What herbicide is effective for controlling large-stage barnyardgrass

Barnyardgrass is the most serious weed in paddy fields, and many farmers find it a headache. If barnyardgrass grows too fast, it becomes very difficult to kill. So what herbicide should be used for large-stage barnyardgrass?

1. What herbicide is used for large-stage barnyardgrass?

For large-stage barnyardgrass, herbicides such as cyhalofop-butyl, fenoxaprop-P-ethyl, penoxsulam, and Rinskor (florpyrauxifen-benzyl) can be used for control. Generally, applying the herbicide at the 2-3 leaf stage gives the best effect. If the application period is missed, not only does the cost of the herbicide increase, but once the barnyardgrass leaf stage is too advanced, it also becomes difficult to control.

2. Why is barnyardgrass in paddy fields so difficult to control?

1. There are many species of barnyardgrass, with great variation between species. It is not strict about its living environment and has strong adaptability. Barnyardgrass is a major malignant weed in China's farmland, with many species, reaching over a hundred; it grows from germinating seeds, and barnyardgrass seeds can survive in the soil for decades. As long as germination conditions are met, they can germinate and grow; moreover, there is great variation between species; it can grow in both flooded and dry environments, with strong adaptability and strong competitiveness. This growth habit is the fundamental reason for the severe occurrence of barnyardgrass.

2. Because barnyardgrass seeds survive in the soil for a long time, and barnyardgrass seeds accumulate year after year, the amount of barnyardgrass seed in the field continuously increases, and the barnyardgrass that germinates and grows also increases accordingly.

3. Barnyardgrass control is not thorough; too little herbicide is used in the early stage, and barnyardgrass occurs severely in the later stage.

4. The development of herbicide resistance in barnyardgrass. In recent years, with the widespread and heavy use of chemical herbicides, and with relatively little alternating use of herbicide varieties, the long-term use of a single variety has induced herbicide resistance in barnyardgrass. The amount used per mu keeps increasing, and the registered dosage often shows no obvious effect.

5. Improper methods of using herbicides. The use of herbicides is determined by their own properties: pre-emergence herbicides can only act on weed seeds, while post-emergence stem-and-leaf treatments can only act on the stems and leaves of weeds; different barnyardgrass-killing agents and different methods of use naturally produce different effects, and the effects can even differ greatly: for example, when using molinate or quinclorac sodium salt, the water does not need to be drained, whereas quinclorac WP and penoxsulam require drainage. The correct use of barnyardgrass-killing agents is one of the key measures for effectively controlling the occurrence of barnyardgrass and improving the herbicide effect.

Barnyardgrass must be killed with herbicide as early as possible; otherwise, once the best period is missed, it becomes extremely difficult to deal with and affects the normal growth of rice.