The vegetables grown in the greenhouse often have yellow leaves and various pesticide problems, what

If the vegetables in the greenhouse often have the problem of yellow leaves, it is necessary to pay attention to choosing the right fertilizer, watering regularly, strengthening sun exposure, keeping the environment warm, and pruning frequently.

We must use all kinds of pesticides scientifically, we need to pay attention to light, we need to pay attention to the situation of moisture, and we need to pay attention to the condition of the soil, so as to better avoid problems.

You should fertilize and spray vegetables appropriately. In this way, it can get nutrients and also get rid of some pests.

It is a nitrogen-deficient plant, with slender and stiff branches, small leaves and small flowers. The leaf color gradually fades from the old leaves to the new leaves, and then appears reddish-purple, until it turns yellow and falls off, and in severe cases, the whole plant loses its green color. Prevention and control methods:

Increase the application of well-rotted human feces, cake fertilizer, manure or ammonium sulfate, urea, ammonium nitrate and other fertilizers. The phosphorus-deficient leaves turn from dark green to copper, and the veins (especially the petioles) are yellow with purple in color. Flower buds are difficult to form, and the flowers are small, few and pale in color, resulting in poor fruit development and even early wilting.

Prevention and control methods: increase the application of bone meal, fish meal, poultry fertilizer or superphosphate, ammonium phosphate, potassium phosphate (phosphorus, potassium compound fertilizer), generally with about 0 10 aqueous solution as root top dressing. Potassium-deficient plants are dwarf, and the stems are soft and prone to lodging.

The leaves are often shrivelled, and the old leaves appear black-brown spots along the leaf edges from the tip of the leaf, and the surrounding leaves turn yellow, while the middle and leaf pulse are still green. Control methods: increase the application of plant ash, 1 2 potassium chloride aqueous solution (bulbs and root flowers are not used), 0 30 0 50 potassium nitrate aqueous solution as root top dressing, potassium phosphate and other inorganic fertilizers can also be used.

Calcium-deficient young leaves are green and shrivelled, the leaf margins are rolled up and have white stripes, the flowers are blocked, and the new leaves are difficult or diseasefully twisted. Prevention and control methods: half a month before sowing or potting, apply an appropriate amount of calcium chloride in the soil, which can play a role in increasing calcium and disinfection (acidic flowers should not be used), and calcium nitrate can also be used as top dressing.

Magnesium-deficient plants do not grow vigorously. The old leaves gradually lose green and turn white from bottom to top from the leaf margin to **, and various spots appear on the leaf veins, and finally the whole leaf turns yellow. Prevention and control methods:

Spray 3-4 times continuously with 0 20 0 40 aqueous magnesium sulfate solution, with an interval of 7 to 10 days each time. Severely magnesium deficient soils are treated with 5 10 kg of magnesium sulfate per mu, which is mixed with basal fertilizer in autumn or winter and applied to the soil. The young sulfur-deficient leaves begin to yellowish from the leaf veins, and finally until the whole leaf turns yellow, and the root system is not developed normally.

Iron deficiency yellows from young to old leaves. Prevention and control methods for sulfur deficiency and iron deficiency: It can be sprayed with 0 30 ferrous sulfate aqueous solution, 3 times in a row, with an interval of 1 week each time, and the fog point should be fine and uniform when spraying.

At the same time, 0 20 urea iron solution can be used for extra-root top dressing.

The planting time of greenhouse vegetables is much shorter than that of open-air vegetables, and at the same time, greenhouse vegetables can be prevented from bad weather, pests and diseases in a timely manner. But we know that greenhouses are generally impermeable, which leads to the dampness inside the greenhouse breeds many bacteria and pests, so how should we prevent the occurrence of vegetable pests and diseases in greenhouses, the following will introduce you to several prevention and control methods.

1. Pay attention to observation and early detection of pests and diseases.

Once it is found that there are water stains and mold on the leaves, it can be determined that the disease has begun to be infected, and attention should be paid to prevention and control in advance. At this time, the number of pathogenic bacteria is small, and the control effect is good. Only 1-2 sprays of protective agent can achieve a good control effect.

Observation position: Grasp the two key positions on the front of the greenhouse and below the air outlet. Downy mildew, gray mold, grape wilt, etc. are all damp-loving diseases, which mostly occur in front of the shed.

