How to spray pesticides scientifically?
Grasp the timing of spraying, often see the vegetable farmers friends used to spray medicine for three days or four days, thinking that this can be safe and worry-free.
In fact, this method is very wrong, not only the cost is increased, but also the drug is particularly prone to cause rapid increase in pest resistance, so that it cannot be controlled when it occurs.
A reasonable method is to use the drug at the beginning of the pest, and the disease is recommended to spray a protective fungicide on a regular basis. At the beginning of the disease, a symptomatic therapeutic fungicide is taken according to the type of the disease. The appropriate amount of liquid spray is not as much as possible.
Usually, there are often vegetable farmers who ask me to spray a few barrels of water when spraying. In fact, this is a problem that cannot be answered. The most reasonable amount of liquid spray when spraying is to spray the leaves to the surface and it is just the best. good.
Scientific experiments have shown that if the amount of liquid remaining on the leaves after spraying the leaves is only about half of that when the liquid drops on the leaves, not only a lot of waste is caused when spraying the dripping water, but also the actual control effect is large. discount.
Some vegetable farmers are accustomed to spraying liquids very little, and the concentration of drugs is very high. This is also unscientific, because it is not only prone to phytotoxicity, but also the phenomenon of leakage is serious, the target is not sprayed, and the control effect is not satisfactory.
Different control targets, different spraying positions If spraying drugs to control pests such as thrips, mites, whitefly, etc., the younger parts or middle and upper parts of the plants should be sprayed. If the general diseases are prevented, the lower middle and lower parts should be sprayed. For the old leaves that are prone to disease, to prevent diseases such as rickets, blight, blight, etc., the stem base should be sprayed with emphasis.
When preparing the pharmaceutical liquid, it is recommended that you use the second dilution method, that is, dissolve the pesticide in a small amount of water, and then add it to the water evenly, so that the agent can be dissolved more uniformly in water and the effect is better.
If the pesticides are mixed in a single application, if there are pesticides , fungicides, foliar fertilizers, etc., you must remember that when you use the pharmaceutical liquid, you must first add foliar fertilizer and then add the powder dosage form. Sterilization or insecticide, and finally add the pesticide of the emulsion type.
In this order, the efficacy of the drug is less affected, and conversely, it may have a great impact or even failure on the effects of various pesticides.
Spraying method If using a manual sprayer, it is best to spray against the blade. If it is a mister or a high-pressure electric sprayer, it should be sprayed parallel to the top of the plant. If the plant is sprayed, there will be many drugs. The liquid is sprayed onto the ground, causing waste.
Spraying insecticides and bactericides is generally a person standing on the upper air vent, spraying the front side or just spraying the left or right side, and spraying the herbicide, especially the ground-sealed herbicide, is generally a reverse spray to destroy the film.
How to dilute pesticides?
First, the dilution method
Percentage concentration: refers to the number of parts of the active ingredient containing 100 parts of the drug solution or powder, expressed in %. For example, 2% urea means 2 kg of urea and 98 kg of water in 100 kg of urea solution.
Multiple concentration: refers to the water addition multiple of 1 part of pesticide, which is usually expressed by weight. For example, prepare 700 times of 50% carbendazim, which is made by mixing 50 parts of carbendazim and adding 700 parts of water.
Second, the conversion method
The percentage concentration is converted to ppm concentration: the conversion formula is 1 part of the pesticide plus water = the percentage of pesticide × 1000000 / the number of ppm to be formulated.
For example, a 40% ethephon is formulated into a 2000 ppm solution of 1 kg, and an ethephon is added in an amount of 40% x 1000000/2000: 200 kg ppm.
Convert to multiple concentration: divide the percentage by the number of ppm and shift the decimal point back by 4 to get the dilution factor.
For example, 40% of ethephon is 1000 ppm. When converted to a multiple concentration, 40 ÷ 10000 = 0.4, and the decimal point is shifted back 4 places, that is, 400 times.
Third, the water method
When several pesticides are mixed, not every additional drug is added once, but the same amount of water is used to calculate the concentration.
For example, 500 times of urea and 1000 times of methyl thiophanate are prepared by adding 2 parts of urea plus 1 part of methyl thiophanate plus 1000 parts of water.
In addition, when it is water, it should be formulated into a mother liquid, that is, first use a small amount of warm water to open the liquid, then add water to the desired concentration, fully dissolve, improve the suspension, improve the efficacy, and prevent phytotoxicity.
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