What is the cause of yellowing of old mandarin leaves?

The cause of yellowing of old leaves of mandarin oranges

1. Soil. 1.In terms of soil fertility:

After years of production, there are no nutrients in the soil, and the fruit growers have a clear understanding of the fruit trees will impose fertilizers containing mineral microbial elements, if they are not fertilized in time, the orange trees will show the phenomenon of yellowing of old leaves in bad weather, and look fragile and without nutrients. The soil texture is sticky, resulting in yellowing of leaves: the soil is in a stagnant environment, and the vitality of the root system is significantly weakened, which hinders the absorption and utilization of nutrients by the roots, resulting in the loss of green and yellow leaves.

2.Soil salinity: high soil salt content will lead to nutrients in the soil is difficult to absorb, most of the soil in the southern hills or mountainous areas is reddish, reddish soil acidity is relatively high, too high acid will lead to nutrients being fixed, citrus fruit trees can not absorb nutrients at all, it is difficult to survive, so there will be a phenomenon of green and yellow orange leaves.

2. Pests and diseases

The invasion of pathogens or viruses produces various secretions that clog the transport system, resulting in an inability to absorb water and nutrients, problems with photosynthesis, and yellowing of the leaves.

3. Human factors

Human factors are poor management, the above three are basically natural factors, poor management of the citrus orchard will also lead to the yellowing of old leaves, over-watering or over-fertilization, will affect the trace elements in the soil, fruit farmers resist pests spraying pesticides improper use will also lead to stunted development of fruit trees, for fruit farmers to regularly fertilize and water spraying, the most important thing is to use the right amount of pesticides and to manage the growth trend of mandarin fruit trees.

Governance Measures:

1.The soil is fertile, the soil is the foundation of the growth of the mandarin orange is also the foundation of growth, for the mandarin orange to have a high yield must have fertile soil, the composition of the soil is the most important, especially the minerals in it are conducive to the growth of Fugong, the fruit farmer can renovate the soil before planting, it is recommended to use green bag fertilizer strong demilcotic agent. If the above phenomena such as soil agglomeration occur, it is recommended to use green bags of fertilopeptide synergist, and the corresponding field management measures should be reasonably managed.

2.Spraying pesticides, the yellow leaves of mandarin oranges are likely to be caused by the infestation of pests and diseases, so it is important to spray pesticides regularly, not only to prevent them, but also to effectively kill pests and diseases.

3.Sufficient light, whether animals or plants can not survive without light, mandarin oranges need sufficient light, even the back side also needs sufficient light, daily light and ventilation are the most important.

It can be due to malnutrition, over-teaching, or soil diseases, all of which can lead to yellowing.

There are two reasons for the yellowing of old mandarin leaves: the first is that not enough fertilizer is given, and the second is because there is not enough light.

It is because there is no timely prevention of pests and diseases, and the secretions produced by pathogen invasion eventually lead to yellowing of old leaves.

Wo mandarin because of the juicy fleshy fat every time it is on the market, it is deeply loved by the public, and even more in order to pick conveniently, they have raised mandarin oranges at home, but they have encountered the problem of new mandarin oranges, so what is the reason for the new yellow of mandarins? How to solve the problem of new mandarin yellow? Let's take a look.

1. High groundwater level: citrus orchards such as low-lying lands, mountain feet, and paddy fields with high groundwater level will have poor root absorption capacity and yellowing due to the long-term exposure of the root system to high moisture and hypoxia in the rainy season;

2. Soil acidity: the most suitable soil pH for the growth of citrus roots is, when the acidity of the soil is large, the effective activity of medium and trace elements such as magnesium, iron, calcium and zinc in the soil is low, resulting in black roots, rotten roots, and the nutrient absorption function of the root system is reduced, which may also cause the yellowing of the tree;

3. Heavy soil viscosity and poor air permeability: this will cause soil hypoxia, poor activity of beneficial microorganisms in the soil, and harmful bacteria such as Fusarium and Phytophthora will grow vigorously, and root or trunk rot will occur, and it will also cause yellowing of the tree;

4. Improper fertilization: In the use of fertilizers, random matching, random mixing and simplification will cause antagonism of various nutrients, resulting in the mineralization and fixation of a large number of elements and medium and trace elements, so that magnesium, iron, boron, zinc and other comprehensive deficiencies will also occur, and yellow flowers and leaves will also appear;

The leaves of the mandarin orange tree first turn yellow and then fall and then wither, there are both management reasons, as well as the reasons for the pest and disease Fang Li Heng face, but generally more common in management reasons, if you want to solve the usual planting must be more careful, if the soil is acidic or compaction leads to the growth of fruit tree roots inhibition, the soil needs to be improved, more organic fertilizer is applied.

