suitable for the disease to develop the disease for a long time, and the susceptibility disease gradually aggravates from the early fruiting stage to the peak fruiting period, and the disease will occur seriously with the weakening of the tree in the later stage of full fruiting.

Hello dear, the symptoms of apple tree rot disease occur in the trunk and main branches, the fungus overwinters on the bark and diseased branches, mainly through wind and rain and insects, and only when the tree is weak, the epidemic peaks in the spring and autumn rainy season. In orchards in North China, there are two peaks of apple tree rot disease: one is from late February to March in early spring, when the first peak period occurs before and after apple tree germination, which is called the "spring peak", which is also the most serious period of the year.

After May, apple trees enter the growth period, and the activity of pathogens weakens, and gradually turns into a low tide. The second peak period in autumn occurs from October to November, called the "autumn peak". After November, the weather gets colder, and the germs spread under the bark, but slowly.

The severity of apple tree rot disease is greatly related to orchard cultivation management and tree strength. Trees with strong body and good nutrition, reasonable load, few wounds, and no frost damage will have mild disease; On the contrary, extensive orchard management, insufficient water and fertilizer or unreasonable fertilization, serious pest and disease damage and frost damage, excessive pruning, many wounds, and large loads, resulting in the weakening of the tree, will induce the epidemic of rot disease.

1. The outer skin of the apple has the function of protecting the tissue cells of the apple, when the outer skin of the apple is damaged by insect bite or impact, the bacteria from the outside world breed in the tissue fluid of the apple, causing the apple to rot;

2. After the apple is ripe, some sugars in the internal tissue are converted into ethanol, which has a certain degree of corrosiveness, and when it reaches a certain amount, ethanol will destroy the apple cells and cause decay.

How to prevent apple tree rot disease, how to **, authoritative interpretation.

Apple tree rot disease is a fungal disease that mainly damages the branches, causing bark cankers and branch blight. The pathogen overwinters on diseased plants and diseased residues in the field with mycelium, conidia and ascomycetes. Conidia and ascospores are dispersed by rain splashes and then spread by wind and rain.

It mainly invades from the wound, of which frostbite is the most conducive to the invasion of germs. There are two peaks in the disease in the spring and autumn of the year. Rot fungus is a weak parasitic fungus, and the weakening of the tree is an important cause of the occurrence of the rot disease, and the number of wounds on the tree and the climatic conditions also have a great impact on the severity of the disease.

The strategy for the prevention and control of rot disease is to strengthen cultivation management and strengthen trees to prevent diseases. Eliminate germs and reduce the amount of bacteria in the orchard; Timely ** lesions, pay attention to protect the wound; Care should also be taken to prevent frost damage from occurring. The effective drugs used in the curettage of lesions include propiconazole, dysenium, difenoconazole, etc.