What are pesticides?

Pesticide nóngyào

[agricultural chemical; farm chemical] is a general term for pesticides, herbicides and other drugs used to ensure and promote the growth of crops.

pesticide(s)

Pesticides used in agriculture to prevent and control diseases and insect pests, regulate plant growth, and eliminate weeds.

According to the control objects, it can be divided into insecticides, fungicides, acaricides, nematicides, rodenticides, herbicides, defoliants, plant growth regulators, etc.

According to the source of raw materials, it can be divided into organic pesticides, inorganic pesticides, botanical pesticides and microbial pesticides. In addition, there are insect hormones.

According to the processing dosage form, it can be divided into powders, wettable powders, soluble powders, emulsions, emulsifiable concentrates, concentrated emulsions, creams, pastes, colloids, fumigants, fumigants, aerosols, and oils. , granules, microgranules, etc.

Most are liquids or solids, and a few are gases.

Different usage methods are adopted depending on the types of pests or diseases and the physical properties of the pesticide itself. For example, it can be made into powder for spreading, made into aqueous solution, suspension, emulsion for spraying, or made into steam or gas for fumigation, etc.

According to the definition of "Chinese Agricultural Encyclopedia·Pesticide Volume", pesticides mainly refer to the prevention and control of harmful organisms (pests, mites, nematodes, pathogenic bacteria, weeds) that harm agricultural, forestry and animal husbandry production. and rodents) and chemicals that regulate plant growth, but usually also include various additives that improve the physical and chemical properties of the active ingredients. It should be pointed out that the meaning and scope of pesticides vary in different eras, countries and regions. For example, in the United States, pesticides were called "economic poisons" in the early days, while in Europe they were called "agrochemicals". Some books and periodicals defined pesticides as "all agricultural chemicals except chemical fertilizers." . Before the 1980s, the definition and scope of pesticides focused on "killing" pests. However, since the 1980s, the concept of pesticides has changed a lot. Today, we do not focus on "killing", but more on regulating. Therefore, pesticides are defined as "biorationa1 pesticides", "ideal environmental chemicals", "biological regulation" "bioregulators". "insectistastics". "anti-inect agents" (anti-inect agents), "environmentally acceptable pesticides or environmentally friendly pesticides", etc. Although there are different expressions, But in the future, the connotation of pesticides must be "effective against organisms and safe against non-target organisms and the environment".

After the founding of New China, my country's pesticide industry went through a period of creation (1949-1960) and a period of consolidation and development. (1960-1983) and the adjustment of variety structure. During the three stages of vigorous development, pesticide varieties and output increased exponentially, and production technology and product quality improved significantly. The State Council decided to stop the production of 666 and DDT from March 1983. The state also decided to stop the production of five pesticides, including dipyrimidine, dibromochloropropane, and diclofenac. In order to meet the needs of agricultural production development, the state concentrated its efforts on investing (expanding) production of dozens of high-efficiency and low-residue varieties, increasing pesticide production. Rapidly increasing. By 1998, the country was able to produce 200 types of pesticides (active ingredients), with a total pesticide output of nearly 400,000 tons (calculated as 100% active ingredients), and the national pesticide production capacity reached 757,000 tons.

my country's pesticide production has been able to meet agricultural needs, and a certain amount is exported, but the variety is still insufficient. Based on the pesticide production in 1998, pesticides accounted for 72%, fungicides accounted for 10%, and herbicides accounted for 16%. Plant growth regulators account for 2%. Therefore, the task of adjusting the structure of pesticide varieties and the proportions of various pesticides in my country is still very heavy. With the gradual deepening of the reform of my country's economic system, this adjustment task will surely be completed in a not too long period of time. Completed. The development of the pesticide industry, the increase in pesticide production, and the improvement of pesticide product quality have played an important role in ensuring a good agricultural harvest. According to statistics from the agricultural department, more than 4 billion acres of chemical pesticides were used in 1996, and the area of ??chemical weeding reached 6.2. billion acres. For every 1 yuan of pesticide used, agriculture can benefit from 8 to 16 yuan.

Herbicides

Title: Herbicides

Category: Pesticides

Subject headings or keywords: pesticides

Column keywords: pesticides and herbicides

Pesticides used to eliminate or control the growth of weeds are called herbicides. The beginning of chemical weeding on farmland can be traced back to the late 19th century. When controlling European grape downy mildew, it was occasionally discovered that Bordeaux mixture could harm some cruciferous weeds but not cereal crops; France, Germany, and the United States also discovered that sulfuric acid and sulfuric acid Copper has a herbicidal effect and is used for weeding in wheat and other places.

