Learn these four skills of using aerosol, and there will be no trouble to prevent and control crop diseases and insect pests in greenhouse in winter.

In winter, the low temperature, high humidity, scarce light and relatively closed environment, coupled with rainy and snowy weather, can easily induce various pests and diseases of fruits and vegetables planted in greenhouses in winter. However, due to the high humidity and weak light in the greenhouse in winter, it is generally not suitable to use spraying method in crop pest control, because spraying liquid medicine is not only easy to further aggravate the humidity in the greenhouse, but also prolong the residual time of drugs and the time for crops to absorb liquid medicine, which is easy to aggravate the disease or induce new pests and diseases, and also easy to cause crop phytotoxicity due to excessive drug absorption.

Therefore, in the management of pests and diseases of greenhouse crops in winter, the safety factor of spraying drugs to control pests and diseases is not as high as that of using aerosol to control pests and diseases, and using aerosol drugs to control pests and diseases in greenhouse in winter is also one of the most commonly used methods for our farmers.

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? Compared with the spraying method, although the use of aerosol medicine to control pests and diseases has the advantages of no increase in humidity in the shed, less drug residue, uniform and comprehensive efficacy, labor saving, simple operation, safety and convenience, etc., if the use of aerosol medicine is inexperienced or improper, not only the efficacy will be reduced, but also crops will be more prone to whitening, scorching and even death.

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? At present, many farmers are using aerosol to control pests and diseases in greenhouses. In order to help you prevent and control pests and diseases more scientifically and reasonably, today I will share with you some points for attention and skills in the use of smog in greenhouses for your reference.

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? First, we should choose the most suitable aerosol drugs scientifically and reasonably.

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? Although they are all aerosols, aerosols can be divided into fungicides and pesticides in pest control, and can be divided into tablets, powders and granules in appearance. In addition, different types of smoke fumigants not only have different effective components, different drug characteristics and different application scope, but also have certain differences in the target objects and dosage of pest control. Everyone should pay attention to flexibly choosing the most suitable smoke fumigant according to the actual situation of their own greenhouses and the types of pests and diseases that need to be controlled.

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? For example, at present, the common bactericidal smoke agents on the market mainly include chlorothalonil smoke agent, sclerotium smoke agent, procymidone smoke agent, and Sukeling smoke agent. Common insecticide smoke agents mainly include isoprocarb smoke agent, aphid control smoke agent and fenvalerate smoke agent. For another example, if diseases such as downy mildew, anthracnose, gray mold, early blight and powdery mildew are prevented, chlorothalonil and procymidone can be used; For example, to control aphids, acaroid mites, liriomyza sativae and other pests, isoprocarb smoke agents, insecticidal smoke agents and smoke-killing smoke agents can be used; For example, to prevent and control pests such as red spider and tetranychus urticae, mite smoke-dead smoke agent can be used; For another example, chlorothalonil fumigant is effective in controlling downy mildew, anthracnose and other diseases, while the effect of using Junzhujing fumigant and Procymidone fumigant in controlling gray mold is more obvious.

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? In addition, because the climatic conditions in winter are very unfavorable to the normal growth of crops, and some crops are sensitive to certain drugs, we should use "azole", "alcohol" and "pyrimethanil" fumigants carefully when using tobacco fumigants to prevent the normal growth and development of crops from being affected after use.

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? At the same time, generally speaking, smoke fumigants are most suitable for use in greenhouses with large space, and medium-sized greenhouses should be used with caution. It should not be used in a small arch shed with insufficient space or a greenhouse with multi-layer coverage, otherwise crop phytotoxicity will easily occur during fumigation. In addition, powder smoke fumigant and granular smoke fumigant are more suitable for greenhouses with relatively large width, and sheet smoke fumigant is more suitable for greenhouses with narrow width.

Second, know the best time to use fumigant.

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? Because smoke fumigant drugs mainly kill germs and pests by releasing medicine gas to penetrate into every corner of crops and greenhouses, the function of smoke fumigant is mainly that fine dust smoke particles of smoke fumigant float and sink in the air and are adsorbed to various tissue parts on the surface of crop seedlings, so it is not conducive to smoke fumigant to exert its efficacy at noon on sunny days or at high temperature. It is more suitable for use in cloudy days, rain and snow, morning and evening when the air humidity is high and the temperature is low, which is more conducive to the more uniform sinking and adsorption of the powder and mist particles of the fumigant, thus giving play to better drug effects;

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? In addition, because the smoke fumigant permeates every corner of the greenhouse and the surface of crop seedlings evenly through the movement, floating and sinking of the dust particles of drugs in the air, it is only suitable for use in a completely closed environment of the greenhouse, not suitable for use in open-air plots and greenhouses with air leakage.

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? According to these characteristics of smoke fumigant, when using smoke fumigant to control pests and diseases in greenhouse, the best weather is cloudy, rainy and snowy weather, and the best time to use smoke fumigant is to close the greenhouse and light it in the evening. Of course, it can also be used when crop leaves are wet, foggy and condensed in the morning and evening.

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? At the same time, the best time for pest control is generally in the early stage of the disease, so is the smoke fumigant. Therefore, on the basis of correctly grasping the weather and time of using smoke fumigant, using smoke fumigant in the early stage of disease occurrence can achieve more remarkable control effect.

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? Third, master the dosage, frequency and safe interval of smoke fumigant flexibly.

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? Although smoke fumigant is good, it is necessary to master the dosage, frequency and safe use interval, which requires everyone to flexibly decide the actual effective dosage according to the space size of their own greenhouse, the occurrence degree of pests and diseases, the effective drug content, the growth situation and growth stage of crops. If the dosage of smoke fumigant is too large, it will easily lead to crop injury and drug residue, and if the dosage of smoke fumigant is too small, it will reduce the effect of pest control, which we should pay special attention to.

