This kind of apple suffers from ring rot, which is a fungal disease caused by single-celled bacteria, causing apple fruit rot and local necrosis, also known as verrucous skin disease or rough skin disease. This fungus is similar to apple dry rot fungus. Its hyphae and conidia overwinter in the diseased tissues of branches and stems, showing gray spore horns. In the spring rain, conidia spread to branch wounds, lenticels and near-pericarp holes, causing bud tubes to invade the tree and then lurk. Fruits with fungi will not develop until they are close to maturity and storage.

It mainly harms the branches and fruits of apples.

1, damaging branches

①? Tumors: On the normally growing branches, after bacteria invade the lenticels, cells in the lenticels are stimulated to proliferate or block, forming tumors.

②? Dry rot disease spot: When trees are under drought stress or grow weakly, the bacteria lurking in the disease tumor expand rapidly, leading to cortex necrosis and forming dead spots.

③? Saddle-shaped lesion: Saddle-shaped lesion is formed when the resistance of trees is strong and the spread of lesion is inhibited. With the growth of the trunk, the disease became more and more serious and the skin became rough.

Step 2 hurt the fruit

But don't worry too much about the above situation. The following methods can prevent this germ.

First of all, use enough organic fertilizer and chemical fertilizer at the right time. 2-3 cubic meters of high-quality organic fertilizer should be applied to early and middle-maturing varieties at the initial stage of fruiting, and 3-4 cubic meters of high-quality organic fertilizer should be applied to late-maturing varieties throughout the fruiting period. ?

Secondly, strengthen cultivation management, reasonably prune, select disease-resistant varieties and disease-free seedlings for new orchards, plant logistics inspection, and pull out diseased seedlings in time when they are found. During plastic surgery, it is forbidden to prune diseased branches and stems downward into young trees, and the pruned parts of diseased stems for one year cannot be piled up near the orchard.

Finally, it is necessary to eradicate the dormant period of overwintering bacteria, cut off diseased fruits, branches of diseases and pests, remove residual leaves from orchards and burn or bury them centrally. Before budding, spray 3-5ml of eradication agent such as staphylococcus on the whole orchard, and apply a mixture of staphylococcus residue and lime plaster on the trunk and branches sensitive to diseases, and brush them well, and do not scrape the bark to prevent weakening.