1 Q: How does anthrax occur?

Ms. Sun Wei A: The disease is a fungal disease. The pathogenic bacteria overwintered on the surface of the annual dendrite, diseased fruit, leaves, spikes, and nodes. When the temperature is higher than 10°C in the following year, a large number of conidia are produced, which are transmitted to the ear by wind, rain, and insects, causing initial infection. The distribution and spread of pathogenic conidia depends on rainwater, germination and invasiveness also require high humidity to complete. After each rainfall, there was a batch of fruit in the field, which usually began in mid-June and entered the peak period in July and August. The occurrence of heavy rains in summer is heavy. For example, when the grape is in high temperature and it is rainy, it often causes the disease to become popular. Excessive management of serious diseases.

Grape anthracnose has latent infection characteristics. When the bacteria invade the green part, they become latent, dizzy, and do not expand. After the host is weakened, the bacteria reactivate and expand, and the spores germinate directly into the skin. The incubation period is 20 days for young fruit and 4 days for fruit in near maturity. The length of the incubation period is related to the content of acid and sugar in the fruit except for the temperature. The high acid content bacteria cannot develop, and no lesion can be formed; the fruit before the hard nuclear stage and the fruit with the reduced acid content in the near maturity period , Germs can be active and form lesions; ripe fruit with less acid, increased sugar content, suitable for the development of the bacteria, a short incubation period. Therefore, in normal years, the disease started to occur from the middle and late June and gradually increased. After the fruits matured in July and August, the disease entered the peak period. In the hot summer season, when the grapes are colored and matured, the diseases often become pandemic; under normal circumstances, the conidial sporophores are a group of colloidal substances that are spread by rainwater splashes. Therefore, the propagation and germination of conidia require a certain amount of moisture or rainfall. The incidence and incidence of the field is closely related to the incidence of disease after a few days after the drought, the disease does not spread significantly during drought. The occurrence of anthrax is related to sunburn, and the sunburned fruit is susceptible to anthrax. The cultivated environment has a significant impact on the occurrence of anthracnose, the line is too dense, the incidence of double-row vineyards is heavy, and the incidence of broad-leaved gardens is light. Severe onset of nitrogen application, combined with the application of potassium fertilizer can reduce the incidence. The disease first occurred from the lower layers of the plant, especially near the surface of the ear and then spread upward. The incidence of sand is light, the incidence of clay is heavy, the terrain is low, and the accumulated water or air does not circulate.

2 Q: What is the incidence of anthrax?

Ms. Sun Wei A: Meteorological conditions: The spores produced by germs need a certain temperature and rainfall. The optimal temperature for spore production was 28-30°C. Spores appeared at 24 hours at the above temperature. Spores were also produced below 15°C, but the time required was longer. It is easy to attack under high temperature and high humidity conditions.

Varieties: Generally, the varieties with thin peels are more severe, early maturing varieties can avoid diseases, and late-maturing varieties are often severely affected.

Cultivation and management: Poorly drained orchards, low shelf type, overly dense foliage, poor ventilation, and other environmental conditions are all conducive to disease.

3Q: How to prevent anthrax?

Sun Wei teacher A:

1. Do a good job in clearing the garden: Combine pruning to remove the sub tips, spikes, stamens, and tendrils left on the plants, and thoroughly remove the ear, vine, and dead leaves that have fallen on the ground, and burn them in a concentrated manner to reduce Orchard source.

2. To strengthen the cultivation and management: the growing season to pick up the heart in time, tying the vines in time, so that the orchard has good ventilation and light in order to reduce the incidence. At the same time, the auxiliary tip must be removed in time to prevent overcrowding of the crown, which is not conducive to the occurrence and spread of the disease. Pay attention to reasonable fertilization, the three elements of nitrogen, phosphorus, and potassium should be properly coordinated, and potassium fertilizer should be added to improve the disease resistance of plants. After the rain, we must do a good job of draining orchards to prevent the accumulation of water in the garden.

3. Spray protection: start from the conidia found in the garden, to the first half of harvest, spray once every 15 days, spray 1:0.7:200 Bordeaux mixture, spray 3-5 times. Focus on protecting the fruit. Also available as 80% Mancozeb WP, or 75% chlorothalonil wettable powder 500-800 times, or 50% carbendazim WP 600 times, or 70% thiophanate-methyl wettable Powder 600 times fluid rotation spraying; control at the critical period after rain can spray 25% azoxystrobin suspension 2000 times, or 10% difenoconazole water dispersible granules 1500-2000 times, after which more than 50% can be used Ling WP, 70% thiophanate-methyl WP, Bordeaux mixture, etc. are used interchangeably.
4 Q: What is the key to prevention and control at the time?

Ms. Sun Hao A: There are three key prevention and control periods: reducing the source of the disease in the spring, cutting off transmission after rain, and preventing reinfection during the mature period.

5 Q: Why is it difficult to control after the onset of anthrax, but downy mildew can save?

Ms. Sun Xia: Grape anthracnose is different from grape downy mildew. Grape downy mildew is a pathogen that can be infected soon after the infection of the leaves and the ear. Mycelium can be seen in the eyes. The grape anthrax disease is different, the disease is harvested from spring to autumn, can all infect the fruit, the difference is that the fruit will only become sweet and mature after onset, even if the infestation of plants before the disease is not disease, known as the incubation period. There are no symptoms on the fruit, but it is actually a sick individual, and it can develop once it is near mature. Farmers generally do not see sickness, and they are not in a hurry to control spraying. Once the disease is severe, they will spray the medicine for three days or two. Sometimes the fruit spots on the fruit are already sticky on the fruit and they continue to spray. medicine. Grape anthracnose occurs as usual. Therefore, in order to prevent fruit from maturation, it should be emphasized in the spring. Spray some control agents, such as 77% copper sulfate calcium 600-800 times, or 80% mancozeb wettable powder 600-800 times, or 50% carbendazim wettable powder 600 times and azole fungicide , spray once every 7-10 days, you can control grape anthrax.