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? In terms of the dosage range of smoke fumigant, under normal circumstances, the dosage of smoke fumigant is about 250 grams per mu in general diseased plots, and the dosage of insecticidal fumigant is about 400 grams per mu. For plots with small greenhouse space or light pests and diseases, or before and at the early stage of crop growth, the dosage per mu can be reduced by about 50-100g according to the actual situation. According to the actual situation, the dosage per mu can be increased by about 50- 100g for plots with large shed space or serious pests and diseases, but the actual dosage must be flexibly determined according to the content of effective components to prevent crop phytotoxicity caused by too little or too much medication.

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? If 10% procymidone fumigant is used to control downy mildew, gray mold and epidemic diseases, the dosage can be about 250-300g per mu at the initial stage of the disease, and it should be increased to 400-500g when the disease is serious, so as to achieve more remarkable results. In addition, the actual dosage of fumigant should be scientifically calculated according to the content of effective components. The dosage should be appropriately reduced if the active ingredient content is high, and increased if the active ingredient content is low. For example, the contents of effective components in chlorothalonil fumigant are 2.5%, 2.5%, 10%, 20%, 28%, 30%, 45% and so on.

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? In terms of the frequency and frequency of use of smoke fumigants, generally speaking, it is enough to use both insecticidal smoke fumigants and bactericidal smoke fumigants once before or at the early stage of occurrence of pests and diseases. However, in the middle and late stage of occurrence of pests and diseases, it is generally necessary to smoke the shed continuously for 2-3 times according to the situation of pest control, and the interval of safe use is generally 7- 10 day 1 time. If the disease is serious or the airtight shed is poor, the safety interval can be shortened to about 5-7 days or the dosage can be increased appropriately, but no matter how many times it is used, the dosage is too large or the interval is too short, it will easily have an adverse impact on the normal growth and development of crops, which everyone needs to pay attention to.

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? Fourth, master the operating methods and specifications of fumigants.

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? 1, to ensure good sealing of the shed.

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? There are ventilation holes or air leakage holes in the greenhouse, which will cause the smoke and dust particles after the smoke fumigant is ignited not to settle evenly on the crops, which will easily lead to the amount of drugs adsorbed on the crops, resulting in bacteria and pests on the seedlings with less drugs adsorbed, while the seedlings with more drugs adsorbed will produce phytotoxicity. Therefore, before using the smoke fumigant, it is necessary to comprehensively check the overall tightness of the greenhouse, all tuyeres should be completely closed, and all holes should be repaired before lighting the smoke fumigant.

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? 2. Pay attention to the use of fumigants.

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? When using smoke fumigant, on the one hand, drugs should be evenly placed on the open space according to the space size of the shed. Generally, 5-8 drug placement points can be set up per mu of shed area; On the one hand, it is necessary to keep a proper safe distance between smoke fumigant and crops (to prevent crops from being hurt by drugs), and it is suggested to put drugs in a safe position 30-40 cm away from crop roots; On the other hand, to avoid putting the fumigant directly on the ground (to prevent the medicine from getting wet), it is recommended to use dry bricks, stones, iron wires, etc. As a bracket, put the medicine about 30 cm above the ground; On the other hand, we should pay attention to the ignition sequence of smoke fumigants, and suggest that everyone ignite smoke fumigants in reverse order from inside to outside in the shed; Finally, after all the smoke fumigants placed in the shed are ignited and generate smoke normally, they should leave the shed quickly, and then completely close the shed door for continuous fumigation. They are not allowed to enter or leave the work shed during the use of drugs.

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? 3. It is necessary to know the duration of fumigant fumigation.

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? When smoke fumigant is used to control pests and diseases in winter, many farmers start to light the medicine at night and close the shed for continuous fumigation. The fumigation time lasted until the next morning, and the drug fumigation time was not only more than 8 hours, but even as high as 10- 15 hours in some greenhouses, which easily caused crops to absorb excessive drugs and produce phytotoxicity. Moreover, the fumigation time of smoke fumigant is long, which leads to various phytotoxicity of crops in the shed.

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? Here, I would like to remind you in particular that under normal circumstances, when using smoke fumigants to control pests and diseases, the curing time of insecticidal smoke fumigants should be appropriately short, generally within the range of 4-6 hours, while the smoke production of bactericidal smoke fumigants is relatively small, so the curing time of bactericidal smoke fumigants can be appropriately long, generally within 6-8 hours.

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? Therefore, when you use smoke fumigant, it is suggested that you order the medicine around 0: 00 -2: 00 at night and ventilate it in the early morning of the next day to ensure that the curing time of smoke fumigant is within a reasonable range.

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? 4. Pay attention to timely and thorough ventilation after fumigation.

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? No matter whether the fumigant of sterilization smoke or fumigant of insecticidal smoke is used, the ventilation in the shed should be opened in time after fumigation is completed, so that the medicine gas remaining in the shed can be discharged out of the shed in time to prevent the medicine gas from being harmful to crops for a long time.

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? Finally, I need to remind everyone that before you plan to fumigate the greenhouse with smoke fumigant, you should pay attention to check the weather forecast of the day in advance, especially the weather forecast of the next day after fumigation. If you encounter bad weather that you can't open the shed for normal ventilation the next day after fumigation, you can't fumigate the day before, so as to avoid that you can't open the shed for ventilation the next day and the drugs will stay in the shed for a long time and cause damage to crops.