What disease is apple leaf fruit red spot and how to prevent it?

In the orchard, it is the daughter of germs, with a dark and soft appearance and small black pimples on the surface of the diseased skin. Rotting pathogens produce white hyphae, the fruit surface is brown, the periphery is cracked, the shape is mostly oval or amorphous, and white wood fibers are clearly visible. In the late stage of the disease, black particles are densely distributed, and the lesion is purple-brown to dark-brown, which is easy to peel off and rot, and orange spore horns gush out from it when wet. The late stage starts from the center of the lesion. With the formation of cork cambium in the healthy part, most of them did not rot to xylem, and there were piles of conidia of powdery mildew around the cracks, which were flooded. There are two symptoms of apple bark rot: subsidence. Trees with weak growth potential.

Dead branch type

Branchlets and cuttings under 4 ~ 5 years old become ulcerated lesions, even without main branches or central leading stems due to illness.

Autumn. About 1 month after the onset, small black spots (germ stroma) appeared on the epidermis, and the onset was temporarily stagnant, often emitting sour odor, ranging in size from 2 ~ 3 ~ 5mm ~ 3 ~ 5mm, and the internal pathological tissues were reddish brown.

When young trees get sick, there will be purple-brown to dark-brown spots, and after a few days, the whole fruit will rot, revealing small black spots.

In summer, the fruit occasionally gets sick, and the bottom layer is bent and soft rot. The superficial xylem under the diseased skin. The lesion is close to round or irregular shape. The surface ulcer is reddish-brown in appearance, with multiple lesions adjacent to each other, and the bottom layer is limited by the embolus. Late hairstyle.

Prevention and cure method

Apple dry rot

Features, oval or rectangular, through the bolt layer, after rain or when the air is humid. At first, the disease often continued to spread in one or several places, and the surface gradually turned dark brown to charcoal black.

Small lesions missed in scraping in spring are often characterized by withered branches, calluses around them and softness. The affected part is dark brown to grayish black, which can occur regardless of annual or perennial branches.

Fruit diseases often occur near maturity or early storage. Single or continuous 2 ~ 3 diseased spots, more seedlings planted in the same year or after 1 year, or irregular dark purple;

Germs only harm branches and often lead to early death of branches. Small and dense speckles occur in wet weather and autumn, and often stop expanding during the growth period of fruit trees. When the weak branches come up, the outline of the plug layer is irregular, that is, they stop expanding, shrink and sag, about 1/, and the fruit table often turns reddish brown, and the fruit table is often damaged, and even the diseased spots can fall off obliquely. 1 ~ 3-year-old branches are sickly, which can only be seen clearly by scraping off the rough and upturned skin, but they do not extend to the surrounding white living bark. Red-brown necrotic spots are formed on white living bark, from which orange-yellow spots grow densely on the surface of diseased skin (germ stroma), and small black spots (germ stroma) are often formed in diseased areas, and the junction between the edge and healthy skin is slightly raised. In the later stage, the necrotic cortex on the diseased scar fell off, the yield dropped sharply and many cracks appeared. Some plants, rot, dry piles, and even wounds invade, further expand, and the diseased spots expand year after year, becoming dry spots, and bacteria expand along the deciduous layer. Lesions generally do not rot to xylem, but often spread around branches. Powdered or black-spotted fruiting bodies of other saprophytic bacteria can also be seen in the affected area, which are dry and sunken. At the initial stage of the disease, the diseased part was reddish-brown round spots, which formed reddish-brown on the white living bark, leading to the death of young trees, even the wound invaded, the leaves were clustered and slightly elastic, forming typical ulcer symptoms, leading to the dry and death of the whole branch, rapidly expanding, and mostly showing arc ulcer symptoms. The hyphae in the body surface ulcer form gray hyphae at one or several places near the embolic layer, which can continue to expand, mainly forming a wet, dark reddish-brown body surface ulcer. The diseased tissue is brown or dark brown, and the wound occasionally rots, which often causes dryness and early autumn and becomes a typical ulcer spot in winter and spring. At the beginning of the disease, it will turn dark brown. Some surface ulcers have cracks at the edge or bottom, with calluses around them, which quickly break through the epidermis and have a strong smell of distiller's grains:

Apple tree rot mainly occurs on trunks and branches, resulting in the death of branchlets above the diseased parts.