The control of summer shoots is directly related to the yield and commodity value of citrus, which is an important concern for fruit growers. While some growers may argue that it is possible to maintain a good yield without controlling the summer shoots, this only applies to citrus varieties with relatively few summer shoots. According to years of practical experience, the yield of mainstream citrus varieties such as sugar orange and mandarin orange is likely to be reduced by more than half if measures are not taken to control summer shoots.
1. Why do you want to control Xia Shao?
Controlling summer shoots is one of the key steps in citrus fruit preservation. The extraction period of summer shoots overlaps with the development period of young citrus fruits. If the amount of summer shoots is too large, a lot of nutrients will be consumed, so that the young fruits will not get enough nutrients to support growth and development, which will lead to shedding and reduce yield. Especially for varieties such as sugar oranges and seedless mandarins, the amount of summer shoots pumped is large, and it is difficult to maintain the fruit without control. At the same time, the overgrowth of summer shoots is also prone to pests and diseases.
High temperatures and increased rainfall in summer are the times when there are a large number of pests and diseases, and the growth of summer shoots increases the probability of damage from pests and diseases, such as anthracnose, canker, citrus psyllid, leaf miner moth, etc. In particular, the damage of citrus psyllids increases the risk of transmission of citrus huanglongbing. Therefore, it is very necessary to control Xia Shao.
2. How to control Xia Shao?
Artificial Engraving:
Manual wiping is one of the most traditional methods, but this method requires a lot of manpower and material resources.
Controlling the pins with pins:
There are two techniques for controlling the shoots with the tips, leaving the shoots according to the size of the canopy. Generally, 10-15 shoots are left for citrus with a canopy of 1 meter, and 20-30 shoots are left for 2 meters. When leaving the shoots, it is necessary to leave the strong and weak, and leave 3~4 leaves for topping the scattered late spring shoots and early summer shoots after flowering.
Inhibitors:
Shoot inhibitors are milder than shoot killers. Common inhibitors are paclobutrazol, 2,4-d, and bud inhibitors. They differ in the nodes of use, the concentration of use, and safety.
paclobutrazol:
The principle of tip control is to reduce the content of gibberellic acid and auxin at the growth point of the shoot to inhibit the growth of the shoot. The control effect can last for 20 days, but in the case of rainy weather, the control time may only reach 15 days. Paclobutrazol can be mixed with most insecticides and fungicides to reduce the cost of multiple sprays.
2，4-d：
The principle of 2,4-d tip control is to achieve the purpose of controlling the tip by inhibiting the growth point of the tip tip.
Bud inhibition mono:
The main component of bud inhibitor is calcium acetate, which inhibits the growth of plant shoot tips by blocking auxin synthesis in the plant body, so as to achieve the effect of tip control.
How to control the growth of shoots?
Fruit control:
For 5-9 year old trees, the summer shoots are less pumped, and high phosphorus and potassium fertilizers, leaf brassicin sprays, seaweed fertilizers and high potassium fertilizers can be applied to the roots to promote the ripening of shoots and ensure the nutrients of the fruits. When the fruit-to-shoot ratio reaches more than 10, summer shoots will be effectively inhibited.
Circumferential cutting pins:
The principle of circumcision is to completely cut the cortex without harming the xylem in order to achieve obvious results. It is best to circumcision on the branches, leaving 1-2 small branches uncircumcised in the lower part for the production of nutrients for the roots. After circumcision, it is best to wrap the peel with a film to speed up healing. For varieties that are prone to fruit dropping, such as sugar oranges, if the tree is vigorous, the number of flowers or young fruits is small, and when there is a lot of rainy weather after flowering, you can perform 2-3 times of circumcision a year.
Through scientific summer shoot control, growers are able to better manage their citrus trees and improve yield and fruit quality.