Black-grass needs to be targeted when it is relatively small, ideally somewhere between growth stages 11 and 13, when the weed has one to three true leaves.
Water rates should be 100 L/ha with a forward speed of 12 km/h, preferably with a flat fan nozzle to maximise coverage.
If you’re using a mesosulfuron-based product, use 1L/ha of Biopower as the appropriate adjuvant.
Black-grass needs to be targeted when it is actively growing in order to maximise the uptake of the herbicide. Also ensure that herbicides are applied to a dry leaf or a drying leaf, allowing a maximum of two hours to dry after application.
If you’re targeting a mix of grass- and broad-leaved weeds, then Bayer recommends Pacifica Plus (mesosulfuron + iodosulfuron + amidosulfuron) at 0.4 kg/ha from 1 Feb, or 0.5 kg/ha after 1 March. Where black-grass or other grass-weeds are the primary target, then 0.33 kg/ha of Monolith is a good option.
Black-grass control is the biggest agronomic challenge facing most UK arable farmers. If you have black-grass, taking steps to reduce the population is key, while farmers fortunate enough to be free of black-grass need to keep it that way.
Bayer’s Jack Hill offers advice on how to carry out a black-grass resistance shoot test, which can provide valuable information to help plan control strategies.