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The reason for spraying liquid fertilizer on apple trees is not too much, but rather the essence

Release time:

2018-05-08 16:28

For the prevention and control of apple trees, many fruit farmers subconsciously spray a lot of liquid fertilizer. In fact, this perception is incorrect. It's not that the more you spray, the more effective the prevention and control measures are. It's important to choose the right fertilizer application at the right time.
Correct understanding of apple diseases and pests:
Main diseases:
Rot disease
Rotten bacteria are a weak parasitic fungus that mainly invades wounds (such as frozen wounds, mechanical wounds, insect wounds, and deciduous layers) and then hides in the wooden layer.
The pathogen overwinter on the bark and diseased branches, and the temperature rises in the following spring and summer. When encountering rainfall, it begins to infect and become infected.
Germs have latent properties, and whether they can infect depends on the resistance of fruit trees. The tree is strong and becomes dormant. Once the tree weakens or dies locally, the bacteria begin to infect and become infected. Therefore, enhancing tree vigor is the key to preventing this disease.
Cercospora leaf spot
(1) Concentric wheel pattern: At the beginning of the disease, there are small yellow brown spots on the leaf surface, gradually expanding into 10-25mm circular disease spots, with a dark brown center and a green halo around it. In the center, there are black particles arranged in a visible wheel pattern, which is the spore disk of the pathogen; The center of the lesion is dark brown on the back, and the surrounding areas are light brown. Sometimes, the center of the old lesion is gray white.
(2) It is needle shaped: the lesion is small, radiating outward in the shape of a needle, without a fixed shape, with slight protrusions. In the later stage, the leaves gradually turn yellow, and the surrounding area and back of the diseased area remain greenish brown. The lesion is smaller than the wheel pattern.
(3) It is a mixed type: the lesion is dark brown, larger, nearly circular or irregularly shaped, with scattered black dots on top, not showing obvious wheel patterns; In the later stage, the center of the lesion is gray white, with a green edge, and sometimes the edge of the lesion is needle like.
Black spot disease
The branches produce circular or nearly circular brown spots, with small black particles growing on them in the later stages. About 5mm. The shape of the lesion is irregular, slightly concave, with slightly bitter flesh and a red halo around it.
Tiger skin disease
In the early stages of the disease, the fruit skin appears light yellow brown, with a flat or slightly undulating surface, or irregular blocky shape. In the future, the color will darken, becoming brown to dark brown, slightly concave. The skin of the diseased part can be torn off in pieces, and several layers of cells under the skin turn brown. The flesh of the diseased fruit is soft and slightly alcoholic. Pathological changes often occur in the non pigmented parts of the fruit's shade, and only extend to the pigmented parts of the shade in severe cases.
Lobular disease
The diseased trees are distributed in patches or rows, and sprout later during the Spring Festival than when trees are built. After spreading the leaves, the top leaves are clustered, and the middle and lower parts of the branches are bare. The edges of the leaves are curled up, brittle and hard, forming a willow leaf shape. Some leaves have green veins, but yellow veins between them. New shoots have short nodes and diseased branches are prone to withering and death. Flowers are few and small, and fruits are small and deformed. Old and diseased trees are almost all small leaves, with empty crowns and low yields.
White silk disease
Mainly damaging the root and neck of 4-10 year old saplings or adult trees. High temperature and rainy seasons are prone to disease. The initial leaves are small and yellow, the branch nodes are shortened, and the fruits are numerous and small. The root is infected and the neck of the root is in a juicy wet rotting state. The diseased part turns yellow brown or reddish brown, and severe cortical tissue rots like mud, emitting a pungent sour taste, causing the xylem to turn gray blue. The diseased area or surface soil is covered with white hyphae. When the humidity is high, many brown or dark brown, rapeseed like fungal nuclei are produced. When the leaves are infected, water stained ring-shaped spots can also appear, with a diameter of about 2 centimeters. Small fungal nuclei can also grow in the center of the diseased area. 1-3 year old saplings die quickly after being infected, while adult trees also suddenly die in the aboveground part after a week of disease.
Bitter acne disease
