The classification methods of pesticides are various. According to their sources, they can be divided into three categories: plant source, mineral source and chemical synthesis. According to the type of compound, they can be divided into inorganic, organic, antibiotic and biological pesticides. Insecticides, fungicides, nematicides, herbicides, molluscicides, rodenticides, plant growth regulators, and the like.
There are many varieties of insecticides, which can be divided into organic synthetic insecticides, inorganic insecticides, and plant insecticides according to their constituent components. Among the currently used insecticides, the most widely used types of organic synthetic insecticides.
First, the mechanism of action of pesticides
1, stomach toxicity: refers to the toxicity caused by insects after swallowing the agent. After being swallowed, the medicament is absorbed by the midgut cell layer, then enters the blood cavity through the intestinal wall, and is quickly transmitted to various parts of the worm body through blood flow, causing poisoning. It mainly acts on pests of chewing mouthparts.
2, contact killing effect: the drug does not need to be swallowed by insects, as long as the contact with the worm can enter the worm from its epidermis, stomata or appendages and cause poisoning. An agent having such a property must spray the liquid onto the worm to play a role in poisoning the insect.
3, fumigation: the agent in the form of gas mainly through the insect's respiratory system into the insect body, and play a poisonous killing effect.
4. Systemic action: The drug is applied to the plant body, absorbed by the plant body, and transmitted to the various parts of the plant body through the transporting tissue. After the pests suck the juice of the plant, they are poisoned and die.
Some inorganic insecticides and plant insecticides have relatively simple insecticidal effects. Some have only stomach toxicity, some have only contact action, and organic synthetic insecticides often have two or three insecticidal effects.
Second, the correct and safe application of pesticides Rational use of pesticides is economic, the main control effect, no harm to crops, the basis for the safety of people, animals, natural enemies, the following aspects should be mastered in the process of use:
1. According to the control object, choose the appropriate medicine and type, and do the medicine for the "symptom".
2. The habits and hazards of various pests are different. The appropriate period of treatment should be based on the sensitive period of the pests. It can achieve better control effects with less chemicals.
3, to avoid the long-term use of a single pesticide, reduce the emergence of resistance.
4. The concentration of the drug should be accurate when dispensing, and the agent should be dispersed evenly in water and fully dissolved.
5, when applying the medicine, strive to achieve uniformity, especially when applying the contact agent, the leaf back and the leaf surface need to be sprayed, and the liquid medicine is sprayed onto the insect body, and there is no phenomenon of losing or leaking the plant to ensure the application of the drug. quality.
6. Generally, it should be applied in the weather without wind or breeze. At the same time, attention should be paid to the temperature. When the temperature is low, most organophosphorus pesticides are not effective. Therefore, it is best to apply the drug around noon.
7. Most pesticides have certain toxicity to humans and animals. If they are used improperly, they will cause poisoning and death accidents. Therefore, safety measures should be taken when using pesticides to prevent human and animal poisoning.
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