Dear friends of Tinder Sannong, do you eat dumplings or drink mutton soup on the winter solstice?
Hey, let's get down to business
Recently we pushed the article "Two years later, sugar oranges are also the fate of Nanfeng oranges?" ", the analysis of sugar orange market trend this year and the future development trend. A friend in the comment area left a message saying that the yellow dragon disease is rampant, and the sugar orange industry may suffer a disaster in two years. Not long ago, I just listened to the report of Teacher Zhou Yan of the Zhongci Institute on citrus yellow dragon disease, so let's talk about this topic today.
<h1>First, the distribution of huanglongbing disease</h1>
At the beginning of the 20th century, citrus yellow dragon disease was first discovered in south China, and more than 100 years have passed. At present, the total area of citrus cultivation in China is more than 39 million mu, the area of citrus huanglongbing disease is nearly 3 million mu, and the epidemic areas are 289 counties in 11 provinces (regions) of Guangdong, Guangxi, Fujian, Taiwan, Hainan, Yunnan, Guizhou, Sichuan, Hunan, Jiangxi and Zhejiang;
At present, the occurrence and trend of citrus huanglongbing disease in related production areas in China:
• Although the prevention and control of the Navel Orange producing area in Gannan has achieved results, the overall pressure on prevention and control is huge;
• Huanglongbing disease and psyllids in shonan producing areas have moved north significantly, and the prevention and control situation is extremely severe;
• Guangxi has been affected by the influx of diseased seedlings in recent years, and the incidence rate has rebounded strongly;
• There is a gradual spread of psyllids and huanglongbing disease in the wide-skinned citrus producing areas of southern Zhejiang, which has endangered the Quzhou production area;
• Huanglong disease in Sichuan was confined to the Liangshan area, and the epidemic situation was basically controlled in Pingshan County, Yibin, through measures such as digging up diseased trees and controlling psyllids;
• The prevention and control situation in some characteristic bases in Yunnan is grim, and the scope of teak lice has spread;
<h1 class="ql-align-justify" > second, the harm and identification of yellow dragon disease</h1>
Yellow dragon disease is preventable and incurable, and once infected, it can only cut down trees, which can be said to be the number one threat to the citrus industry. Under the ravages of the Yellow Dragon, guangdong Sihui, Zhaoqing, Qingyuan, Yunfu and other places millions of acres of sugar oranges, Guangxi millions of acres of oranges and Nanfeng oranges, Jiangxi Gannan hundreds of thousands of navel oranges, Yunnan Dali Binchuan County 200,000 acres of oranges... In just a few short years, all were lost.
Preventable and incurable, it is particularly important to find it in time.
There are many methods for the identification of huanglongbing disease, which can be summarized as:
1, from a distance: there are a few trees in the orchard that appear yellow, and on one tree, a few branches appear yellow. This situation is more in line with the characteristics of the yellow dragon disease pathogenesis strain. If it is all yellow and yellowed in a short period of time, this situation is most likely not huanglongbing.
2. Close-up: the mature leaves and old leaves on the first-degree branches of the Yellow Dragon Disease branch are mostly mottled, while the new leaves on the secondary branches are mostly uniform yellowing, zinc deficiency or atypical mottled;
On the other hand, the fruit of the diseased tree is now characterized by developmental deformities, "red nose fruit", and easy to fall;
3, planing to see: fruit trees with severe symptoms of yellow dragon disease, digging roots can see a large number of root rot, or no fine roots.
4. Professional institution testing
Of course, the above are judged by symptoms, if there is a toxic situation but there are no symptoms for the time being, it can be determined by virus identification testing. Accurate (more reliable than symptom judgment), fast (generally 1 day out of the results), is to spend a little money, this is their own discretion.
<h1>3. Prevention and control of huanglongbing disease</h1>
Since there is no cure for huanglongbing disease, it is necessary to adhere to the strategy of "prevention in the disease-free area and control the spread of pathogens in the ward".
Huanglong virus mainly relies on the transport of poisonous seedlings, scion, and the harm of wood lice to spread harm, according to its transmission path, it can be prevented and controlled from the following aspects:
1. Strict quarantine, cultivation and planting of detoxification seedlings
In recent years, the development speed of citrus has been hot, and at the same time, it has driven the seedling market, and violence has driven many growers to join the ranks of selling seedlings and branches, and unlicensed seedlings have been circulating freely, which has undoubtedly aggravated the spread of yellow dragon disease.
