Pesticides are the general term for chemical agents used to prevent diseases such as diseases, insects, grass, and rats in agriculture, forestry, animal husbandry, and environmental hygiene. Pesticides play an important role in production and life, but if they are used improperly or are eaten improperly, they can cause phytotoxicity, environmental pollution, and human and animal poisoning. In order to make better use of pesticides that prevent crop pests and diseases, the following describes the basic knowledge of pesticides and commonly used pesticides.
I. Classification of Pesticides Pesticides are many in variety. For ease of identification and use, they are often classified according to their origin, use, and mode of action.
(a) Classification by purpose
1. Insecticides. Pest control agents, such as dimethoate, dichlorvos, and all spirits. These agents can only be used to kill insects and cannot be used to prevent disease.
2. Acaricides. Medications used to prevent and treat lice, such as konjac and amitraz.
3, fungicides. Agents used to control plant diseases, such as Rhizoctonia, Chlorothalonil, Zelenzin, Triadimefon and others.
4, nematicides. Medications used to control nematodes, such as iron extinct grams, grams of phosphorus and so on.
5, rodenticide. Used to prevent rat poison.
6, herbicides. The herbicide used for weeding.
7. Plant growth regulators. An agent used to promote or inhibit plant growth.
(B) Classification according to the mode of action According to the mode of action, insecticides (apicides) can be divided into the following categories:
1, stomach poisons. Drugs that enter the worm through the digestive system kill them, such as trichlorfon and rodenticides.
2, contact killer. By contacting the epidermis or infiltrating the body of the worm to kill the agent, such as pyrethrum.
3, fumigants. In the state of gas, through the respiratory system into the worm to poison the agent, such as dichlorvos, methyl bromide and so on.
4, absorb insecticides. Through the plant's roots, stems, leaves absorbed into the plant body, in the plant body to guide, disseminate, retain or produce metabolites, pests in the intake of plant tissue or sap, which made poisonous agents, such as dimethoate.
5, specific insecticides. It has special effects on pests, but it is non-toxic, such as antifeedants, infertility agents, and repellents.
According to the same way of action, fungicides can be divided into the following categories:
1, protective agent. Before the plants become susceptible, the spray covers the surface of the plant, inhibits the germination of pathogenic spores or kills the germinating pathogenic spores, and protects the plants from the agents that harm the pathogens. Such as Bordeaux fluid and so on. These agents should be applied before the onset of the disease. After the onset of the disease, the pathogen has invaded the interior of the plant tissue.
2. Therapeutic agent. After the plant is infected, the pharmaceutical agent can penetrate from the plant epidermis into the interior of the plant tissue, but cannot be guided or spread in the plant body, and can inhibit the germination of the spores of the pathogen or kill the germinating pathogenic spores to eliminate the agents of the disease. Such as Daisen ammonium, chlorothalonil and so on.
3, within the suction fungicide. An agent that absorbs into the plant through its roots, stems and leaves, and transmits, spreads, and persists in the body, killing or inhibiting pathogens. Such as Rhizoctonia, B-aluminum (Kemiling), triadimefon, thiophanate and so on.
4, remove the agent. After the plant has become infected, the agent is administered, and the agent is killed by direct contact with the pathogen on the surface of the plant (or infiltrated into the plant tissue). Such as formaldehyde, pentachlorophenol and so on.
5, preservatives. An agent that does not kill pathogen spores but inhibits the germination of pathogen spores. Such as borax, ferrous sulfate and so on.
Second, the main issues that should be noted when using pesticides are the safe, accurate and effective use of pesticides. In the work, great attention should be paid to the safe use of pesticides, the amount and concentration of pesticides, and the mixing of pesticides.
(1) Toxicity of pesticides Generally speaking, pesticides that can kill pests and diseases are chemical agents harmful to humans, animals and other animals and have certain side effects on crops and the environment. Therefore, it is necessary to fully understand the toxicity of pesticides to humans, livestock and other animals, and to the toxic effects of crops and the environment.
