FOR THE first time in five years, cereal growers have a rare window of opportunity to hit black-grass hard, according to Phillippa Overson, who has recently joined BASF as a specialist for herbicides and PGRs.
The kind autumn, decent sowing conditions and high black-grass dormancy, mean that many farmers are taking solace from reduced weed pressure, but Ms Overson is rallying farmers not to let up on driving black-grass populations as low as they can.
“A clean black-grass year would bring huge relief and welcome yield gains following stubbornly high populations resulting from the seed burden legacy of the wet autumn of 2012,” she suggested.
“But before breathing a sigh of relief and closing the metaphorical gate on spring weed control, we need to be mindful that warming, wet soils over the coming months could encourage a flush of black-grass, as well as other grass and broad-leaved weeds.”
Her argument is simple. Usually, at this time of year, weeds are large, abundant and, in winter cereal crops, requiring a robust contact herbicide programme to try and knock back numbers.
“However, this season we have a rare opportunity to use pendimethalin-based residual chemistry instead. It’s perfect timing, just when the autumn residuals – which, incidentally, worked well in 2016 – are running out of steam” she added.
“These offer alternative modes of action to the traditionally applied sulfonylureas (SU) at this point in the season, taking pressure off contact herbicide options, such as Atlantis WG.”
Ms Overson recommended two residuals, Stomp Aqua and Picona, which she said were also strong at controlling other grass and broad-leaved weeds, including those that are susceptible to ALS-resistance, such as poppy and chickweed.
Where spring crops are concerned, take all the cultural opportunities that you can. “Do as you would do in the autumn, use stale seedbeds and opt for high-tillering, compact varieties of spring barley, or spring wheat, such as KWS Kilburn and Belepi, plus, make sure seed rates are appropriate for the situation and that you apply a pre-emergence residual.
"Prepare as good a seedbed as you can and then wait, wait, wait until you have a market agreed if you are opting for spring barley.”
The residual herbicide options for spring application are outlined below.