When citrus huanglongbing is rampant, what should farmers do?

A small test strip can help the entire orchard defend against citrus huanglongbing. "The innovation and entrepreneurship team led by students from the School of Pharmacy of Nankai University is committed to the research and development of rapid and early detection technology for citrus diseases, so that fruit trees can stay away from diseases as soon as possible. Since 2019, their technology has been explored and applied in several nursery bases and thousands of acres of navel orange orchards in southern Gansu, guarding this "orange sea" that brings hope for prosperity.

Citrus huanglongbing is a national quarantine disease that seriously threatens the safety of the citrus industry, and is known as cancer on citrus trees. Infected citrus loses fruiting ability or even dies within 3-5 years, spreading and causing damage to entire gardens. At present, the situation of citrus huanglongbing is very serious, and there are frequent reported cases of citrus huanglongbing in various areas of Shuifu County, Yunnan Province.

In recent years, Shuifu County has taken effective measures to strengthen the prevention and control of citrus huanglongbing, prevent the spread of citrus huanglongbing from the source, and ensure the safety of citrus production in the area.

Mottled yellowing is a typical feature of Huanglongbing leaves, which is characterized by asymmetrical yellowing spots, which are different from uniform yellowing caused by element deficiency.

The mottled leaves are caused by the gradual accumulation of huanglongbing pathogens in citrus leaves, resulting in necrosis of the phloem of the leaf veins.

From the picture, we can see that most of the leaves turn yellow first from the bottom of the leaves. If they also exhibit hardness and brittleness, there is a high probability of huanglongbing.

How to deal with it? In areas where huanglongbing occurs, most fruit farmers still regard red spider mites, which do not cause dead trees, as the number one important pest of citrus, but they do not pay attention to or even understand the psyllids that can infect huanglongbing and destroy citrus. Deng Mingxue emphasized that the change of concept is very important.

First of all, it is necessary to establish the idea that citrus huanglongbing is the first important disease and citrus psyllids are the first important pest. In addition, any disease is mainly preventive, such as scab, anthrax, sarpa peel and ulcer, especially for the control of the devastating disease huanglongbing. To do a good job in prevention, planting disease-free seedlings is the foundation, killing citrus psyllids is fundamental, and killing psyllids is preferential to cutting down diseased trees.

Diseased trees should only be cut down and excavated if they are effectively killed by psyllids, otherwise pathogens will spread.

If the tree is diagnosed with huanglongbing, the garden needs to be carefully inspected to see if there is a similar disease. Since there are more psyllids in July and August, it is necessary to kill the psyllids first, and then carry out ** on the diseased trees. Chlorpyrifos, cypermethrin and nicotine can be selected as agents.

If it weren't for huanglongbing. It is physiological yellowing, and it is recommended to drench the sea elf biostimulant.

After cutting down trees, it is best to remove the diseased trees along with the roots to prevent them from becoming a new source of infection.

First, spray the tree infected with citrus huanglongbing with the agent against citrus psyllids to kill a part of the citrus psyllids; 2. After spraying for 3-5 days, cut down the yellow dragon diseased tree, remember not to drag it away immediately, and wait until the psyllid is completely killed before dragging the diseased tree away, so that it will not infect the healthy tree near the branch of the disease.

Dig up the diseased plants. Once it is found that it is a tree with huanglongbing, immediately dig up and leave no residue, carefully inspect the three shoots of spring, summer and autumn every year, especially the autumn shoots, and immediately dig up the diseased plants or suspicious diseased plants, and burn them intensively. Strengthening the detection and control of citrus psyllids and cutting off the transmission route is an important part of preventing the epidemic of huanglongbing.

In addition, shelterbelts are planted around orchards, which can hinder the migration of psyllids.

For farmers, it is best to use some pesticides to inhibit this disease.

Trees suffering from citrus huanglongbing are found in time and then cut down. The seedlings are tested before they are cultivated and the saplings with pathogens are removed.

The source of the disease should be blocked, and all the diseased trees should be cut down and burned so that they do not come into contact with other trees.

<>1, drug prevention and control of huanglongbing: with the occurrence of citrus huanglongbing, scientists have also developed a special drug, now the prevention and control of huanglongbing with drugs has become an ideal way to prevent this disease, people can use huanglongbao fertilizer spraying, can be sprayed with chloresellin to prevent citrus deficiency symptoms. 2. Isolation of infection:

Citrus huanglongbing is a very contagious disease, after finding that the fruit tree has the disease, it must not be distressed, it is necessary to control the root in time, and clean up the environment.