The harmful effects of pesticides on humans and livestock are direct and indirect. Direct poisoning is caused by pesticides coming into contact with humans and animals and causing direct toxic effects. Indirect poisoning is caused by the transfer of drugs through intermediate objects such as soil, running water, plants, and food, which ultimately produces toxic effects to humans and livestock.
The toxic effects of pesticides on animals are usually divided into acute, chronic and subacute toxicity types:
1, acute toxicity. Acute toxicity refers to acute pathological reactions caused by a large intake of drugs from the respiratory tract, digestive tract, and skin in a short time (usually within 48 hours). Usually expressed as lethal medium (LD50) or lethal concentration (LC50), the unit is mg/kg body weight or mg/l.
2, subacute toxicity. Subacute toxicity refers to the gradual pathological reaction of the test animals in a certain period of time (usually about three months), continuous intake of a certain dose of the drug (lower than the dose of acute poisoning).
3, chronic toxicity. Chronic toxicity is the pathological process that the test animal slowly takes for a long time (more than one year) to ingest a certain dose of drug.
Pesticide toxicity is not only the above three reactions, but also can reflect its impact on future generations (such as teratogenic, etc.) and the pollution of the natural environment, leading to ecological imbalance and other serious consequences.
(b) Safe use of pesticides Pesticides are toxic to animals. Therefore, when using it, we must pay great attention to the safety of people and livestock. In order to fully understand the toxicity and mechanism of pesticides used, special attention should be paid to the following aspects:
1. Wear clothes, shoes, and caps to prevent direct contact with the skin.
2. Wear masks and gas masks to prevent pharmacy from entering the body through the respiratory tract.
3, deep-buried medicine packaging and residual liquid medicine, can not easily discard the packaging and the remaining liquid.
4. It is not allowed to clean the spraying utensils and packaging materials of Sheng Medicine at the source of human and animal drinking water and fish ponds.
5, to avoid the application of drugs under high temperature and hot sun, to avoid spraying the medicament in the wind, so as not to cause operator poisoning.
6, the drug-applied crops and the plants contaminated by the drug liquids must be consumed for a period of time so as not to cause poisoning to humans, livestock, poultry, and fish.
7. If someone finds symptoms of poisoning, they should leave the field as soon as possible and send them to the hospital in time.
8, pesticide storage must be someone, special library, and to prevent leakage and disaster.
In addition, care must be taken not to cause phytotoxicity and pollute the environment.
(C) the concentration of pesticides and dilution concentration method The effective composition of pesticides, that is, the expression of the content and specific dilution in use, is a common problem encountered in the use of pesticides. There are mainly the following representations:
1, percent concentration method. The percent concentration indicates the number of active ingredients contained in 100 parts of the pharmaceutical agent and is indicated by the symbol "%". For example, 40% of dimethoate emulsion means that 1 kg of dimethoate emulsion contains 0.4 kg of dimethoate effective ingredient. This method is mainly used to indicate the content of active ingredients in commercial drugs.
2, million parts concentration (ppm) method. The parts per million concentration indicates the number of parts of pesticides contained in 1 million doses. The symbol is “ppm†(or micrograms/ml, g/m3, etc.) also known as “unitsâ€. If 100ppm (or 100 units) of agricultural streptomycin is applied, it means that 100g of agricultural streptomycin is taken, 1000kg of water is added, and the liquid is used for application. This method is mainly used to indicate the diluted concentration when pesticides are applied in the field.
3, multiple method. The multiple method indicates that the amount of the drug diluted is the number of times the original pesticide. If 40% dimethoate EC is sprayed at 1500 times, it means that 1 dimethoate should be added to 1500 parts of water-compensation liquid for spraying. The multiple method is used to indicate the concentration of dilute pesticide when applied in the field.
4 Concentrations of commonly used pesticides represent the conversion between methods. In order to accurately grasp the concentration of pesticides, it is necessary to grasp the relationship between various expressions of pesticide concentration.
The commonly used concentration expressions are mainly percentages, parts per million, and multiples. The relationship between these three concentrations can be illustrated by the following examples.
