Excessive dosage, improper application period and improper use are often the main causes of phytotoxicity. The herbicide does not act according to the requirements of the instructions. For example, the herbicide butachlor in the paddy field is sprinkled with poisonous soil after being inserted. The seedling is more than 150ml per mu. The seedling is weak and does not return to green. When the water layer is too cold, the rice layer can inhibit rice. Growing and tilling, even dead seedlings. For the rice field weeding, it is necessary to strictly control the dosage and application conditions. The temperature must exceed 28 degrees and the dosage should be appropriately reduced. Ultra-high-efficiency herbicides such as bensulfuron-methyl and pyrazosulfuron-methyl have high herbicidal activity and are easy to produce phytotoxicity. Butachlor is safer to apply toxic soil after rice is greened. However, if combined with land preparation before insertion, it will inhibit rice growth, delay tillering, encounter low temperature, abnormal high temperature or too deep water layer, and the disease will be more serious or even die. seedling. For herbicide concentrations of stem and leaf sprays that are too large, repeated sprays can also cause local phytotoxicity.