Agronomy tips for East Anglian growers this autumn: wheat drilling, weed control and cover crop management

Rachel’s agronomy tips for October

1) Getting Roundup^® right before drilling wheat

A lot of stubbles will have been sprayed off in September, either ahead of drilling last month or in preparation for drilling in early October, helping to break the green bridge for barley dwarf virus infections.

Where a second application of Roundup^® is required, remember to use an alternative method of control in between if there are survivors of the previous application, you potentially can use a lower dose. If you’re applying within 48 hours of drilling, or in mix with pre-emergence herbicides, the maximum dose is 540g a.s/ha.

If it is the first spray then potentially there will be bigger weeds, where a higher rate might be required, such as tillered grass weeds or perennial weeds.

As weather gets catchier, the benefits of using a branded Roundup® product only increase with good rainfastness, while when applying pay attention to keeping the boom 50cm above the target, and going slower to ensure good coverage and efficacy. From working with NIAB, we have trials data that shows if you get your glyphosate application wrong it has a big impact on your grass weed populations year on year.

2) Pre-em. and follow-up spray choices for October drilling

For those who have just drilled in late September and yet to apply a pre-em., or are drilling in October, as we get into cooler weather, it’s important to choose actives that will last for a decent length of time. That will help provide efficacy for longer, in the event the weather closes in and you can’t come back with a follow up.

In this situation, the use of a Proclus^® in mix with a metribuzin co-form, such as Alternator^® Met, Cadou^® Met or Octavian^® Met is a good first shout. Proclus^® can only be applied pre-em., but gives long-lasting protection and works well with the metribuzin products.

Where a pre-em. has already been applied, what you use as a follow up will depend on what’s been used initially. If you’ve used Liberator^® + Proclus^® or a cinmethylin-based pre-em., then again the metribuzin co-forms will fit nicely as a follow up spray, although in really difficult Italian rye-grass situations after a Bayer pre-em., then cinmethylin is a strong choice.

Winter barley is a little simpler, where a Liberator^® + Proclus^® pre-em. followed by a metribuzin co-form is a strong programme for grass weeds, giving that sequence effect without compromising crop safety. Barley is more sensitive that wheat, so we don’t recommend any additional products with pre-em. sprays.

It also means that paying attention to seedbed conditions, which is important with wheat as well, is vital. Make sure you have 32mm of settled, consolidated soil above the seed, and avoid spraying if heavy rain is immediately forecast. The same applies if you’re using a disc drill and the slots haven’t closed as you don’t want to be applying herbicide directly onto seed.

3) Consider an autumn Atlantis^® OD for sterile brome

This one fits into the know your weeds box, and what you’re likely need to use for control in the spring. But there might be some cases where bringing an Atlantis^® OD application forward to the autumn could help with control, for example of autumn-germinating brome species.

Earlier applications will hit the grass weeds at a smaller size improving chances of success, but it does use your only shot of a grass weed-active ALS-inhibitor product, and that might be something you want to hold back until the spring.

So the decision will need weighing up which timing will have more benefit in your situation.

4) Optimising glyphosate strategies for effective cover crop termination

Cover crops have got off to a good start, with plenty of opportunity to drill in August with the early harvest. That could lead to some quite big biomass crops by the time they need to be terminated around or just after Christmas, depending on when you expect to drill a following crop.

Most crops will have glyphosate applied whether that’s as a standalone spray, or after grazing or rolling on a frost. When you come to spraying off, look at what species you have. Big biomass species with big root systems are generally harder to control and will need higher doses of glyphosate, as will species with waxy or hairy leaves where glyphosate isn’t taken up as well.

Check our cover crop controllability guide from a few years ago for some guidance or get in touch with one of our technical managers for help.

Shading of smaller species by larger biomass plants is another aspect to consider, mowing and then waiting for regrowth might be worth considering before spraying to get even coverage. Otherwise, do check efficacy after applications, looking carefully for any surviving grass weeds that might need cultivating to remove.

Allow at least four weeks before you plan to drill the following crop for spraying the cover crop, and another two weeks to give a long enough window to get the job done in a period where weather might not be very conducive to spraying.

5) Put the sprayer to bed

It will be on the list to do, but there’s nothing worse than coming into a shed after spring, all fired up to get the first spray job of the spring out of the way to find a burst pipe on the sprayer or some other mechanical issue.

Use the winter period to make sure any maintenance on the sprayer is done and then go away and spend some time enjoying the slightly less hectic winter period on an arable farm.

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Alternator® Met, Cadou®Met and Octavian® Met contain diflufenican, flufenacet and metribuzin. Atlantis® OD contains iodosulfuron-methyl-sodium and mesosulfuron-methyl. Liberator® contains diflufenican and flufenacet. Proclus® contains aclonifen. Roundup® contains glyphosate. Alternator®, Atlantis®, Cadou®, Liberator®, Octavian®, Proclus® are registered Trademarks of Bayer. Roundup® is a registered Trademark of the Bayer Group.All other brand names used are Trademarks of other manufacturers in which proprietary rights may exist. Use plant protection products safely. Always read the label and product information before use. Pay attention to the risk indications and follow the safety precautions on the label. For further information, including contact details, visit www.cropscience.bayer.co.uk or call 0808 1969522. © Bayer CropScience Limited 2025