The pathogenic fungus of apple tree rot, Cladosporium of Cladosporium of Ascomycetes.

The asexual generation is Hemiptera cysticercus.

Latin scientific name: sporangium. (sex type, Walsamali);

Attachment 1

Rhizoctonia solani; ;

Alternaria alternata

Armillaria mellea; ;

Sclerotinia sclerotiorum; ;

Fusarium. ;

Cytospora sp. (sex type, Walsamali);

A pathogen of poplar rot —— Aureosporium sp.

Attached two

English name: apple tree rot

English name: apple tree rot

Chinese aliases: rotten skin disease, rotten skin disease and wet skin.

Latin scientific name: Valsa mali Miyabe et Yamada

Harmful crops: deciduous fruit trees and broad-leaved trees such as pears, peaches, cherries, plums, willows and poplars.

Symptoms: Rot mainly damages the branches of bearing trees, and young trees and seedlings can also be killed. The injured cortex is rotten and necrotic, and the symptoms are ulcer and branch blight, mainly ulcer.

Ulcerative symptoms, the onset site is reddish brown at first, slightly raised, watery and soft tissue, and yellow-brown juice often flows out of the affected area in the later stage, and the diseased skin is easy to peel off. The rotten cortex is bright red and brown, moist and rotten, and smells of distiller's grains. Sometimes, the lesions are deep and dark wheel lines with unclear edges.

Morphological characteristics of pathogenic bacteria: in the cortex, hyphae gather into gray hyphae layer, then spread with cyan particles, gradually grow into a cone, and penetrate the epidermis to become a black tumor, that is, the outer stroma. In autumn, under or beside the outer pedestal, the inner pedestal is generated. There is a clear black dividing line between endosperm and host tissue, and there are also mixed host cells. The ascus is oval or spindle-shaped, with a wide end and a blunt or flat top, and its size is 28 ~ 35 microns x 7.0— 10.5 microns.

Apple tree rot pathogen not only harms apples and Malus plants, but also infects deciduous fruit trees and broad-leaved trees such as pears, peaches, cherries, plums, willows and poplars.

Classification: It is called apple black rot shell, belonging to Ascomycetes, and the asexual stage is sporothrix. It belongs to Hemiptera.

Distribution area: distributed in all apple producing areas.

Pathogenic characteristics: Rot pathogen is a kind of weak parasitic bacteria. When germ spores germinate and invade, they first grow and settle on dead tissues, and they are in a latent state. Summer is the active growth period of apple trees, and it is not a favorable opportunity for the spread and disease of germs. From June 1 1 to June 1 the following year, the number of patients increased sharply. In the deep winter festival (dormant period), the spread of germs is slow and the symptoms are not obvious. The peak of appearance symptoms appeared in early spring (February-March), and the lesions spread rapidly, which was the most serious. In May, the peak of the disease ended. In the growing period, the disease spots left over are no longer active, and only the disease spots on the old and weak branches can slowly expand. In late autumn, the occurrence of rotten spots appeared a small peak again. Apple rot is closely related to tree load, nutritional conditions, callus ability, natural injury, pruning and other factors. Healthy trees will not rot, even in the ward for many years. This tree is very strong and has strong resistance. Any factor that causes trees to weaken will be conducive to the occurrence of decay.

Epidemic trend: Rot disease has two peaks in a year, which are March-April and August-September. Spring is more important than autumn.

Prevention and control methods: Comprehensive prevention and control measures such as strengthening cultivation management, enhancing tree vigor and disease resistance, improving orchard sanitation, and treating diseased spots in time must be taken to achieve good results.

(1) In order to strengthen the cultivation management, it is necessary to cultivate the tree body and shape and prune it reasonably to keep the tree body in a moderate state. According to the requirements of fruit tree growth and development, nitrogen, phosphorus and potassium fertilizer should be applied, but nitrogen fertilizer should not be applied in a partial way. Whitening in autumn can prevent colds and diseases. This is more important for young apple trees.

(2) Cleaning the Garden In the process of pruning orchards in winter and summer, pay attention to removing dead branches, diseased branches, residual piles and broken branches. Concentrate on burning or moving away from the orchard. Don't throw it away in or near the orchard to reduce the source of bacteria.

3) Cure the lesion completely, and scrape off healthy skin with a width of 0.5 cm at the edge of the lesion. After repeated scraping, the bark becomes a new tender tissue with strong vitality, no necrotic tissue and no natural peeling layer for several years. In this way, the number of infections and diseases in trees is greatly reduced.

(5) Drug eradication In order to control the lesions on the deciduous layer formed in summer, prevent the ulcer spots on the body surface and prevent the emergence of new necrotic lesions in late autumn, the Yubiqing emulsion was applied to the trunk twice in late June of 1 1 and early October of1,mainly on the trunk, the three main branches at the base and the fourth main branch in the central trunk.

(6) Prevention and control of other pests and diseases Strengthen the prevention and control of trunk pests (moths, biting insects, etc.). ) and pay attention to the prevention and control of leaf spot, red spider and other diseases and insect pests that are easy to cause defoliation are also important measures to reduce the occurrence of rot. In addition, some diseased trees can be bridged in the diseased area to help restore the tree vigor and enhance the disease resistance of trees.