Pay attention to the application of aerosol in greenhouse

In winter and early spring, vegetables are easy to induce a variety of diseases and insect pests because of the low temperature and high humidity in the plastic greenhouse. Using aerosol to control vegetable diseases and insect pests in greenhouse is a new technology to control diseases and insect pests by condensing pesticides into smoke particles or directly dispersing pesticides into smoke particles after pesticide gasification. It has the advantages of simple and labor-saving, good efficacy, avoiding the increase of humidity in the greenhouse, low cost and less pesticide residues, and the control effect is obviously better than spraying, powder spraying and other application methods, especially in rainy days or disease epidemic periods. However, if it is not used properly, it can not achieve the desired effect. In order to improve the quality of control, we must pay attention to the following points in the process of application:

First, check the shed surface. Smoke agent is to use smoke as the carrier to achieve the purpose of application, so it is necessary to check the greenhouse surface before using smoke agent in the greenhouse, fill up the loopholes, make the greenhouse surface closed tightly, and the stricter the prevention and control effect is, the better.

Second, choose the appropriate dosage form. There are many kinds of smoke agents in the market, including tablets, dust agents and granules. According to the characteristics of the greenhouse, tablets are most suitable for more narrow and long leek sheds, and powders and granules are suitable for wide greenhouses such as tomatoes, cucumbers and other vegetables and fruits.

Third, apply medicine to the disease. Before applying medicine, it is necessary to find out the occurrence of diseases and insects and use drugs for symptoms. For the control of downy mildew, blight, gray mildew, etc., 10% chlorothalonil smoke agent or 15% carbendazim smoke agent, 200 grams per mu, 15% carbendazim smoke agent, 250 grams per mu, and 22% dichlorvos smoke agent or aphid control agent, 300 grams per mu can be used for the control of aphids.

Fourth, use medicine as early as possible. During the period of vegetable growth, it is necessary to strengthen the investigation of the occurrence of diseases and insect pests and control them timely. The general control of diseases should be used before or at the initial stage, once every 7-10 days, continuously for 3-4 times, and pest control should be used in the initial period and controlled as soon as possible.

Fifth, the dosage is appropriate. The amount of aerosol used in the greenhouse can neither be too high nor too low. If the dosage is too high, it will waste chemicals and aggravate the pollution; if the dosage is too low, it can not achieve the ideal control effect. Therefore, the best dosage should be selected. The details should be determined according to the space size of the greenhouse, the occurrence degree of diseases and insect pests and the effective content of smoke agent. If you want to control cucumber downy mildew and gray mildew, you can choose 45% chlorothalonil aerosol, 200 grams per mu, smoking once every 7 to 10 days, 3 times in a row. The greenhouse with serious disease or poor closure can increase the dose appropriately.

Sixth, the method of pesticide application should be correct. The main results are as follows: (1) the determination of discharge point: there is a large space in the greenhouse, and all kinds of smoke agents with active components can be used. The active ingredient content of smoke agent is generally 10%-50%, and there can be more discharge points, which can be set up at 6-10 points per 667 square meters. In order to prevent drug damage caused by high concentration smoke fumigation for a long time near the discharge point, the discharge point should be slightly away from crops; in relatively small greenhouses, smoke agents with low active components (10%, 15%) should be selected, and the discharge point can be increased appropriately; small sheds with a height of less than 1.2 meters should not use smoke agents, otherwise they are easy to cause drug damage. (2) discharge method: because the smoke deposition has the characteristic of avoiding heat, the effect of application under sunlight is not good, and it is the best to use it at the end of work after sunset in the evening. The smoke at the entrance of the shed should be lit sequentially from inside to outside the shed room, and the smoke agent at the entrance of the shed should be lit at last. Pay attention to blow out if there is an open fire after lighting, make it smoke normally, seal the greenhouse quickly after lighting, and then carry out farming operation after ventilation in the early morning of the next day.

7. Alternate and alternate use of drugs. In the prevention and control of diseases and insect pests, two or three kinds of smoke agents should be used alternately and alternately according to the control objects, so as to avoid using the same smoke agent for many times.

Aerosol should be stored in a dry place. To avoid approaching the source of fire, aerosol can be used alone or alternately with dust and spray.