Five crop insights to help you manage crops this winter

Crop Progress

Virtually all cereal drilling except for crops after roots, vegetables and maize has been drilled. Usually it is drilled earlier in the west than east because of the wetter climate in the west.Most crops have gone into good conditions and seedbeds. Aphids are in some crops though, so keep monitoring to decide whether they will need spraying to prevent barley yellow dwarf virus infections.Oilseed rape, as ever, is looking variable. Many of the early drilled crops look good, later drilled is more of a field-by-field basis. We have had fewer reports of cabbage stem flea beetle attacks in the west, but slugs have been more of an issue.

Tom’s agronomy tips for November

1. Consider top up residual or contact herbicides in wheat

Mild temperatures and moisture in seedbeds will have contributed to good levels of activity from pre-emergence residual herbicides in earlier sown crops, but also a diminished half-life in the warmer temperatures.That means flufenacet and cinmethylin based treatments will likely be running out of steam soon. It will be well worth, if you can travel, to top up with a flufenacet-based product or a contact-acting where grass-weeds are a threat.I would break it down into three options. If grass-weeds are emerging and are mostly up to one true leaf, I would go down the residual route. Options include Alternator Met or Octavian Met (flufenacet + diflufenican + metribuzin) at 0.5 L/ha. This can be used up until the end of November, and contains three modes of action, including metribuzin, which will give some contact alongside the residual activity on small weeds.Applying this at peri-emergence can give the best efficacy, but also the most chance of crop damage. In all likelihood most crops will be at true post-emergence timing in November, given drilling dates.Where grass-weeds, especially Italian ryegrass and black-grass, has reached 2-3 TL, I would switch to using a predominately contact herbicide, containing mesosulfuron, as residual chemistry on its own will have more limited activity.The weeds need to be actively growing, which it should be in the current warmer temperatures, and the spray applied to a dry or drying leaf for maximum efficacy. Options for this include Atlantis OD (mesosulfuron + iodosulfuron) or Hamlet (mesosulfuron + iodosulfuron + diflufenican), and it can be topped up with a residual partner, such as pendimethalin or Liberator (flufenacet + diflufenican) for activity against emerging weeds.If conditions are good, it is likely to be better to use a contact herbicide in the autumn rather than waiting until the spring when grass-weeds will be bigger and application conditions can be less than optimal. Most Italian ryegrass and black-grass emerges in the autumn.The last option is where grass-weeds are emerging like a carpet. In this situation, short-term pain for the long-term gain is worth considering even at the current high commodity prices, and spraying the field with glyphosate and starting again with a spring crop.

2. Pre-emergence or post-emergence for late drilled crops

For November drilled crops there will be a choice of using a pre-emergence herbicide – if you can drill, hopefully you can spray too.Where the usual difficult grassweeds are an issue, then a pre-emergence residual, such as Liberator will be the best option. Add in other modes of action as necessary depending on risk.However, some late drilled crops after roots or vegetables will be on lighter land where annual meadowgrass and broadleaf weeds will be the key targets. On these crops Liberator remains a good option, but if unable to travel soon after drilling, post-emergence contact products, such as Othello (mesosulfuron + iodosulfuron + diflufenican) or Hamlet continue to work effectively for growers.

3. Monitor for oilseed rape diseases

Earlier sown oilseed rape crops should be at less risk of Phoma because of plant size, but higher risk of light leaf spot, especially if there is a wet, cool winter. Variety will also influence risk.Keep an eye on the AHDB Phoma and light leaf spot forecasts and monitor crops for thresholds for spraying.Our SpotCheck service with ADAS to check crops for oilseed rape diseases is again available through March. If you would like a sample pack please get in touch with me. It’s a good way of assessing risk of these key diseases.Most growers will look to apply one fungicide in the autumn, and it makes sense to use one with activity against both diseases. That could be Proline (prothioconazole) at 0.32-0.46 L/ha or Aviator (bixafen + prothioconazole) at 0.5-0.75 L/ha.We’ve seen benefits in both disease control from Aviator and physiological benefits in glasshouse trials at the University of Nottingham – in particular increased rooting. That will help increase nutrient use efficiency – helping roots explore more of the soil around them for nutrients and potentially giving scope to reduce artificial nitrogen applications.

4. Maximise cover crop growth but terminate in time for spring cropping

Establishing over wintered cover crops has been a bit more difficult this season with the dry weather hampering early growth. Obviously you will want to maximise growth for as long as possible over winter to get the most benefit, but, especially on heavier land, consider terminating around 4-6 weeks ahead of anticipated spring crop drilling dates, especially spring barley, to avoid any nitrogen lock up or excess moisture impacting establishment.Glyphosate is the most reliable method of termination, although sheep grazing or rolling on a frost can be effective. If you’re just using glyphosate for termination, match dose to the most difficult species or weeds in the cover crop.Some common cover crop species, such as brassicas are quite easily destroyed, but leguminous species, such as vetches, will need a higher dose, especially if they are going into stem extension when glyphosate won’t be translocated to the roots as well.Cover crops can also harbour difficult grass-weeds, such as black-grass and Italian ryegrass and these will need an appropriate dose too, as we don’t want to increase the risk of resistance developing.The Roundup branded products have superior adjuvant systems within the formulation, which means they work well in cooler conditions, albeit slowly.Application technique is important – keep water volumes high enough to get coverage of the canopy, and make sure the cover is actively growing to help the glyphosate translocate through the plant.

5. Consider signing up to FieldView

Our digital platform FieldView is a very helpful, intuitive tool that can help you pull and manage data into one place, and give you insights into crop performance.If you would like to give it a go for free for one year, find out more here.   

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