Technical points for safe and efficient use of aerosols in greenhouse vegetables

Aerosol control shed vegetable effect

First, the characteristics of aerosol

The common feature of smoke is that the particles are fine, often in the range of 0.01 to 10 microns, so they can be suspended in the air for a long time without sinking. In the process of air diffusion, the smoke particles do not slowly fall vertically, but a kind of curved motion, moving irregularly in all directions, sinking on the side, so the settlement is very slow, how this characteristic acts on smoke. great influence. After the application of the aerosol, the particles can be deposited in various parts of the treated object, in all directions, throughout the crop and in various parts of the pest. It has good permeability, and it can penetrate into the crops by itself after the formation of smoke, which produces good deposition effect and achieves good efficacy and control effect. The aerosol particles are very fine, so the deposition density on the crop is also very high. Under the same dosage and application conditions, the number of particles deposited per unit area of ​​the smoke method is thousands of times larger than that of the spray method. The distribution is also uniformer than the conventional spray method, and the control is more thorough, avoiding the waste of the conventional spray pesticide. Since the use of aerosols saves labor and equipment costs, the cost of use is also low.

Second, the variety of aerosols and the scope of prevention

At present, the commonly used cigarettes in the production and production are mainly chlorothalonil, chlorpyrifos, carbendazim, chlorpyrifos, and chlorpyrifos. Creamy mildew (bacterial cream) smoke agent, thiabendazole smoke agent, zodiazepine smoke agent, dichlorvos smoke agent, etc., is mainly used for the prevention and control of common pests and diseases of greenhouse vegetables. Such as early blight, late blight, downy mildew, powdery mildew, blight, anthracnose, scab, gray mold, blight, sputum, sclerotinia, aphids, whitefly and so on. Pre-prevention of chlorothalonil can be used before planting in the greenhouse. When the leaf mold of tomato and cucumber in the greenhouse is used, the quick-acting smoke agent can be used. If multiple diseases occur at the same time, the composite smoke agent can be used for prevention and treatment.

Third, the determination of smoke agents and ignition points

The space of the greenhouse is large, and the smoke agent with a high content of the active ingredient can be selected, and the smoke agent with a low content of the active ingredient can also be selected. When using the smoke agent with the active ingredient content (30%, 20%, 10%), the discharge point may be less, generally 3~5 points per acre; when using the smoke agent with high active ingredient content, to prevent discharge The vicinity of the point is caused by long-term high-concentration smoke fumigation, and the burning point per acre can be increased to more than 5, generally 7 to 10 per acre. The shed is relatively short, suitable for the use of low-activity (10%, 15%) smoke agents, the ignition point can also be increased appropriately, generally 7 to 10 per acre to ensure the safety of medication. For small sheds less than 1.2 meters, it is not suitable to use smoke agents, otherwise it will cause phytotoxicity.

Fourth, the determination of the dosage

According to the size of the indoor space of the shed, the degree of occurrence of pests and diseases and the effective content of the smoke agent. Under normal circumstances, the common dosage of common smoke agents is 0.3~0.4 g/m3, which is equivalent to 300~400 g of smoke agent per acre. Prevention and treatment of diseases should be applied at the beginning of the disease. Generally, every 7 to 10 days, once every 2 to 3 times; pest control should be used at the beginning of the period to facilitate early control. If the pests are serious or the sealing performance of the shed is poor, the dosage may be increased or the interval between administrations may be shortened. Such as the prevention and treatment of cucumber downy mildew, blight, tomato early blight, late blight and gray mold, etc., 45% bactericidal smoke remover, 200~250 grams per acre; prevention and control of cucumber powdery mildew, optional 15 % Pythium · chlorobacteria clearing agent, 250 grams per acre; for the prevention and treatment of sclerotinia sclerotiorum, 10% procymidone can be used, each time 250 ~ 300 grams per mu; control aphids, white meal, optional 22% dichlorvos agent, 300~400 grams per acre.

Five, use precautions

1. Strictly sealed. In the greenhouse to control pests and diseases, before using aerosols, it is necessary to check the shed surface and make up the loopholes so that the greenhouse can be closed tightly and the more stringent the better.

2. Choose the time to cast. When applied in the sun, the body temperature of the vegetable plants is basically the same as the temperature of the aerosol particles, and the smoke is not easily deposited, which affects the efficacy and reduces the effect. Therefore, the application time is best to ignite after the grass cover is covered in the evening, and it is best to ignite the disease prevention and pest control in the cloudy evening.

3. Pay attention to the application method. The aerosol should be placed in a large shed in a greenhouse, and the distribution should be uniform. When it is discharged, it should be ignited from the inside of the shed from the inside to the outside with a dark fire. Finally, the aerosol of the shed is ignited. After all the ignited, the person must leave the greenhouse and quickly close the stern. Overnight in the greenhouse, the greenhouse ventilator will be opened the next morning, and the personnel can pass the shed after the ventilation is over.

4, the use of fire. At present, many factories produce smoke agents to increase the safety and use a method of ignition. For example, 45% chlorothalonil (safe type) is one of them. When used, the igniter is first rolled into a cylinder having an inner diameter of 1 to 1.5 mm and an outer diameter of about 4 mm, which is covered from the cigarette carton. The reserved holes are inserted and left about 3 mm for easy ignition.

5. Pay attention to safety. When applying the smoke agent, place the smoke agent in the aisle, pad it with bricks, avoid crops and flammable materials, the aerosol is flammable, and store it in a safe place away from fire. The aerosol is susceptible to moisture. Once it is damp, it cannot be grilled with fire. It should be placed in a cool, ventilated place and slowly dried. Dispatchers should pay attention to their own safety and prevent poisoning.