Two new pre-emergence tank mixes based on Defy (prosulfocarb) were unveiled by Syngenta at Cereals 2008 to help meet demand for replacement herbicide strategies once IPU and trifluralin are no longer available.

The first, 5 litres/ha of Defy plus 0.1 litres/ha of DFF will be the company’s core pre-emergence recommendation against blackgrass, says technical manager Iain Hamilton.

“It’s given an average 93% control of blackgrass across a number of trials, performing better than the 4 litre/ha rate of Crystal. DFF makes a useful contribution to pre-emergence blackgrass control, boosting it by 10-15%.”

The second mix, which will be advised for tougher blackgrass situations, is 4 litres/ha of Defy with 0.4 litres/ha of DFF/flufenacet.

“This one has given 96% control in our trials,” adds Mr Hamilton.

The costs of the two mixes are £30/ha and £40/ha, respectively. “Growers who question whether it’s worth spending more on the second mix should think about its improved performance and what a difference that could make on their farm.”

For the control of annual meadowgrass, growers can make use of lower rates of Defy +DFF, using 1.5-2 litres/ha of Defy with 0.1 litres/ha of DFF. “IPU has had a very valuable role with annual meadowgrass control.”

In winter barley, growers can partner Defy with flupyrsulfuron, DFF or DFF/flufenacet, he advises.