China's citrus has developed rapidly in recent years, especially In Guangxi, after several years of development, the planting area has now exceeded 7 million mu. The results are gratifying, but there are many problems, because the citrus planting area in Guangxi is mostly scattered, the planting technology is uneven, and many farmers are following the trend of planting, and there is almost no planting technology.
Planting citrus is the need to have a certain technical content of the work, no technology in the planting process will inevitably not have problems, I have been asked by many farmers, my family orchard has a few fruit trees a few days ago is fine, how did it suddenly fall leaves and die after a few days? After interviewing and investigating, the author found that most of them are caused by these three reasons.
<h1>The cause of the sudden death of the orchard citrus tree:</h1>
Reason 1: The circumcision is too heavy
Circumcision is an important means of fruit preservation in citrus fruit trees, because the branches, fruits and root growth of citrus trees need nutrient supply, and the nutrients absorbed by the roots are mainly transmitted to the aboveground part through the xylem, and the aboveground part such as the photosynthetic product converted by the leaves through photosynthesis is mainly transmitted to the underground part of the citrus tree to provide nutrients.
The main principle of circumcision is to cut off the phloem part of the trunk, block the passage of photosynthetic products to the underground part, and temporarily lock the nutrients originally transported to the underground part for fruit growth. Because the circumcision work is carried out around the eighth layer of the spring shoots, the nutrients accumulated by the upper part of the aboveground circumcision are supplied to the growth and development of young fruits, so that the fruit retention rate is greatly improved.
· But everything has advantages and disadvantages, proper circumcision, the fruit retention rate of citrus is greatly improved, but also conducive to the slow healing of circumcision wounds, to the fully healed state, citrus young fruits also entered the stable fruit period at the same time. However, the control of the circumcision is not good, resulting in deep egg cutting or circumcision of the weaker tree, which will have a great impact on the healing speed of the circumcision wound. Because of proper circumcision, there are still some xylem cells in the circumcision that are not mature, and there are also a small number of cells in the forming layer, both of which have the ability to regenerate by division, and the wound heals quickly and the wound heals slowly.
· If the wound left by the circumcision is too large, it will definitely affect the healing speed of the wound, the wound healing time will be very long, the root will not get the timely supply of nutrients, and it will be in a state of hunger for a long time, which will eventually lead to root rot, leaf veins will be yellowed, and a large number of leaves will fall and eventually die. For farmers, the trees cultivated in the past three years are gone, resulting in huge losses of profits.
Cause 2: Root disease - foot rot
In addition to the root disease of citrus, there is also gum rot, etc. Today I will mainly talk about the more serious foot rot. As mentioned earlier in the introduction of circumcision, the xylem and phloem of the tree body are both channels for transporting nutrients for the tree, and if the citrus is infected with foot rot, the bark at the base of the trunk stem will first ulcerate and eventually dry off.
At the same time, the root system in the underground part will also be seriously decayed, with almost no capillary roots, the main root cracks, losing the ability to absorb nutrients, and finally the leaves wilt and dry, fall, and the whole tree dies. Especially in the hot and rainy season, as well as low-lying orchards that are prone to water, the most frequent and the most serious occurrences.
Cause three: root insect pests - tianniu, popcorn worms
The Brown Celestial Bull, the Star Celestial Bull and the Light Shield Green Celestial Bull are the three kinds of celestial cattle that are more harmful in citrus, and there are certain differences in their living habits, but the harm to citrus is almost all devastating. They mainly lay eggs in the trunk, the fork of the trunk or the crack in the bark, and then hatch the larvae to drill the trunk or branches of the borer tree for harm, causing the trunk or branches to be eaten into hollows, blocking the transport channel of nutrients and water of the tree, the tree slowly weakens, the leaves wilt and dry, fall, and finally the whole citrus tree dies, and after the damage of the moth trunk, the process of dying only takes a few days.
Citrus popcorns are also a major pest that can easily cause the entire citrus plant to die, although its adults only eat young leaves, but the larvae hatched from their eggs are very harmful. The newly hatched larvae will begin to moth the bark, the damaged part will slowly flow out of the gum, and then to the bark of the tree, drilling out many worm paths, seriously affecting the phloem of the tree for nutrient transport, while causing the bark to die, fall or burst, the leaves wilt and fall, and finally the whole citrus tree dies.
