How to cure grape downy mildew?

Grape downy mildew is a worldwide grape disease and one of the main grape diseases. Grape downy mildew occurs in all grape producing areas in China, especially in rainy and humid areas. when the disease is serious, the leaves scorch and fall early, the new shoots grow badly, the yield decreases, the quality becomes worse, and the cold resistance of the plant is poor. Let's take a look at how to treat the grape downy mildew.

Disease condition

Grape downy mildew mostly occurs in autumn, and the cool and humid climate is favorable for the disease. The temperature range of oospore germination is 1333 ℃, the suitable temperature is 25 ℃, and there should be sufficient water or rain at the same time. The temperature range of sporangium germination is 5: 27 ℃, the optimum temperature is 10: 15 ℃, and free water is needed. The sporangium formation temperature is 13: 28 ℃, the sporangium formation is the most about 15 ℃, and the relative humidity is 95: 100%. The range of temperature for zoospore production is 12: 30 ℃, the optimum temperature is 18: 24 ℃, and there must be water droplets. Therefore, low temperature and heavy rain in autumn can easily lead to the epidemic of the disease.

Harmful symptoms

The main results are as follows: 1. The leaves were killed: small spots with unclear edges in the shape of light yellow water stains, and then gradually expanded into brown irregular or polygonal spots, and several spots were connected to become irregular spots. When the disease is serious, the diseased leaves wither early and fall off early.

2. Damage to tender shoots: form watery spots, and then turn into brown slightly sunken spots. When seriously ill, the new shoots are twisted, growth stops, and even dies. Tendrils, rachis and petioles can sometimes be killed, and their symptoms are similar to those of tender shoots.

3, the young fruit is killed: the diseased part fades, hardens and sinks, and the white downy mildew grows on it, which is easy to atrophy and fall off. The fruit was damaged when the fruit was half large, the diseased part was brown to dark, and the soft rot was early. The fruit is no longer infected after coloring.

Agricultural prevention and control

1. Clear the source of bacteria, clean the orchard thoroughly in autumn, cut off the diseased tip, collect the diseased leaves, bury them deeply or burn them.

2. Strengthen orchard management, cut in time in summer, bind branches, and improve ventilation and light transmission conditions of shelf surface.

3. Pay attention to weeding, drainage and reducing ground humidity.

4. Proper application of phosphorus and potassium fertilizer and application of lime to acid soil to improve plant disease resistance.

3. The non-drop anti-fog film is selected as the outer covering material of the facility to reduce the air humidity and prevent the occurrence of fog.

4. The room temperature should be quickly raised to more than 30 ℃ during the day, the night temperature should be maintained at 10: 15 ℃, and the air humidity should not be higher than 85%.

5. Setting up rain shelter facilities in the vineyard can prevent Rain Water from splashing and cut off the spread of grape downy mildew pathogen.

Chemical control

1, treatment measures: "Liang Guoan" 300x plus "Wofengsu" 600x mixed with "garlic oil" 1000 times and "silicone" spray twice, each time at an interval of about 10 days.

2. Prevention program

Half a month before sprouting, ① used "Liangguoan" 60-fold liquid and sprayed throughout the garden to kill bacteria and nourish the tree.

② was sprayed with 300x liquid of "Liangguoan", 600times of "Wofengsu" and twice of "silicone" at an interval of 10 days during flowering.

③ uses "Liangguoan" 30000x plus 600x plus "silicone" spray during its first physiological fruit drop.

During the growing period of ④ fruit, "Liangguoan" was sprayed regularly, with an interval of 10 to 15 days.

After picking fruit in autumn, ⑤ was sprayed with 200,300x and 600x of "Liangguoan" and "silicone" once.

After 2 / 3 of ⑥ defoliation, the whole garden was sprayed with "Liang Guoan" 60 / 100 times liquid to kill bacteria and nourish the tree.