1. The demand for fertilizer is relatively large. It is prone to deficiency of trace elements such as magnesium, zinc and boron. Therefore, it is necessary to supplement micronutrient fertilizers on time. Bottom fertilizer should be fully applied before planting, and top dressing should be applied less in the later stage.

2. The soil fertility of some orchards is weak, and the loss of boron and magnesium due to rainwater erosion and the yellowing of old leaves have a great demand for magnesium, so special attention should be paid to the supplement of magnesium fertilizer.

Summary. If the citrus fruit stalk is dry, the fruit is yellow, and the phenomenon of falling, it is likely that the fruit stalk is infected with anthracnose, this type of anthracnose is not like the usual common anthracnose will show typical lesions and wilting on the leaves and branches, because the germs are concentrated in attacking the young tissues, that is, the young citrus fruits, so it does not look so obvious, but it has a great impact on the young fruits, which will cause a large number of fruit drops.

If the citrus fruit stalk is dry, the fruit is missing and yellowing, and the phenomenon of falling, it is likely that the fruit stalk is infected with anthracnose, this type of anthracnose is not like the usual common anthracnose will show typical disease spots and wilting on the leaves and branches, because the germs are concentrated in attacking the young tissues, that is, the young citrus fruits, so it does not look so obvious orange sleepy, but it has a great impact on the young fruits, which will cause a large number of fruit drops.

Treatment measures: 1. The primary source of infection in the orchard is mainly dead branches and diseased fruit stems, and only a few are from the diseased spots on the leaves. It is necessary to do a good job of clearing the garden, cut off the diseased fruit stalks in time, remove fallen leaves and diseased fruits, and reduce the source of initial infection.

2. Cut off the closed branches to increase the light transmittance of the tree. Liquid matter strengthens fertilizer and water management, increases organic fertilizer, enhances tree strength, improves disease resistance, and pays attention to orchard drainage. 3. Before the fruit tree is infected with anthracnose, it can be prevented with mancozeb, propylzeb, thiophanate-methyl (methyl tobuzin), stone sulfur mixture, Bordeaux liquid and other agents.

If the fruit tree is unfortunately already diseased, you can use prochloraz, difenoconazole, bromide high nitrile, mycloconazole, pyraclostrobin, etc. It can also be prevented and treated with agents such as mancozeb + prochloraz. Pay attention to the rotation of medication, be thoughtful and uniform when spraying, spray wet branches and leaves without dripping, spraying too much or insufficient liquid medicine will affect the effect.

1. What is the reason for the new yellow shoots of mandarin oranges?

1. High groundwater level: citrus orchards such as low-lying lands, mountain feet, and paddy fields with high groundwater level will have poor root absorption capacity and yellowing due to the long-term exposure of the root system to high moisture and hypoxia in the rainy season;

2. Soil acidity: the most suitable soil pH for the growth of citrus roots is, when the acidity of the soil is large, the effective activity of medium and trace elements such as magnesium, iron, calcium and zinc in the soil is low, resulting in black roots, rotten roots, and the nutrient absorption function of the root system is reduced, which may also cause the yellowing of the tree;

3. Heavy soil viscosity and poor air permeability: this will cause soil hypoxia, poor activity of beneficial microorganisms in the soil, and harmful bacteria such as Fusarium and Phytophthora will grow vigorously, and root or trunk rot will occur, and it will also cause yellowing of the tree;

4) Improper fertilization: In the use of fertilizers, random matching and random mixing will cause antagonism of various nutrients, resulting in the mineralization and fixation of a large number of elements and trace elements, so that magnesium, iron, boron, zinc and other comprehensive deficiencies will also occur, and yellow flowers and leaves will also appear;

2. How to solve the new yellow of mandarin orange.

The leaves of the mandarin orange tree first turn yellow and then fall and then dry, there are both management reasons, there are also reasons for pests and diseases, but generally more common in management reasons, if you want to solve the usual planting must be more careful, if the soil is acidic or compaction leads to the inhibition of the growth of fruit tree roots, you need to improve the soil and apply more organic fertilizer.

