North: Help with key agronomy decisions for May

Crop Progress

Let’s start with some positives – the weather improved a bit during April. I don’t think it was unseasonably wet, but the high-water table did mean it didn’t take much rain to start coming back through the top.

But there were some decent days that allowed growers to make some progress, and where crops did establish in the autumn, they now look a bit more positive, considering everything that’s been chucked at them with the sheer amount of water.

Spring cereals drilling has more or less stopped as this is written with about 10 days left in April, as it starts getting a bit late.

Potatoes started to go in up on the Wolds, but less had been planted on the land around the Vale of York at that point.

Tom’s agronomy tips for May

Will it continue to be high disease pressure in wheat at T2?

Not many crops received a T0 spray, which, combined with the weather increasing disease threats, led to a bumping up of T1 sprays.

In some cases that included the use of Univoq® (fenpicoxamid + prothioconazole) or our new option of Vimoy® (isoflucypram) + Proline® (prothioconazole).

Both could also be options at T2 for flag leaf sprays, but remember you can only use one application of each of fenpicoxamid and isoflucypram during a season so no repeating what you did at T1 if you used these products.

Vimoy as an active is strong against Septoria, yellow rust and brown rust, whereas fenpicoxamid is really good against Septoria but relies on prothioconazole in Univoq for its rust control.

If disease pressure remains very high and neither Vimoy® or Univoq® were used at T1, there’s also the option of bringing both isoflucypram and fenpicoxamid together through our Vimoy® + Jessico® One (fenpicoxamid) co-pack.

If the weather has changed tack by the time of T2 sprays and disease pressure has subsided or crop potential doesn’t justify the extra expense of the newer chemistry, Ascra (bixafen + prothioconazole + fluopyram) is an excellent one-can solution that will offer decent all-round disease control at a cost-effective price.

Consider Ramularia for T2 winter barley sprays

Wet weather diseases such as Rhynchosporium and net blotch have been reasonably easy to find in winter barley this spring, along with brown rust in hybrid barley.

Crops under stresshave been shown to be more likely to be infected with Ramularia, so given the conditions this season, it could be more of a threat this season and require considering at T2.

Where Ascra was not used at T1 then it could be a decent choice for the awns emerging spray, with the fluopyram adding to Ramularia control.

Alternatively, mefentrifluconazole could be used, while Siltra® (bixafen + prothioconazole) is another option where the other foliar diseases are more of a threat. Adding folpet to Siltra® could help against Ramularia.

One spray programme for spring barley?

The drilling window for spring barley was closing as we approached the end of April, with a lot drilled in mid-April.

With much of the crop later drilled, and not always into the best conditions, most growers will be thinking about a one spray fungicide programme. Where the crop is going for feed that makes sense, but malting barley crops could be worth two sprays, especially if it establishes well.

If you’re using one spray, consider going down the Ascra® route around GS31/32, which will provide good all-round disease control.

Where two sprays are being considered then Siltra® fits into one of the timings – probably the first spray at end of tillering, followed up by Ascra® two to three weeks later at awns emerging.

Prolonged oilseed rape flowering could need second spray

Oilseed rape crops were in full flower by mid-April but it’s not been uniform with often one end of the field much more forward than the other end. That’s likely to mean flowering is going to be prolonged and with the wet weather conditions have been relatively conducive to Sclerotinia, if a little cold for spore germination.

If wet weather continues and temperatures rise a second spray for Sclerotinia may well become necessary in early May – typically three weeks after an initial application.

Product choice could be Proline® (prothioconazole) or Aviator® (bixafen + prothioconazole) at 0.5 L/ha.

Watch for quick emergence of potatoes

Potato planting was only just getting going from mid-April in Yorkshire, mostly on the Wolds. Further west and in the Vale of York it was still a bit wet.

Once planting does start it’s likely to be with seed that has broken dormancy and into warming soils meaning crops may emerge more quickly than from earlier plantings.

That means, if you’re using a true pre-emergence herbicide like Emerger® (aclonifen) making sure it has been applied well before emergence has started. Emerger needs applying at least seven days before first shoots appear.

It’s a good option as it covers a wide range of broadleaf weeds, such as poppies, chickweeds, speedwells and thistles, and can be bolstered by the addition of tank mix partners, including Artist® (flufenacet + metribuzin) or Sencorex® Flow (metribuzin) on tolerant varieties.

For advice on good application practice with Emerger®, please go here.

A Tandem approach to beet weed control

Sugar beet drilling has also been delayed by the weather. Some growers will be using pre-emergence residual herbicides this season with conditions suitable for good efficacy.

This will help with taking the immediate urgency away from post-emergence herbicide applications, perhaps to two true leaves of the crop rather than expanded cotyledon, potentially lessening any crop damage.

With over 30% of the crop not treated with neonicotinoid seed dressings, keeping those crops growing as fast as possible to the 12-16 TL stage when beet becomes more tolerant of aphids carrying virus yellows will be important.

When using post-emergence herbicides, such as Betanal® Tandem® (phenmedipham + ethofumesate) there’s a delicate balance between crop safety and efficacy. The use of a methylated rapeseed oil, such as Mero® , will improve efficacy, but use the forecast high temperature on the day of spraying to adjust dose to minimise crop damage risk.

Acknowledgements

Vimoy containts isoflucypram. Iblon contains isoflucypram. Univoq contains fenpicoxamid + prothioconazole. Proline contains prothioconazole. Jessico One containts fenpicoxamid. Siltra contains bixafen + prothioconazole. Ascra contains bixafen + prothioconazole + fluopyram. Emerger contains aclonifen. Artist comntains flufenacet + metribuzin. Sencorex Flow contains metribuzin. Betanal Tandem contains phenmedipham + ethofumesate. Vimoy, Iblon, Proline, Jessico One, Siltra, Ascra, 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