After the beginning of autumn every year, the condition of citrus yellow trees will increase significantly. We call this phenomenon “autumn yellow”. It directly indicates the health of the fruit tree. If the fruit tree is yellow, the harvest this year may also be affected.
There are many reasons for yellowing: nutrient imbalance, root damage, improper circumcision yellowing, yellow dragon disease etc. Yellowing is not terrible. Different orchards need to analyze specific problems in detail, and to find out the reasons for targeted yellowing control is the fundamental solution to the problem.
What are the hazards of yellowing?
The yellowing of citrus will cause the leaves to lose green and become yellow, and the photosynthesis capacity will be greatly reduced. The deterioration of tree vigor will cause a series of problems, such as weakened disease resistance and poor ability to absorb water and fertilizer. The final result is low yield and poor fruit quality, which affects the economic value of the fruit.
What are the main causes of yellowing?
Yellowing caused by root problems
The yellowing problem caused by the root system is not a large area in the orchard, but scattered. The yellowing of the variable area is mostly small trees. Fruit trees are usually partially blue and green on one side and yellow on the other side. From the appearance of the leaves, the leaves begin to lose green and turn yellow evenly, and the veins first yellow, expand to the entire leaves, and finally fall off.
Yellowing caused by lack of nutrients
During this period, fruit swelling requires a lot of nutrients, as does the germination of autumn shoots, including the third peak of citrus roots. If the amount of fruit is too large, the nutrient supply is insufficient, especially the middle and trace elements, which will easily lead to yellowing of the tree.
Yellowing caused by pests and diseases
Pathogens such as pathogens invade the citrus tree and produce various secretions that can block the citrus transport system, resulting in the inability to absorb water and nutrients, and the raw materials necessary for photosynthesis cannot be supplied, and the leaves will appear chlorosis.
For example, the well-known “citrus AIDS” citrus yellow dragon disease is caused by a bacteria born in the phloem tissue of citrus. Its transmission methods include grafting and transmission of citrus psyllids. The whole citrus leaves turn yellow, the fruit is diseased, and eventually die.
There is also the phenomenon of citrus yellowing caused by root problems caused by diseases and insect pests, which is particularly prominent. The main reason is that the citrus root nematode disease invades the roots of the plants. In severe cases, the roots are twisted and formed into a cake shape, and finally necrosis, the leaves on the ground lose their luster, and the phenomenon of falling leaves and fruit appears; when the damage is less, it is not seen from the ground. Any symptoms of disease appear, but the signs of disease can be seen from the root system, and preventive measures can be taken at this time.
Yellowing to green solution
There are many phenomena of yellowing, the above examples are only a small part, but no matter what the cause of yellowing is? We should all be diligent in management, supplement tree nutrition, strictly prevent pests and diseases, strong tree vigor and healthy root system, in order to resist the invasion and chlorosis of various pests and diseases.
1. irrigation: seaweed liquid (Dolfen), 500 times dilution
Yellowing to green test effect
Before use: The yellowing of the leaves of the orange leaves is severe, the growth stops, and no new buds can be drawn.
After use: On the 15th day, observe the growth of the fruit tree: the leaves have all turned green, the curved leaves have spontaneously expanded, and new leaves and shoots are growing, which is full of vitality!
Sugar tangerines hang on fruit trees, and the leaves are severely yellowed.
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