<h1>Countermeasures to prevent the death of whole citrus plants:</h1>
The previous analysis of several reasons for the death of the whole citrus plant, one is too heavy circumcision, the second is foot rot, the third is the harm of tianniu and explosive skin insects, and the causes can be analyzed one by one, and corresponding measures can be taken, of course, pests and diseases should be mainly prevented.
1. Appropriate circumcision and excessive circumcision remediation
· Not all citrus trees need to be circumcised when preserving fruit, if the growth is more vigorous and moderate growth of the hanging fruit tree can be circumcised, you can choose to use the No. 1 knife for circumcision, the tree that declines do not need to be circumcised, which is like some people themselves are relatively thin, then it is not suitable for him to donate blood.
Weak trees do not circumcise
· At the same time, we should pay attention to the time of circumcision, choose to be after the citrus flowering, the spring shoots are ripe for about eight or nine layers, so that it will not affect the green and old ripening of the spring shoots, grab the nutrition, but also provide more nutrients for the growth and development of young fruits, and improve the fruit set rate.
· If the circumcision is too heavy, first of all, the circumcision wound should be treated in time, and the 30% imidamine suspension can be applied to the wound for sterilization and disinfection, and then the tape is used for bandaging, which is conducive to the rapid healing of the wound. Secondly, during the wound healing period, the absorption capacity of the root system of the citrus tree is very weak, and the root fertilization cannot absorb the fertilizer at all, at this time, the foliar fertilizer should be sprayed for topdressing, and the tree body should be replenished in time to restore the tree momentum. Finally, the roots can be leached with microbial agents or humic acid water-soluble fertilizers to stimulate the growth and development of the root system, nourish the roots, and restore the vitality of the root system.
2. Prevention and treatment of foot rot
Citrus foot rot is mainly caused by Phytophthycosis and Fusarium infestation, of which Phytophthora is the main pathogen and Fusarium is the secondary pathogenic pathogen. Phytophthora is a low-class fungus, but also a soil-borne disease, every year from June to August is the season of high incidence, because this time is a high temperature and rainy weather, is conducive to the breeding hazards of pathogenic bacteria.
Pathogenic bacteria will be from a variety of wounds, such as mechanical damage, insect injuries and other places of infection hazards, so to strengthen the management of the field, in the process of agricultural operations as far as possible not to cause artificial wounds to citrus trees, while increasing the application of organic fertilizer or microbial bacterial fertilizer, not only can improve the soil, but also with bacteria to inhibit bacteria, prevent soil-borne diseases, do a good job of drainage and irrigation measures, to prevent water accumulation, so that the orchard ventilation and ventilation, reduce the harm of diseases and insects.
For fruit trees that have been infected with disease, the soil is planed for root sterilization at the beginning of the disease, and the rotten part of the disease is scraped off, and then the potassium permanganate solution is sprayed for disinfection, and finally the disease site is applied with agents such as fine nail cream and alkenyl morpholine.
3. Prevention and control of Tianniu and popcorns
For the prevention and control of Tianniu, it is still mainly based on prevention, and chemical agents are used to prevent Tianniu from spawning. 35% bifenthrin thiamethoxorin suspension can be used 2000 times, and in May-June of each year, the mating and spawning peak of adult Tianniu can be evenly sprayed on the stem base and trunk of the plant for 2 consecutive times, with an interval of 7-10 days.
If there is already a tianniu starting to harm, it is necessary to manually capture the adult tianniu, and for the larvae that have invaded the trunk for harm, it can be watered 500 times with 35% bifenthrin and thiamethoxam suspension agent to water the intrusive port, and then use mud to block the orifice.
For the prevention and control of explosive skin insects, the methods and methods are the same as the prevention and control work of Tianniu, but the most important thing is to do a good job in clearing the garden, burn the dead branches of the diseased leaves, and use mineral oil 200 times + 500 times the manganese zinc of Daisen to spray the whole garden to kill the overwintering diseases and insects. Use more organic fertilizers, microbial bacterial fertilizers, etc., to improve the soil, improve the growth environment of the root system, cultivate a robust root system, promote the growth of plants, and improve the ability to resist diseases and insect pests.
In short, a good citrus tree suddenly died in a few days, the reason is nothing more than the above situations caused, the majority of fruit farmers in the prevention and control should be based on the situation of their own orchard to find out the pathogen, the right medicine, in order to save in time.