Pyrethrin is a natural organic compound with good insecticidal effect. It is extracted from the flowers of Chrysanthemum cinerariaefolium, a plant in the chrysanthemum family. Pyrethrin is a natural organophosphorus compound composed of six isomers, namely pyrethrin I, pyrethrin II, cinerin I, cinerin II, jasmolin I and jasmolin II.

Pyrethrin is mainly used to control health pests and livestock pests. It is a plant
source pesticide which is very safe for humans and animals, no harm to plants, no residue, and does not pollute agricultural products and the environment. Pyrethrin is
also safe for warm-blooded animals. The toxicity to insects is strongest in pyrethrin I, followed by cinerin I, followed by pyrethrin II, and the weakest in cinerin II.

Pyrethrins are widely used in domestic and international markets. In agriculture, pyrethrin is widely used as an insecticide and can be used to control a variety of pests, including mosquitoes, cockroaches, spiders, fleas, aphids, etc. Pyrethrin has an efficient, rapid insecticidal effect, and is relatively safe for humans and animals, so it has been widely used in agricultural production.

In addition, pyrethrins are also used in the field of family health and public health. It can be used for indoor and outdoor insecticidal operations, such as spraying indoor insecticides, insect repellents, insecticides, etc. The use of pyrethrin in homes and public places can effectively control various pests and provide a comfortable and hygienic environment.

Pyrethrins have some important chemical properties. It is a fat-soluble compound that is soluble in organic solvents such as alcohols, ethers and ketones. It can also form a suspension in water. Pyrethrins are relatively stable in the air and break down when exposed to ultraviolet light in sunlight. It is sensitive to light and heat, so care needs to be taken to avoid exposure to high temperatures and sunlight during storage and transportation.

Pyrethrin's physical form is colorless to light yellow crystal or powder. It has a Characteristic smell that some people may find irritating. Pyrethrin has a density of about 1.0g/cm³ and a melting point of about 50-70°C.

The chemical properties of pyrethrins are as follows:

1. Stability: Pyrethrin is relatively stable at room temperature, but it is easy to decompose under high temperature, sunlight and ultraviolet irradiation. Therefore, it is necessary to avoid exposure to high temperatures and sunlight during storage and use.

2. Solubility: Pyrethrins are fat-soluble compounds that dissolve in organic solvents such as alcohols, ethers, and ketones. It is less soluble in water, but can form a suspension.

3. Photosensitivity: Pyrethrins are sensitive to light, especially ultraviolet light. Long-term ultraviolet radiation will cause it decompose and fail, so it is necessary to avoid exposure to strong light during storage and use.

4. Thermal stability: Pyrethrins also break down at high temperatures, so exposure to high temperatures needs to be avoided.

5. Toxicity: Pyrethrin is relatively safe for humans and animals, but at high concentrations it may have an irritating effect on skin and eyes. Therefore, it is necessary to pay attention to protective measures during use to avoid direct contact.

Pyrethrin is a kind of natural organic compound with excellent insecticidal effect. It is widely used in agriculture, family health and public health fields. Pyrethrin is chemically stable but sensitive to light and heat.

The mechanism of pyrethrin poisoning is mainly related to its effect on insect’s nervous system. The following is a general overview of the mechanism of pyrethrin poisoning:

1. Neurotoxic effects: Pyrethrin plays an insecticidal role by acting on the nervous system of insects. It mainly affects the electrical signal transmission of insect’s nerve cells. Pyrethrin can interfere with the sodium ion channels of insect’s nerve cells, causing increased excitability of nerve cells, resulting in abnormal electrical signal transmission and nerve conduction block. This leads to dysfunction of the insect's nervous system, eventually leading to paralysis and death.

2. Selectivity of neurotoxic effects: Pyrethrin is relatively selective in its effect on the nervous system of insects and has less effect on the nervous system of mammals and humans. This is because insect and mammalian’s nerve cells have some structural and functional differences, resulting in pyrethrin's effect on the insect nervous system is more obvious, while the effect on the mammalian’s nervous system is less.

3. Metabolism and detoxification: Some pyrethrin will be metabolized in insects and produce some metabolites. These metabolites may have a more toxic effect on the insect's nervous system. However, certain insects may also reduce the toxicity of pyrethrin through a number of detoxification mechanisms. These detoxification mechanisms can include the activation of metabolic enzymes and the ability to exclude pyrethrin

4. Potential harm: Although pyrethrin has little impact on humans and mammals, it may still cause some uncomfortable symptoms at high concentrations and prolonged exposure, such as eye and skin irritation, respiratory discomfort, etc. Therefore, when using pyrethrin, it is still necessary to follow the correct use methods and safe operating procedures to avoid excessive exposure.

Pyrethrin acts as an insecticidal agent by interfering with the electrical signal transmission of insect’s nerve cells. Its effect on the nervous system of insects is relatively selective, and its effect on the nervous system of humans and mammals is less. However, it is still necessary to follow safe operating procedures during use to avoid excessive contact.