Therefore, on the one hand, the government needs to strengthen quarantine and strictly control the entry of diseased seedlings and scion into disease-free areas. At the same time, he led the establishment of disease-free nurseries and advocated the planting of detoxified seedlings.
2. Isolation planting, disease differentiation tablets update
Isolation planting: in the new garden in the ward to choose a place away from the disease park, if there are yellowing trees in the citrus orchard next to them, they do not cut down trees, nor manage, do not implement the prevention and control of yellow dragon disease, you do not plant, plant also white seeds, soon infected. At the same time, insect net greenhouse cultivation can also be used to isolate the spread of psyllids.
Fragmentation update: The orchards of 100 acres in the ward are not all sick, it may be that the yellow dragon disease of several acres and ten acres is more severe, you can cut down these trees, do a good job of prevention and control measures, and then plant again.
However, it should be noted that after the yellow dragon disease tree is dug up, the root hairs left in the soil are still poisonous, so the tree cannot be planted immediately. If it is dryland, it must be rotated for 2-3 years, and if it is paddy field, it must be rotated for 1-2 years before it can be planted. If it is mountainous, it is best to dig deep.
Two reasons: 1, root hair can spread yellow dragon disease; 2, citrus cultivation is not ripe.
3. Timely spraying and killing of the vector - wood lice
Nine incense and yellow bark trees are also the host plants of wood lice, and if there are any near citrus groves, they will be dug up immediately after spraying.
Pygosites are mainly harmful to the young leaves of new shoots, so every time the young shoots are beaten, especially each time the shoots are 1-2 cm long, pyromidoxine, cypermethrin, thiamethoxine, chlorpyrifosine, chlorpyrifos and other agents to kill the pyllids. Spray from the periphery to the middle, not from the middle to the periphery. As a result, the tree should do a good job of wiping buds and controlling shoots in the summer, and in the winter, combined with the Qingyuan Garden, eliminate the wood lice that overwinter on the back of the leaves.
It should be noted that in winter, when the garden is cleared, the spray will accelerate the migration of poisonous psyllids, and the correct approach should be to spray the insecticide before clearing the garden.
4. Resolutely dig out the diseased tree
Huanglong virus is unevenly distributed in trees and has different incubation periods. Therefore, a tree sometimes only part of the branches of the disease, some fruit farmers use to cut off the sick part, the result of the next year another part of the disease, the source of infection has not been eliminated. Therefore, when a diseased tree is found, we must make up our minds to dig up the whole tree thoroughly to prevent the infection. After cutting down the diseased tree, the large stump is difficult to dig up, and it needs to be completely destroyed by the black film cover after the glyphosate is drizzled.
It should be noted that before cutting down the tree, it is necessary to spray the drug to completely kill the psyllid before cutting the tree, otherwise the psyllid will cut the tree before it is dead, and the psyllid will be driven to the healthy tree and spread the source of the disease.
Diseased trees are cut down and left untreated, and new shoots are still the source of transmission
Finally, back to the original question: after two years, will the sugar orange industry be "killed" by yellow dragon disease?
Tinder thinks [no].
From the level of consciousness, after experiencing the tragic lesson of "citrus yellow dragon disease flooding" in Guangdong, whether it is the government or farmers, the awareness of yellow dragon disease prevention and control has reached an unprecedented height. Many epidemic areas regard the prevention and control of yellow dragon disease as an important performance appraisal, and the leaders in charge sign a letter of responsibility, and those who fail to achieve the goal will be held accountable. For growers who are currently enjoying the "dividend" of sugar oranges, they are more concerned about the prevention and control of huanglong disease, after all, the direct threat to the prevention and control of huanglong disease is their own rice bowl.
From the technical level, the "three axes" of Huanglong disease prevention and control summarized by exploration have been upgraded in various places and proved to be effective. By the end of 2017, the incidence of yellow dragon disease in the 10 major citrus producing provinces in the country decreased by 12% compared with 2016, and the area of occurrence continued to decline for two consecutive years. In Meizhou, Guangdong Province, where the spread of yellow dragon disease has increased the spread of yellow dragon disease, after several years of efforts, the spread trend of citrus yellow dragon disease has been effectively curbed, and the disease rate of citrus crops in the city has been controlled to 0.75%.
Therefore, before there is no more excellent alternative species (taste, ripening period, storage properties are all better than sugar oranges), yellow dragon disease is not enough to worry, and excellent sugar oranges are not so easy to "die".
unless......
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