1. Classification according to the nature of action 1. Herbicides <br> Some herbicides, indiscriminately kill all kinds of weeds and crops, this herbicide is called a herbicide, such as sodium pentachlorophenol, gram Trace, glyphosate, etc. Solar Garden Light,Solar Garden Light ,Solar Powered Garden Lights,Solar Camping Lamp NINGBO ZHENGUO INTELLINGENT LIGHTING CO.,LTD , https://www.intellingentlighting.com
2, selective herbicide Some herbicides can kill some weeds, but not for other weeds, for some crops, but for other crops, this is selective, weeding with this characteristic The agent is called a selective herbicide. For example, 2 to 4 chlorine can only kill weeds such as ragweed, water leek, sedge, water sedge, etc., but it is ineffective against grass weeds such as valerian, double-spotted damselfly, safe for rice, suitable for rice fields. It is used in wheat fields and corn fields, but it has serious phytotoxicity to broad-leaved crops such as cotton, soybeans and vegetables. Another example is that the enemy can kill the weeds and protect the rice; the West Majin can kill a variety of annual weeds such as crabgrass and crickets, and it is safe for corn; and the grasses and wild swallows can kill wild oats. Safe for wheat, etc.
The selectivity of the herbicide is not absolute, but relative, that is, the choice of herbicide does not affect the crop at all, can kill the weeds, but chooses under certain objects, dosages, time, methods and conditions. Sex, selectivity is determined by the selectivity coefficient, which is the ratio of the herbicide killing (or inhibiting) the dose of less than 10% of the crop and the dose of killing (or inhibiting) more than 90% of the weed. The larger the safer, the selectivity of a selective herbicide greater than 2 can be promoted.
Herbicide selectivity coefficient =
Kill or (inhibit) doses within 10% of the crop to kill or (inhibit) more than 90% of the weeds
2. Classification according to mode of action 1. Systemic herbicides Some herbicides can be absorbed by weed roots and leaves separately or simultaneously, transported to various parts of the plant through the transport organization, destroying its internal structure and physiological balance, resulting in Plant death, this method is called systemic, herbicides with this characteristic called systemic herbicides, such as 2 methyl 4 chlorine, glyphosate can be absorbed by the stems and leaves of plants, and then moved to plants Various parts of the body, including underground rhizomes, so glyphosate can prevent annual weeds, but also effectively prevent perennial weeds.
2. Contact herbicides Some herbicides are sprayed onto plants and can only kill the part of the plant tissue that is in direct contact with the agent, but cannot be internally absorbed. A herbicide with this characteristic is called a contact herbicide. This type of herbicide can only kill the aerial parts of weeds, and has a poor effect on perennial weeds in the lower part of the weeds or underground reproductive organs, such as herbicide ether and sodium pentachlorophenol.
3. According to the classification of the application object 1. The soil treatment agent sprays the herbicide on the surface layer of the soil or mixes the herbicide into the soil by mixing operation to establish a herbicide sealing layer to kill the germinated weeds. . In addition to the use of physiological and biochemical selectivity to eliminate weeds, soil treatment of herbicides in many cases uses time difference or difference to selectively kill grass. Such as fluoxetine, herbicide ether, simazine, Afida and so on.
2. The stem and leaf treatment agent dilutes the herbicide into a certain amount of water or other inert filler, sprays the weed seedlings, and uses weed stems and leaves to absorb and conduct to eliminate weeds. Stem and leaf treatment mainly uses the physiological and biochemical selectivity of herbicides to achieve the purpose of killing grass and protecting seedlings.
4. Classification according to application time 1. Pre-sow treatment means that the soil is sealed before the crop is planted. For example, the use of trifluralin in cotton fields and the use of wild wheat in wheat fields are all sprayed with herbicides before cotton or wheat sowing. The soil is mixed into the soil to a certain depth to absorb the weed roots and shoots, and to prevent or reduce the volatilization and photolysis loss of the herbicide.
2. After the sowing, the pre-emergence treatment agent is used for soil treatment before emergence of the crops. This method is mainly used for weeds and young leaves to absorb herbicides that are transmitted to the growth point, and is safe for crop shoots.
3. Post-emergence treatment means that the herbicide is sprayed directly onto the weed plant after the emergence of the weed. Some herbicides such as paraquat and glyphosate can be eliminated in the middle and late stages of weed growth. Herbicide is generally a herbicide that is absorbed by stems and leaves and can be transmitted to other parts of the plant.