The flesh under the skin of the diseased part first becomes diseased, producing brown spots with deep external color. Dark purple red spots appear on red varieties, dark green spots appear on green varieties, and gray brown spots appear on cyan varieties. In the later stage of the disease, the flesh of the fruit will dry and shrink, and the epidermis will necrosis, showing sunken brown spots, reaching a depth of 2-3 millimeters to the flesh, with a bitter taste. Mild diseased fruits generally have 3-5 diseased spots, while severe ones have 60-80 spots spread throughout the fruit surface.
Anthrax disease
Mainly harmful to fruits, but also to branches and fruit stands. In the early stages of fruit disease, small pinhead sized light brown spots appear on the surface of the fruit, which are circular and have clear edges. In the future, the lesion gradually expands, becoming brown or dark brown in color, with a slightly concave surface. Cut longitudinally from the diseased part, the flesh of the diseased fruit turns brown and rotten, with a bitter taste. The surface of the fruit initially shows light brown small round spots, which expand into dark brown, well-defined, and sunken round spots. The flesh of the diseased fruit is funnel-shaped and soft rotting towards the heart, brown, with a bitter taste. When the diameter of the lesion is 1-2 centimeters, small black spots arranged in a circular pattern appear in the center, protruding and breaking through the epidermis, emitting red mucus. Several spots merge and the entire fruit rots. The diseased fruit loses water and becomes stiff, hanging on the tree for a long time.
Dark brown and irregularly shaped lesions appear on the epidermis of branches and fruit stands, with slight depressions. The surface of the spot produces small black spots, which later ulcerate, crack, and expose the xylem, causing diseased branches to wither and die.
From this perspective, the prevention and control of apples is particularly important. So choosing fertilizers suitable for apple crop growth is also a top priority for fruit farmers.
Phosphorus calcium zinc silicon
Spraying on the leaf surface can be quickly absorbed by the leaves. Phosphorus can be transported up and down within the crop, opening up the nutrient channels of crops, improving the transmission efficiency of large, medium, and trace elements such as phosphorus, calcium, and zinc within the crop, and driving nutrients in the soil to quickly enter the crop, thereby improving the absorption and utilization rate of various nutrients. Thus,
1. Make the leaves shiny and thick, greatly improving photosynthesis.
2. Delaying leaf aging, improving functional leaf function, and laying a solid foundation for later crop fruit expansion.
3. Roots nourish leaves, leaves nourish roots, and roots nourish tree bodies. Continuous long-term spraying of phosphorus, calcium, zinc, and silicon can make the tree strong, increase the amount of fruit, and thus increase yield.
4. Phosphorus, calcium, zinc, and silicon in the process of transformation can stimulate the production of phytoalexins and oxidase in crops, kill true bacteria in crops, improve crop disease resistance, reduce the use of pesticides, reduce the cost of pesticide use, and improve fruit yield and quality.
5. For weak trees (trees with poor nutrition), quickly replenish tree vigor, restore leaf function, and carry out photosynthesis.
Potassium phosphite
1. For plants that grow normally, spray at 20% of flowering and 2/3 of withered flowers to reduce abnormal flowers, exposed flowers, etc., increase photosynthesis intensity, accelerate dry matter accumulation, promote shoot aging, and add nutrients such as sugar and starch to young fruits.
2. The growth of the tree is relatively vigorous, and it can be focused on spraying the vigorous part. Generally, spraying new shoots is the main method to promote the aging and ripening of new shoots, so that the vigorous growth of new leaves can quickly become functional leaves, enhance leaf photosynthesis, increase leaf dry matter accumulation, and balance the tree vigor.
3. Potassium phosphite differs from potassium dihydrogen phosphate:
The phosphorus in potassium dihydrogen phosphate not only has poor mobility in the soil but is also easily fixed by the soil, becoming ineffective phosphate fertilizer that cannot be absorbed and utilized by crops. It can also cause soil compaction and reduce soil permeability. Phosphorus, on the other hand, has a rapid mobility within the crop and is easily absorbed by the crop roots, quickly supplementing the crop with effective phosphorus fertilizer and conducting it up and down within the crop.
4. Sterilization is not resistant to drugs. Potassium phosphite enters the plant, eliminating pathogens. In addition, it can activate the defense system inside the plant, producing a large amount of phytoalexin. The defense hormones in the crop body (phytoalexin is a type of compound produced by the plant itself when attacked by pathogenic microorganisms) also kill bacteria, activating other cells that have not entered the defense state to enter the defense state and eliminate pathogens! Unlike ordinary heavy metal fungicides, they only passivate proteins and increase pathogen resistance! Potassium phosphite does not make pathogens resistant to drugs.