Midlands: Useful pointers for key agronomy decisions in May

Crop Progress

Land work and crops finally started to move forward in April. Growers applied fertiliser, there’s been a reasonable amount of spring barley drilled, which was continuing as we approached the end of April.

It’s getting late for spring barley drilling, with around 60% planted of what was planned after the winter. Any further drilling will likely have come with a yield penalty and on heavier land growers have started to write it off in favour of fallow, rectifying soil damage, improving drainage to get it right for next season. Others have put land into Sustainable Farming Incentive schemes.

There’s barely any spring beans in the ground, which isn’t likely to change, while potatoes and sugar beet have been planted or drilled on and off since the beginning of April.

Some T0s were applied late, if at all, in wheat because growers were still focusing on herbicides, with the applications restrictions with tebuconazole and mesosulfuron preventing both applications at the same time. That left more scope for higher spends on T1s with disease pressure high.

Ellie’s agronomy tips for May

Finish off any remaining T1s

Most T1s should have been applied, weather permitting, in late April, which should only leave later drilled wheat crops left to treat.

Those crops are likely to be the latest drilled ones, where yield potential will have been compromised to some extent and growers are likely to be planning to reduce spend.

In that situation a product like Ascra® (bixafen + fluopyram + prothioconazole) is a great choice. It’s both cost-effective, while also performing exceptionally well last season, up with the newer chemistry.

The dual SDHI loading also provides physiological benefits leading to improved rooting and nitrogen use efficiency, which will be beneficial in these later drilled crops.

It’s made with our Leafshield formulation, which improves rainfastness, a crucial attribute in a catchy season.

Assess disease pressure as T2 approaches

Disease pressure, especially Septoria, has been high in wheat following the showery April. There’s also yellow rust and brown rust in susceptible varieties, which in the case of brown rust is pretty early for it to start showing, even in a susceptible variety like Crusoe.

If the showery weather continues through May, probably in conjunction with warmer temperatures, Septoria pressure will remain high for the flag leaf timing, and is likely to benefit from one of the newer fungicide options.

Where Vimoy® (isoflucypram) + Proline® (prothioconazole) was not used at T1, that could be a good choice. As well as excellent activity against Septoria, Vimoy® also good control of both brown and yellow rust.

If Septoria pressure is extremely high, and neither Vimoy® or a fenpicoxamid containing product was used at T1, there’s also the option to use Vimoy® + Jessico One® (fenpicoxamid), which means you’re applying two of the best Septoria actives available.

You’ll no doubt recall the challenges when applying fenpicoxamid, if you’ve considered or have used Univoq® (fenpicoxamid + prothioconazole). The same best practice guidance will apply with Jessico One® , so check our advice here.

Where disease pressure is lower because either it has hardly rained between T1 and T2, or for later drilled crops, or possibly where a very robust T1 fungicide was perfectly timed and weather hasn’t been too wet, then Ascra could become a viable T2 option. The rate can be tailored to situation but 1.2 L/ha is a good starting point.

Manage diseases in winter barley with a well-timed T2

Winter barley area in Lincolnshire is considerably down on usual, thanks to the autumn weather. Rooting has been poor which is a concern for yield but disease will still need to be managed with wet weather diseases such as Rhynchosporium and net blotch relatively easily found in untreated crops.

If you didn’t use Ascra at T1 then it is a good option for the awns emerging timing at 0.7 L/ha. As well as controlling wet weather diseases it also has the rooting benefits, drought tolerance and protects against barley brackling – straw strength could be down this season because of poorer uptake of nutrition.

Ascra also has reasonable activity against Ramularia. Winter barley crops are physically stressed which increases the expression of Ramularia. With nutrition more or less set by this point, fungicides remain the only way of reducing further crop stress.

Alternatively, where foliar diseases are the main risk, Siltra® (bixafen + prothioconazole) is a solid choice.

One or two sprays for spring barley disease control?

The optimum approach for spring barley disease control would be a two-spray fungicide programme – it will help protect and retain tillers.

But in this region, this season, I would imagine a reasonable proportion of spring barley crops drilled in April could be a one-spray programme. Crops will likely be rush through growth stages very quickly and it could be difficult to fit in a two spray approach.

Both Ascra® and Siltra® are good options for either one or two spray approaches. For one spray, I’d favour Ascra® as the stronger product overall and especially against Ramularia. Timing for one spray can be anywhere between GS31 and GS43 – I think product choice is probably more important than timing with this tactic.