The period of organic chemical herbicides began with the discovery of the selective herbicide dinitrophenol in 1932. The emergence of 2,4-D in the 1940s greatly promoted the rapid development of the organic herbicide industry. Glyphosate, synthesized in 1971, has the characteristics of broad herbicidal spectrum and no pollution to the environment. It is a major breakthrough in organophosphorus herbicides. Coupled with the emergence of a variety of new formulations and new application technologies, the herbicidal effect has been greatly improved. In 1980, herbicides accounted for 41% of the world's total pesticide sales, surpassing insecticides and ranking first. After that, the development of herbicides in the world gradually stabilized, with the main development being high-efficiency, low-toxicity, broad-spectrum, and low-dosage varieties. Disposable treatment agents with little environmental pollution gradually became the mainstream.

Herbicides can be classified according to various aspects such as mode of action, application site, and source of compounds.

Herbicide

refers to a pesticide that can completely or selectively kill weeds. Sodium chlorate, borax, arsenic acid, and trichloroacetic acid have a dieback effect on any type of plant, but as these have residual effects they should not be used in fields. Selective herbicides, especially derivatives of nitrophenol, chlorophenol, and carbamic acid, are most effective, including O-isopropyl-N-phenylcarbamate [O-isopropy-N-phe-nylcarbamate, abbreviated IPC: C6H5NHCOOCH-(CH3)2], sodium dinitro-O-cresylate, etc. The most famous herbicide with auxin effect is 2,4-D. It is believed that it can disrupt the hormone balance in plants and cause physiological disorders. However, it is a very effective herbicide for plants other than Gramineae. It is generally believed that this selectivity is determined by the intensity of the detoxification effect of the plant species on 2,4-D, or because the concentration of 2,4-D varies with different plant species.

Herbicide technical series

Acetochlor

English common name: Acetochlor

Chinese common name: Acetochlor

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Other English names: Hsrness

Other Chinese names: Hsrness, Hsrness, Hsrness

Chemical name: 2,-ethyl- 6,-Methyl-N-(ethoxymethyl)-2-chloroacetanilide

Molecular formula: C14H20ClNO2

Pesticide Category: Herbicide

Physical and chemical properties: blue-violet oil, melting point 0℃, vapor pressure 4.53nPa (25℃), boiling point 162℃/7mmHg, specific gravity 1.1358 (20℃), solubility in water 223mg/L (25℃), soluble in a variety of organic solvents middle. It will not decompose during the year at 20℃.

CA registration number: 34256-82-1

Structural formula:

alachlor

English common name: alachlor

Chinese common name: Alachlor

Other English names: Lasso, Otraxal, CP50144

Other Chinese names: Lasso, Otraxal, the grass is not green, Weed lock

Chemical name: α-Chloro-2,6,-diethyl-N-methoxymethylacetanilide

Molecular formula: C14H20ClNO2

Pesticide Category: Herbicide

Physical and chemical properties: The original drug is milky white crystal, melting point 39.5-41.5 ℃, boiling point 100℃ (0.02mmHg), vapor pressure 2.9mPa (25℃), specific gravity 1.133 (25 ℃), solubility in water 242mg/L (25 ℃), soluble in ethanol, ether, acetone, chloroform and other organic solvents, decomposition temperature 105 ℃, decomposes under strong acid and alkali conditions.

CA registration number: 15972-60-8

Structural formula:

Butachlor

English common name: Butachlor

Chinese common name: butachlor

Other English names: Machete

Other Chinese names: Machete, bezachlor, dechlorin, butachlor< /p>

Chemical name: 2,6-diethyl-N-(butoxymethyl)-chloroacetanilide

Molecular formula: C17H26ClNO2

Pesticide category: Herbicide

Physical and chemical properties: amber liquid, melting point -5 ℃, boiling point 156 ℃/0.5mmHg, vapor pressure 0.6mPa (25 ℃), specific gravity 1.070 (25 ℃), corrosive to steel, soluble in Most organic solvents, including ethyl acetate, acetone, ethanol, benzene, hexane, etc., decompose at 165°C and are stable to light.

CA registration number: 23184-66-9

Structural formula:

Atrazine

English common name: atrazine

Chinese common name: Atrazine

Other English names: Atranex

Other Chinese names: Atrazine, Atrazine, Atrazine, Yuanbao Net

Chemical name: 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine

Molecular formula: C8H14ClN5

< p>Pesticide category: herbicide

Physical and chemical properties: The pure product is white powder, melting point 175.8℃, vapor pressure 0.039mPa (25℃), density 1.187 (20℃), solubility at 20℃: Water 33mg/L, chloroform 28g/L, acetone 31g/L, ethyl acetate 24g/L, methanol 15g/L. Stable in neutral, weakly acidic and weakly alkaline media.

