Compared with insecticides and fungicides, herbicides require higher technology. Improper use of pesticides and fungicides may only affect the control effect. The improper use of herbicides is related to the safety of crop growth. In order to ensure the safe and efficient use of herbicides, the following describes its key technologies for reference.

1. Strictly control the sensitivity of crops to herbicides. Different crops have different sensitivity to herbicides. If the herbicides are not selected according to the sensitivity of crops to herbicides, even if the herbicides used are safe for crops, sometimes they are also prone to harm. Generally, the herbicides for controlling broad-leaved weeds are sensitive to dicotyledons, while the herbicides for controlling gramineous weeds are sensitive to Gramineae.

2. The sensitive period and application period of crops should be strictly controlled. The sensitivity of crops to insecticides and fungicides is different in different growth stages, and the sensitivity to herbicides is even different. Under normal conditions, crops are particularly sensitive to herbicides before germination, 3 leaves and flowering and filling period, which are easy to cause damage. The herbicide before germination can only be absorbed by the radicle, coleoptile or hypocotyl of the weed, but it can kill the weed. When it is used after the emergence of the weed, it generally has no or very low herbicidal effect. Post sprout herbicides should also be used at a certain growth stage of weeds or crops in order to be safe and effective.

3. Strictly select the type of herbicide. There are several types of herbicides, which should be selected "according to grass conditions". (1) selective herbicide: this kind of herbicide can selectively kill some harmful plants when it is used within a certain dose range, and the crops are safe. (2) killing herbicide: this kind of herbicide has killing effect on all plants, and this kind of herbicide is limited to killing weeds in leisure field and idle field. (3) contact herbicide: this kind of herbicide only damages the parts of the plant that are in contact with the agent, and has no effect on the parts that are not in contact with the agent. (4) internal absorption and conduction weeding type: the effective components of this kind of herbicide can be absorbed by the roots, stems and leaves of plants, and quickly transmitted to the whole plant, so as to kill harmful plants.

4. Strictly control the dosage and concentration of herbicide. The selectivity of herbicide is within a certain dosage range, so even if the herbicide is selective, beyond the specified dosage range, it will cause harm to crops.

5. Strict use of herbicides. The application methods of herbicides include stem and leaf treatment, soil treatment and weed killing film weeding. The most commonly used methods are stem and leaf treatment in growing period and soil treatment before sowing. The treatment of stem and leaf in growth stage is a method of spraying herbicide on the stem and leaf of weeds at a certain growth stage after emergence of crops. In this way, herbicides not only come into contact with weeds, but also may come into contact with crops. Therefore, herbicides are required to have high selectivity or directional spray so as to achieve safe use of pesticides. Soil treatment after sowing and before seedling is a method of spraying herbicide on the soil surface before emergence.