First, watch the weather spray.
If the yin is not bad, you should choose to spray in the morning, otherwise you should not spray. To choose a spray with a finer spray or a better atomization, spray evenly. Do not spray too much on the young shoots and young parts of the crop. Do not spray directly at close range. Do not drop the liquid without any large dew point. The leaf surface before the cover is not wet.
Second, reduce the dilution concentration of the drug solution or reduce the total amount of medication, lengthen the interval between sprays.
At present, it is necessary to mix pesticides at a ratio of 3/4 of the usual drug concentration. It is best not to mix a variety of pesticides at the same time; if it is usually administered, 4 barrels per acre, it can be reduced to 3 barrels under low temperature conditions. Of course, depending on the length of the cloudy day and the type of crop and the tenderness of the foliage, the concentration of the spray and the amount of the pesticide can be flexibly controlled. In winter greenhouses, vegetables have serious diseases, and some vegetable farmers spray once every 5 days. The optimal spraying interval for most pesticides is about 10 days, so especially when it is cloudy, farmers should not spray drugs. If you have a special illness, it is best to spray it once in 10 days to protect the vegetables from disease.
Third, do not spray immediately after the sunny day.
After a few days of cloudy days, the leaf surface of vegetables is not strong due to prolonged photosynthesis, resulting in thin, yellow and tender leaves, and weak fibrous tissue, which is easy to cause phytotoxicity. It should be ventilated for 2-3 days before spraying. If the vegetable leaves have severe wilting, it is necessary to use a method of pulling a straw curtain in time. Or use warm water (25 ° C ~ 30 ° C) plus 150 grams of sugar, love to collect 3 ml of water to 15 kg of the method of spray relief. If the shed film is dirty, do not rush to wipe it, and then wipe off the leaves of the plant without wilting. If the disease is seriously eager to spray control, the drug solution can be mixed with S-Elicitin 1 bag and 1 fresh amine ester. At the same time, the agricultural operation is strengthened to achieve comprehensive prevention and treatment.
4. Care should be taken when using pyrimethanil or an agent with the word "oxazole" or "alcohol".
It is best to use caution or not to use 20% or more of pyrimethanil in cloudy days. It is long-term and slow to evaporate on cloudy days. Due to the particularity of pyrimethanil, it is especially Eggplants such as eggplant and cowpea are prone to brown spots on the leaf surface. Of course, there are many medicines that contain higher pyrimethanil components, but the packaging does not necessarily indicate that the vegetable growers do not know about it beforehand. It is best to use a large area after a small area test. An agent containing an "azole" or an "alcohol" in an active ingredient has a side effect of inhibiting the growth of a crop, and is liable to produce a dwarf strain. Even the weather is not suitable for crop growth, and the improper growth of crops is even more affected.
5. The cloudy shed should be cautious.
Even cloudy days, because the air in the shed is not smooth, it may cause the accumulation of harmful gases and cannot be discharged out of the shed in time. Therefore, the smoked shed is more likely to cause gas damage under cloudy conditions. If some vegetables have white leaves or yellow leaves, some flower buds, young fruits and so on are easily detached. Most vegetable farmers mistakenly believe that cloudy sheds are a good way to use drugs. I don't know if the weather can't turn sunny or the snowy weather can't be released the next day after the shed, it will seriously affect the crop environment and cause crop damage. Therefore, it is necessary to combine the weather forecast with the cloudy sky, and it is even more cautious if it is even cloudy.
Six, spray dust should pay attention.
Even cloudy days are high-risk periods of various diseases such as gray mold, sclerotium, blight, downy mildew, and bacterial. When the disease is serious, do not rush to cure the disease and produce powder poisoning in a single dose. Because many of the dusts contain not only pyrimethanil, but also ingredients such as "oxazole" or "alcohol", there may be components such as sclerotia and Other susceptible Chinese medicines. The correct method of application is to spray powder in the space between the rows of crops. Do not spray directly on the foliage or plants. The amount of use should be used according to the instructions.
Seven, to symptomatic medication.
Even cloudy days often lead to a mixture of various diseases, gas hazards, fertilizers, phytotoxics, and physiological diseases in greenhouse vegetables in winter. The actual production of vegetable farmers should pay attention to distinguish between the symptoms and the symptoms, otherwise the disease should be used according to the disease. Prevention and control have worsened the adverse symptoms of vegetables and affected production.
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