The wet weather we've endured this summer has been depressing but it does have some advantages related to controlling troublesome brome grassweeds.
Brome plants have been able to establish well in moist seed beds in the last few weeks allowing us to take a stale seed bed approach to controlling them. Meanwhile, cereal crop drilling has been delayed by showers and this opens up a bigger window to get a head start on weeds before the crop goes in.
Brome is an ongoing problem for us in the North East. We've had a long term issue with sterile and great brome but more recently we're seeing increasing levels of soft meadow and rye brome appearing too, even in plough based systems. It seems the levels are increasing and control is more challenging.
Narrowing control window
Sterile brome is largely a cultural problem brought about by our need to drill early in order to establish crops ahead of winter and cold/wet soils. Traditionally, sterile and great brome have taken advantage of the short gap between harvest and drilling. This narrow window leaves agronomists and growers with little opportunity for stale seed beds and cultural control.
The problem is greatest in min till or direct drill systems. Ploughing helps to bury the seed and aids control because seeds buried to 15cm depth cannot emerge. This year however, plentiful moisture has encouraged rapid emergence of sterile brome. This, combined with delayed drilling due to the wet weather, should leave us with more opportunity for action and reduced levels of this troublesome weed.
In wheat and barley a combination of Avadex backed up by a full rate of flufenacet is a good starting point in a sterile/great brome control programme. However, these products need to be applied ahead of the weed's emergence for optimum efficacy.
The serrafalcus group (soft/rye/meadow bromes) which are now also causing us trouble are a more difficult proposition. In theory they should be left to mature in the stubble post harvest to allow them to ripen before cultivation begins. In reality this is difficult for us to do in the north and seeds are often inverted only to reappear causing headaches in the early spring.
For this reason residual herbicides are of limited use on this group and even the combination of Avadex/flufenacet will struggle to give season-long control. Ploughing will help to dilute the problem and, in most cases, reduce the concentration of seed on the surface. This is the best approach ahead of a barley crop. In wheat, Palio/Broadway Star used in the early spring can still give effective control of this group of weeds.
Brome is likely to remain an issue for us in parts of England and it's been singled out as a grassweed that could face resistance challenges. But every cloud has a silver lining and this year wet weather may well help us gain more control of brome.
Agronomist in North East England
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