CA registration number: 1912-2-9

Structural formula:

2,4-D butyl ester

English common name: 2,4-D

Chinese common name: 2,4-D

Other English name: Esteron

Chemical name: 2,4-dichlorobenzene Oxyacetic acid

Molecular formula: C8H6Cl2O3

Pesticide category: Herbicide

Physical and chemical properties: The pure product is a colorless oily liquid, boiling point 169℃/2mmHg, specific gravity 1.2428. Crude oil is a brown liquid with a specific gravity of 1.21 at 20°C and a boiling point of 146-147°C. It is difficult to dissolve in water and easily soluble in a variety of organic solvents. It is highly volatile and decomposes when exposed to alkali.

CA registration number: 94-80-4

Structural formula:

Metolachlor

English common name: Metolachlor< /p>

Chinese common name: metolachlor

Other English names: Dual, Bicep, Milocep

Other Chinese names: Dual, Daolesi

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Chemical name: 2-ethyl 6-methyl-N-(1,-methyl-2,methoxyethyl)chloroacetanilide

Molecular formula: C15H22ClNO2

Pesticide category: herbicide

Physical and chemical properties: colorless to light brown liquid, boiling point 100 ℃, 0.001mmHg, vapor pressure 4.2mPa (25 ℃), density 1.12 (20 ℃), Solubility in water: 488 mg/L (25°C), miscible with benzene, xylene, toluene, octanol, dichloromethane, hexane, dimethylformamide, methanol, and dichloroethane, insoluble in ethylene glycol, propanol, and Petroleum ether is stable below 300°C and can be hydrolyzed by strong acid, strong alkali and strong inorganic acid.

CA registration number: 51218-45-2

Structural formula:

Prometryn

English common name: Prometryn

Chinese common name: Prometrex

Other English names: Gesagard, Caparol, Merkazin, Polisin, Prometrex

Other Chinese names: Prometrex, good for cutting grass, Putongtong

Chemical name: 4,6-bis(isopropylamino)-2-methylthio-1,3,5-triazine

Molecular formula: C10H19N5S

Pesticide Category: Herbicide

Physical and chemical properties: white powder, melting point 118-120 ℃, vapor pressure 0.169mPa (25℃) (OEOD-104), density 1.157 (20℃), solubility Water 33 mg/L (25 ℃), acetone 300, ethanol 140, hexane 6.3, toluene 200, n-hexanol 110 (g/L, 25 ℃), 20 ℃ neutral medium, stable in slightly acidic and slightly alkaline media, heat Hydrolyzes in acids and alkalis, decomposes under UV light, pKb9.9.

CA registration number: 7287-19-6

Structural formula:

Pendimethalin

English common name: Pendimethalin

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Chinese common name: pendimethalin

Other English names: Stomp, Penoxalin, Prowl, Herbadox

Other Chinese names: Dimethalin, pendimethalin , Shitianbu, pendimethalin

Chemical name: N-(1-ethylpropyl)-2,6-dinitro-3,4-dimethylaniline

Molecular formula: C13H19N3O4

Pesticide Category: Herbicide

Physical and chemical properties: Orange crystalline solid, melting point 54-58℃, boiling point decomposes during distillation, vapor pressure 4.0mPa (20℃ ), density 1.19 (25℃), Kow152000, solubility water 0.3mg/L (20℃), acetone 700, xylene 628, corn oil 148, heptane 138, isopropyl alcohol 77 (g/L, 26℃), Easily soluble in benzene, toluene, chloroform, methylene chloride, slightly soluble in petroleum ether and gasoline, stable storage at 5-130°C, stable to acids and bases, decomposes slowly under light, less than 21 days in DT50 water.

CA registration number: 40487-42-1

Structural formula:

Paraquat

English common name: Paraquat

Chinese common name: Paraquat

Other English names: Gramoxone

Other Chinese names: Gramoxone, Quatrac

Chemical name: 1 ,1,-dimethyl-4,4,bipyridyl cation

Molecular formula: C12H14N2Cl2

Pesticide category: herbicide

Physical and chemical properties: colorless, Hygroscopic crystal, melting point is about 300℃ (decomposition), vapor pressure <0.1mPa, density 1.24-1.26 (20℃), solubility 700g/L (20℃), almost insoluble in most organic solvents, neutral and acidic media Stable, hydrolyzes rapidly in alkaline media, and decomposes in aqueous solutions and under ultraviolet light.