If you use one thousandth of a 40% dimethoate emulsion to kill aphids, a 1 in 1000 solution will be written when expressed as a percentage; if you use a multiple method, it can be written as a 40% solution of dimethoate. Emulsion 1000 times to kill aphids; if expressed in parts per million, write a 1000 ppm 40% dimethoate emulsion to kill aphids. Simply express the relationship between the three liquid concentrations can be written as:
1/1000 Pharmacy = 1000 times Pharmacy = 1000 ppm Pharmacy (IV) Mixture of pesticides In agricultural production, a crop, a hillock, often occurs simultaneously with several diseases, several kinds of pests, or both pests and diseases, and To top-dressing. At this time, in order to achieve simultaneous cure of several diseases, insects, or promote the healthy growth of crops, it is common to use several pesticides or chemical fertilizers in combination. This will not only increase the number of objects to be controlled, but also save the labor force and make the pests less likely to develop resistance. Medicinal.
1. Several methods for the mixture of pesticides (1) Insecticides and insecticides are used together. The stomach poison is mixed with the contact agent and fumigant; the contact agent is mixed with the inhaler and stomach poison. Such as dichlorvos and dimethoate mixed.
(2) Mixed use of fungicides and fungicides. For example, it is a mixture of zessenzin and diammonium.
(3) Mixture of pesticides and fungicides. If dimethoate is mixed with zeson zinc.
In addition there are pesticides, fungicides mixed with fertilizers, insecticides, fungicides and herbicides mixed with a variety of mixed use.
2. Several problems that should be paid attention to when pesticides are mixed (1) Understanding the chemical nature of pesticides. Pesticides are almost all chemicals, and their chemical properties can be simply divided into three categories: neutral, acidic and alkaline.
Neutral agents: various synthetic, plant-based pesticides, various fertilizers that do not contain calcium, and some inorganic pesticides.
Acidic agents: mainly copper sulfate, sodium fluorosilicate, platinum, molybdenum superphosphate and so on.
Alkaline agents: lime sulfur, Bordeaux mixture, calcium acrylate, dexamethasone, soap, lime, etc.
(2) The principle of compounding between various chemical pesticides. Neutral and neutral agents, acidic agents and acidic agents, neutral agents and acidic agents do not produce chemical and physical changes and can be mixed with each other. Between the acidic agent and the alkaline agent, strong alkaline agents such as lime sulfur, rosin mixture and alkali chemicals cannot be mixed.
(3) The following situations cannot be mixed.
After the emulsion was mixed with water, there was a floating oil layer, and there was a precipitation phenomenon.
Wet powder, milk powder, concentrated solvent can be mixed with water after flocculation and a large number of precipitation phenomenon;
Microbial insecticides and fungicides cannot be mixed with insecticides and fungicides.
The use of pesticides after mixing is a more complex problem. In the specific application of the operation, it is necessary to pay attention to the test and observation, so as to avoid causing harm and unnecessary losses.
(5) Pesticides prohibited by the state
1. A total ban on the sale and use of methamidophos, parathion, methyl parathion, monocrotophos and ammonium phosphate in the domestic five highly toxic organophosphorus pesticides.
2. Pesticides (18 species) that are banned from use by the State: 666, DDT, toxaphene, dibromochloropropane, insecticidal hydrazine, dibromoethane, herbicidal ether, aldrin, dieldrin, mercury preparations , Arsenic pesticides, lead pesticides, adversarial bis, fluoroacetamide, fluoridation, tetramine, sodium fluoroacetate, tetrazolium.
3. Pesticides (19 species) that cannot be used on vegetables, fruit trees, tea, and Chinese herbal medicines: methamidophos, methyl parathion, parathion, monocrotophos, phosphoamine, phorate, methyl iso Phosphorus, tert-butyl phosphorus, methyl thiophosphorus, phosphorus phosphide, phosphorus uptake, carbofuran, aldicarb, pyrophosphate, phophorus, fly phos-phorus, chlorfenoxa, chlorpyrazol, benzene Phosphorus. 4. Restricted use of pesticides (2 types): Dicofol and fenvalerate should not be used on tea plants. In addition, any pesticide product must not be used beyond the approved scope of use for pesticide registration.
