What is the reason for the appearance of leaf burning in cucumbers under low temperature and strong

Leaf burns caused by bright light at low temperatures are a physiological disease. Late autumn and mid-winter stubble usually occur in solar greenhouses, and the low temperature period from November to March generally occurs in the middle and upper leaves of the entire greenhouse, and most of the leaves on the south side of the plant are damaged. In the case of a single leaf, the southeastern part of the leaf is badly damaged.

The disease is mostly attributed to cucumber varieties, some of which have poor low temperature tolerance and strong light tolerance, and will appear when cultivated in the low temperature season. The authors found that in the same greenhouse, some varieties had damaged leaves, but the more resistant ones could grow normally. In addition, some non-standard greenhouses have thin walls, short rear roofs, and small elevation angles, resulting in poor overall thermal insulation performance, low night temperatures, and large temperature differences between day and night, especially low soil temperatures, and leaves that are easy to burn under strong light.

Cucumber leaf burning often occurs in the production of cucumbers in protected areas, which will cause huge yield losses in severe cases. Leaf burning mostly occurs in the middle and upper leaves of plants, especially those near or in contact with the greenhouse film. At the beginning of leaf burning, chlorophyll decreases, and some leaves turn white, then turn yellow and die.

When cucumber leaves are burned, only the edge of the leaf is mild, and half or the whole leaf will be burned. When the sunlight is too strong, the temperature difference between indoor and outdoor in the shed is too large, and it is inconvenient to release air to cool down, or when the air still cannot be reduced to the required temperature after releasing air, sunshade can be used to cool down. Lightly burned leaves occur only in the jagged part of the leaf margin, and most of the leaves die in severe cases.

The color of the dead spots is uniform, the surface is clean, and there are no special infectious disease symptoms.

After watering or after rain, the condition is relieved and stops developing. Cucumber leaf burns mostly occur in facility cultivation, and the middle and upper leaves of plants are affected by light, water and other environments. In the middle and late stages of cucumber cultivation in winter or spring greenhouse, the soil is dry, the air is not suitable, the air is not released at noon on a sunny day or the air volume is not enough, the relative humidity in the greenhouse is lower than 80%, and the temperature is about 40, the leaves are easy to burn, especially the leaves directly exposed to the sun near the southern air outlet are easy to burn.

In the latter case, most of it is the breed itself. Some varieties are not resistant to strong light, while the greenhouse film has good light transmittance, but the greenhouse has poor thermal insulation performance, low night temperature, and is easy to burn leaves.

This occurs because cucumbers are very resistant to low temperatures and are not tolerant to bright light, which can occur if grown during the season when the temperature is low. It is advisable to choose a good growing environment and buy varieties that are well tolerated in adverse environments for planting.

It may be because it lacks water to burn leaves, and it should be given more nutrients and water at ordinary times, so that it can be prevented.

This is the lack of trace elements of the element, supplement the water-soluble micro fertilizer seedlings to make money, containing manganese, zinc, boron and other elements, high content, good fertilizer effect, quick effect, such as manganese can promote the development and growth of cucumbers, promote the formation of cucumber chlorophyll, lack of manganese cucumber plants dwarf, narrow and short leaves, serious dark brown spots, zinc, boron, copper and other elements can also be conducive to the growth and development of cucumbers.

You can buy some pesticides to beat cucumbers, tell the merchant according to the corresponding **, the merchant will match you with the corresponding pesticides, you just need to bring it back to fight.

If you want to remedy it, you must determine the cause, if it is because of pests and diseases, you should buy pesticides to spray, if it is because of malnutrition, you should strengthen fertilization.

Cause analysisThis is leaf fever caused by strong light in a low temperature environment, which is a physiological disease, and mostly occurs in solar greenhouses during low temperature periods. This disease occurs in the cucumber varieties themselves, some varieties have poor low temperature and no resistance to strong light, and this phenomenon occurs when planted during low temperature periods. In addition, some non-standard greenhouses, although the film transmits light very well, due to the thin walls, the overall thermal insulation performance of the greenhouse decreases, especially the low soil temperature, and the leaves are easy to be burned under strong lighting.

Preventive measuresThis disease is a chronic adversity physiological disease, and some vegetable farmers often cannot solve the underlying problem by taking temporary warmth, which is time-consuming and laborious, and the old people lose money. William Shakespeare, Hamlet, Health) Therefore, the selection of varieties with strong resistance to adverse environments and the construction of high-standard, high-performance solar greenhouses are fundamental to solving this disease.

It has now become one of the most common vegetables in our daily life. The refreshing taste and rich nutrients are loved by consumers. It can be said that the current planting area of cucumbers in China is about 20 million mu, in recent years, with the development of facility agriculture, the planting area of cucumbers in plastic greenhouses has been close to half of the total planting area, and the development is very rapid.

Farmers who are engaged in planting and production know that the reason why cucumbers in plastic greenhouses can develop so quickly is because overwintering planting and production are more important in many favorable conditions. Generally speaking, the wrong cucumber production in winter has a certain advantage, so under the premise of ensuring the yield and quality, farmers who are engaged in the cultivation of cucumbers in winter greenhouses can obtain better benefits.

But there are pros and cons, cucumbers in plastic greenhouses in winter are easy to grow, a little difficult to grow. This is because, in the special climate environment outside the winter, the facility greenhouse can provide a suitable small environment for cucumbers, but the small environment in the greenhouse has a lot to do with the producer's farming operation for cucumbers, so the difficulty of cucumber planting management is increasing. Improper management of cucumbers in winter plastic greenhouses, prone to problems, affecting the final quality and yield of cucumbers, today Li Nong wants to talk about cucumbers and "super edge leaves", which is due to improper management, cucumbers in winter plastic greenhouses often occur and harm a physiological disease.

A lot of friends might say that. "The 'super-edged leaves' of cucumbers are not due to improper wild film that causes the edges of cucumber leaves to dry out, but to end with reasonable ventilation. How can the losses be greater than those of pests and diseases that directly damage fruits in winter, the East China Sea, etc.?

Friends who have this kind of doubt definitely have a misunderstanding about the ultra-marginal leaves of cucumbers. First of all, cucumbers have many triggers for ultra-marginal leaves, and different prevention and remedies are different for different triggers. If you don't get the right medicine, it's hard to avoid it.

Secondly, the cucumber plant is the whole system. Other parts of the leaf-infested plant are also affected. After the occurrence of cucumber's "super-marginal leaves", the yield of cucumber reaches 20% to 30%, and in severe cases, the sandbar may become extinct.

Therefore, farmers who are engaged in cucumber planting must have full attention and deep understanding of it.

It is better to choose the kind of varieties with strong resistance to adverse environments, this disease is a physiological disease of chronic stress, and some people use temporary warming methods, but it does not solve the fundamental problem, and it consumes time, energy and money. Therefore, a high-standard, high-performance solar greenhouse is the fundamental solution to this disease.

If you are planting cucumbers in winter, it is best to use greenhouses to plant vegetables to maintain temperature, so as to ensure that cucumbers burn leaves.

Preventive measures include the selection of varieties with strong resistance to adverse environments. Choose land with fertile soil, water it in time when planting, and manage water properly, not more or less. To fertilize the vegetable field in time, reasonable fertilization, but also need to effectively prevent the infestation of pests.

Maintain a proper temperature, the temperature of the protective ground should be controlled at 20 25, and the temperature should be ventilated and cooled in time when the temperature is too long.

In the middle and late stages of cucumber growth, due to the strong light, the influence of strong light can be weakened by removing the edge film or top film and covering the shade net.