Italian ryegrass is arguably more difficult to control than black-grass, being less responsive to cultural controls, but a new herbicide is helping to get on top of the weed.
Speaking at an Arable Weed Week webinar, NIAB weed biologist John Cussans said while it is predominantly in ‘hotspot’ areas such as Kent, the North Essex coast and some areas of Yorkshire, it is spreading out. “It is a weed of increasing concern. We need to understand the best management practices. The root of it is resistance. We are seeing outright resistance to flufenacet as a pre-em herbicide.”
Cultural controls follow a similar pattern to black-grass but tend to be less effective, said Mr Cussans. “Delayed drilling reduces the density of the ryegrass weed you’re trying to manage but does not have such a profound effect as for black-grass. Spring cropping provides a further reduction in ryegrass plant numbers but not as large as for black-grass. Critically, in spring crops, individual plants are capable of returning incredibly high levels of seed.”
Ben Binder, farm manager at the Belmont Estate, Kent, where ryegrass is an issue, said control starts with destruction of the previous crop. “This quite often involves Round-up to spray it off and stale seedbeds. We use shallow cultivations and minimum disturbance drilling and get on with a pre-em.”
Where ryegrass cannot be controlled, Mr Binder takes an early decision to silage the crop.
This season he has trialled pre-em Proclus (aclonifen) + Liberator (flufenacet+diflufenican). “I’m astounded by the success we’ve had this year. We followed the guidance in terms of timing and rigidly stuck to it. When I’m winding down for Christmas I look at where we are on weed control and this year we’ve cracked it. That’s not to say it is 100 per cent but it is a big step forward.”