What are the serious harms of canker disease in citrus?

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.

Leaf symptoms.

In the early stage of the lesion, the lesion produces round, pinhead-sized slightly protruding oily translucent spots on the back of the leaf, usually dark green, and the tissues around the lesion fade and appear a yellow halo, and the posterior spot gradually rises to a nearly round beige color. With the development of the disease, the surface of the lesion is cracked, spongy, and the bulge is more prominent, and the cork begins to begin, gradually forming a rough, gray-white or gray-brown surface, and a fine ring pattern and a central depression. There is often a brown glaze edge just outside the halo.

In the later stage, the lesion** is obviously depressed, like a "crater"-like cracking. The diameter of the lesion is generally 3 5mm, and multiple small lesions are connected to form irregular large lesions, which cause early leaf shedding in severe cases.

Shoot symptoms. The characteristics of lesions that occur on young shoots are similar to those on leaves. However, the degree of cork and bulge of the lesion, as well as the cracking or sagging of the middle of the lesion, were more pronounced than on the leaves, and there were no yellow halos around the lesions on the branches. After the seedlings and young shoots are damaged, the leaves fall off, and even die in severe cases.

Fruit symptoms. The fruit is damaged, and the symptoms are similar to those on the leaves. However, the degree of cork is higher, the crater-like cracking is more significant, hard and rough, there is generally no yellow halo, and the lesions are usually larger than the leaves, generally 4 5 mm in diameter, and the largest can reach 12 mm. The lesions are confined to the pericarp and do not develop into the pulp.

Diseased fruits tend to fall off.

Citrus canker bacteria can damage leaves, shoots and fruits. Nursery disease, poor growth of seedlings, low quality, delay in leaving the nursery; Adult fruiting trees are diseased and weakened, often causing a large number of fallen leaves, fallen fruits, and even dead shoots; The lightly diseased fruits that have not fallen off form cork and cracked lesions, which seriously affects the economic value of the fruits. According to the experiment, the defoliation rate or fruit drop rate of citrus increased with the increase of disease grade. The size and quality of the fruit decreased with the increase of disease grade.

Once the disease occurs, it is difficult to completely destroy the diseased orange seedlings, diseased fruits and diseased trees in the new orange area, so as to achieve the purpose of completely eliminating the disease.

The disease mainly infects citrus shoots, branches and leaves and unripe fruits. The leaves are damaged, initially appearing yellow or dark yellow-green pin-sized round dots with oil, which gradually enlarge, and at the same time, the two sides of the leaf gradually bulge, becoming light brown, nearly round lesions. The lesions penetrate the front and back sides, the surface is rough, the wood is corked, protruding, ** concave and fine ring lines, there is glaze around it, and the later ** rupture is like a crater.

However, the scab disease has only one protrusion on one side, and there is no yellow halo on the periphery. The fruit is damaged, and the initial lesions have a thick yellow translucent protrusion, and the top is slightly wrinkled; In the later stage, there is often a circle of faded glazed edges at the junction of the diseased and healthy parts, with obvious concentric wheel-like lines, and radial tears. On the other hand, the scab lesions do not have a dark yellow color and have no folds at the top.

In the later stage, there is no glazed edge and wheel-like pattern on the periphery.

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 implementation of quarantine. The transportation of citrus seedlings, scion, rootstocks, seeds and fruits should be strictly quarantined in accordance with regulations to prevent the spread of canker. Diseased trees and seedlings were found in the reserve and immediately burned.

Cultivating disease-free seedlings. The nursery should be established in a disease-free area with no citrus plants above 1 000 meters around, and establish a disease-free high-quality mother garden, and in situ ** disease-free scion. FYI.

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

Prevention and control methods of citrus canker: Strict quarantine. This disease is the object of quarantine at home and abroad, and it is forbidden to import seedlings, scion, rootstocks, seeds and fruits from the disease area.

Cultivating disease-free seedlings. Scions are selected from disease-free areas or disease-free orchards; The rootstock seeds are soaked in 55 56 warm soup for 50min. When the seedlings are out of the nursery, they must be strictly inspected and soaked with 600 700mg kg of streptomycin (the bunches of seedlings are soaked in the liquid medicine for 1h, and 1% alcohol or liquor is added before soaking to enhance the osmotic effect).

When planting new orchards, susceptible and disease-resistant varieties should be planted in sections, and mixed planting is strictly prohibited.

Reasonable fertilization, control the growth of summer and autumn shoots, and promote neat shoots.

