Precautions for Using Butachlor and Key Points for Safe Application

Butachlor is an amide-type selective systemic conductive herbicide. The pure product is a pale yellow oily liquid with a slight aromatic odor. It is poorly soluble in water and easily soluble in various organic solvents. It is chemically stable at room temperature and under neutral or weakly alkaline conditions. Under strongly acidic conditions, its decomposition is accelerated, and it can be degraded in soil. It is low in toxicity to humans and livestock, irritating to the skin and eyes, and highly toxic to fish. Butachlor is mainly absorbed through the young shoots of weeds and then translocated throughout the plant to take effect. It can be used both before emergence and at the seedling stage. After plants absorb butachlor, it inhibits and destroys proteases within the plant, affects protein formation, and inhibits the normal growth and development of weed shoots and young roots, thereby causing the weeds to die. When used on clay loam and soils with high organic matter content, the chemical can be absorbed by soil colloids and is not easily leached, with a residual effect lasting up to 1-2 months.

Precautions

1. Butachlor has good control efficacy against weeds before emergence but poor efficacy against large weeds, so it should be applied before sowing or transplanting as much as possible.

2. Butachlor works better when the soil has a certain degree of moisture. In dry fields, water should be applied by irrigation or spraying before application to improve efficacy.

3. During the sowing period of cucurbit and solanaceous vegetables, using this product may cause some phytotoxicity, so it should be used with caution.

4. Butachlor mainly controls monocotyledonous weeds and is ineffective or only slightly effective against most broadleaf weeds. In vegetable plots with many broadleaf weeds, consideration should be given to switching to other herbicides.

5. Spraying should be as uniform as possible to prevent phytotoxicity caused by excessive local application or missed spraying.

6. When used in paddy fields and direct-seeded rice fields, the amount of 60% butachlor must not exceed 150 cm per mu, and the field surface must never be flooded. In general, the lower limit of the dosage should be used in southern China. If the temperature is below 15°C when applying in early rice seedling fields, phytotoxicity of varying degrees may occur.

7. Butachlor has poor efficacy against barnyardgrass at the three-leaf stage or later, so it must be applied before the one-leaf stage of weeds or at the three-leaf stage, and water must not submerge the rice seedling hearts.

8. At present, butachlor is generally not used for weed control in wheat fields. If used in vegetable plots where soil moisture is too low, it will affect the expression of its efficacy.

9. Butachlor is highly toxic to fish and must not be used in fish farming. Water from paddy fields after application must not be discharged into fish ponds.