Try to discharge the dew on the shed film to the outside of the shed to avoid water accumulation in the front of the shed, resulting in excessive humidity and easy to induce moisture-loving diseases.

2. Do a good job of air disinfection.

The air disinfection technology is in line with the plant protection policy of "prevention first, comprehensive treatment", with outstanding effects and unique advantages. Air disinfection can kill pathogens in the transmission stage, especially suitable for gray mold, downy mildew, leaf mold and other diseases that mainly rely on airborne transmission. Compared with conventional methods such as fumigation and spraying, air disinfection tablets do not act directly on the vegetable body and are safer for vegetables.

There is no air damage with normal use, and there is no need for separate ventilation the next day. Moreover, the air disinfection tablet plays a gas role and will not adhere to the vegetables, so there is no residue after use, and there is no impact on the safety of vegetables. When the ventilation is normal on a sunny day, the occurrence of diseases is less, and the shed can be smoked once a week, and the prevention effect is very good.

When encountering cloudy days, watering or disease, the frequency of use should be increased, and it can be used once every 2-3 days. When discharging the medicine, it should be carried out sequentially from the inside of the shed to the outside of the shed, and the action should be rapid to avoid inhaling the disinfectant gas.

3. Reduce the source of disease and completely remove diseased branches and rotten vegetables.

In winter, gray mold, sclerotinia and cotton blight are common in fruit rot. Vegetable farmers often use symptomatic drugs for prevention. The main reason is that the diseased branches and rot are not removed, resulting in the continuous infection of the disease. To prevent disease, special attention should be paid to reducing pathogenic bacteria in sheds.

Clean up the shed in time after picking vegetables. Eggplant, tomatoes and other vegetables need to be harvested in large quantities to ensure ventilation and light transmission and reduce the occurrence of diseases. However, after picking the leaves, vegetable growers should pay attention to cleaning them from the shed in time to avoid the spread of germs.

Do a good job of surface sterilization, and the disease prevention effect is better. Most diseases overwinter and summer in the soil, and infections also spread from the soil. Good surface sterilization treatment can reduce the number of pathogens at the source and greatly reduce the occurrence of diseases.

It is necessary to do a good job of prevention, to use pesticides, fungicides, herbicides in a timely manner, to ensure ventilation, to ensure temperature, but also to ensure soil fertility.

Spraying pesticides immediately is the most correct way, and you also need to pay attention to the temperature, and slowly these pests and diseases will disappear.

You can eliminate pests and diseases, and you can also use some insecticides on the vegetables in the greenhouse, so that all pests and diseases can be eliminated.

Growing vegetables in greenhouses is prone to fertilizer damage, what are the fertilizer damages? The phenomenon of chemical fertilizer damage in vegetable reserve areas is more serious. There are many reasons for this. The fertilizer loss of greenhouse vegetables can be broadly divided into three categories.

One is that the amount of chemical fertilizer is too large or too close to the plant, and the crop is burned by high concentration of chemical fertilizer, such as too much urea at one time will burn the seeds or seedlings.

Second, the excessive application of one nutrient leads to a deficiency of other elements. For example, excessive application of potassium fertilizer will result in a lack of calcium and magnesium in the crop.

The third is closed management, excessive application of nitrogen fertilizer, no soil covering or timely ventilation after application, resulting in ammonia or nitrite gas poisoning.

So how to scientifically and reasonably prevent the harm of these three fertilizers in the process of greenhouse vegetable planting?

1. Scientific and reasonable fertilization. In particular, it is necessary to prevent excessive fertilization at one time; After the basal fertilizer is applied, the soil should be covered in time or the basal fertilizer should be well mixed with the soil. When greenhouse vegetables are covered, they should be rinsed with water according to the required concentration.

If it is spraying or sub-application, the sub-application should be deep and covered in a timely manner. After fertilization, it should be watered in time. Spraying fertilizer on the greenhouse floor is not allowed and is no longer managed.

2. Pay attention to the balanced fertilization of greenhouse vegetables. Especially when applying potassium fertilizer, do not blindly assume that applying more potassium fertilizer can flower and bear fruit and increase yield. Greenhouse vegetables also need to be nutriently balanced, and the application of potassium fertilizer should also pay attention to the appropriate amount and frequency.

