How is citrus canker disease transmitted and harmed?

Citrus canker is a bacterial disease. The pathogenic bacteria overwinter in diseased leaves, branches and diseased fruit tissues. In the second year, water overflowed from the diseased area and was transmitted through rainwater and insects over a short distance. It is spread over long distances through the transportation of seedlings, scions and fruits, infected packaging, tools, soil, etc.

When the tissue is young, the bacteria invade from the stomata, skin hole and wound, and the incubation period of the growing season is 6 40 days. The pathogen can survive for months to several years in the lesions on branches and leaves. The occurrence and prevalence of the disease are closely related to climatic conditions, cultivation management measures and varieties.

High temperature, high humidity and heavy rain are conducive to the occurrence and epidemic of diseases. susceptible to illness after storms and typhoons; Improper cultivation management, host wounds caused by pests such as leaf miner moths will significantly aggravate the disease. Insufficient fertilization, partial application of nitrogen fertilizer, increase of long branches, and severe disease; Young trees and seedlings are more diseased than adult trees and old trees. In terms of susceptibility of varieties, sweet oranges, pomelos and citrus aurantium are highly susceptible, lemons are also susceptible, and wide-skinned oranges are more tolerant.

When citrus canker occurs, it not only reduces fruit quality and yield, but also causes leaf loss, fruit drop, and poor plant growth, etc., and the quarantine department will carry out prevention and control treatment in accordance with relevant national laws and regulations.

Tomato canker is a bacterial disease caused by the pathogenic type of tomato canker disease of Coleum Michigan. The pathogen can overwinter inside and outside the seeds and on diseased residues, and can survive in the soil with diseased residues for 2 to 3 years. The fungus is mainly invaded by various wounds, including damaged leaves and young roots, and can also invade from the stem or flower stalk of the plant, enter the embryo of the fruit through the vascular bundle, and infect the seed umbilicus or seed coat, causing the fungus to carry the fungus in the seed.

When the diseased and healthy fruits are mixed and harvested, the pathogens will contaminate the seeds, resulting in the external carrying of the seeds, and the seed carrying rate is generally 1% 5%, and the serious ones can reach. In addition, pathogens can also invade directly from leaf trichomes and the epidermis of young fruits. The long-distance transmission of the disease mainly depends on the transportation of seeds, seedlings and unprocessed fruits. Proximity transmission mainly depends on rainwater and irrigation water, especially even rain and storms, through agricultural operations such as seedling transplanting and pruning and pruning, and once the pathogen invades, it expands in the host body through the phloem.

The optimal temperature for the development of pathogens is 25 27, warm and humid, with long condensation duration and heavy rainfall, and severe disease. After the onset of the disease, nitrogen fertilizer was applied partially, and the disease spread rapidly due to flood irrigation. Greenhouses or greenhouses with sprinkler irrigation are prone to disease.

Canker is one of the most serious citrus fruit trees, whether it is seedlings, young trees, or fruiting trees, they are very susceptible to canker disease, and branches, leaves, flower buds, and fruits will be affected by canker disease. After the appearance of ulcers, the tree declines, and the branches die by mixing the recommended agent into a liquid medicine with water, and the amount of use per mu is 200 grams. Mainly spray citrus seedling leaves, spray evenly on both sides and spray until the citrus tree drips.

The prevention efficiency can reach more than 85.9 percent, which is a very good medicine. The first is to cut off the diseased branches and leaves. In the early stage of canker disease, the infected branches and leaves can be cut off, or the seedlings can be uprooted and burned, so as to prevent the spread of canker and affect other healthy saplings or orchards.

<> citrus pests and diseases are mainly spider mites and cankers. Spider mites are serious, which will inevitably affect our photosynthesis, increase wounds, and lead to some infections of germs. For example, there is a lot of rain, because the germ likes to spread through rain, wounds, and citrus cankers, and can be distributed on citrus parts, leaves, and fruits.

In the prevention and control of the specific agent is less, in the whole orchard, if the canker disease is brought about by negligence to prevent, the pathogenic bacteria will gradually develop and grow in the entire orchard, if there is an epidemic must be cut down and burned to isolate the source of infection, it is best to stop for a year and then plant, can not buy unlicensed seedlings in the citrus epidemic area, establish a closed orchard, regular drug prevention of fruit trees and surrounding plants, you can effectively prevent canker disease, you can use the Chinese herbal medicine fungicide Liangguoan to prevent and control citrus canker disease on the effect is good, Liangguoan is an organic pesticide, which is very safe, and will not produce resistance when used continuously, and more importantly, it is chelated with Chinese herbal medicine, which is sterilizing and nutritious. Avoid copper preparations + copper preparations, inorganic copper + other metal ion pesticides, and do not use inorganic copper preparations monotonously for a long time, so as not to superimpose drug damage. 1.

