Yellowing of the leaves of fruit seedlings? What causes yellowing of fruit tree leaves?

The yellowing of the leaves of fruit trees is mainly caused by the weakening of the tree, and there are many reasons for the yellowing of the leaves. First, due to the occurrence of bacterial scabs, jujube rust, dry rot and other diseases, it causes early defoliation, insufficient nutrients in the tree body, and the tree is weakened, resulting in yellowing of leaves; The second is that the nail mouth does not heal well, the tree is weak, and the lack of water and nutrients causes the leaves to turn yellow; third, the terrain is low-lying, the waterlogging is serious, and the leaves appear yellowing; Fourth, root diseases or excessive application of chemical fertilizers, resulting in fertilizer damage, rotten roots, dead roots, insufficient water and nutrient supply, resulting in yellow leaves; Fifth, some symptoms of deficiency, such as iron deficiency, nitrogen deficiency, phosphorus deficiency, sulfur deficiency, copper deficiency, zinc deficiency, manganese deficiency, etc., will cause leaf yellowing.

To prevent and improve the yellowing of leaves of fruit trees, we must first analyze and diagnose the causes of leaf yellowing, and then prescribe the right medicine. For example, when yellow leaf disease occurs due to nutrient deficiency, the tree nutrition should be supplemented in time, but it is difficult for jujube trees to absorb some iron, zinc, phosphorus and other elements alone, so we must pay attention to the way of supplementing fertilizer.

Underground top dressing can be taken, and well-rotted farmhouse fertilizer or multi-element organic and inorganic compound fertilizer should be selected, or amino acid chelated fertilizer should be used for root irrigation treatment. Foliar fertilizer can also be sprayed, sprayed every 15 days with flower bud treasure or full nutrient amino acid chelation, such as amino acid chelated iron, calcium, zinc, manganese, Tianda 2116 plant cell membrane stabilizer, jujube tree advanced nutrients, etc.

1. Temperature. If the temperature is too high or too low, the leaves will turn yellow. If the temperature continues to be too high, the stomata of the leaves will become larger, and they will turn yellow due to water loss; The temperature continued to be too low, and the stomata of the leaves were closed, and they turned yellow due to the shutdown.

Although fruit trees are highly drought resistant, fruit trees will also show yellowing and wilting on the leaves due to lack of water or water loss. Fruit trees are broad-leaved trees, and the so-called "spring river plumbing duck prophet, a leaf falls to know the world in autumn" is this truth.

2. Lack of nutrients. Fruit trees eat the elements, and the growth of the leaves first needs the support of various elements, and the yellowing of the leaves is often directly related to the lack of various elements. Iron deficiency produces yellow leaf disease, zinc deficiency produces leaf disease, molybdenum deficiency produces mosaic disease, copper deficiency produces early defoliation disease of fruit trees and peach, walnut, kiwifruit, grape gum disease, iron deficiency yellow leaves from top to bottom, potassium deficiency yellow leaves from bottom to top, nitrogen deficiency of the whole tree leaves lose green and yellow, calcium deficiency leaves roll up, boron deficiency leaves roll down, magnesium deficiency leaf veins green leaf flesh yellow.

Of course, the inorganic chemical fertilizer is too heavy, urea and diammonium are applied partially, the trace elements are too large, and the concentration of water-soluble fertilizer is too high, which is also easy to produce fertilizer damage and cause yellowing of leaves.

3. Drug damage. The concentration of the liquid medicine is too high and the leaves are burned; In summer, spraying at noon in summer is easy to burn the leaf edge; Herbicides can also scorch the leaves if they hit them; The absence of alternate or single application not only makes pests and diseases resistant, but also often leads to yellowing of leaves; Some drugs will also have a counterproductive effect due to the wrong container, resulting in poisoning and yellowing of the leaves; The transmission of the virus disease to the leaves will also produce yellowing.

Fourth, diseases. The so-called diseases mainly refer to infectious diseases, the orchard is closed, the terrain is low-lying, the dry is not in place, the drainage is not smooth, the tree disk is damp, etc., the diseases and pests are often serious, brown spot, spot defoliation, anthracnose leaf blight, round spot, gray spot, it is easy to infect the leaves, causing the leaves to yellow and fall off.

5. Soil. No or less application of bio-organic fertilizer and long-term dependence on chemical fertilizers, especially urea and diammonium, destroy the soil aggregate structure, cause soil compaction, and obstruct the nutrient cycle; Flood irrigation leads to suffocation and death of roots; The abuse of fertilizers leads to soil acid-base imbalance and inhibits the effective absorption of medium and trace elements. Beneficial microbial bacteria are reduced, growth-promoting malignant bacteria are rampant; deterioration of the soil environment by sewage or plastic films; Improper fertilization methods, too close, too shallow, too concentrated, etc., cause root burning; Bottom fertilizer application in spring; In spring and summer, rotary tillage and weeding, fertilization and root breaking.

