What are the five methods to identify ineffective pesticides?

First, observation method: the powdery pesticide is obviously caked or kneaded into a block by hand, which is not easy to crush, indicating that the drug has long been ineffective and cannot be used. Generally, the moisture content of powdery pesticides is below 55%, which is caused by excessive moisture absorption after long-term storage, resulting in the dissolution of related components. It is found that emulsion pesticides have precipitation and layered flocculation in pesticides. You can put this medicine bottle in boiling water and let it stand 1 hour. If the sediment dissolves, the floc will fade, which shows that the pesticide is reasonable. Otherwise, it cannot be used again.

Burning method: This method is used to identify powdery pesticides. Take 10-20g powdery pesticide, put it on a copper sheet and burn it on the fire. If it smokes, confirm that the pesticide is not invalid, otherwise it is invalid. This method is generally used to evaluate 5% Duoyinling powder.

3. Shake method: This method is used to identify emulsified pesticides. According to the characteristics that emulsified pesticides are easy to delaminate, we should first look at whether they are delaminated. If they are not delaminated, the pesticides are reasonable. If it's layered, you can wave it around several times to make it symmetrical, then let it stand for 40-60 minutes, and then observe it carefully. If it is stratified again, it means that the pesticide is invalid and cannot be used.

Dissolution method: This method is used to identify the deposited emulsified pesticides. Soak the medicine bottle in water at 40℃-60℃ for 60 minutes. If the sediment at the bottom of the bottle melts, it means that the pesticide is not ineffective. If the precipitate does not dissolve, it can be filtered out, a small amount can be taken and injected with appropriate warm water. If the sediment melts, it means that the pesticide can still be used.

Water method: This method is used to distinguish powder, wettable powder and emulsion pesticide. If it is powder, 50 grams of medicine can be put into a glass teacup, and appropriate amount of cold water can be added, stirred to dissolve it, and allowed to stand for 30 minutes. If the particles float evenly and there is no precipitation at the bottom of the bottle, it means that the pesticide is not ineffective. Wettable powder is easy to agglomerate when stored, so it can be ground into powder first and added with a little cold water. If it melts quickly, it means that the pesticide is reasonable, otherwise it can't be applied.

In addition, pesticide samples can be lightly sprinkled on the water surface, and reasonable pesticides will sink into the water within 1 minute; If the floating water surface is not wet for a long time, it is an ineffective or ineffective pesticide. If it is emulsion, you can put a small amount into a glass, add a small amount of water to stir and let it stand for 30 minutes. If there are no oil beads on the water surface and no sediment in the cup, the pesticide is reasonable.