I. Classification of Pesticides Pesticides are many in variety. For ease of identification and use, they are often classified according to their origin, use, and mode of action.
(a) Classification by purpose
1. Insecticides. Pest control agents, such as dimethoate, dichlorvos, and all spirits. These agents can only be used to kill insects and cannot be used to prevent disease.
2. Acaricides. Medications used to prevent and treat lice, such as konjac and amitraz.
3, fungicides. Agents used to control plant diseases, such as Rhizoctonia, Chlorothalonil, Zelenzin, Triadimefon and others.
4, nematicides. Medications used to control nematodes, such as iron extinct grams, grams of phosphorus and so on.
5, rodenticide. Used to prevent rat poison.
6, herbicides. The herbicide used for weeding.
7. Plant growth regulators. An agent used to promote or inhibit plant growth.
(B) Classification according to the mode of action According to the mode of action, insecticides (apicides) can be divided into the following categories:
1, stomach poisons. Drugs that enter the worm through the digestive system kill them, such as trichlorfon and rodenticides.
2, contact killer. By contacting the epidermis or infiltrating the body of the worm to kill the agent, such as pyrethrum.
3, fumigants. In the state of gas, through the respiratory system into the worm to poison the agent, such as dichlorvos, methyl bromide and so on.
4, absorb insecticides. Through the plant's roots, stems, leaves absorbed into the plant body, in the plant body to guide, disseminate, retain or produce metabolites, pests in the intake of plant tissue or sap, which made poisonous agents, such as dimethoate.
5, specific insecticides. It has special effects on pests, but it is non-toxic, such as antifeedants, infertility agents, and repellents.
According to the same way of action, fungicides can be divided into the following categories:
1, protective agent. Before the plants become susceptible, the spray covers the surface of the plant, inhibits the germination of pathogenic spores or kills the germinating pathogenic spores, and protects the plants from the agents that harm the pathogens. Such as Bordeaux fluid and so on. These agents should be applied before the onset of the disease. After the onset of the disease, the pathogen has invaded the interior of the plant tissue.
2. Therapeutic agent. After the plant is infected, the pharmaceutical agent can penetrate from the plant epidermis into the interior of the plant tissue, but cannot be guided or spread in the plant body, and can inhibit the germination of the spores of the pathogen or kill the germinating pathogenic spores to eliminate the agents of the disease. Such as Daisen ammonium, chlorothalonil and so on.
3, within the suction fungicide. An agent that absorbs into the plant through its roots, stems and leaves, and transmits, spreads, and persists in the body, killing or inhibiting pathogens. Such as Rhizoctonia, B-aluminum (Kemiling), triadimefon, thiophanate and so on.
4, remove the agent. After the plant has become infected, the agent is administered, and the agent is killed by direct contact with the pathogen on the surface of the plant (or infiltrated into the plant tissue). Such as formaldehyde, pentachlorophenol and so on.
5, preservatives. An agent that does not kill pathogen spores but inhibits the germination of pathogen spores. Such as borax, ferrous sulfate and so on.
Second, the main issues that should be noted when using pesticides are the safe, accurate and effective use of pesticides. In the work, great attention should be paid to the safe use of pesticides, the amount and concentration of pesticides, and the mixing of pesticides.
(1) Toxicity of pesticides Generally speaking, pesticides that can kill pests and diseases are chemical agents harmful to humans, animals and other animals and have certain side effects on crops and the environment. Therefore, it is necessary to fully understand the toxicity of pesticides to humans, livestock and other animals, and to the toxic effects of crops and the environment.
The harmful effects of pesticides on humans and livestock are direct and indirect. Direct poisoning is caused by pesticides coming into contact with humans and animals and causing direct toxic effects. Indirect poisoning is caused by the transfer of drugs through intermediate objects such as soil, running water, plants, and food, which ultimately produces toxic effects to humans and livestock.