Another flowering spray in oilseed rape?

Oilseed rape area is also considerably down in the Midlands, and in crops remaining flowering started from around mid to late March – perhaps three weeks earlier than usual probably because of a stress reaction to the season.

The positive is that it has stayed in flower so far for 4-6 weeks, which hopefully is positive for pod development and yield. It also could mean a second flowering spray might be required as fungicides only protect against Sclerotinia for three weeks.

High humidity will have increased risk from that disease, although temperatures have been cooler which will have had the opposite effect.

Where first sprays have been applied three weeks previously and the crop is still flowering strongly a second spray of Aviator® at 0.5 L/ha or Proline® will help protect from a disease that can be extremely damaging.

Safety a priority with sugar beet weed control programmes

Sugar beet drilling has been ongoing from the first week of April, so some crops have emerged in rows, while others still sit in the seed bag with 10 days left in April.

With warm, moist soils pre-emergence herbicides should have worked well, which can then be followed up with a contact + residual partner post-emergence programme.

Betanal® Tandem® (phenmedipham + ethofumesate) makes a good base for such an approach, with various partners including metamitron, lenacil and triflusulfuron to broaden out weed spectrums and provide more residual activity.

With a high virus yellows forecast this spring, reaching 12 TL as quickly as possible will be a priority even where crops have been treated with a neonicotinoid seed treatment, so minimising crop growth checks with herbicide is important. With warming soils, sugar beet will be emerging quite quickly, making them susceptible to herbicide damage.

Keep an eye on forecast temperatures on the day of spraying with Betanal® Tandem® mixes. Adding a methylated vegetable or rapeseed oil will help with efficacy but the rate will vary according to maximum forecast temperature. For more details visit our website here.

For those growing Conviso Smart herbicide tolerant sugar beet remember the Conviso® One (foramsulfuron + thiencarbazone) herbicide should be applied in a single dose at 1.0 L/ha, when the crop is 4-8 TL and an indicator weed, usually fat hen, is 2-4 TL.

It’s also crucial to remove any bolters in this system – later drilling should have minimised the risk from bolters, but follow the guidance in the stewardship section on our website here.

Weed control in potatoes

Potato planting is also ongoing, although again with a late start we’re probably at least two weeks behind schedule.

Later planted crops will emerge more quickly than those planted in colder soils at the beginning of April, which means thinking about herbicide timing, especially if you’re using either Roundup® (glyphosate) or a true pre-emergence product like Emerger® (aclonifen).

With both be careful that the crop is still pre-emergence – with Emerger® we advise applying it at least seven days before emergence. Using the cereal pre-emergence advice of applying no more than 48 hours after drilling is probably worth considering this season.

Emerger is a good base for weed control, and efficacy can be improved and widened by Artist® (flufenacet + metribuzin) especially for grassweeds, and by Sencorex® Flow (metribuzin) for broadleaf weeds.

Spray off potato dumps and volunteers

While there have yet to be any findings of the fungicide resistant blight strain EU_43_A1 and EU_46_A1 in the UK, the fact they were detected on mainland Europe is a worrying development.

These strains have shown resistance to CAA fungicides like mandipropamid and OSBPI fungicides found in Zorvec® (oxathiapiprolin).

Good potato hygiene is one of the first rules of preventing blight infections and that will be doubly important with the potential added threat from these strains, so make sure you have destroyed any dumps, outgrade piles and control any volunteers to minimise risk.

Acknowledgments

Ascra contains bixafen + prothioconazole + fluopyram. Vimoy containts isoflucypram.Iblon contains isoflucypram. Proline contains prothioconazole. Jessico One containts fenpicoxamid. Siltra contains bixafen + prothioconazole. Aviator contains bixafen + prothioconazole. Betanal Tandem contains phenmedipham + ethofumesate. Conviso One contains foramsulfuron + thiencarbazone. Roundup contains glyphosate. Emerger contains aclonifen. Artist comntains flufenacet + metribuzin. Sencorex Flow contains metribuzin. Zorvec contains oxathiapiprolin. Ascra, Vimoy, Iblon, Proline, Jessico One, Siltra, Aviator, Betenal Tandem, Conviso One, Roundup, Emerger, Artist and Sencorex Flow are registered trademarks of Bayer. 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