Pharmaceutical prevention and control. Spray pesticides at the right time to protect young shoots and fruits; At the same time, attention should be paid to the prevention and control of leaf miners to avoid pathogens from invading from wounds. Seedlings and young trees, mainly to protect the shoots, should be sprayed once in spring, summer and autumn the day after the shoots germinate.

Adult trees are mainly to protect the fruit, supplemented by the protection of shoots, and it is suitable to spray once the day after the flowering. The types of pesticides are: 72% agricultural streptomycin sulfate 3000 times solution plus 1% alcohol as an adjuvant, or lime excess Bordeaux liquid, or copper soap liquid (copper pine sulfate mixture 2kg, water 200kg), which can not only prevent diseases, but also treat mites.

It can also be used in rotation with 500 800 times of 77% killable wettable powder, or 500 1000 times of 30% chrynucleomycin wettable powder, 50% Garinone wettable powder, etc.

The garden is cleared in winter. Combined with pruning, cut off diseased branches and leaves and diseased fruits, and sweep away fallen leaves and fruits, and burn them intensively.

Citrus canker is one of the important diseases of citrus and is the object of quarantine at home and abroad. It occurs in China's citrus producing areas, especially in the southern provinces. Canker disease damages citrus leaves, branches and fruits, causing defoliation, shoot wilting, fruit scars, and severe fruit drop, causing certain economic losses to fruit farmers.

It is recommended to use Demer Tianye's ulcer fast penetration, a special drug for citrus ulcers, and an excellent alternative to copper preparations.

Grapefruit: Under natural conditions, spring shoots sprout on March 10 and reach 100% at the end of October; The leaves are first seen in April, and the leaves are fully displayed in mid-April; At the end of April, the initial self-cutting will be seen, and the self-cutting will end at the end of the month. When the average daily temperature stabilized above 20 in mid to late April for 10 15 days, the leaves of the new shoots began to keratinize in early May, and the first lesions appeared in the field.

In May, the temperature is mostly around 20, the development of the disease is slightly slower, and the disease is increasing daily; When it is continuously higher than 25 10 days, the daily growth rate of the disease reaches; The peak period of the disease is in mid and late May, and then the temperature drops in the rainy season, and the rise of the disease in spring slows down until it is stable, and the onset period is about 30 days long. Summer shoots sprout from the end of May and early June, after 3 days of leaf development, 6 8 days after leaf development (mid-June), that is, the first disease spots, the plum rainy period is short, the disease grows rapidly, and the condition is stable in late June. In early July, the late summer shoots were extracted, the rainy period was long and the high temperature and drought period were short, and the new leaves were conducive to the infection of pathogens, and the disease was still developing by the end of July.

Due to the irregular hair extraction in summer, the duration of the onset period also varies, about 15 40 days. Autumn shoots sprout in late August, disease spots appear in early September, the weather is hot and dry from the end of August to early September, the relative humidity is small, the disease develops slowly, and rises slightly after mid-September, but the leaves are basically aging, and the disease is mild. There are often short periods of rain in August and September, with high relative humidity and rapid disease growth.

In the event of a typhoon or rain, the number of cases increased dramatically in the following 5 6 days. However, autumn is dominated by dry weather, and the severity of the disease is significantly less severe than that in summer. The recurrent area of eugratic ulcer disease conformed to the logical Sidi model, and the mild area conformed to the exponential model. Autumn shoot disease conforms to the index model.

Four seasons pomelo: The disease develops slowly in the early stage of spring, until the beginning of August, and the onset period is as long as 90 days, and there may be a phenomenon of hidden bacteria. According to local cultivation habits, all the summer shoots of pomelo in all seasons are erased.

The spring shoot disease of pomelo is the most important factor that induces the onset of autumn shoots, and the budding stage of autumn shoots is the key period for the development of disease level, and the early onset of the disease occurs from mid-August to early September, and the late onset occurs in early to mid-September. After September 20, the temperature dropped to about 20, and the condition of Qiu Shao was stable. The prevalence of canker disease in the spring shoot of pomelo conforms to the index model. The occurrence year of severe illness in autumn conformed to the logical Sidi model, and the occurrence year of mild illness conformed to the exponential model.

Snow mandarin seedlings: 1-year-old seedlings, no disease in spring, summer shoots began to show onset on June 19, slow onset, to September 4 leaf incidence index of disease, autumn shoots to October 5 leaf incidence index of disease index. The prevalence of canker disease in summer and autumn in citrus seedlings was in line with the index model.