"Citrus huanglongbing" is the most devastating disease in global citrus production, which has hit Florida in the United States, Sao Paulo in Brazil, Guangdong, Guangxi, Jiangxi and other important citrus producing areas in China, and there is still no cure for huanglongbing in the past century.
Recently, more and more huanglongbing-diseased trees have been found in orchards, and the huanglongbing fungus is spreading:
We often receive consultations from fruit growers about huanglongbing in the technical exchange group, and we find that one of the main reasons for the difficulty in the prevention and control of huanglongbing is that most users generally lack the ability to identify huanglongbing, because there is an incubation period when citrus is first infected with huanglongbing, and there may be regreening in spring and summer, which causes a lot of interference for growers to accurately identify huanglongbing, and provides an opportunity for the spread of germs.
However, it was found that October to December of each year is the period when the content of huanglongbing pathogens in host plants reaches its highest, so autumn and winter are the peak periods for huanglongbing symptoms, and it is also the best field identification period for huanglongbing.
Fruit growers must seize the golden period of autumn and winter to comprehensively investigate huanglongbing!
How to identify huanglongbing more accurately and quickly?
Unidentified mottled yellowing branches
Red-nosed fruits, green soft fruits
Psyllids have erupted in orchards
Psyllids have erupted in orchards
The correct way to deal with citrus huanglongbing
Before cutting down trees
Before cutting down diseased trees, the garden should be cleared with a drug that can effectively kill citrus psyllids, sprayed first, and then cut down the trees to prevent poisonous psyllids feeding on Huanglongbing trees from flying to other healthy trees when cutting down trees. Medication can be used avermectin, imidacloprid, chlorpyrifos, thiamethoxam, thiamethoxam, biphenyl imidacloprid, avi thiamethoxam and so on.
Because citrus psyllids have high disease transmission, close dispersal and rapid toxicity, and adults can tolerate low temperatures of 4 hours to 10 °C, it is important not to cut down trees directly without spraying pesticides first because they cannot be seen in the orchard, or because they want to save pesticides and labor.
This is an important reason why many orchard huanglongbing trees are cut down every year, and the more they are cut, the more they are cut.
Chop down trees
After spraying for 3-5 days, cut down the Huanglongbing tree 10 cm close to the ground, leaving the diseased tree in place until the leaves dry up before dragging it away.
If the diseased tree is not sprayed at all or the psyllids are not completely killed after the spray is applied, and the diseased trees are dragged away, the psyllids that are still on the diseased trees will infect the healthy trees on both sides of the road and near the storage of diseased branches, resulting in artificial transmission of short-distance transportation. This is an important reason why healthy trees on both sides of the road and around the burned diseased trees are increasingly becoming infected with huanglongbing.
Deal with diseased trees
Method 1:
After digging out the diseased trees, they can be replanted directly in situ without diseased seedlings.
Citrus psyllids are the only non-human vector of huanglongbing in orchards, soil, running water, high winds, pruning, other insects and animals cannot transmit huanglongbing, so as long as there are no citrus psyllids in the orchard, huanglongbing will not spread. Orchards that have been infected with citrus huanglongbing can be replanted in situ as soon as the diseased trees are properly handled, without the need for crop rotation or a few years before starting to grow citrus again.
Method 2:
That is, use a saw or knife to cut (saw) twice in a row on the cross-section of the saw's edge, and cut (saw) out a "ten" shape.
Pour diesel or glyphosate on the tree pocket
Cover with a black plastic bag to block light and prevent the tree pocket from re-germinating
Finally, turn over the soil and cover the entire tree pocket
After the treatment of the tree pocket can be immediately replanted next to it, the original diseased tree pocket will not be infected by the root system to the seedlings replanted next to the Huanglongbing; the Huanglongbing fungus must first pass through the soil to enter the roots of the replanted seedlings, and the Huanglongbing pathogen will die as long as it enters the soil, so the Huanglongbing pathogen can not be artificially cultivated.
Wrong way
1. If the diseased tree is not treated correctly, the re-issued young shoots still carry huanglongbing. Young trees replanted directly next to it increase the risk of contracting huanglongbing, which can cause unnecessary losses.
2. As soon as it was cut, it was dragged away, causing some trees to be infected with huanglongbing again.
3. Do not spray the psyllidicide before cutting the tree or do not completely kill the psyllid. Avermectin, imidacloprid, chlorpyrifos, thiamethoxam, thiamethoxam, biphenyl-imidacloprid, thiamethoxam, etc.
This situation will bring your work to zero, so be sure to kill the psyllids before cutting down the tree, after all, the psyllid are living creatures and are difficult to control. Or you can also cut it when you go to the clear garden, you can use mineral oil + avermectin, or super affordable stone sulfur mixture to spray it first, and then cut down the tree.
4. Not enough attention to yellowing!
Many fruit farmers have yellowing trees, do not pay attention to it, thinking about waiting for the spring of next year to see if the leaves turn green or not, turn green and do not cut, do not turn green to cut, but do not know that the leaves of the huanglongbing tree can also turn green in the spring, and the spring new shoots are pumped, the psylle are coming again, the psylle bites, and then fly, it will infect more trees.