With the advancement of the times, the pesticides on the market are different from the past. It is far from enough to apply pesticides only by relying on past experience. It is also necessary to systematically master some knowledge of pesticide use, especially the contraindications of some pesticides must be kept in mind. Otherwise, it will not be effective, and there may be phytotoxicity problems. Let's follow the Xiaobian to understand it.
First, avoid using live water to prepare pesticides. Because there are many impurities in the living water, it is easy to block the nozzle of the sprayer by using the medicine, and it also destroys the suspension of the liquid to cause precipitation.
Second, avoid increasing the amount of water. Because too much water is added, the concentration of pesticides is lowered, and only a small amount of pesticide is left on the crop, which is not enough to kill the pests, and some will completely fail and lose the killing ability. Excessive addition of water can also cause the loss of pesticides and lead to environmental pollution. Therefore, when formulating pesticides, the amount of water added should be strictly controlled according to their concentration range.
Fourth, avoid using pesticides in the rainy days or in the hot sun. Spraying pesticides during windy will cause pesticide powder or liquid to scatter, while spraying pesticides on rainy days, the chemicals are easily washed away by rain and reduce the efficacy. Spraying pesticides under the scorching sun, the plant metabolism is strong, the leaves are open, and drugs are prone to occur. It is easy to make the drug volatilize and reduce the control effect. Therefore, it is advisable to master the best application time, 9-11 am, 3-6 pm.
Fifth, avoid increasing the amount of pesticides. Because the pesticides must pass the strict field efficacy test before being approved for production and sales, and then determine the actual use data such as the amount of the drug, the time of administration, and the number of times of application. Therefore, apply in the amount specified in the instruction manual. It can achieve the effect of prevention and control, and the increase in the amount of drug will not only increase the input, but also cause phytotoxicity of crops, increase the amount of pesticide residues in agricultural products, and increase environmental pollution. 6. Avoid mixing unreasonable pesticides. Some pesticides can increase the control effect, reduce the dosage, or achieve the effects of pests, grasses or insects, and cure the disease, and the mixed application is more labor-saving, but some can't, such as most of the organophosphorus pesticides are alkaline. Pesticide or alkaline medium will rapidly decompose and fail; replacing urea herbicide with phosphate ester pesticide will cause phytotoxicity to cotton seedlings; mixed use of enemy emulsifiable oil and organophosphorus pesticide will make rice unable to decompose enemy phlegm and cause phytotoxicity . When you need to mix pesticides, you must understand the nature and characteristics of various pesticides, and find out whether they can be mixed. Please consult the relevant technical personnel before mixing.
7. Avoid using expired pesticides at will. Pesticides must be used within the shelf life, otherwise it will cause losses.
Eight, avoid spraying pesticides during the flowering period of crops. In the flowering and young fruit stages of crops and fruit trees, the tissue is young, the resistance to stress is weak, and it is prone to phytotoxicity. Therefore, it is necessary to avoid the flowering (flowering) period and the fruit tree and young fruit period when spraying.
9. Avoid spraying pesticides before harvesting crops. Generally, the period of high-efficiency and highly toxic pesticides is about 60 days, and the period of high-efficiency and low-toxic pesticides is about 15 days. Therefore, whether it is food, vegetables, or fruit trees, it is forbidden to apply drugs before harvesting to avoid food or food poisoning.
Ten, avoid abuse of pesticides. The corresponding pesticide should be used according to the variety of crops, the object of control and the performance of the drug, so as to cure the problem and avoid using a certain agent for a long time.
Identification of whether pesticides are ineffective
For new purchases of pesticides, first of all, pay attention to their production date and shelf life. Drugs that are close to or close to the shelf life should not be purchased as much as possible to reduce the risk of drug failure or partial failure. The following is a brief introduction to the identification method of pesticide failure:
1 intuitive method
For powder pesticides, first look at the appearance of the medicament. If it has been obviously agglomerated by moisture, the taste of the medicine is not strong or has other odors, and it can be smashed into a group by hand, indicating that it has basically failed; for the emulsion pesticide, the medicine bottle is first allowed to stand, if the medicine The liquid is turbid or stratified (ie, oil-water separation), precipitate formation or floc suspension, indicating that the agent may have failed.
2 heating method
Suitable for powder pesticides. Take 5-10 grams of pesticides and heat them on a piece of metal. If a large amount of white smoke is produced, and there is a strong pungent smell, it means that the medicine is good. Otherwise, it means that it has failed.
3 floating method
Suitable for wettable powder pesticides. First take 200 grams of water, then weigh 1 gram of pesticide, gently and evenly spread on the water surface to observe carefully, wet in 1 minute and can sink to the water is the non-failed pesticide, otherwise it is a failed pesticide.
4 suspension method
Suitable for wettable powder pesticides. Take 30-50 grams of pesticides, put them in a glass container, add a small amount of water to make a paste, then add 150-200 grams, stir well with water, and let stand for 10 minutes to observe. The pesticides that have not failed are well soluble. The suspended particles in the medium are fine, the sedimentation rate is slow and the amount of sedimentation is small, and the pesticide is reversed.
5 oscillation method
Suitable for emulsion pesticides. For pesticides with oily water layer, first shake the vial with force and let it stand for 1 hour. If stratification still occurs, the agent has deteriorated.
6 hot melt method
Suitable for emulsion pesticides. Put the pesticide with the precipitate into the warm water (the water temperature should not be too high, preferably 50 ° C -60 ° C), after 1 hour, if the sediment slowly dissolves, the agent has not expired, and the precipitate is dissolved. After that, it can continue to be used; if the precipitate is difficult to dissolve or dissolve, it means that it has failed and can no longer be used.
7 dilution method
Suitable for emulsion pesticides. Take 50 grams of pesticide, put it in a glass bottle, add 150 grams of water, and shake it vigorously for 30 minutes. If the liquid is evenly milky white, it will be a failed pesticide, and the more the upper layer of oil, the worse the drug.
If the newly purchased pharmacy has any of the following appearances, it should not be purchased; if the stock agent is close to or has passed the shelf life, but it does not want to be wasted, it can be identified by the following method. Without any of the following symptoms, after the partial experiment Used.
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