5. Classification according to the application method <br> Herbicides can be applied in many ways, such as spray treatment, including constant spray, low-volume spray, micro-spray, or herbicide with a certain amount of Fine soil mixes and spreads. Some herbicides such as emulsifiable concentrates, such as He Da Zhuang, Cao Cao Dan, and Cao Cao Ling, can be bottled or instilled in rice fields using a drip device. The different physicochemical properties of herbicides determine the application method. For example, volatile herbicides such as trifluralin must be treated with soil and require mixed soil. If the spray is effective, it is not only very effective, but also easy to make. The crop has phytotoxicity.
Six according to the scope of application of the classification 1, full application is to evenly and comprehensively spray the whole field, including weeds and crops. This applies to the case where highly selective herbicides and weeds are weeded in crops that are common throughout the field and are dense.
2, the strip application of the drug solution in a limited range, the use of fan-shaped nozzles, such as about 5cm of the crop planting belt spray treatment to eliminate inter-plant weeds on the crop belt, for the seed belt The field weeds are intercropped or artificially assisted. Strip spray can save one-half to two-thirds or more of the dose, but requires more sprayer attachments and reduces the amount of work by about 15%.
3, point-like application of medicinal treatment to treat a limited area, such as grass or as a crop after the full spray treatment, local re-spraying or the distribution of weeds in the core (such as perennial weeds such as fragrant aconite). This method is highly targeted and economical.
4. Directional spray control spray direction of the liquid, apply to weeds or ground, and try not to touch the crop as much as possible. This is a protective spray for post-emergence crop treatment with some of its biocide or contact herbicides.
Seven according to the classification of the dosage form <br> The processing dosage form and processing quality of the herbicide have great influence on the efficacy of the herbicide. It should be processed into a suitable dosage form according to the physical and chemical properties and action modes of various herbicides, in order to fully exert its medicine. effect. At present, water agents, water-soluble, wettable powders, suspending agents, emulsions, oils, granules, powders and the like are commonly used.
1. The water-soluble herbicide is formulated to have a certain concentration of water solubility, such as 20% 2A 4 chlorine water agent and 10% glyphosate water agent.
2, water-soluble powder is a solid herbicide that can be directly dissolved in water, sprayed with water, economical and convenient, use soft water (river water) when using, if you use hard water, you should add sodium carbonate or sodium bicarbonate in water before softening. For example, 2,4-D sodium salt, sodium pentachlorophenolate, 2 methyl 4-chloro, sodium salt, etc. can also be mixed with soil.
3, wettable powder This kind of original drug is often difficult to dissolve in water or organic solvent, so it is evenly mixed with inert filler and wetting agent, crushed to 300 mesh or more fineness, can be diluted with water to form a suspension, can be used as a stem Leaf spray or soil spray. In addition, it can also be mixed with soil. It is currently the main processing agent in China, such as herbicide, chloromeron, simazine, diuron.
4, the suspension agent, also known as the suspension, the original drug is insoluble or rarely soluble in water and organic solvents, is a fineness of the original drug and a certain amount of wetting agent, diffusing agent, thickener, etc. The suspended concentrated liquid is converted into a stable suspension after watering. It is suitable for spraying stems and leaves. Because of the high fineness, good suspension property and strong adhesion of this dosage form, it is better than the wettable powder when spraying on the foliage.
5. Emulsifiable oil is a liquid form of uniform oil. It is made up of a mixture of herbicides, organic solvents and emulsifiers. It is diluted with water and sprayed into an emulsion. This dosage form is commonly used for stem and leaf treatment, such as propanil, butachlor and the like.
6. Herbicide dosage form of granule granules. After it is applied to the soil to absorb water, the medicament is gradually diluted from the granules and absorbed by the weeds, and is mostly used for soil treatment, especially in the paddy field, which is simpler and safer than other dosage forms.
7. The oil agent is made of the herbicide original drug plus appropriate organic solvent (oil agent), and it is not used for watering when used, and is suitable for ultra-low volume spraying.
8. The original powder of the powder herbicide is mixed with the inert powder and mixed. It can be sprayed with a duster or made into toxic soil.
Eight according to chemical structure classification <br> Different chemical structure types of herbicides and different gene substitutions on similar compounds have regular effects on the biological activity of herbicides. Therefore, the chemical structure classification of herbicides is scientific, systematic and detailed. It is easy to remember.
The existing herbicides are roughly classified into phenols, phenoxycarboxylic acids, benzoic acids, diphenyl ethers, bipyridines, carbamates, thiocarbamates, amides, substituted ureas, and Triazines, dinitroanilines, organophosphorus, phenoxy and heterocyclic oxyphenoxypropionates, sulfonylureas, imidazolinones and other heterocyclics.
Classification of pesticide herbicides