The toxic effects of pesticides on animals are usually divided into acute, chronic and subacute toxicity types:
1, acute toxicity. Acute toxicity refers to acute pathological reactions caused by a large intake of drugs from the respiratory tract, digestive tract, and skin in a short time (usually within 48 hours). Usually expressed as lethal medium (LD50) or lethal concentration (LC50), the unit is mg/kg body weight or mg/l.
2, subacute toxicity. Subacute toxicity refers to the gradual pathological reaction of the test animals in a certain period of time (usually about three months), continuous intake of a certain dose of the drug (lower than the dose of acute poisoning).
3, chronic toxicity. Chronic toxicity is the pathological process that the test animal slowly takes for a long time (more than one year) to ingest a certain dose of drug.
Pesticide toxicity is not only the above three reactions, but also can reflect its impact on future generations (such as teratogenic, etc.) and the pollution of the natural environment, leading to ecological imbalance and other serious consequences.
(b) Safe use of pesticides Pesticides are toxic to animals. Therefore, when using it, we must pay great attention to the safety of people and livestock. In order to fully understand the toxicity and mechanism of pesticides used, special attention should be paid to the following aspects:
1. Wear clothes, shoes, and caps to prevent direct contact with the skin.
2. Wear masks and gas masks to prevent pharmacy from entering the body through the respiratory tract.
3, deep-buried medicine packaging and residual liquid medicine, can not easily discard the packaging and the remaining liquid.
4. It is not allowed to clean the spraying utensils and packaging materials of Sheng Medicine at the source of human and animal drinking water and fish ponds.
5, to avoid the application of drugs under high temperature and hot sun, to avoid spraying the medicament in the wind, so as not to cause operator poisoning.
6, the drug-applied crops and the plants contaminated by the drug liquids must be consumed for a period of time so as not to cause poisoning to humans, livestock, poultry, and fish.
7. If someone finds symptoms of poisoning, they should leave the field as soon as possible and send them to the hospital in time.
8, pesticide storage must be someone, special library, and to prevent leakage and disaster.
In addition, care must be taken not to cause phytotoxicity and pollute the environment.
(C) the concentration of pesticides and dilution concentration method The effective composition of pesticides, that is, the expression of the content and specific dilution in use, is a common problem encountered in the use of pesticides. There are mainly the following representations:
1, percent concentration method. The percent concentration indicates the number of active ingredients contained in 100 parts of the pharmaceutical agent and is indicated by the symbol "%". For example, 40% of dimethoate emulsion means that 1 kg of dimethoate emulsion contains 0.4 kg of dimethoate effective ingredient. This method is mainly used to indicate the content of active ingredients in commercial drugs.
2, million parts concentration (ppm) method. The parts per million concentration indicates the number of parts of pesticides contained in 1 million doses. The symbol is “ppm†(or micrograms/ml, g/m3, etc.) also known as “unitsâ€. If 100ppm (or 100 units) of agricultural streptomycin is applied, it means that 100g of agricultural streptomycin is taken, 1000kg of water is added, and the liquid is used for application. This method is mainly used to indicate the diluted concentration when pesticides are applied in the field.
3, multiple method. The multiple method indicates that the amount of the drug diluted is the number of times the original pesticide. If 40% dimethoate EC is sprayed at 1500 times, it means that 1 dimethoate should be added to 1500 parts of water-compensation liquid for spraying. The multiple method is used to indicate the concentration of dilute pesticide when applied in the field.
4 Concentrations of commonly used pesticides represent the conversion between methods. In order to accurately grasp the concentration of pesticides, it is necessary to grasp the relationship between various expressions of pesticide concentration.
The commonly used concentration expressions are mainly percentages, parts per million, and multiples. The relationship between these three concentrations can be illustrated by the following examples.
