Pesticide purchase in the pesticide market, if you do not have payment, it is impossible for you to open the inspection. There are seven methods of identification from the appearance, which can help you to make more confirmation when purchasing:
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) has precipitate formation or flocculation, indicating that the agent may have failed.
2. Heating method. Suitable for powder pesticides. Take 5-10 grams of pesticides and heat them on the metal sheet. 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 it has failed.
3. Floating method. Suitable for wettable powders. First take 200 grams of water, take 1 gram of pesticide, gently and evenly spread on the water surface, carefully observed, wet in 1 minute and soluble in water, is a pesticide that has not expired; otherwise it is a pesticide that has failed.
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 150-250 grams of water to shake, and let stand for 10 minutes to observe. The pesticides that have not failed are well soluble and suspended in the liquid. The powder is fine, the sedimentation rate is slow and the amount of precipitation is small; the pesticide that is ineffective is the opposite.
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 solution has deteriorated.
6, hot solubility. Suitable for emulsion pesticides. Put the pesticide with the precipitate into the warm water of 50-60 °C and observe it after 1 hour. If the precipitate dissolves slowly, the pesticide has not expired. If the precipitate is not dissolved or difficult to dissolve, it means that it has failed.
7. Dilution method. Suitable for emulsion pesticides. Take 50 grams of pesticide, put it in a glass bottle, add 150 grams, shake it vigorously and let it stand for 30 minutes. If the liquid is evenly milky white, and there is no oil on the oil, there is no precipitation under it, indicating that the agent is good; otherwise it is a pesticide. .
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