1. Prevention and control methods of citrus huanglongbing

1. Drugs for the prevention and treatment of huanglongbing.

1) With the harm of citrus huanglongbing, scientists have also developed special drugs, and now the use of drugs to prevent and control huanglongbing has become the main way of prevention.

2) Huanglongbao fertilizer can be sprayed, or chloreocexin spraying can be used to prevent citrus deficiency symptoms, and it must be used in time at the beginning of spring every year, so as to effectively reduce the occurrence of huanglongbing.

2. Isolation of infection:

1) Citrus huanglongbing is a very contagious disease, when it is found that the fruit tree is diseased, it must be uprooted in time, and the environment must be cleaned up.

2) When cultivating new citrus seedlings, it is necessary to stay away from the area where huanglongbing is endemic, and then use plastic greenhouses to isolate the seedlings to prevent infection.

3) In addition, the occurrence of citrus psyllids must be strictly controlled in spring, which is the main way to spread citrus huanglongbing.

2. Symptoms and causes of citrus huanglongbing

1. Symptoms of citrus huanglongbing.

1) The leaves are mottled.

Yellowing of irregular yellow-green mottled leaves from near the base of the veins or at the edge of the leaves, and the new shoots of the leaves drawn from the diseased branches generally remain green near the main and lateral veins, but the mesophyll will appear yellowing.

2) Yellowing (yellow shoots).

Individual shoots will be diseased first, then yellow shoots, and very few plants will show symptoms of whole plant disease at the beginning.

3) Fruit deformity (red nose fruit).

The following spring will bloom in advance, the flowers are small and deformed, the fruit is relatively small, the fruit will also be deformed, the fruit is small and very similar to a table tennis ball, the coloring is uneven, the coloring near the fruit pedicle is commonly known as the "red nose fruit", the fruit taste is relatively sour, and the quality is very poor.

4) Roots. The main manifestation is the rot of the roots, the severity of which is very symmetrical with the above-ground shoots.

The roots of the branches and leaves generally do not rot in the early stage of the disease, and when the leaves are yellowed and fall off, the fibrous roots and branch roots will also begin to rot, and later spread to the lateral roots and taproots, and the cortex will be broken and separated from the woody.

2. The cause of citrus huanglongbing.

1) If there is a pathogen in the orchard or near the orchard, there is an opportunity to develop the disease, such as huanglongbing.

2) Orchards or near orchards can also be affected by vectors, i.e., citrus psyllids.

3) Citrus psyllids can be poisoned after 5 hours of feeding on diseased trees.

4) If there is an unevenness in the orchard and tender shoots occur at any time, it will attract citrus psyllids to feed and spread the poison.

Summary. 1. How to prevent and control citrus huanglongbing?

The traditional anti-citrus psylloid agent for the prevention and control of citrus huanglongbing can be used bifenthrin, chlorpyrifos, clothianidin, thiamethoxam, etc., and then when the new shoots germinate, fast-acting pesticides can be used, such as:

bifenthrin resin 1000 times; chlorpyrifos 1000 times; 1000 times chlorocyanide chlorpyrifos, etc.

The second medication is 7-15 days after the first use, and the specific time interval is related to the effectiveness of the agent in different seasons, the interval is about 12-15 days in spring, and the interval between summer and autumn is about 7-10 days.

20% clothianidin 3000 times; 25% thiamethoxam 2500 times, etc.

2. New drugs for the prevention and control of citrus psyllids.

Although the above drug regimen is indeed effective in the prevention and control of citrus psyllids, the resistance of psyllids is also increasing, and highly pesticides such as chlorpyrifos have gradually withdrawn from the market due to their high toxicity, and the opponents of citrus psyllids have also appeared new faces

5% d-limonene, a natural insecticide extracted from orange peel, can break through the wax of the epidermis of citrus psyllids, so that psyllids lose water and die, which is a physical insecticide, this agent has strong lethality, how to prevent huanglongbing disease in citrus replanting.

1. How to prevent and control citrus huanglongbing? The traditional anti-citrus psyllids for the prevention and control of citrus huanglongbing can be used bifenthrin, chlorpyrifos, clothianidin, thiamethoxam, etc., and then when the new shoots germinate, fast-acting pesticides such as: bifenthrin 1000 times; 1,000 times the chlorpyrifos; 1000 times chlorocyanide chlorpyrifos, etc.

