Herbicides operating technology
Herbicides are more demanding than their insecticides and fungicides. Insufficient use of pesticides and fungicides may only affect the control effect. The use of herbicides is not good, but it is related to the safety of crop growth. To ensure safe and efficient use of herbicides, the key technologies are described below for reference.
Strictly control the sensitivity of crops to herbicides. Different crops are sensitive to herbicides. If the pesticide is not selected according to the sensitivity of the crop to the herbicide, even if it is a herbicide safe for crops, it is sometimes apt to produce phytotoxicity. Herbicides that generally control broadleaf weeds are sensitive to dicotyledonous crops, and herbicides that control grass weeds are sensitive to gramineous crops. For example, 2,4-D, Dimethyltetrachloride and the like have good effects on broad-leaved weeds, but are sensitive to broad-leaved crops such as cotton, rapeseed, melons, beans, peanuts, potatoes, tobacco, etc., which are prone to phytotoxicity. . Acetochlor is suitable for broad-leaved crops such as corn, peanuts, cotton, and soybeans, but it is susceptible to phytotoxicity to wheat. It can be used to control grass weeds in the field of broad-leaved crops, but it is harmful to grass crops such as wheat, rice, millet and corn.
Strictly control the sensitive period of the crop and the period of application. Crops are sensitive to insecticides and fungicides at different growth and development stages, and their sensitivity to herbicides is even different. Under normal conditions, crops are particularly sensitive to herbicides during germination, pre-leaf 3 and flower filling stages, and these periods are prone to phytotoxicity. Pre-emergence herbicides can only be absorbed by the radicle, cochlear or hypocotyl of weeds, killing weeds and using them after weed emergence. Generally, there is no herbicidal effect or low herbicidal effect. Post-emergence herbicides are also safe and effective for use in weeds or crops at a certain stage of growth. For example, the grass grass can be used in the 3~5 leaf stage of weeds, and the control effect on grass weeds is usually 90~100%, but the effect is lower after the 5th leaf stage.
The type of herbicide is strictly selected. Herbicides are of the following types and should be selected as "suitable for grass". (1) Selective herbicides: These herbicides are used within a certain dosage range to selectively kill certain harmful plants while crops are safe. Proper use in crop fields can achieve the goal of killing only weeds without harming the crops. (2) Killer herbicides: These herbicides have a killing effect on all plants, such as gram-free, sodium pentachlorophenol, glyphosate and the like. Such herbicides are limited to grass fields in leisure fields and idle places. (3) Contact-type herbicides: These herbicides only damage the parts of the plant that come into contact with the drug, and have no effect on the parts that are not exposed to the drug, such as gram-free, enemy, and herbicide ether. (4) Systemic-type herbicidal type: The active constituents of such herbicides can be absorbed by the roots, stems and leaves of plants and rapidly transmitted to the whole plant, thereby killing harmful plants such as glyphosate, covering grass and stabilizing Ether, etc.
