The pathogenic factors of grape white rot, grape white rot occurs every year, what are the causes of

1. The occurrence of grape white rot has a great relationship with rain, and the early and late rainfall and the amount of rainfall determine the early and late occurrence of grape white rot and the severity of the occurrence of grape white rot that year. The rainy season comes early, grape white rot occurs early, high temperature, high humidity, and rainfall are the peak period of the disease, so the more rainfall, the greater the rainfall, the more opportunities for germination and infection of pathogens, and the higher the incidence. High temperature, high humidity, rain, and continuous rain are the main factors for the occurrence and prevalence of diseases.

2. Since grape white rot bacteria invade from wounds, all conditions that cause wounds such as pruning are conducive to the occurrence of grape white rot. For example, wind damage, insect pests and agricultural operations such as artificial topping and fruit thinning have caused wounds that are conducive to the invasion of germs. In particular, the effect of wind damage often causes severe occurrence of grape white rot after each storm.

The occurrence of the disease is closely related to the growth period of the host, and the fruit enters the coloring and ripening stages, and the degree of susceptibility increases gradually.

3. The location of the ear also has a great relationship with the onset of the disease. According to the survey, some diseased ears occur on fruit ears less than 50 cm above the ground. The fruit ears close to the ground are susceptible to the infection of pathogens after overwintering, and the lower part has poor ventilation and light transmission and high humidity, which is easy to induce grape white rot.

4. Grape white rot is seriously affected near the ground and under the conditions of heavy soil clay, low-lying terrain and poor drainage.

Suggested prevention and control programs:

The occurrence of orchard white rot is closely related to rain. The rainy season comes early, and the disease occurs early, and the rainy season comes late, and the disease occurs late. When the disease occurs in the orchard, there is often a peak after the rain. Generally, high temperature and rain are conducive to the epidemic of diseases.

Since the white rot fungus invades from the wound, all the conditions that cause the wound are conducive to the onset of the disease. For example, wind damage, insect pests, topping, fruit thinning and other agricultural operations can cause wounds and facilitate the invasion of germs. In particular, the impact of wind damage is even greater, and white rot is often prevalent after each storm.

The occurrence of diseases is closely related to the growth period of the host. As the fruit enters the coloring and ripening stages, the degree of susceptibility to the fruit increases gradually.

The location of the ear also has a lot to do with the onset of the disease. According to the survey, 80% of the diseased ears occur on the fruit ears below 40 cm above the ground, of which more than 60% are below 20 cm. This is due to the fact that the fruit ears close to the ground are susceptible to the infection of pathogens after overwintering, and at the same time, the lower part has poor ventilation and light transmission, and the humidity is high, which is easy to induce disease.

It usually starts on the fruit stalks, and at first produces watery, light brown, irregularly shaped lesions, and then gradually expands and affects the lower part of the fruit spikes, causing dryness. The fruit is sick, first at the base becomes light brown water stained, and gradually soft rot in the early stage of the leaf appearance of V-shaped lesions, and spread to the periphery, not controlled, the whole leaf is dry and defoliated, if the timely application of medicine to control the disease, no longer continue to develop, only in the position of the lesion is dry and broken, so as not to damage the whole leaf.

<> Proper fertilization: For the growth of the grape plant and the development of the root system. It is necessary to focus on high-quality organic fertilizer or soil miscellaneous fertilizer to increase soil fertility, improve soil, and improve the disease resistance of plants.

Strengthen field management, remove diseased branches and fruits in time, leave no branches and ears on the ground 60 cm, reduce the infection of pathogens, and timely topping, so that the garden is ventilated and light, and the humidity is reduced.

remove the diseased fruit and leaves in time during the growing season, and cut off the diseased vines; After the autumn harvest, the diseased skin is completely scraped off, the garden is cleaned well, and the sick and remnants are taken outside the garden to be burned. The germ is invaded by the wound, so all the conditions that cause the wound are conducive to the occurrence of the disease. For example, wind damage, insect pests, topping, fruit thinning and other agricultural operations, among which wind damage has the greatest impact, and the probability of true infection of fruits entering the coloring stage or ripening stage increases.

Do a good job of clearing the garden to reduce the source of primary infection. Remove diseased tissues such as diseased fruits, diseased vines, and diseased leaves in a timely manner. Sweep away the dead branches and leaves on the ground, and burn them or bury them deep to reduce the source of infection.

Do a good job of drainage, reduce the humidity in the garden, and minimize unnecessary wounds.

Grape white rot, also known as rot disease, the pathogen is white rot shield shell mold, which occurs more commonly in various vineyards across the country, the fruit loss rate is 10-15%, and more than 60% can be lost in serious years, and even the harvest is lost, and the disease is quite serious in the high temperature and high humidity season. , it should be switched to Fuxing, methyl tobuzin and other agents**. In the chemical control of white rot, we should pay attention to three points:

First, it is necessary to spray the spray within 12 hours after the occurrence of strong winds, heavy rain and hail, otherwise, if it is delayed too late, the prevention and control effect will be very poor.

In fact, white rot is a relatively serious disease, the germs generally enter the plant from the wound, and the incorrect pruning method will lead to white rot, so it must be avoided carefully.