All in all, the yellowing of fruit leaves is caused by a combination of many causes, and we cannot completely prevent it with just one drug.

The yellowing of the leaves of the fruit seedlings is caused by a lack of nutrients, you can supplement him with some phosphate fertilizer, nitrogen fertilizer, potassium fertilizer or compound fertilizer.

It could be a charcoal disease.

Bordeaux liquid can be sprayed.

Bordeaux liquor is an inorganic copper bactericide. It is a sky blue gelatinous suspension formulated from about 500 grams of copper sulfate, 500 grams of hydrated lime and 50 kilograms of water. The ingredient ratio can be appropriately increased or decreased as needed.

It is generally alkaline and has good adhesion properties, but it is suitable to be used for a long time or made of dehydrated Bordeaux powder, and then mixed with water when used.

The solution is a protective bactericide, which inhibits the spore germination or hyphal growth of pathogenic bacteria by releasing soluble copper ions. Under acidic conditions, when a large amount of copper ions are released, it can also coagulate the cell protoplasm of pathogenic bacteria and play a sterilizing role. In the case of high relative humidity and dew or water film on the leaf surface, the efficacy is better, but it is easy to cause pesticide damage to plants with poor copper tolerance.

It has a long effective period, and is widely used to prevent and control a variety of diseases such as vegetables, fruit trees, cotton, hemp, etc., and has a particularly good effect on downy mildew, anthracnose, potato late blight and other leaf diseases.

Bordeaux liquor is a protective biocide. The active ingredient is basic copper sulfate, which can effectively prevent the germination of spores, prevent the infection of pathogens, and can promote the leaf color to be dark green, grow robustly, and improve the disease resistance of the tree. The preparation has the characteristics of wide bacteriological spectrum, long duration of effect, no resistance to pathogens, low toxicity to humans and animals, etc., and is a fungicide with the longest application history.

Bordeaux liquid itself does not have a bactericidal effect, and when it is sprayed on the surface of the plant, it is adsorbed on the surface of the crop due to its adhesive properties. In the process of metabolism, plants will secrete acidic liquid, coupled with the acidic substances secreted by bacteria when they invade plant cells, so that a small amount of basic copper sulfate in Bordeaux solution is converted into soluble copper sulfate, thereby producing a small amount of copper ions, which will coagulate the proteins in the cells after entering the bacterial cells. Copper ions can also destroy certain enzymes in their cells, thus preventing the normal metabolism in the bacterial body.

Under the influence of these two effects, the bacteria can die.

Prevention and control objects. To prevent and control early apple defoliation, charcoal disease, and ring pattern disease, you can start to spray lime doubling Bordeaux liquid 200 to 240 times after apple flowering, spray once every half month, and alternately use with other fungicides, a total of 3 to 4 times. To prevent and control apple rot disease (ring pattern disease, charcoal disease), you can spray lime doubling or multi-volume Bordeaux liquid 200 times 10 to 15 days before the appearance of diseased fruit in previous years, spray 1 time every 15 to 20 days, spray 3 to 4 times, and stop using 25 days before fruit picking.

To prevent and control apple mildew heart disease, 200 times of lime multiple-type Bordeaux solution should be sprayed at the beginning of the apple budding period. To prevent and control apple and pear rust, you can spray 160 times of lime equivalent Bordeaux liquid on the juniper cypress around the apple orchard. To prevent and control grape black disease, charcoal disease, and downy mildew, you can spray a small amount of lime Bordeaux liquid 160 times, spray 1 time every 12 to 15 days, a total of 2 to 4 times.

After the rainy season, Bordeaux juice is used to control grape diseases.

1.The soil lacks medium and trace element fertilizers.

Nitrogen, phosphorus and potassium macro-element fertilizers were the main fertilization, and medium and trace element fertilizers were neglected, resulting in the lack of nutrients in the soil and yellow leaves.

Partial application of a large number of elemental fertilizers causes elemental antagonism, and it is difficult to absorb medium and micro fertilizers.

Soil acid-alkali imbalance, soil too acidic or too alkaline is easy to cause crop yellow leaves.

2.Weak or damaged root system.

If a strong root system is not cultivated in the early stage, or after harvesting a stubble, the intermediate fertilizer is not on the top of the plant, which is easy to cause the follow-up weakness of the plant, resulting in a lack of nutrients and yellow leaves. In the case of low ground temperature, large watering, long rooting time or excessive amount of fertilizer at one time, it will cause root damage and weaken root vitality, resulting in yellow leaves due to insufficient absorption capacity of the root system.

3.The fruit-to-leaf ratio is not suitable, there is a lot of malnutrition, and the removal of a large number of good functional leaves will also lead to malnutrition of the plant and the production of yellow leaves 4(1) Pests and diseases and virus infection cause yellowing of leaves.

2) Pesticide damage (herbicide drifting), air damage, incorrect selection of pesticides, large dosage or incorrect application methods, resulting in pesticide damage, accelerated aging of leaves, and yellow leaves.

