What chemistry is best to tackle brome?
How best do you tackle sterile brome and what restrictions are there with soil acting herbicides?
The main restriction for use of soil acting herbicides is on drilling depth and seedbed quality (including stone content!). Crop safety can be compromised if label restrictions on these factors are not adhered to.
For example, with Avadex (tri-allate), if the seed is shallow drilled, Id advise a post-em application instead, which might then compromise efficacy.
With IPU crops must be drilled to a minimum 25mm depth and well covered with soil. On stony or gravely soils there is a risk of crop damage especially if heavy rain falls soon after application.
Such restrictions place more emphasis on post-emergence applications and contact herbicides. So use stale seedbed cultivations to stimulate weed germination and facilitate their removal with a non-selective herbicide before drilling.
Early post-emergence isoproturon followed by a spring contact may be required to tackle sterile brome. The new spring product from Bayer, Attribut (propoxycarbazone) appears to have the edge over Monitor (sulfosufuron).
But beware: both Monitor and Attribute are known as ALS inhibitors (the latter is not a sulphonyl urea, but has same mode of action). They cannot therefore be used if a sulphonyl urea, for example Lexus (flupyrsulfuron-methyl), has been used in the autumn.
So if blackgrass is also targeted with a Lexus mix in the autumn, this precludes use of the two new products for Brome in the spring.
Sterile brome is relatively easy to control so long as you use stale seedbeds and chemical control after drilling. In a direct drill only system, I would say control of this weed is very difficult. So a shallow cultivation is required.
So long as you have a chaff spreader on your combine then trash can be handled successfully and will have no effect with the chemicals I would prescribe for Sterile brome control. It is also very important that you are able to drill at 4 – 5cm depth.
So make your stale seed bed, spray off the sterile brome with glyphosate before drilling and then apply Avadex granules within two days of drilling – hence the drilling depth.
The follow up product is your choice. Prebane (terbutryn) pre-em or IPU at the 1-2 leaf stage of the brome. Monsanto would probably recommend Monitor, but I havent seen enough of this sequence to comment yet.
With this technique I am positive that you can control or reduce your sterile brome problems on brash soils.
Various treatments have been on trial on sterile, meadow and soft brome in the Arable Event trials, here on FWi. Monitor was found to be good on soft and meadow brome, but virtually useless on sterile brome. Click here for more.