Pesticides have a certain shelf life, use in the warranty period to ensure safety and effectiveness. Once crops have been used for pesticides that exceed their shelf life, they will not only have the effect of eliminating diseases and pests, but will also make the pests resistant to insecticides, delaying the best period of pest control, and making it difficult or impossible to prevent and control diseases. It is the phytotoxicity of crops that causes irreparable consequences. Therefore, farmers' friends must prohibit the use of expired pesticides.
First, pesticide failure seven methods
1, intuitive method. For powder pesticides, first look at the appearance of the drug. If it is obviously damp and agglomerate, the smell is not strong or there are other odors, and it can be smashed by hand, these drugs will basically fail; for emulsion pesticides, the bottle will be put to rest first. The liquid is turbid or delaminated (ie oil-water separation), precipitates are formed or the flocs are suspended, and the agent has failed.
2, heating method. Suitable for powder pesticides. Take 5-10 grams of pesticide and put it on a piece of metal to heat it. If there is a lot of white smoke and there is a strong pungent odor, it means that the medicine is good. Otherwise, the instructions have expired.
3, floating method. Suitable for wettable powder pesticides. Take 200 g of fresh water and take 1 g of pesticide. Gently and evenly sprinkle on the surface of the water and observe carefully. Wet and soluble in water within 1 minute are non-failure pesticides, otherwise they are failure pesticides.
4, suspension method. Suitable for wettable powder pesticides. Take 30-50 grams of pesticide, place it in a glass container, add a small amount of water to make a paste, add 150-200 grams of water to mix well, and let stand for 10 minutes to observe. The pesticide without failure is good in solubility and suspended in the liquid. The fine particles are small, the sedimentation rate is slow and the amount of precipitation is small, and the failure of pesticides is the opposite.
5, oscillation method. Applicable to emulsion pesticides. For pesticides with oily water layer, shake the vial vigorously and observe after standing for 1 hour. If delamination still occurs, it indicates that the agent has deteriorated.
6, hot melt method. Applicable emulsion pesticides. Put the precipitated pesticide in a bottle and put it in warm water (the water temperature should not be too high, preferably 50-60°C) for 1 hour. If the substance is dissolved, it means that the agent has not yet failed, and it can be reused after the precipitate is dissolved. If the precipitate is difficult to dissolve or insoluble, it means that it has failed.
7, dilution method. Suitable for emulsion pesticides. Take 50 grams of pesticide, place it in a glass bottle, add 150 grams of water, and shake it for 30 minutes. If the liquid is uniformly milky white, and there is no slick oil, there is no sedimentation, indicating that the drug is good. Otherwise, it is a failure of pesticides, the more the upper oil, the worse the drug.
Second, the remaining pesticides are carefully kept. Improper storage of the remaining pesticides will reduce the insecticidal effect and even produce phytotoxicity. Therefore, the pesticides purchased by the farmers in the current year have not been used up yet, and they are ready to be used again in the next year. The following points should be made in the storage process:
1, sealed and stored. Some pesticides are volatile and cause air pollution. The bottle caps must be tightly tightened during storage and sealed.
2, keep the temperature. Most powdered pesticides are susceptible to quality at high temperatures. The higher the temperature, the more easily the pesticide melts, decomposes, volatilizes, and even burns and explodes. Some emulsion pesticides will also destroy their emulsifying properties and reduce their efficacy after they encounter high temperatures. Some bottles of liquid pesticides freeze when they encounter low temperatures, forming a block, or the bottle burst, in the preservation of such pesticides should maintain the room temperature above 1 °C.
3, avoid light. Some pesticides are afraid of light, long-term exposure to light exposure, will cause decomposition and deterioration of pesticides, in the storage to avoid high temperatures and sunlight.
Keep dry. Powder pesticides and plant regulators, it is easy to absorb moisture and agglomerate. Therefore, the place where custody and storage of pesticides should be kept dry to prevent rain and snow. Also have windows to allow ventilation, keeping the relative humidity below 75%.
5, to avoid mixing. Pesticides are classified as alkaline, acidic and neutral. Alkaline pesticides include propanil, lime sulfur, Bordeaux mixture, etc. Acidic pesticides include deltamethrin, etc. Neutral pesticides include chlorfenone. These three kinds of pesticides of different nature should be stored separately during storage and storage, and the distance should be maintained at 0.5 meters or more. Otherwise, the deterioration of pesticides will be lost.
6, rigorous mixing. For two kinds of pesticides that are not finished in the same year, they cannot be mixed in one bottle to avoid failure.
Third, the remaining pesticides are labeled well. The remaining pesticides stored by farmers must have complete bottle stickers, and the names of agricultural drugs, batch numbers, production date, and shelf life should be clear. If the bottle is damaged, the peasant household must write the shelf life and precautions for use of the pesticide and stick it on the outer package of the pesticide.