6Q: Sometimes pesticides used to treat anthrax are sprayed 7-10 days. There are still rotting phenomenon.

Ms. Sun Hao A: It may be the quality of spraying. When selecting the medicine, the fruit grower must first choose and control the anthracnose on the road, and the preventive medicine includes 77% copper sulfate calcium WP, 80% mancozeb WP, 80% wettable powder thiram, therapeutic effect. There are 50% carbendazim WP, 70% thiophanate-methyl wettable powder, 10 difenoconazole water-dispersible granules, 25% propiconazole, and so on. The right prevention and treatment will only have good control effect, but even if it is used to control the roadside agents, the control effect of different family farmers is not the same. The key is the quality of spraying, whether there are less spray, missed spray plants, whether the whole plant with liquid medicine, especially the ear should be more even and thoughtful, otherwise the usual incidence of rotten particles. Sometimes, when a farmer uses drugs, he observes the quality of spraying in the vineyards. He still finds that there are no liquids in some of the ears. Therefore, the spraying machinery and personnel must be slow to avoid leakage.

7Q: There is no missing spray when spraying, and there are often morbid particles. Why?

Ms. Sun Junyi: Because the surface of the grape granules has a layer of fruit cream, this layer of fruit cream is a kind of protection body that controls the invasion of various pathogens. At the same time, it also makes it difficult for the spraying liquid to adhere to the surface of the fruit. Or can not form a film on the surface of the fruit, but a small water droplets, and there will be a large gap between the small water droplets and small water droplets, such gaps can account for about half of the total grain area. This means that each time only half of the fruit is sprayed on each fruit, and the other half is not used. This will result in spraying the medicine every time, and it will also cause the disease. It is also suggested that the spraying agent be added with the spreading agent. The liquid adheres to the surface of the fruit and enhances the preventive effect of the medicine.

8Q: How can we make the liquid form a film on the surface of the fruit, so that there will not be gaps between the droplets and the droplets?

Ms. Sun Haoyi: Generally, when spraying, we must choose those products that have good development and strong adhesion. We can also add some spreading agents before spraying. The best spreading agent on the market is silicone, such as 100. % Good wet agent, 100% soft water agent, 5 ml of water, 15 liters of water, can be quickly expanded on the fruit after adding, no blank area will appear, and the intended purpose is achieved.

9Q: What are the symptoms of house blight?

Sun Wei teacher A: grape house blight is also known as ear blight, grain blight.

Cob: A round, oval, or irregular round spot appears near the fruit, dark brown to grayish black, slightly concave. Some of the cobs are dry and the fruit growth is poor, and wrinkles appear on the fruit surface. Pathogens invade the nearby fruit from the rachis, causing lesions.

Fruit: The fruit surface is also infected. Fruit lesions dark brown to purple brown. Coarse and fruit lesions form sparse black spots on the surface. The late fruit turns into a stale fruit and remains on the plant for a long time. The diseased fruit of house blight does not fall off.

Leaves: Grayish white, round lesions appear onset.

10 Q: How does house blight spread? What are the conditions of the disease?

Ms. Sun Wei A: The pathogens of the house blight were transmitted to the grapes by the wind and rain, which caused the disease. The wintering of the conidium and the ascus shells in the affected area. During the second year of May, the conidia and ascospores spewed out from the conidia and ascospores in a high temperature and rainy season, which is suitable for the spread of this disease. Fruit usually begins in late June and early July, and becomes more severe in the near-mature period.

In general from July to September, temperatures can occur at 15-35°C, but 24-28°C is most suitable for onset. Grapes in the Eurasian system are generally more susceptible to disease, such as longan, etc.; grape diseases in the American system are lighter, such as black tiger aroma. In damp and poorly managed orchard-deprived orchards, the incidence is heavier.

11 Q: How to prevent house blight?

Ms. Sun Hao A: Pay attention to the health of the orchard. In the fall, you must thoroughly remove the diseased branches, leaves, fruits, etc., and burn them centrally or deeply.

Strengthen the orchard management, pay attention to drainage, cut the auxiliary tip in time, improve ventilation and light transmission conditions, increase fertilization, and enhance plant resistance.

Before the grape is sprayed on the shelves, it is sprayed with a 3-5 degree of bolier sulfur. After the grapes fall, they start to spray 1:0.7:200 Bordeaux mixture. Once every half month, they spray 3-5 times, or use 25% azoxystrobin suspension 2000 times. Liquid, or 10% difenoconazole water dispersible granules 1500-2000 times, or 50% Tuzet WP 500-800 times, or 80% Capitacum WP 1500 times, 50% more Diosperm wettable powder 600 times liquid, spraying should pay attention to the uniform medicine. Severely affected areas have two drug intervals of 7-10 days, and areas with lighter disease may be appropriately extended. Prevention and treatment of drugs throughout the year advocate the use of two or more alternatives. Note: Bordeaux liquid should not be used when young fruit, so as to avoid fruit rust.

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