What Should You Do If a Ponkan Mandarin Gets Huanglongbing? A Detailed Guide to Prevention and Control Methods
What should you do if a ponkan mandarin gets huanglongbing?
Answer: Comrade Nong Wenguang:
Hello. Citrus huanglongbing is a devastating disease that spreads rapidly, and all existing citrus cultivars are susceptible to it. Therefore, comprehensive measures must be taken to control citrus huanglongbing before good results can be achieved.
1. Strictly implement quarantine. The transport of nursery stock and infected material (such as scions) from affected areas to new areas and disease-free areas must be strictly prohibited. Within affected areas, infected or possibly infected nursery stock should be planted in a controlled, relatively concentrated manner to prevent further spread. All newly established orchards must be planted with disease-free seedlings.
2. Establishing disease-free nurseries and cultivating disease-free seedlings is a key measure for controlling citrus huanglongbing. Disease-free seedlings free of huanglongbing and certain dangerous diseases (such as citrus canker and exocortis) must be produced for planting in new orchards in new areas and disease-free areas.
3. Dig out and remove diseased plants. Given that there is currently no effective method that can cure citrus trees suffering from huanglongbing, and that diseased trees left in the field serve as a source of infection, immediately digging out and removing any tree found to have huanglongbing is an important measure for controlling the spread of the disease. The procedure is as follows: during the 3 shoot-flush periods each year in spring, summer, and autumn, especially the autumn shoot-flush period, carefully inspect every tree; if diseased or suspicious diseased trees are found, immediately dig them out and burn them in a centralized manner. Before digging out diseased trees, spray the diseased trees and nearby plants with agents such as a 40% omethoate 1000-fold solution to prevent the Asian citrus psyllid from moving from the diseased trees to surrounding areas and spreading the disease. In new citrus orchards with an incidence below 10% and old citrus orchards with an incidence below 20%, disease-free seedlings can be used for replanting after the diseased trees are dug out.
4. Control the Asian citrus psyllid. The Asian citrus psyllid is the vector insect that transmits huanglongbing. It lives on the new buds and tender shoots of citrus. Control shoot emergence through water and fertilizer management so that the new shoots emerge uniformly and the shoot-flush period is shortened. When new shoots have grown to 1-2 cm, spray insecticide comprehensively 1-2 times. In winter, Asian citrus psyllids tend to fly to orange jasmine (Murraya paniculata) near the orchard to overwinter. Spraying insecticide on orange jasmine has a certain effect on reducing the number of psyllids. In addition, planting shelterbelts around the orchard can obstruct the migration and flight of psyllids.
5. Strengthen management, especially water and fertilizer management for fruit-bearing trees, maintain vigorous tree growth, and improve disease resistance. This plays an important role in reducing the occurrence of huanglongbing and the losses caused by the disease.
6. Transform affected areas into new areas. For some orchards where citrus huanglongbing has occurred very severely and economic value has already been lost, affected-area transformation should be carried out. This means digging out all the citrus trees in the entire orchard (including those citrus trees that may already be infected but have not yet shown symptoms), and then replanting with disease-free citrus seedlings. By doing a good job in pest control, promptly digging out diseased trees, and strengthening management, the affected area can be transformed into a new disease-free area.
The above content is for reference only.
Hello. Citrus huanglongbing is a devastating disease that spreads rapidly, and all existing citrus cultivars are susceptible to it. Therefore, comprehensive measures must be taken to control citrus huanglongbing before good results can be achieved.
1. Strictly implement quarantine. The transport of nursery stock and infected material (such as scions) from affected areas to new areas and disease-free areas must be strictly prohibited. Within affected areas, infected or possibly infected nursery stock should be planted in a controlled, relatively concentrated manner to prevent further spread. All newly established orchards must be planted with disease-free seedlings.
2. Establishing disease-free nurseries and cultivating disease-free seedlings is a key measure for controlling citrus huanglongbing. Disease-free seedlings free of huanglongbing and certain dangerous diseases (such as citrus canker and exocortis) must be produced for planting in new orchards in new areas and disease-free areas.
3. Dig out and remove diseased plants. Given that there is currently no effective method that can cure citrus trees suffering from huanglongbing, and that diseased trees left in the field serve as a source of infection, immediately digging out and removing any tree found to have huanglongbing is an important measure for controlling the spread of the disease. The procedure is as follows: during the 3 shoot-flush periods each year in spring, summer, and autumn, especially the autumn shoot-flush period, carefully inspect every tree; if diseased or suspicious diseased trees are found, immediately dig them out and burn them in a centralized manner. Before digging out diseased trees, spray the diseased trees and nearby plants with agents such as a 40% omethoate 1000-fold solution to prevent the Asian citrus psyllid from moving from the diseased trees to surrounding areas and spreading the disease. In new citrus orchards with an incidence below 10% and old citrus orchards with an incidence below 20%, disease-free seedlings can be used for replanting after the diseased trees are dug out.
4. Control the Asian citrus psyllid. The Asian citrus psyllid is the vector insect that transmits huanglongbing. It lives on the new buds and tender shoots of citrus. Control shoot emergence through water and fertilizer management so that the new shoots emerge uniformly and the shoot-flush period is shortened. When new shoots have grown to 1-2 cm, spray insecticide comprehensively 1-2 times. In winter, Asian citrus psyllids tend to fly to orange jasmine (Murraya paniculata) near the orchard to overwinter. Spraying insecticide on orange jasmine has a certain effect on reducing the number of psyllids. In addition, planting shelterbelts around the orchard can obstruct the migration and flight of psyllids.
5. Strengthen management, especially water and fertilizer management for fruit-bearing trees, maintain vigorous tree growth, and improve disease resistance. This plays an important role in reducing the occurrence of huanglongbing and the losses caused by the disease.
6. Transform affected areas into new areas. For some orchards where citrus huanglongbing has occurred very severely and economic value has already been lost, affected-area transformation should be carried out. This means digging out all the citrus trees in the entire orchard (including those citrus trees that may already be infected but have not yet shown symptoms), and then replanting with disease-free citrus seedlings. By doing a good job in pest control, promptly digging out diseased trees, and strengthening management, the affected area can be transformed into a new disease-free area.
The above content is for reference only.