Group A Herbicides in Fallow

Using Group A herbicides for control of grass weeds in fallow

With the increasing frequency of glyphosate resistance, growers require alternative solutions to control grass weeds in fallow. The use of Group A herbicides in fallow to control grass weeds such as the Chloris species – feathertop Rhodes grass (Chloris virgata) and windmill grass (Chloris truncata) – has shown to be a viable option for controlling young weeds. However, Group A herbicides have a high frequency of resistant individuals in unselected populations, so will quickly develop resistance if survivors are not controlled.

Key Points

• Target weeds up to the early tillering growth stage only.
• Ensure weeds are fresh and actively growing.
• Medium to medium-coarse droplet spectrum. Minimum water rates of 50 to 70L/ha; higher water rates should be considered in heavy stubble conditions.
• One application per fallow, targeted at the main spring flush.
• Always follow up with a double knock after approximately seven days. Ensure all survivors are controlled.
• Apply the second spray in a double-knock program in the opposite direction to the first.
• Avoid tank mixing where possible. Consider adding required tank mix herbicides to the second knock.
• Consider rotational constraints before planting cereals, sorghum or maize into treated areas.

Useful Resources