There is a high probability of this happening in the case of increased rainfall. If the rainy season comes early, the disease will be early, and in the hot, humid and rainy weather, it will also lead to the onset of the disease. When rainfall increases, so does the chance of germs invading.

The first point is likely to be caused by diseases in the soil, the second point is likely to be caused by insufficient watering at that time, and the third point is likely to cause bacterial infection.

Germs usually enter the plant through the wound, and incorrect pruning methods can lead to white rot. The most common are fruit and vegetable topping, insect pests, pruning, wind damage, etc. In addition, if the rainy season comes early, the disease will also come early, and in the hot, humid and rainy weather, it will lead to the onset of disease.

When rainfall increases, so does the chance of germs invading.

(1) Select disease-resistant varieties: In the fields where diseases are often prevalent, avoid planting varieties as much as possible, and choose high-resistance and medium-resistant varieties with good resistance, good quality and high commodity rate.

2) Increase the application of organic fertilizer: increase the application of high-quality organic fertilizer and biological organic fertilizer, cultivate soil fertility, improve soil structure, promote the development of plant root system, grow luxuriantly, and enhance disease resistance.

3) Elevate the fruiting part: according to local conditions, the scaffolding planting is adopted, combined with vine binding and thinning flowers and fruits, so that the fruiting part can be increased to more than 40 cm as much as possible, which can reduce the chance of contact with pathogenic bacteria on the ground and effectively avoid the infection of pathogenic bacteria.

4) Flower thinning and fruit thinning, according to the fertility level and growth of the vineyard, combined with pruning and flower and fruit thinning, reasonably adjust the fruit load of the plant, avoid only pursuing the temporary benefits of high yield in the immediate direction, and weaken the growth advantage of grape fruit trees, and reduce the disease resistance of grapes.

5) Fine management: strengthen regular field management work such as fertilizer and water, topping, vine tying, picking secondary shoots, cultivating and weeding, drainage in the rainy season and other pest control.

6) Do a good job of field cleaning and hygiene: do a good job of field sanitation during the growing season, remove field source pollution and infections, combine management and frequent inspection, timely cut off the diseased fruit ears and diseased branches found in the early stage, clean up the diseased grains that fall to the ground, and take them out of the garden for centralized treatment, which can reduce the source of re-infection in the year, reduce the disease and slow down the development of the disease.

Pharmaceutical prevention and control. 1) Pollution-free prevention and control: key incidence months: Liaoning and other northern regions generally start to develop the disease from June to July, and the incidence is peak from August to September; In Guangdong, Hunan and Shanghai, the onset of the disease began from late May to July, and the peak period of the disease was from mid to late June to early July.

Medication times and drug times: Before the onset of the disease, use fast and net 500 times of 500 times of dilution to carry out comprehensive spraying of plants. The frequency of medication depends on the specific situation, and the general interval is 7-10 days for 1 spray.

In recent years, the occurrence of grape white rot has been increasing year by year, and the occurrence law and prevention technology of the disease are introduced as follows.

1.Symptoms occur.

It mainly harms leaves, new shoots, cobs and fruits. In the early stage of the disease, the disease starts from the cob or small fruit stalk close to the ground, and the light brown irregular water-stained lesions appear, which gradually spread to the fruit grains, and the fruit grains first turn light brown at the base and are soft rot, and then the whole grain turns brown and rots, and the fruit stalk is dried and shrunken.

2.Etiology and occurrence patterns.

Diseased residues scattered on the ground and topsoil are the main source of infection at the beginning of the next year, and the pathogens can rot and survive in the soil for more than 3 years. At the base of the conidia on the stiff fruit, there are some dense mycelium, which are highly resistant to adverse environments and can survive for more than 10 years in dried panicle specimens. Conidia are spread by rainwater and invade through plant wounds.

Climatic conditions of high temperature and humidity are the main factors for the occurrence and prevalence of the disease. Orchards with clayy soil and poor drainage are severely ill; Orchards with poor ventilation and light transmission are severely ill; The disease is also severe when the individual load of plants is large; The fruit entered the coloring and ripening stage, and its susceptibility gradually increased.

3.Control technology.

Eliminate the source of disease: remove diseased leaves and fruits in time during the growing season, and cut off diseased vines; Immediately after the autumn harvest, collect the fallen leaves, ears, vines, grains and other disease residues on the ground, clean them, and evenly spray the trunks and branches to protect the tree, which can quickly form a protective film, suffocate disinfection and sterilization, and further remove the source of infection.

Reasonable fertilization: Fertilization is mainly based on basal application and organic fertilizer, and an appropriate amount of nitrogen fertilizer is applied before flowering to promote the growth of branches and vines. After fruiting, nitrogen, phosphorus and potassium were applied together, and micro-fertilizer was appropriately supplemented, combined with foliar fertilizer before grape flowering, young fruit stage, and fruit expansion stage, sprayed with an appropriate amount of melon and fruit Zhuangtiling, through the thickening of the nutrient transport duct of the tree, the amount of nutrient transport was increased, and the reproductive growth and vegetative growth were uniformly reproduced and vegetative growth through self-regulation of nutrient matching, and the disease resistance of the plant body was improved.

