Seven ways to keep crops growing to their potential in April in the north

Crop Progress

Cereal crops were looking full of potential as we came to the end of March. Some did sit in the wet following the February storms but a good couple of drying weeks has helped.

There’s Septoria on the lower leaves of wheat, but not much yellow rust so far, but that could easily change as we enter April.

Tom’s agronomy tips for April

1. Knock out yellow rust early in wheat

Most T0 fungicides in wheat will be applied in early April. Keeping that spray to around three weeks before the usual T1 timing of mid-late April will help give flexibility to get the T1 timing spot on.

Target varieties with yellow rust infections primarily, or varieties with a known weakness to it as getting the jump on yellow rust usually helps reduce cost chasing it later in the season. In recent seasons it has been the varieties with low resistance scores to yellow rust which have responded most to fungicide programmes.

Watch out for mildew as well – a mildewicide can be added where necessary.

2. Dissect plants to identify leaf three at T1

There’s nothing better for identifying the correct timing for T1 sprays than dissecting plants. Going just by nodal growth can be misleading as it doesn’t always tie into the leaf layer emerging.

But it’s vital to get T1 timing correct – too early and you’re spraying leaf four rather than leaf three leaving it unprotected, while too late means you’ve left it unprotected for too long and infection could already have taken place.

A good all-rounder, such as Ascra (bixafen + fluopyram + prothioconazole) will help control all the key diseases that could threaten wheat crops – Septoria, yellow rust, mildew and eyespot. It also provides physiological benefits that help keep the plant green.

3. Protect winter barley from aborting tillers through disease at T1

Winter barley crops are carrying a lot of mildew as we approach the end of March, and were generally looking quite lush.

T1 sprays will be due when the crop reaches GS30/31 – unlike wheat the exact leaf layer is not so critical, but this spray is the most important one for winter barley as you’re looking to stop the plant aborting tillers through disease infections. Tiller retention is what drives high yields.

Watch out for Rhynchosporium and net blotch, as well as mildew at this timing. Ascra now also has label approval for barley crops, but you can only use it once on this crop. That means choosing between T1 and T2, where it will help suppress Ramularia. My recommendation would be to use at T1 though, particularly where disease pressure is higher.

In barley the recommended rate is 0.9 L/ha. Siltra (bixafen + prothioconazole) remains an excellent alternative.

4. Save Ascra for T2 in spring barley

In contrast, the T2 spray tends to be the timing where you get greater return on investment in spring barley, so that’s where I would suggest using Ascra to take advantage of its Ramularia suppression. Ramularia tends to pose the greatest threat to spring barley.

Many spring barley crops will have been drilled in March, but early drilled ones might be ready for their T1 fungicide in late April from around late tillering. Rates can be reduced a little compared to winter barley so 0.4 L/ha of Siltra is a good option.

If you’re still drilling spring barley in early April, remember that Liberator (flufenacet + diflufenican) now has an on-label approval for spring barley weed control, but, unlike the old EAMU, it’s for pre-emergence use only.

5. Invest in protecting oilseed rape crops

At current oilseed rape prices you need very little in the way of yield increase to pay for any fungicide input this spring, and generally the crop looks good and has potential, although some fields were hammered by pigeons.

The two main threats are light leaf spot and potentially Sclerotinia, although that doesn’t occur every season. Aviator (bixafen + prothioconazole) at 0.75 L/ha just before mid-flowering will help protect against both diseases.

In Forward Farmer strip trials Aviator has yielded 0.3t/ha on average more than the farmer’s standard treatment.

6. Remove weed competition early in sugar beet

With a high virus yellows forecast for this season following the mild winter, getting sugar beet crops to 12 true leaves, when the threat reduces, as quickly as possible will be important, even if seed has been treated with a neonicotinoid seed dressing.

Removing weed competition without checking the crop is an important part of achieving that. Betanal Tandem (phenmedipham + ethofumesate) will give good control of a wide range of broadleaf weeds, including some of the harder to control ones like fumitory, nettles and groundsel.

The first application at expanded cotyledon of the crop should be at 1.0 L/ha plus a residual partner, with subsequent applications at 1.5 L/ha. Add in oil but be careful to use the correct rate of oil tailored to the likely high temperature on the spray day to minimise any check to crop growth.

More growers have opted for Conviso Smart varieties this season. This system allows the use of Conviso One (foramsulfuron + thiencarbazone-methyl) herbicide containing two sulfonyurea crops on varieties bred to tolerant to it.

You only get one spray of Conviso One so pay attention to the application to make best use of it. Apply it at 1.0 L/ha in 150-300 L/ha water, when the weeds are at 2-4 true leaves and the at 4-8 true leaves.

Also concentrate on stewardship – many growers are using it as a way to control weed beet, but that will be only temporary if you don’t control any bolters during the season.

7. Don’t apply Emerger too late after planting potatoes

The main potato planting season will be on us in April. The area this year may well be reduced with high fertiliser and fuel costs not matched by contract prices it seems.

As usual weed control will be important for those crops that are planted. Emerger (aclonifen) is a good base product for broadleaf weed control, while Artist (flufenacet + metribuzin) can be added to bring extra grass weed control, and improve control of weeds such as cleavers and sow thistle.

Remember Emerger is pre-emergence only and ideally should be applied within 48 hours of planting on settled ridges. It works by creating a film over the soil surface through which the weeds grow and take up the chemical. Make sure you apply it at least seven days before the potatoes emerge.

For potato cyst nematode control, our liquid nematicide Velum Prime (fluopyram) offers flexible application methods to suit your system, which is adds to its user friendly profile alongside a low application rate and much reduced packaging.

It can be applied either as an in-furrow application on the planter, or an overall spray followed by incorporation. If the latter, then make sure to apply after destoning to get the best efficacy.