In cloudy winter days, the humidity in the greenhouse decreases, and the humidity often increases, which often causes an outbreak of diseases. Many vegetable farmers choose to use fumigants or powders to prevent or treat vegetable diseases. However, the reporter recently discovered in an interview that many vegetable farmers experienced phytotoxicity after using fumigant or powder. After the Wang Cun Wang master of the ancient city street of Shouguang City, the tomatoes used to have a whitening edge due to the use of a fumigant, some of the flower buds were detached, and the dry edges of the upper leaves were severe. So, how to use the fumigant to avoid the occurrence of injury?
The first is the choice of drugs. There are many pharmaceuticals, vegetables are more sensitive to them, if you do not choose to use it, it is very easy to cause injury. Therefore, it is better not to use the flue gas that contains pyrimethanil or "azole" or "alcohol".
The second dose should be accurate. The dosage of the medicine should be determined according to the size of the indoor space in the shed and the degree of the occurrence of pests and diseases. The height of the shed, the space in the shed, and the seriousness of pests and diseases may increase the amount of the smoke agent. Such as the prevention of downy mildew, early and late blight, etc., can use 45% chlorothalonil smoke agent 300-350 grams per mu; control gray mold, sclerotia, etc., can use 50% of procymidone agent 350-400 per mu Grams or vinyl sclerotinia smoke agent 200-250 grams per mu; control locusts, leaf miners, whitefly, etc., can choose to use 10% Isothermal Smoke agent 400-500 grams per mu. If pests are to be controlled at the same time, the amount of bactericide and insecticide should be appropriately reduced.
The third smoking time is well controlled. General smoking time can not be too long, normal smoking time is generally about 6-8 hours, the longer the time, the easier it is to have problems. After the smoked medicine is finished, it is timely ventilated to prevent the gas from staying in the shed for a long time, resulting in the failure of normal growth of the vegetables.
The fourth is to watch the weather forecast in time. If the sky is too heavy to pull the shed, the smoke cannot be smoked. In this case, because the air in the shed does not circulate for a long time, if the smoked medicine fails to release the wind in time, it is easy to cause damage to the shed crop. Therefore, the weather forecast should be watched in a timely manner. If it is determined that the next day can be successfully turned to sunny weather or the straw curtain can be ventilated, smoking can be performed the night before.
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