Take advantage of good conditions
With no extended cold snap to keep black-grass in check many plants are now strong and well rooted. Attention to detail in post-em applications is a must if maximum control is to be gained, says Bayer CropScience.
Dry weather, season-long germination and good conditions for growth have challenged the earliest pre-em treatments applied over three months ago so many growers are now facing a mix of robust and very young black-grass going into the spring.
"Temperatures have been consistently high throughout November, December and into January - growth simply hasn’t stopped," says Jane Heatherington, commercial technical manager, based in Suffolk. "Sporadic rainfall in the autumn has meant several flushes of grass weeds."
Trials in Lincolnshire are supporting what is being seen in the field. "Black-grass is still coming through and can be found at one leaf," says Simon Gage, Lincolnshire’s commercial technical manager. "Pre-em efficacy could be seen up until Christmas and there’s already a big difference between the treated and untreated plots.
"Populations are higher than this time last year, so to achieve the same control we need to up our game by paying even greater attention to detail when applying post-emergence herbicides.
"An additional pressure is that growth has continued underground too. Black-grass is quite well rooted already."
While the weather hasn’t halted the growth of troublesome grass-weeds it does mean that conditions are suitable for travel. Spraying in January/February looks to be a viable option for growers in most places this year.
"Given the current good conditions many are getting on with Atlantis WG (mesosulfuron and iodosulfuron) now," reports Gareth Bubb, who works in the West Midlands and Wales area. "We don’t know what conditions we’ll have later in spring, it’s possible that an extended wet or cold spell could close this spray window and then we may not have another opportunity until much later in the spring when black-grass is much bigger.
"Atlantis WG is most effective on small grass-weeds and given that even those at the one leaf stage already have robust root systems, it’s logical to go on now. As long as plants have a chance to take up the active substances subsequent cold weather won’t impact on its efficacy."
"This timing will also keep Atlantis WG applications away from T0 and PGRs," he adds.
The recent full label approval of a sequential application of Liberator (flufenacet and diflufenican) is an additional tool for growers facing varied growth stages.
"Tank-mixing this robust residual with Atlantis WG is a good option for those wanting to tackle late germinating black-grass. On its own it is also useful for very late drilled crops that didn’t get a pre-em, following potatoes for example."
