Advice for potential November or winter agronomy jobs for northern growers

Article overview

Current situation (21 October)

Compared with further south, the north (for once) has had the better weather this autumn. Decent drilling progress has been made, particularly north of the Humber and on the Yorkshire Wolds, having mostly missed the really heavy rain in September. Further west and along the A1 corridor many are also not far off where they would want to be for mid-late October, despite a bit more rain during the month.

Potato harvest is also continuing although the weather has hindered progress during October especially.

Tom’s agronomy tips for November and through winter

1) Weed control tactics for wheat crops

Most pre-emergence herbicides seem to have been applied where wheat crops have been drilled, although as always there will be a few cases where that didn’t happen where perhaps drilling was prioritised, seedbed quality was poor, or weather stopped spraying.

Where they have been applied, particularly in September-drilled crops, residual herbicides will start to run out of steam in November and will likely need topping up where difficult grassweeds are present.

That’s particularly the case for Italian ryegrass, which can have quite a prolonged germination period.

Options for a top up in this situation include our range of metribuzin products, which also contain flufenacet and diflufenican. Following last year’s label change these can now be used at a full 1.0 L/ha dose and in theory through to the spring with a growth stage cut-off of GS25. This makes them more flexible than previously and as well as grassweeds will also control a wide range of broadleaf weeds, which can be helpful.

In heavy grassweed situations, and assuming it wasn’t used as the pre-emergence, cinmethylin is also an option. Following a Liberator (flufenacet + diflufenican) + Proclus (aclonifen) pre-emergence this would be a good choice, albeit not the cheapest.

Where the pre-emergence spray was missed, most of these options will remain in play. Remember Proclus cannot be used post-emergence, but otherwise the same residuals you would choose from as a pre-emergence are available.

Depending on difficult grassweed pressure, I’d be looking to tank mix in other actives, such as pendimethalin, prosulfocarb, or tri-allate as appropriate with a metribuzin-based product.

In “easier” annual meadowgrass plus broadleaf weeds situations then a Liberator or metribuzin product alone might be enough, depending on what broadleaf weeds are present.

Where wheat crops are still being drilled, hopefully there will have been the opportunity to kill off any grassweed germination beforehand with glyphosate. Weed pressure should also be lower, but establishing a competitive crop is vital. That will mean increased seed rates, and also achieving as good a seedbed as possible – admittedly not always the easiest thing to do in November in a wet autumn.

The quality of seedbed will determine whether you can realistically use a pre-emergence residual herbicide. Seed should be buried to a consistent depth with at least 32mm of soil covering.

If that has been achieved then applying a Liberator + Proclus if you’re in a field with difficult grassweed risk, will give you a head start on weed control.

2) Assess disease risk in oilseed rape

While the total area of oilseed rape crops drilled this year is down, those established in early to mid-August in good conditions currently look good, and perhaps needed a bit of slowing down. The only crops that I’ve heard that failed were some where growers drilled in the middle of September.

There haven’t been many reports of Phoma as yet, but that’s probably not surprising if AHDB’s forecast, which suggests 10% incidence in plants of Phoma won’t be until late October and into November.

Keep monitoring for both Phoma and light leaf spot and if pressure warrants it, consider applying with Proline (prothioconazole) or possibly Aviator (bixafen + prothioconazole).

3) Check glyphosate rates for cover crop destruction

Terminating cover crops around a month ahead of the intended spring crop drilling date seems safest for ensuring there isn’t any yield penalty caused by either nutrient lock up by the dying cover crop or problems with excess moisture at drilling.

While grazing or rolling on the frost are options for termination, using glyphosate remains perhaps the most effective method, or at least necessary after either of those alternatives to finish things off.

When using glyphosate particularly where there is a large biomass to kill off, knowing what species are present and their growth stages at spraying is important. Some species are harder to kill than others and will need higher doses. We’ve seen a few cases in the past year where suboptimal doses were used, leading to lower levels of kill.

Liberator® contains flufenacet and diflufenican. Proclus® contains aclonifen. Proline® contains prothioconazole. Aviator® contains bixafen and prothioconazole. Liberator, Proclus, Proline and Aviator are registered trademarks of Bayer. 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 2024. 