Strict quarantine, according to the local conditions to choose resistant and disease-resistant varieties for planting. 2.Strengthen cultivation management, winter pruning and garden clearing.

Reasonable pruning, pruning, and thorough pruning of diseased branches and leaves on the tree.

The disease affects citrus leaves, shoots and fruits. Seedlings and young trees are particularly seriously damaged, which will cause leaf loss and dead shoots, affecting the tree potential; The fruit is seriously damaged, and the light one has disease scars and is not resistant to storage, which greatly reduces the commercial value of the fruit, increases the cost of pest control and damages the economic benefits.

Canker disease of citrus is mainly a disease that harms citrus leaves, branches and fruits, and greatly affects the normal and healthy growth of citrus, and can occur on leaves, new leaf tips and fruits. When the canker disease is severe, it will cause leaf loss, fruit drop, poor plant growth, and some die, which will directly affect the yield and quality of citrus. It brings serious economic harm to growers.

The leaves of the plant first appeared a pin-sized thick yellow oil-stained round spot, then the front and back of the leaf bulged, spongy, and then the diseased part ** cracked, the wood plug was corked, and it was gray-white crater-shaped. The lesions are mostly nearly round, often whorled or threaded, surrounded by a dark brown greasy outer ring and a yellow halo. The lesions on the fruits and branches were similar to those on the leaves, but the degree of cork of the lesions was more serious, and the pass-like cracking was more significant.

After such a situation, it is necessary to water in time, and at the same time, it should also be fertilized in time, and ventilation should be done well, and then insecticides and fungicides should also be sprayed in time.

In such a situation, I think you can buy some pesticides, and then you must pay attention when spraying pesticides, be sure to spray when it is cloudy, and then protect yourself and don't expose your own pesticides.

It is necessary to ventilate in time, remove problematic plants in time, spray some pesticides in time, and choose excellent varieties for planting.

There were significant differences in disease resistance among different citrus varieties, among which sweet orange was severely susceptible, followed by lime, pomelo, citrus aurantium and citrus aurantium, while wide-skinned citrus was more tolerant, while kumquat was disease resistant. The stomata of the newly extracted young shoots and young fruits have not yet been formed, and the pathogen cannot invade. The stomata of young shoots and leaves were formed in the open stage at 20 to 55 days after germination, and the young fruits were in the open stage at 35 to 80 days after flowering, and the pathogens were easy to invade and cause a large number of diseases.

The temperature range of citrus canker disease is 20 35, and the optimal is 25 30, and high temperature and humidity weather is a necessary condition for epidemic. Storms and typhoons cause a large number of wounds to the host, which is more conducive to the spread and invasion of germs.

Bacterial wilt is one of the important diseases of eggplant in southern China, which occurs every summer. Solana fruits are prone to diseases in heavy crops, acidic soils, clay soils, high groundwater levels, and poor drainage. Prevention and control methods:

Crop rotation with non-Solanaceae crops for 2 years. The best effect is between water and upland rotation. There are differences in disease resistance between varieties, and disease-resistant varieties are selected, or grafted are adopted.

Seeds are collected from disease-free fields and disease-free plants. 100 150 kg of nitrate lime was applied per mu in the severely affected land to adjust the soil pH to pH 8. Protected areas should be protected to increase ventilation and proper shading, and reduce soil temperature.

Cultivate the furrow in the open field, spread straw, wheat straw, etc., to prevent the ground temperature from rising. At the beginning of the disease, 4000 times of 72% agricultural streptomycin sulfate soluble powder, or 500 times of 50% copper succinate wettable powder, each plant was irrigated with liters, once every 10 days, a total of 3 4 times.

Citrus canker disease is a major stubborn disease affecting the development of the global citrus industry. Citrus canker probably originated in India or Java, and was first developed in China in 1919 on sweet oranges, pomelos and mandarins in southern China. The disease occurs from early April to late November every year.