The second medication is 7-15 days after the first use, and the specific time interval is related to the effectiveness of the agent in different seasons, the interval is about 12-15 days in spring, and the interval between summer and autumn is about 7-10 days. 20% clothianidin 3000 times; 25% thiamethoxam 2500 times, etc. Second, the new drug for the prevention and control of citrus psyllids Although the above drug regimen is indeed very effective in the treatment of citrus psyllids, the resistance of psyllids is also constantly strengthening, and highly pesticides such as chlorpyrifos have gradually withdrawn from the market due to their strong toxicity, and the opponents of citrus psyllids have also appeared new faces: 5% D-limonene, a natural insecticide extracted from orange peel, can break through the wax of the skin of citrus psyllids, so that psyllids lose water and die, which is a physical insecticide, and this agent has strong lethality. Ask about custom messages].

Summary. Dear, there is no time limit for this, as long as the correct **citrus huanglongbing can be reloaded, but you must ensure that your citrus tree huanglongbing has been completely cured, you can go to the market from the new market.

Dear, there is no time limit for this, as long as the correct **citrus huanglongbing can be overloaded to catch Liang Mingminji, but you must ensure that your citrus tree huanglongbing has been completely cured, and the oak branch can be listed from the new Huai Buji.

How is huanglongbing**.

Okay, wait a little bit, pro.

Pro, first of all, the oak medicine to kill lice must be the first place in the treatment of citrus huanglongbing disease, to kill lice first and then cut down the tree, not to cut the tree and then kill lice, otherwise it is easy to cause the poisonous psyllid to eat on the Huangliang hand-to-hand dragon disease tree in the process of cutting the tree to run to the healthy tree for harm.

Dear, after spraying for three to five days, after the tree is completely dead, the Huanglongbing disease tree is cut down near the ground, and the diseased tree is stranded in place first, and then dragged out of the orchard after the leaves on the tree are dry.

After cutting down the diseased tree, all the roots are removed. Or you can use a straw bench to hold glyphosate or glufosinate-ammonium, or you can use waste engine oil to pour on the tree pocket, and then wrap it with a black plastic bucket film to cover it, so that it does not see light, cannot sprout and grow again, and will naturally dry up and rot in the future.

Dear, the above is the method of citrus huanglongbing, you can follow the method to **citrus huanglongbing.

Citrus huanglongbing is a devastating disease, once an orchard develops, it will spread and spread rapidly, often destroying an economic industry within a few years. It can be said that citrus huanglongbing is a cancer of citrus trees, and I have not heard of any special medicine that can **! But it can be prevented.

As for the spread of citrus tree huanglongbing disease, it can be divided into two types: long-distance transmission or close-distance transmission.

A suitable place for planting citrus, when introducing seedlings from other citrus planting areas, citrus growers must pay attention to the citrus seedlings and grafted scion they introduce can not have huanglongbing disease, which is an important part of preventing citrus huanglongbing.

Citrus huanglongbing is transmitted in close proximity and can also be said to be disease transmission between orchards. Its transmission route is mainly caused by citrus psyllids, artificial tools, grafting infection and other ways to make citrus seedlings suffer from huanglongbing. Then the prevention and control methods of huanglongbing between orchards I personally think there are:

1. We all know that people with good physical fitness are much stronger than people with poor physical fitness in terms of disease resistance. In the same way, strengthening the water, fertilizer and management of citrus can also improve the disease resistance of citrus trees.

2. Psyllids are the main pests of huanglongbing, so citrus orchards must strictly control psyllids, and spray carefully in spring, summer and autumn. At this time, it is best to control psyllids in the whole orchard at the same time, and the effect will be better.

3. When it is found that there are yellow shoots (golden flowers) on the upper or top of the citrus green crown or the old leaves and many years of leaves that have turned green, the fruit growers should judge in time or ask experts to see if the fruit trees are suffering from huanglongbing, and after confirming the huanglongbing, they should dig up and burn all diseased trees in time to remove or reduce the pathogenic trees.

4. When pruning citrus, it is better to use tools that do not carry the virus of huanglongbing (prune the fruit trees first, and prune the diseased trees last).

5. When grafting citrus seedlings, the knife that cuts the grafted surface cannot carry the virus; The grafted scion must not carry the virus.

In short, although I heard that citrus trees have just suffered from huanglongbing, tetracycline hydrochloride** can have a certain control effect, but my personal attitude is that it is better to get rid of a hundred citrus trees suspected of huanglongbing than to let go of a citrus tree with huanglongbing.