UNCONTROLLED black-grass and ryegrass are rearing their heads this season, and experts are advising acting now to save time and money later.
ADAS’ Senior Research Scientist and weed specialist, Dr Sarah Cook, said black-grass doesn’t just die back but will re-tiller from the bottom and produce heads later.
“Once it starts producing seed, it stops thinking about producing new tillers and concentrates on producing seeds, that’s the time to take it out,” she said.
Nick Sanderson of Tynegrain Agronomy, based in Northumberland, highlighted the importance of taking measures beyond those plants you can see above the crop.
“If you’re spraying off a patch and can see the ‘end’, give it an extra metre or two. Often when you look beneath the crop canopy, there are extra tillers or smaller plants. If you stop at the patch edge, you won’t catch these and they will seed.”
Stuart Kevis, Business Development Manager at BASF, also advised the need to target smaller grassweeds, stressing that even after haulm topping, both ryegrass and black-grass can regrow and seed.
“Smaller plants that are growing beneath the canopy are unaffected,” he said, adding: “Grassweeds can re-tiller and go on to produce viable seeds later in the season. It may require multiple passes to stop any regrowth setting seed.
“Spraying off is probably the most reliable and practical way to remove in-crop grassweeds. It is important to completely kill the plants. Ensuring glyphosate penetrates the crop canopy is needed to catch those shorter grassweeds.”
Simon Roberts from CCC Agronomy in the South East says knowing precisely where the grassweeds are is essential for short and long-term control.
“Where we share apps with farmers and operators, we will drop a pin wherever there are wild oats, black-grass or ryegrass. At this time of year, they will either go back out and mow, rogue or spray it with glyphosate.”
“Mapping helps inform harvest and drilling – avoid harvesting the worst fields first, if possible, to prevent further spread around the farm with the combine, or leave patches within a field until last then clean the combine thoroughly ideally not in the field gate way.
“In autumn the maps will determine which fields we should delay drilling. Maximising the opportunity for grassweed germination before the crop is drilled.”