Prevention and control methods:1) Physical control seed disinfection: first pre-soak with 50 52 hot water for 5 minutes, then soak in 55 58 warm water for 50 minutes, take it out and put it into room temperature water to cool down, and the surface can be sown after being slightly dry. Seedling and scion disinfection:

Seedlings without budding and without soil, scion are washed after soaking in mercury solution for 3 minutes, seedlings with soil are sprayed with Bordeaux liquid, and those that have been sprouted are soaked in 700 units of streptomycin per milliliter plus alcohol as an adjuvant for 30 60 minutes.

2) Chemical control of seedlings and young trees is mainly to protect shoots, 20 30 days after the germination of new shoots, the length of the shoots is cm, the leaves are just turned green when spraying once, and then every 10 15 days, spraying 3 4 times in a row, until the new leaves completely turn green; Adult trees are mainly preserved fruits, sprayed once the day after the flower, and should be sprayed in time after typhoons and storms. The optional agents are: 10% agricultural streptomycin sulfate (ulcer) 1000 times liquid, 64%.

3) Agricultural control Carry out timely prevention and control of leaf miners, butterflies, weevils, etc. Erase summer shoots and some early autumn shoots in time, and put them together at the end of July or August. If diseased leaves, branches and fruits are found, they should be cut off in time after the leaves are dewed and dried, and the diseased spots on the trunk should be scraped off; Plants with particularly serious susceptibility should be dug up as a whole and sealed with stone sulfur mixture.

Strict quarantine is in place. It is forbidden to import citrus seedlings, scion, rootstocks, seeds, fruits, etc. from the sick area. If citrus propagation material must be introduced from the diseased area, it should be planted on a trial basis in the isolation area, and after 1 or 2 years, it can be planted in the disease-free area after it is confirmed that there is no canker disease.

Apply disease-free seedlings. The nursery should be located in a disease-free area, with no citrus plants at least 1 km around. Rootstock seeds should be harvested from disease-free fruits, and harvested from disease-free areas or disease-free orchards.

Both rootstocks and grafts must be sterilized before they can enter disease-free nurseries. During the seedling period, the diseased plants should be burned in time, and sprayed to protect the nearby healthy seedlings, and the seedlings out of the nursery should be strictly quarantined to confirm that there is no disease, and then they are allowed to go out of the nursery. Strengthen fertilizer and water management to make its tips uniform and neat.

In the shoot stage, especially in the autumn shoot stage, the prevention and control of leaf miner moth should be done in time. If diseased plants are found, they should be dug up and burned in time, and sprayed to protect the surrounding healthy seedlings, and then replanted with disease-free seedlings.

How can citrus "canker" be effectively prevented? Stick to this method, and the effect is significant.

When the temperature is suitable and the humidity is high in the following year, the bacteria overflow from the disease, and the pathogenic bacteria are transmitted over a short distance by wind, rain, insects and branches and leaves, and the pathogenic bacteria fall on the young tissues of the host, invaded by stomata and wounds, and the incubation period is 3 10 days, and the disease is epidemic when it is high temperature and rain. The optimal temperature for the occurrence of the disease was 25 30, and the disease was most severe in the field with summer shoots, followed by autumn shoots and spring shoots.

Canker disease can occur from early April to late October, with the peak incidence of spring shoots in mid-May, the peak incidence of summer shoots in summer, and the peak incidence of fruits from June to early July.

Citrus canker disease, master the time and method of prevention and control, save money and increase efficiency!

You can use 12% copper pinein acid page spraying, with 2000 pounds of water, more suggestions can go to the harvest of agricultural materials to find expert consultation, pesticide procurement is also assured, are direct sales from manufacturers, ** is also very suitable.

If it doesn't rain, you can put an ulcer on it and wear it quickly.

3.In orchards where canker disease is common, before and after typhoons or storms: diluted with 800 kg of water and sprayed on the whole tree.

4.Pharmaceutical prevention and control. The focus of pesticide control is in the autumn stage and the young fruit stage, and the whole tree is sprayed after diluting the golden hundred grams according to 500 times of the solution;

Note: When ulcer disease occurs, spray in time for prevention and control, spray evenly and spray 2-3 times in a row, spray once every 7-10 days, and spray regularly for prevention and control in the future.

5.The garden is cleared in winter. Diseased branches, leaves, and fruits are pruned and burned intensively.

Our fruit farmers have used copper preparations and agricultural streptomycin, the effect is not very good, and later after the introduction of Demer's ulcer speed wear, the effect can be said to be very fast, and there is no ** situation until now.