Herbicide is one of the necessary pesticides for friends of the people. It is mainly used for weeds growing in farmland. At present, there are many kinds of herbicides in the market. According to the difference in the conductivity of the pesticides in the weeds, they were classified into contact killing type and conductive type. The contact type caused trauma, and the efficacy was rapid. However, when the spray was uneven, the weeds would revive; the conduction type was internal injury, and the efficacy was relatively slow, but the damage to the weeds was not easy to recover.

Classification of herbicides

1. Contact herbicide

After contacting with weeds, these herbicides only act on the contact parts, but can not or rarely transmit in plants. This kind of herbicide should be applied as evenly as possible. For example, if paraquat is only covered with a small amount of weeds, the rest of the leaves can still carry out photosynthesis normally. The weeds will show symptoms of damage, be restrained to a certain extent, and then slowly recover their growth ability.

2. A new type of herbicide

After being absorbed by weeds, this kind of herbicide can transmit in its body, and the herbicide can reach the uninjured parts and even spread throughout the whole plant. For example, glyphosate can be absorbed by the stems and leaves of weeds, and can be transmitted to the rest of the parts, even to the roots, causing the weeds to die completely.

Some herbicides can be touched and inhaled, but there will be a way that is the main way of action. For example, Huwei can touch and kill leaves, and can also be absorbed by roots, but it is mainly used to kill leaves in application. Similar to the classification of weeds, the above methods should be considered in connection with each other. For example, paraquat is a contact killing agent for stems and leaves, and acetochlor is an internal absorption and conductive selective soil treatment agent.