When applying zinc, iron and other trace element fertilizers, do not mix directly with phosphate fertilizers, but it is best to mix them with organic fertilizers or other nutrient fertilizers before applying, the effect will be better.

3. Pay attention to the appropriate amount of nitrogen fertilizer applied to greenhouse vegetables. When nitrogen fertilizer is applied to greenhouse vegetables, if nitrogen fertilizer is applied excessively, it is easy to cause ammonia and nitrite gas to accumulate in the greenhouse soil, and after volatilization, it will cause ammonia combustion damage to greenhouse vegetables. In addition to the proper application of nitrogen fertilizer, it is best to apply it in combination with phosphorus, potassium fertilizer and other fertilizers.

After application, it should be washed with water or covered with soil in time, so that the nitrogen fertilizer can be fully absorbed and utilized by greenhouse vegetables as much as possible.

4. In the process of greenhouse vegetable planting, organic fertilizers, slow-release and controlled-release fertilizers should be applied as much as possible. Because fertilizers with slow nutrient release can not only make it easier for greenhouse vegetables to fully absorb and utilize, but also reduce the production of harmful gases and inhibit the production of nitrite gas. It can also use some nitrification inhibitors in a timely and appropriate manner to further prevent the production of nitrite gas.

In short, in the process of greenhouse vegetable planting, it is necessary to pay attention to scientific and reasonable fertilization, balanced fertilization, especially the rational application of nitrogen fertilizer. In addition, we should develop the good habit of observing frequently, being good at thinking, and summarizing. When we find that there is fertilizer damage, we should find the cause in a timely and reasonable manner, and apply the drug to the case to avoid unnecessary economic losses caused by fertilizer damage.

If the nutrient concentration is too high, it is a fertilizer type. Chemical fertilizers or organic fertilizers are often applied too much at one time, exceeding the amount required for vegetables; Toxic gas fertilizer damage. It mainly refers to ammonia, nitrogen dioxide and sulfur dioxide gas poisoning.

Other fertilizer damage phenomena. Use urea as seed fertilizer or seed dressing, because urea is a high-concentration fertilizer, containing a certain amount of biuret, so that it loses its germination ability; Dehydrated fertilizer. Due to too much chemical fertilizer at one time, or insufficient soil moisture, the concentration of fertilizer solution in the soil after fertilization is too large, resulting in reverse osmosis of water in crop cells, resulting in crop dehydration

Growing vegetables in greenhouses is easy to fatten. What are the fat damages? The phenomenon of vegetable reserves being destroyed by chemical fertilizers is more serious.

There are many reasons for this. The fertilizer loss of greenhouse vegetables can be roughly divided into three categories. One is that the amount of chemical fertilizer is too large or too close to the plant, and the crop is burned by the high concentration of chemical fertilizer.

For example, if there is too much urea at one time, it will burn the seeds or seedlings. The second is that the overapplication of one nutrient leads to the deficiency of other elements.

There is a possibility that there will be rotting, many plants may be burned to death, be sure to pay attention to the use of farm fertilizer, be sure to pay attention to the use of urea.

There are many reasons why vegetable leaves turn yellow, and they cannot be solved by blind fertilization alone. First of all, find the location and reason for the yellowing of the leaves, if it is an old leaf, it is a normal yellow leaf, if the soil unexpectedly PH changes, it becomes alkaline soil, it is necessary to use the acid fertilizer ammonium ferrous sulfate or grass, leaves watered to improve; If there is a serious lack of nitrogen fertilizer, urea, ammonium carbonate, etc. should be watered; If it is chemical pollution, it is necessary to block the source of pollution and improve the polluted environment; If it's stagnant water, drain it, and so on.

Vegetable. First of all, let's analyze the main reasons for the total yellowing of vegetable leaves. The reasons that usually cause the yellowing of vegetable leaves are improper fertilization (such as insufficient trace element fertilizer), improper watering (insufficient water or excessive water resulting in nutrient loss), low ambient temperature leading to obstruction of nutrient absorption of vegetable plants, and insufficient light leading to obstruction of nutrient synthesis of vegetable plants.

According to the above analysis, we can see that most of the causes of yellowing of vegetable leaves are related to the lack of nutrients, so the main measure to prevent yellowing of vegetable leaves is to ensure the nutrient supply of vegetables, that is to say, fertilization is very important in this process.

