Legacy means farmers need to start forward planning

UK - August 02, 2012

The season has been ‘concertinaed’ thanks to the unusual weather this summer, according to Stuart Jackson, Cereal Herbicide Specialist at Dow AgroSciences.

“Wheats will probably be harvested a little later than usual and farmers need to start thinking about weed control now for winter wheat, even though it seems early. There’s a heck of a lot of blackgrass seed that has gone back into the seed bank,” he says.

Mr Jackson says that certain soils may be wetter than usual going into the autumn and blackgrass will be able to chit.

Post harvest the first step is to create a stale seedbed and encourage recently shed blackgrass seed to germinate prior to drilling the next crop. This is best achieved via light cultivations and consolidation. Deep cultivations at this point will only bury the seed too deep rather than encouraging it to germinate.

Mr Jackson says: “You wouldn’t drill your wheat seed deep and expect it to germinate evenly and quickly so why cultivate your blackgrass seed in deep?
 “Ideally farmers should do it all again – certainly do at least two stale seedbeds in combination with delayed drilling in fields that have been hit badly by blackgrass,” he advises.

“Once the surface is clean don’t be tempted to cultivate deeper when preparing the crop seedbed as this will only pull up blackgrass seed from deeper down the soil profile,” Mr Jackson says.

Post drilling there should be a pre-em, such as Crystal, applied 24 to 48 hours after drilling. This should be followed by a post-emergence herbicide when the blackgrass is small and actively growing at the 1-3 leaf stage.

“For UNITE, our new pyroxsulam with flupyrsulfuron-methyl herbicide, an early autumn window is optimum to act against blackgrass. If you wait for the spring it may be too big to control effectively and will have competed with the crop reducing the yield,” says Mr Jackson.

UNITE has a wide range of compatibilities to allow stacking to deal with specific weed challenges. An autumn application will also provide outstanding control of other grass weeds including bromes, ryegrass and wild oats plus an extensive range of broad leaved weeds.

He says: “There are a lot of wild oats about across the country at the moment. Whatever grass weeds growers are trying to get rid of, they need to aim to get them out as small as possible and as soon as possible to take away crop competition.”

Mr Jackson warns that some growers don’t give the stale seedbed a chance to work, they drill too early and end up having to glyphosate the crop off and re-drill, costing time and money.

“Don’t fall into this trap.  Instead, prioritise bad blackgrass fields as those to be drilled late.  This will afford you the opportunity for multiple stale seedbeds prior to drilling,” Mr Jackson adds.

UNITE is compatible with many other products and offers growers the opportunity to use the useful residual activity from flupyrsulfuron-methyl in their blackgrass programme without subsequent ALS broad leaved weed herbicide restrictions, as UNITE can be followed with an extensive range of ALS broad leaved weed herbicides such as florasulam,  metsulfuron-methyl, thifensulfurion-methyl and tribenuron-methyl combinations. UNITE is an ALS herbicide, therefore it is important to use the product within a herbicide programme and in accordance with WRAG (Weed Resistance Action Group) Guidelines.