CA registration number: 4685-14-7

Structural formula:

Quizalofop-p

English common name: Quizalofop-p -ethyl

Chinese common name: Quizalofop

Other English names: NC302D(+),Assurell,Pilot,super,Tarqa,super

Others Chinese name: Jinghecao Gram

Chemical name: R-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]

Molecular formula: C19H17ClN2O4

Pesticide category: herbicide

Physical and chemical properties: light brown crystal, melting point 76-77℃, boiling point 220/26.6Pa, density 1.35g/cm2, vapor pressure 110nPa (20℃ ), solubility 0.4mg/L (20℃), solubility in solvent (20℃), acetone 650, ethanol 22, hexane 5, toluene 360 ??(g/L, 20℃), half-life 20h at PH9, acidic, neutral Stable in medium, unstable in alkali.

CA registration number: 100646-51-3

Structural formula:

2-methyl-4-chloride

English common name: MCPA

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Chinese common name: 2-methyl-4-chloro

Other English names: 2,4MCPA

Chemical name: 2-methyl-4-chlorophenoxyacetic acid

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Molecular formula: C9H8Cl103-Na

Pesticide category: herbicide

Physical and chemical properties: colorless crystal, melting point 119-120.5℃, vapor pressure 2.3*10(-5 ) Pa (25℃), solubility water 734mg/L (25℃), ethanol 1530, ether 770, methanol 26.5, xylene 49, heptane 5g/L (25℃).

CA registration number: 94-74-6

Structural formula:

Imazethapyr

English common name: Imazethapyr

< p>Chinese common name: imazapyramide

Other English names: Pivot, Pursuit

Other Chinese names: Pivot, Pursuit, Imazethapyr, Mesozofen, Pursuit, Pursuit Smoke

Chemical name: 5-ethyl-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-2-pyridinecarboxylic acid

Molecular formula: C15H19N3O3

Pesticide category: herbicide

Physical and chemical properties: colorless crystal, odorless, melting point 169-174°C, vapor pressure <0.013 mPa (60℃), 25℃ solubility water 1.4g/L, acetone 48.2, methylene chloride 185, dimethyl sulfate 422, heptane 0.9g/L, methanol 105g/L, isopropyl alcohol 17g/L, toluene 4g /L, degrades rapidly under sunlight.

CA registration number: 81385-77-5

Structural formula:

Fomesafen

English common name: Fomesafen

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Chinese common name: Fomesafen

Other English names: Flex, PP021

Other Chinese names: Huwei, Polaris, Fomesafen, Diosulfate< /p>

Chemical name: 5-[2-chloro-4-(trifluoromethyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide

Molecular formula: C15H10ClF3N2O6S

Pesticide category: herbicide

Physical and chemical properties: colorless crystal, melting point 220-221℃, vapor pressure <0.1mPa (50℃), density 1.28g/ ml (20℃), solubility in water (mg/l, 20℃) is about 50, <10 (PH1-2), >600 (PH7) (20℃, mg/l), stored at 50℃ for more than 6 months, It decomposes when exposed to light and is not easily hydrolyzed in acid-base media.

CA registration number: 72178-02-0

Structural formula:

Clomazone

English common name: clomazone

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Chinese common name: Dimethazon

Other English name: Dimethazon

Other Chinese name: Dimethazon

Chemical name: 2 -(2-Chlorobenzyl)-4,4-dimethylisoxazol-3-one

Molecular formula: C12H14ClNO2

Pesticide category: Herbicide

< p>Physical and chemical properties: colorless transparent to light brown viscous liquid, melting point 25℃, boiling point 275℃, density 1.129 (20℃), vapor pressure 19.2mPa (25℃), solubility in water 1.1g/l (25℃), It can be miscible with acetone, acetonitrile, chloroform, cyclohexanone, methylene chloride, methanol, toluene, etc. It can be stored at room temperature for at least 2 years and at 50℃ for 3 months.

CA registration number: 8177-89-1

Structural formula:

Benzalin

English common name: Benazoline-ethyl< /p>

Chinese common name: Cao Chu Ling

Other English names: Galtak, Cornox

Other Chinese names: Galtak, ethyl ester

Chemical name: 4-Chloro-2-oxo-3(2H)benzothiazole ethyl ester

Molecular formula: C11H10ClNO3S

Pesticide category: Herbicide

Physical and chemical properties: colorless crystalline solid, melting point 79.2℃, vapor pressure 0.37mPa (25℃), density 1.45 (20℃), solubility (20℃), water 47mg/L, acetone 229mg/L, methylene chloride 603mg/ L, ethyl acetate 148mg/L, methanol 28.5mg/L, toluene 198mg/L, stable below 300℃ and in acid and neutral solutions.

CA registration number: 3813-05-6

Structural formula:

Legal definition of pesticides:

The so-called pesticides refer to the A chemical synthesis or a substance or a mixture of several substances derived from organisms or other natural substances that is used to prevent, eliminate or control diseases, insects, weeds and other harmful organisms that harm agriculture and forestry, as well as to purposefully mediate the growth of plants and insects. and preparations thereof.