How to prevent and treat citrus canker?

As we all know, there are many kinds of ulcers on the human body. The most well-known ones include oral ulcers, throat ulcers, gastrointestinal ulcers, etc. In comparison, citrus ulcer disease is very unfamiliar to many people. This is an ulcer disease that occurs on plants. For people who grow citrus, once this disease occurs, the losses will be great, so they should take preventive measures in normal times.

Citrus canker prevention and treatment methods:

(1) Strictly implement quarantine. The transportation of citrus seedlings, scions, rootstocks, seeds and fruits must be strictly quarantined in accordance with regulations to prevent the spread of canker disease. Diseased trees and seedlings found in the protected area will be burned immediately.

(2) Cultivate disease-free seedlings. The nursery should be established in a disease-free area with no citrus plants at a distance of more than 1,000 meters, and a disease-free high-quality mother garden should be established to supply disease-free scion on site.

(3) Reduce damage to fruits and leaves. You can create windbreaks to reduce wind speed in the orchard (especially in areas with typhoons, which can significantly reduce the occurrence of diseases); and promptly prevent and control pests such as leaf miners to reduce insect damage.

(4) Prevention and control with high-lipid film (emulsion) or green and pollution-free Chinese medicine preparations: Focus on the summer and autumn shoot sprouting period and the young fruit stage. Dilute the solution 300 times and spray the whole plant evenly to effectively prevent diseases such as ulcer disease, resin disease, anthracnose, scab, etc., while enhancing the plant's immunity and improving the plant's disease resistance.

(5) Chemical control: Bordeaux mixture copper sulfate 0.5-0.8 kg, lime 1-1.6 kg, water 100 kg, copper soap solution copper sulfate 0.25 kg, rosin mixture 1 kg, water 100 kg, 0.2-0.3 degrees Baume lime sulfur, 72% agricultural streptomycin wettable powder 2500 times diluted, 3% aureomycin aqueous solution 300 times diluted, 77% Keshade 2000 type 800 times diluted, 80% essential wettable powder 400-600 times diluted, 20% Longke fungicide copper suspension 500 times diluted, 12% Chloramphenicol emulsifiable concentrate 500 times diluted.

(6) Cleaning the garden in winter. Cut off diseased branches, leaves and fruits and burn them in a concentrated area.

Conditions of disease:

There are significant differences in disease resistance among different citrus varieties. Sweet oranges are seriously susceptible to the disease, followed by sour oranges, pomeloes, trifoliate oranges and oranges. Broad-skinned citrus varieties are more resistant to the disease, while kumquats are resistant. The stomata of newly sprouted tender leaves and newly formed young fruits have not yet formed, so pathogens cannot invade. The stomata of young leaves are mostly formed and are in the open stage 20 to 55 days after germination, and of young fruits 35 to 80 days after flower drop, making it easy for pathogens to invade and cause massive disease. The temperature range for citrus canker is 20-35℃, with the most suitable temperature being 25-30℃. High temperature and high humidity weather are necessary conditions for its epidemic. Storms and typhoons cause a large number of wounds on the host, which is more conducive to the spread and invasion of pathogens.