What symptom does cucumber late blight have? How to prevent and cure?

Cucumber is a functional vegetable, which has the effects of anti-tumor and anti-aging, preventing alcoholism, lowering blood sugar, invigorating the brain and calming the mind. Therefore, farmers who grow cucumbers all hope that the cucumbers planted can achieve high yield. However, some diseases and insect pests often occur in the process of cucumber planting, such as cucumber late blight, what are the symptoms of cucumber late blight? How to prevent and cure?

What are the symptoms of cucumber late blight?

Cucumber late blight caused damage to cucumber seedlings, starting from the cotyledons and the edges of true leaves, producing round or irregular waterlogged spots; in heavy cases, the stem tip and lateral buds showed dark green water-stained soft rot, and the leaves withered. The disease occurred after the plant shook the vine, and the leaf appeared irregular water-like disease spot from the leaf edge, which expanded rapidly. When the weather is wet, the disease spot expands very quickly, often causing the whole leaf to rot; when the weather is dry, the disease spot is dark green at the edge, light brown in the middle, and often dry and brittle.

Second, how to control cucumber late blight?

1. Select disease-tolerant varieties, disinfect seeds before sowing, and rotate with non-melon crops for more than 5 years.

2. Grafting to prevent disease.

3. To strengthen field management and improve plant disease resistance, rational fertilization (especially nitrogen fertilizer) should be applied, light transmission intensity should be improved, ditches should be opened in time to drain water, and field temperature should be reduced.

4. Chemical control. Spray a protective fungicide before the onset of the disease or before the rainy season. Frost Bell 30ml mixed with water 15kg spray from seedling stage, once every 5-7 days. The 15kg spray of 50ml of Shuangbel + 15-20ml of garlic oil with water can be controlled once every 3-5 days.

Matters needing attention in cucumber planting

1. Heavy application of chemical fertilizer, neglect of organic fertilizer some people think that the more chemical fertilizer, the higher yield, so blindly compare the amount of chemical fertilizer, light application of organic fertilizer, resulting in soil hardening, serious salinization, the formation of green moss on the surface, and the formation of red moss in serious cases. The development of roots in high concentration of soil solution is blocked, leaves are aging, vegetative growth is poor, and yield decreases. This kind of greenhouse should increase the application of organic fertilizer and apply little or no chemical fertilizer to reduce fertilizer damage.

2. A large amount of diammonium was used during the melon setting period, which was not in line with the growth law of cucumber. Topdressing notes: fruit expansion elements: carbon, potassium, nitrogen, silicon, calcium, boron. 1. CO2;2 and potash fertilizer should be potassium nitrate fertilizer; 3, nitrogen fertilizer and urea; 4, silicon fertilizer should be sprayed twice and 4 times in a lifetime; 5. Foliar transformation of calcium and boron elements is the fastest, so foliar spraying topdressing is recommended.

3. In order to reduce the temperature, excessive shading with grass grass in the initial stage of planting, the light intensity is large, in order to reduce the temperature, moderate shading is possible, but if shading is excessive or winter shading, it will cause insufficient light, affect flower bud differentiation and reduce yield. The temperature should be lowered by venting.

4. When many kinds of pesticides are mixed, the concentration is too high and the amount of liquid is too high. First, there is a chemical reaction between some pesticides, which reduces the efficacy. Second, many medicines are compound medicines, and they have already been mixed. Third, with the increase of concentration, the leaves are often immersed in high concentration solution, which leads to the decline of leaf function, acceleration of aging and reduction of photosynthesis.

5. Do not administer medicine without disease, use medicine indiscriminately when there is disease, disease prevention should be based on prevention, treatment should be supplemented, prevention should be used in advance, not only the cost is low, but also the effect is good.