Vegetable. In fact, in the countryside, when we grow vegetables in the vegetable garden or on our own balcony, we pay the most attention to the bottom fertilizer of the land preparation, and rarely go to the middle of the top dressing, even if they encounter problems, many people are just blindly seeking solutions, so there is a situation of abuse of chemical fertilizers and pesticides.

When it comes to pesticide damage to vegetables, in fact, pesticide damage can also cause yellowing of vegetable leaves to a certain extent. For example, when we use drugs, in order to take effect quickly, we often increase the concentration of pesticides, and although the effect is reached, it is often easy to cause pesticide damage to vegetables. In this case, it should be rinsed with water in time, and an appropriate amount of brassinin should be added to promote the growth of vegetables.

Vegetable. The vegetable plant itself is injured, such as the root is damaged, resulting in obstruction of nutrient absorption, and it is also one of the most common reasons for the yellowing of vegetable leaves, sometimes even because the roots of the plant are damaged, causing vegetables to wilt is also very common, this situation mostly appears in the transplanting process of vegetables, of course, sometimes the bottom fertilizer is too thick, it will also cause the vegetable to burn the roots, which is still the yellowing of vegetables caused by improper fertilization.

Therefore, for different vegetables, we also need to use different fertilizers and adopt different fertilization methods. For example, leafy vegetables, we usually use nitrogen fertilizer and organic fertilizer; Fruits and vegetables should pay attention to the application of base fertilizer, pay attention to the ratio of nitrogen, phosphorus and potassium fertilizer, and root vegetables should not only pay attention to base fertilizer, but also not ignore top dressing.

Vegetable.

The reasons for the small and yellowish growth of vegetable leaves are too much water, insufficient nutrients, and soil hardening. It is necessary to loosen the soil, make the soil permeable and air permeable, and appropriately spray trace element foliar fertilizer and chelated trace element iron fertilizer to improve these conditions.

Why is it not pests and diseases that destroy your greenhouse vegetables, but pesticide damages?

What should I do if I use it incorrectly?

If the vegetables in the shed have symptoms such as wilting and death of the parietal leaves and leaf edges, after opening the tuyere and thoroughly releasing the air, sweep away the water droplets on the roof film of the shed, spray love more in time, brassinolide, etc., apply well-rotted organic fertilizer, top dressing to eat less and eat more meals, prevent overdose and other measures to rescue.

This is the first common type of pesticide damage, tobacco pesticide damage. The following is the second type of drug harm that often occurs, hormone drug damage.

Nowadays, the use of plant growth regulators has become very common, such as gibberellin, mequatin, ethephon, etc. are commonly used in vegetables. To be honest, these hormone drugs have a good effect on increasing vegetable yield and improving quality. At the same time, if we use it improperly, it is often harmful.

Such as excessive spraying of paclobutrazol, mequaticin, etc., often cause vegetables not to grow, which has to be sprayed with antidotes, such as Aiduo, gibberellin, brassinolide and other growth promoters.

If the dosage is too large, it will often cause tomato fruit deformity, such as peach-shaped fruit, spire-shaped fruit, tumor-shaped fruit, eccentric fruit, bean-shaped fruit, etc., and hollow fruit, cracked fruit, etc.; Dropping on the leaves will cause the leaves to be distorted, slender and bent, and the new leaves will not spread.

If there are symptoms of this pesticide damage, we have to spray gibberellin in time to rescue, and at the same time strengthen the application of phosphorus, potassium fertilizer and organic fertilizer. However, nitrogen and potassium fertilizers should not be applied to split fruits, and calcium fertilizers and boron fertilizers should be supplemented in time.

Although gibberellin can alleviate hormone damage, excessive use of gibberellin will also cause drug damage, if the fruit is stiff, cracked, fruity and astringent, and the plant is greedy for green and late ripening. For gibberellin damage, paclobutrazol must be sprayed to inhibit the synthesis of gibberellin in the plant itself, and at the same time spray anti-falling hormone to relieve the symptoms of hormone poisoning.

No matter what kind of hormone overuse causes pesticide damage, it is necessary to strengthen management, such as increasing greenhouse temperature, strengthening water and fertilizer management and other agricultural measures, enhancing the nutrient supply of plants, and promoting the absorption of nutrients by vegetable roots, which can speed up the recovery and minimize the loss.