If you use one thousandth of a 40% dimethoate emulsion to kill aphids, a 1 in 1000 solution will be written when expressed as a percentage; if you use a multiple method, it can be written as a 40% solution of dimethoate. Emulsion 1000 times to kill aphids; if expressed in parts per million, write a 1000 ppm 40% dimethoate emulsion to kill aphids. Simply express the relationship between the three liquid concentrations can be written as:
1/1000 Pharmacy = 1000 times Pharmacy = 1000 ppm Pharmacy (IV) Mixture of pesticides In agricultural production, a crop, a hillock, often occurs simultaneously with several diseases, several kinds of pests, or both pests and diseases, and To top-dressing. At this time, in order to achieve simultaneous cure of several diseases, insects, or promote the healthy growth of crops, it is common to use several pesticides or chemical fertilizers in combination. This will not only increase the number of objects to be controlled, but also save the labor force and make the pests less likely to develop resistance. Medicinal.
1. Several methods for the mixture of pesticides (1) Insecticides and insecticides are used together. The stomach poison is mixed with the contact agent and fumigant; the contact agent is mixed with the inhaler and stomach poison. Such as dichlorvos and dimethoate mixed.
(2) Mixed use of fungicides and fungicides. For example, it is a mixture of zessenzin and diammonium.
(3) Mixture of pesticides and fungicides. If dimethoate is mixed with zeson zinc.
In addition there are pesticides, fungicides mixed with fertilizers, insecticides, fungicides and herbicides mixed with a variety of mixed use.
2. Several problems that should be paid attention to when pesticides are mixed (1) Understanding the chemical nature of pesticides. Pesticides are almost all chemicals, and their chemical properties can be simply divided into three categories: neutral, acidic and alkaline.
Neutral agents: various synthetic, plant-based pesticides, various fertilizers that do not contain calcium, and some inorganic pesticides.
Acidic agents: mainly copper sulfate, sodium fluorosilicate, platinum, molybdenum superphosphate and so on.
Alkaline agents: lime sulfur, Bordeaux mixture, calcium acrylate, dexamethasone, soap, lime, etc.
(2) The principle of compounding between various chemical pesticides. Neutral and neutral agents, acidic agents and acidic agents, neutral agents and acidic agents do not produce chemical and physical changes and can be mixed with each other. Between the acidic agent and the alkaline agent, strong alkaline agents such as lime sulfur, rosin mixture and alkali chemicals cannot be mixed.
(3) The following situations cannot be mixed.
After the emulsion was mixed with water, there was a floating oil layer, and there was a precipitation phenomenon.
Wet powder, milk powder, concentrated solvent can be mixed with water after flocculation and a large number of precipitation phenomenon;
Microbial insecticides and fungicides cannot be mixed with insecticides and fungicides.
The use of pesticides after mixing is a more complex problem. In the specific application of the operation, it is necessary to pay attention to the test and observation, so as to avoid causing harm and unnecessary losses.
(5) Pesticides prohibited by the state
1. A total ban on the sale and use of methamidophos, parathion, methyl parathion, monocrotophos and ammonium phosphate in the domestic five highly toxic organophosphorus pesticides.
2. Pesticides (18 species) that are banned from use by the State: 666, DDT, toxaphene, dibromochloropropane, insecticidal hydrazine, dibromoethane, herbicidal ether, aldrin, dieldrin, mercury preparations , Arsenic pesticides, lead pesticides, adversarial bis, fluoroacetamide, fluoridation, tetramine, sodium fluoroacetate, tetrazolium.
3. Pesticides (19 species) that cannot be used on vegetables, fruit trees, tea, and Chinese herbal medicines: methamidophos, methyl parathion, parathion, monocrotophos, phosphoamine, phorate, methyl iso Phosphorus, tert-butyl phosphorus, methyl thiophosphorus, phosphorus phosphide, phosphorus uptake, carbofuran, aldicarb, pyrophosphate, phophorus, fly phos-phorus, chlorfenoxa, chlorpyrazol, benzene Phosphorus. 4. Restricted use of pesticides (2 types): Dicofol and fenvalerate should not be used on tea plants. In addition, any pesticide product must not be used beyond the approved scope of use for pesticide registration.
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