What is a selective herbicide?

Selective herbicides that can only kill one or a certain type of weeds without harming crops and other weeds and other weeds. Such as 2,4D butyl, atrazine and so on. The selectivity of this type of herbicide is achieved through the application site, time, morphological characteristics of crops and weeds, and biochemical reactions, among which biochemical effects are the main reason for achieving selectivity. For example, a herbicide that has the effect of promoting enzyme activity is harmless to plants, but it can promote the action of oxidase after entering the plant, and the production of toxic substances is harmful to the plant. In this way, weeds or crops with a lot of oxidase are easily damaged, while those with a low content are not harmed or very light.

What is a non-selective herbicide?

There are also some herbicides that are harmful to plants, but after entering the plant, they lose their herbicidal activity under the action of enzymes or other substances. This is called the inactivation of herbicides. For example, atrazine, a herbicide of triazine, is affected by ketone-containing substances after entering the plant body, causing a denitrification reaction and becoming a very low-toxic derivative. For weeds or crops that contain a lot of ketones, this kind of weeding becomes ineffective, so it can achieve the purpose of selective weed killing. Non-selective herbicides are also called biocidal herbicides. They treat plants regardless of good and bad ones, and kill when they see green. Such as paraquat, glyphosate, sodium pentachlorophenate and so on. This kind of herbicide can achieve safe weeding through the selection of application site and time and the use of protective devices.