3. How to manage the yellowing of yellow leaves of mandarin oranges.

1. The demand for fertilizer is relatively large. It is prone to deficiency of trace elements such as magnesium, zinc and boron. Therefore, it is necessary to supplement micronutrient fertilizers on time. Bottom fertilizer should be fully applied before planting, and top dressing should be applied less in the later stage.

2) In some orchards, the soil fertility is weak, and the loss of boron and magnesium is caused by rainwater erosion, and the demand for magnesium is great due to the yellowing of old leaves, so special attention should be paid to the supplement of magnesium fertilizer.

Summary. Hello dear <>

High temperature exposure, low rainfall, large water evaporation, small absorption, easy to roll leaves, fallen leaves, fruit drops, and wilt. Insufficient fertilizer and water, small and weak trees, small branches and leaves, yellowing leaves, low nutrient reserves, shallow root system, high temperature exposure, water shortage and high temperature of topsoil, poor stress resistance of shallow roots, easy to wither and rot. Especially on the slopes, the soil quality is poor, the heat of the weathered stone is easy to conduct, and it is a steep slope, the water retention and fertility are poor, the root system is shallow, the vitality is weakened, and the loss of water causes leaf rolling, leaf fall, and root rot.

Fruit trees grown in mountainous areas with inadequate irrigation facilities.

What's going on with the yellow hair curls of the mandarin leaves.

Hello dear <>

High temperature exposure, low rainfall, large water evaporation, small absorption, and Shensen are prone to leaf rolling, leaf dropping, fruit dropping, and wilting. Insufficient fertilizer and water, small and weak trees, small branches and leaves, yellowing leaves, low nutrient reserves, shallow root system, high temperature exposure, water shortage and high temperature of topsoil, shallow roots are wide and disorderly, and the mu has poor stress resistance, which is easy to wither and rot. Especially on the slopes, the soil quality is poor, the heat of the weathered stone is easy to conduct, and it is a steep slope, the water retention and fertility are poor, the root system is shallow, the vitality is weakened, and the loss of water causes leaf rolling, leaf fall, and root rot.

Fruit trees grown in mountainous areas with inadequate irrigation facilities.

There are many reasons for this. If there is a lack of positive and magnesium and calcium deficiency, etc., if you say that it is yellow and rolled, if there is an inverted V-shaped yellowing, it should be a magnesium deficiency. I wish you a happy life! Hope mine is helpful to you ha.

According to the causes of yellowing, yellowing is generally divided into yellowing due to nutrient deficiency, yellowing caused by root problems, yellowing of tree decline, yellowing of trees with ring cuts, and yellowing of residual grafted films. 1. The lack of nitrogen, potassium or trace elements in yellowing citrus will cause yellowing, but at present, fruit farmers and friends have applied a large number of nitrogen, phosphorus and potassium (sulfur-containing) compound fertilizers, so most orchards will not be deficient in nitrogen, phosphorus, potassium and sulfur. There is mainly a deficiency of calcium, magnesium, iron, manganese, zinc, boron and molybdenum and other trace elements. 01 The main diseases of calcium deficiency are:

The upper leaf margin of the young spring shoot leaves is first yellow or yellowish-white; yellowing between the main and lateral veins and near the leaf margin, and the mesophyll of the main and lateral veins and their vicinity is still green; Later, the yellowing part expands, the leaf surface is large and yellowing, and produces dead spots, and the diseased leaves are narrow and small, and soon fall off; Symptoms appear first in the young leaves. The main symptoms of calcium deficiency yellowing 02 magnesium deficiency in pomelo are: the old leaves and leaves near the fruit are the first to occur, and the symptoms are more obvious; The diseased leaves have irregular macula along both sides of the midrib, and gradually expand to the leaf margin, so that the lateral veins appear rib-like yellowish-white bands to the mesophyll, and the maculas are united with each other later. Most of the leaves are yellowed, and only the triangular or inverted V-shaped green part of the midrib and its base is left in the dead part of the leaf or the remnant cave at the tip of the leaf.

The main symptoms of magnesium deficiency yellowing 03 iron deficiency in pomelo are: the lesions of the new slightly young leaves are thin and yellowing, and the mesophyll is pale green to yellowish-white; The leaf veins are distinctly green reticulated; The young leaves at the tips of the twigs are more pronounced; The old leaves of the diseased tree remain green. 04 The main diseases of manganese deficiency are:

The shape of the leaves is basically normal, and the yellowed part is green. The leaves turn yellow-green, and the mesophyll loses green and appears pale green; The veins are dark green; Symptoms appear first in the young leaves.