What is pyrethroid and what does it do

Pyrethroid is a biomimetic synthetic insecticide, which is a synthetic ester derived from changing the chemical structure of natural pyrethroids. Natural pyrethroid is an ancient plant-based insecticide, which is the active ingredient of pyrethroid, and its chemical structure was not determined until the 40s of the 20th century, after which, the synthesis of similar substances began.

Pyrethroids are a class of broad-spectrum insecticides that can control a variety of pests, and its insecticidal virulence is 10 100 times higher than that of older generation insecticides such as organochlorine, organophosphorus and carbamate. Pyrethroids have a strong contact killing effect on insects, and some varieties have both stomach toxicity or fumigation effects, but none have systemic effects. Its mechanism of action is to disturb the normal physiology of insect nerves, causing them to die from excitement, spasm to paralysis.

Due to the small dosage and low concentration, pyrethroid is safer for humans and animals and has little pollution to the environment. Its disadvantages are mainly high toxicity to fish, and it is also harmful to some beneficial insects, and long-term repeated use will also lead to pests developing resistance.

<> pyrethroid insecticides include deltamethrin (dimethrin), cypermethrin (Xingmianbao), fenvalerate (rapid dibutyl) and other drugs. Precautions for the use of pyrethroid insecticides: pyrethroid insecticides are highly toxic to aquatic organisms and cannot pollute water sources when used; If this type of drug is used continuously, it is easy for pests to develop resistance, so it should be used in rotation or mixed with other types of insecticides.

Pyrethrum can not only kill mosquitoes, but also kill pests of crops, trees and fruit trees. Together with tobacco and poisonous fish vine, it is known as the "three major plant pesticides". Between summer and autumn, the soon-to-be-blooming pyrethrum flowers are picked, dried in the shade, ground and passed through a 120 150 mesh sieve.

Add 200 300 times of water per catty of pyrethrum inulin, and add soap to make a suspension, stir well and spray, which can control a variety of pests in agriculture. Even if the whole pyrethrum grass is soaked in 20 times the water, it has a good control effect. If 50% insecticide inulin, 48% elm bark powder, 1% naphthol, and 1% toner are mixed together, and then a certain amount of water is added to make a paste, it can be made into mosquito coils.

1) English common name pyrethrins

2) Trade name: Chrysanthemum.

3) Dosage form: 3% water emulsion, % emulsifiable concentrate.

4) Properties and functionsPyrethrin is prepared by using artificially planted pyrethrum flowers and extract extracted by solvent method. It belongs to the Asteraceae family and is a perennial root-bearing plant. Pyrethrin (mainly found in flowers) is a typical nerve agent, which has contact killing, stomach poisoning and repellent effects, and can act on the peripheral nervous system, central nervous system and other organs and tissues at the same time.

It has strong knockdown power against pests, a wide insecticidal spectrum, low concentration, low toxicity to humans and animals, and is safe for plants and the environment.

5) How to use to control fruit tree aphids, leafhoppers and other pests, with 5% pyrethroid emulsifiable concentrate (active ingredient) mixed with water spray. It can also be sprayed with 1 kg of pyrethrum pollen (dried flower crushing), kg of neutral soap, and 400 600 liters of water. Method:

After dissolving the soap with a small amount of hot water, add insecticide inulin, then add enough water, stir evenly and use, which can control a variety of pests such as aphids, leaf beetles, and Tsubaki elephants.

6) Precautions.

Pyrethrin is easy to decompose when it is light, and it is best to spray it in the evening.

Pyrethrin cannot be mixed with alkaline pesticides such as stone sulfur mixture, Bordeaux liquid, and pine resin mixture.

Commercial preparations need to be stored in an airtight container, away from high temperatures, humidity and direct sunlight.

Pyrethrum is a strong contact killing agent, and the agent must be in contact with the insect body to be effective, otherwise the effect is not good.