Strengthen cultivation management: reasonable pruning, improve the fruiting parts, and apply callus antiseptic film to the pruning mouth in time, disinfect and sterilize, and reduce the chance of bacterial infection; Tie vines in time, topping, tie secondary shoots and properly thin leaves and fruits, improve ventilation and light transmission conditions, do a good job in drainage, and reduce humidity.

Pesticide control: After the grapes bear fruit, the lower ears should be checked frequently, and the diseased grains and ears should be removed in time. The diseased plots can be sprayed in rotation with 70% methyl tobuzin 1000 times solution and 50% Fumeishuang 500 times solution, and foliar micro-fertilizers such as potassium dihydrogen phosphate can be mixed with each medication.

Seriously ill gardens can sprinkle sterilization drugs on the ground at the initial stage. In the prevention and control of pesticides, an appropriate amount of new high-lipid film must be added to improve the efficacy, reduce the pesticide residue, and improve the quality of the fruit.

The following measures should be taken to control grape white rot:

Disease-resistant varieties are selected according to local conditions, such as rose incense, longan and other varieties are more resistant to white rot.

Do a good job of clearing the garden, remove diseased fruits, diseased vines, diseased leaves and other diseased tissues in a timely manner, sweep the dead branches and leaves on the ground, and burn or bury them in a concentrated manner to reduce the source of infection. Do a good job of drainage, reduce the humidity in the park, minimize unnecessary wounds, and reduce the chance of germ infection. After flower dropping, mulch is applied to both sides of the vine to prevent the spread of germs in the soil and reduce the chance of infection.

Strengthen cultivation management, carry out chemical control in a timely manner, and master the critical period of drug prevention and control.

Liangguoan 400-600 times liquid + mycloconazole 800-1200 times liquid + silicone.

Pest control: 48% chlorpyrifos 800-1200 times.

Remarks: In order to prevent and control lobular disease, prevent fruit shrinkage disease, and improve fruit setting rate, suitable zinc and boron can be supplemented.

Grape white rot, commonly known as "water rot" or "ear rot", is often accompanied by the concurrent epidemic of grape anthracnose in rainy years in southern, southwestern and northern China, causing great losses. Grape white rot is common in China and is known as one of the four major grape diseases of grapes. In recent years, it has occurred in a large area, the epidemic is fast, and the damage is heavy, causing a large number of rotten ears and rotten fruits, which not only makes it difficult to sell fresh fruits but also affects the storage of grapes.

Causing huge economic losses.

[Main symptoms].

Seedlings: The pathogens mostly invade from the wound, and the initial appearance is water-soaked light brown lesions, and expands longitudinally into concave dark brown spots, and the epidermis is densely covered with gray-white small spots. The lesions wrap around the branches, and the upper part of the vine dies.

The lesions on the leaves are light brown, nearly round, and have inconspicuous concentric whorls, and are easy to break after drying.

Fruit: For grapes with low trellises or fruiting sites, grapes close to the ground are the first to get sick. The fruit peduncle or cob is first infected, and gradually spreads to the fruit grains.

After the disease reaches the fruit through the fruit stem, it occurs from the base of the fruit, and the lesion first turns yellow, then brown, and when it spreads to the whole fruit, it turns brown and rots. Small grayish-white dots are scattered under the skin of the diseased fruit. This is followed by small brown pustule-like protrusions that form small spots (conidia) under the epidermis but do not break through the epidermis.

Mature conidia are small, grayish-white dots. The formation of the conidia leads to the inflow of air, which makes the fruit appear whitish, and the conidia are grayish-white, so this disease is called white rot. The diseased fruit loses water and becomes a dead fruit of pig liver color, which is easy to fall.

Favorable weather can also cause the lesions to spread to the cobs, and when they reach the main cob, they can cause most or all of the ears to rot.

Initial symptoms. Late symptoms.

Fruit peduncle and cob: the disease site first produces light brown water-soaked near-round lesions, the diseased part rots and turns brown, and soon spreads to the fruit grains, the fruit becomes brown and soft rotten, and the surface of the diseased fruit and the cob produces gray-white small granular conidia in the later stage, and the gray-white conidia overflow from the conidia when the humidity is high, and the diseased fruit is easy to fall off, and the diseased fruit is brown or gray-white stiff when it shrinks.

Cob symptoms. Late symptoms of cob onset.

Branches: White rot generally damages branches that are not lignified first, so the new branches of the year are susceptible. The knots, cuts, wounds, and areas close to the ground are the points of damage.

At first, the lesions are long, sunken, brown, necrotic spots, and then the lesions are dry and torn, and the cortex is separated from the woody and arranged in a longitudinal linen. Around the lesions, there is a callus formation, and a "swelling" around the lesion will be seen. If the lesion circles around the branch, the upper part of the branch "swells" and thickens, and eventually, the upper branch dies.

Lesions on shoots can form conidia. Seedlings, grafted seedling rootstocks, and in the first year after planting, grape branches are susceptible to white rot.