Classification of herbicides
Herbicides can be classified according to the mode of action, the site of application, the source of the compound, and the like.
Classified according to mode of action
(1) Selective herbicides: Herbicides have different degrees of resistance to different types of seedlings. This agent can kill weeds and is harmless to seedlings. Such as grass can be, trifluralin, chlorpyrifos, simazine, ger herbicides and so on.
(2) Herbicides: Herbicides are toxic to all plants, as long as they are in contact with the green part, regardless of seedlings and weeds, they will be killed or killed. It is mainly used before sowing, before emergence after sowing, and on the main and auxiliary roads of the nursery. Such as glyphosate and so on.
Classification according to the movement of herbicides in plants
(1) Contact-type herbicide: When the agent is in contact with the weeds, only the part in contact with the agent is killed, and the local killing effect is exerted, and the plant body cannot be transmitted. It can only kill the aerial parts of weeds, and it is less effective for the underground parts of weeds or perennial deep-rooted weeds with underground stems. Such as herbicide ether, paraquat and so on.
(2) Systemic herbicides: After being absorbed by roots or leaves, spores or stems, the agents are transported to the plants to cause the plants to die. Such as glyphosate, chlorpyrifos and so on.
(3) Systemic absorption and contact killing herbicides: It has the functions of systemic conduction and contact killing, such as herbicide.
Classification according to chemical structure
(1) Inorganic compound herbicide: a compound composed of a natural mineral raw material and containing no carbon, such as potassium chlorate or copper sulfate.
(2) Organic compound herbicide: mainly synthesized by organic compounds such as benzene, alcohol, fatty acid and organic amine. Such as ethers - Gore, s-triazine - chlorpyrifos, substituted urea - herbicide No. 1, phenoxyacetic acid - 2 - 4 - chloro, pyridine - licorice, dinitrogen Alkyl anilines - trifluralin, amides - cable, organophosphorus - glyphosate, phenols - sodium pentachlorophenol.
Classified by usage
(1) Stem and leaf treatment agent: the herbicide solution is watered and sprayed evenly on the plant with fine mist droplets. The herbicide used in this spraying method is called stem and leaf treatment agent, such as grass, glyphosate, etc.
(2) Soil treatment agent: the herbicide is evenly sprayed onto the soil to form a drug layer of a certain thickness, and when the seedlings, seedlings and roots of the weed seeds are contacted and absorbed, the grass killing action is exerted. Herbicides, called soil treatment agents, such as simazine, chlorpyrifos, trifluralin, etc., can be applied by spraying, pouring, or toxic soil.
(3) Stem and leaf, soil treatment agent: can be used for stem and leaf treatment, but also for soil treatment, such as atrazine.