Yellow leaves have appeared, what should I do?

We should determine the cause of yellow leaves according to the actual situation in the field, and then take targeted measures.

In the first category, the yellow leaves caused by the lack of medium and trace elements in the soil, we can spray foliar fertilizer containing medium and trace elements (Haifu calcium, magnesium, boron zinc) to quickly supplement, and then apply medium and trace element fertilizer + Haifu fish protein peptide at the root.

For the second type of yellow leaves caused by weak or damaged roots, first spray foliar fertilizer containing medium and trace elements (Haifu calcium, magnesium, boron zinc) to quickly alleviate the nutrient deficiency, and at the same time, each time per mu, 1kg of Haifu alginic acid + 5kg of Haifu fish protein peptide + Fuyou root, used 2-3 times, can effectively improve the root growth environment, activate the root system, generate new roots, strengthen the roots, and alleviate leaf yellowing.

In view of the yellow leaves caused by the uncoordinated fruit-to-leaf ratio of the fourth type, the excess fruits should be thinned firstly, the plant type should be arranged, the old leaves that lost photosynthesis in the lower part should be knocked out, the ineffective branches at the bottom should be removed, and all functional leaves and effective branches should be retained.

In view of the yellowing of vegetable leaves caused by pests and viruses in category 5, the types of pests and diseases are first judged, and pesticides are applied to control the pests and diseases, which can be sprayed with foliar fertilizer.

If it is a virus infection, it is also necessary to pay attention to the prevention and control of whiteflies and other transmission vectors, seriously infected plants, directly uprooted, and then spray amino-oligosaccharides (Fuyoukang) + brassinin + morpholinoguanidine hydrochloride + Fuyou leaves, spray 2-3 times in a row, with an interval of 7 days, while controlling pests and viruses, it can also quickly repair the damaged parts, so that the leaves can turn from yellow to green as soon as possible.

The reasons for the yellowing of the leaves of fruit trees are as follows:

1. Watering too often or lack of water.

There is no obvious change in the old leaves, but the young leaves will turn yellow, so it is necessary to control the water in time. Dry yellow, that is, caused by lack of moisture. This is the old leaves that are yellow first, so it is necessary to replenish water as soon as possible to allow the fruit tree to absorb the appropriate amount of water.

2. The temperature is too high or too low.

If the temperature is too high or too low, the leaves of the fruit tree will turn yellow. When the temperature is persistently too high, the stomata of the leaves become larger and turn yellow due to water loss. The temperature continued to be too low, and the stomata of the leaves were closed, and they turned yellow due to the shutdown.

3. Lack of elements.

The growth of fruit tree leaves first needs the support of various elements, and the yellowing of leaves is often directly related to the lack of various elements. For example, iron deficiency in fruit trees will produce yellow leaf disease, iron deficiency yellow leaves from top to bottom, potassium deficiency yellow leaves from bottom to top, nitrogen deficiency of the whole tree leaves lose green and yellow, magnesium deficiency leaf veins green leaf flesh yellow. Knowing this, we can identify the symptoms of fruit trees from the different yellowing phenomena of the leaves.

4. Disease occurs in fruit trees.

If the orchard is closed, low-lying, and the tree plate is damp, it is easy to produce brown spot disease, spotted defoliation and other diseases, which infect the leaves of fruit trees, causing the leaves to turn yellow and fall off.

5. Fat yellow. That is, it is caused by improper fertilization. Excessive fertilization or too high fertilizer concentration will cause fertilizer damage and yellowing.

Excessive fertilization, improper fertilization leads to high nitrogen fertilizer (urea, manure, etc.), and the ground temperature will also rise when the summer temperature is high, resulting in damage to the capillary roots and inability to absorb nutrients normally.

A large number of compound fertilizers are used, and granular fertilizers are used for fertilization during the growth period of some fruit friends, digging pits and trenches, resulting in broken roots and cutting off nutrient sources, and yellowing of leaves.

In short, the yellowing of fruit leaves is sometimes not a single cause, but may also be caused by a variety of reasons, so it must be determined according to the specific situation in the judgment.

Summary. Yellow leaves of fruit trees are caused by a lack of fertilizer. The main fertilizers that are lacking are nitrogen, magnesium and iron.

Yellow leaves of fruit trees are caused by a lack of fertilizer. The main fertilizers that are lacking are nitrogen, magnesium and iron.

But when there is no shortage of fertilizer, the leaves sometimes turn yellow. There are several main reasons for the occurrence of yellow leaves:

Heavy soil clay can easily cause yellow leaves, and overwatering or excessive rain can cause yellow leaves. Frost damage causes yellow leaves, which is common in grapes that are cold in winter and are not buried in the soil to protect against cold, resulting in late bud and yellow leaves in spring. Excessive ring stripping causes yellow leaves, and ring stripping should be determined according to the strength of the tree.

The application of uncooked organic fertilizer results in yellow leaves. Herbicide damage causes yellow leaves.

Hope it helps.