Advice on five core agronomy practices likely in Scottish fields this April

Crop Progress

As we approached the end of March, wheat crops were extremely lush in Scotland, after a predominantly mild and dry winter. We probably have the highest percentage of successful establishment for many years, with the majority drilled in September.

Pigeons did pull back some of the oilseed rape crops, but they are growing away now with first flowers appearing.

The commodity price is supporting investment in these crops, albeit with similarly high input prices, and the potential is there to achieve excellent yields.

Craig’s agronomy tips for April

1. Robust rates of fungicides likely to be needed in wheat crops

Septoria can be found on the lower leaves, albeit at relatively low levels currently in March. Mildew is also popping up and I have heard a couple of reports of yellow rust, although not seen any myself yet. But I wouldn’t be at all surprised, given the susceptibility ratings of varieties grown in Scotland if it doesn’t start to appear in April.

Similarly, with the early drilling and lush crops, when we do get moisture Septoria is likely to spread up the plant.

That all adds up to likely needing to use robust rates when we reach the T1 timing towards the end of April, as disease pressure could be high.

Crops on the east coast of Scotland where yellow rust is more of an issue will probably require a T0 spray in early April, but further inland growers may decide to miss this timing unless Septoria is really threatening.

Timing is crucial for T1 sprays, and attention to detail matters – you want to be applying this spray preventatively rather than curatively on leaf three. But with variable temperatures in spring it can be difficult to get the timing of this spray right. Regular crop walking and dissection of plants to identify when final leaf three has fully emerged.

The main focus should be on Septoria and yellow rust, although there are lot of varieties grown with varieties that low eyespot resistance – Skyscraper and Extase, for instance, so that’s another thing to consider.

Our SDHI-containing fungicide Ascra (bixafen + fluopyram + prothioconazole) is a good option at rates of 1.0-1.2 L/ha to cover all of these diseases.

2. Protect winter barley crops at key T1 timing

In winter barley the T1 timing for disease control is the most responsive to fungicide inputs. You’re looking to prevent tillers from aborting as maximising ear numbers is what drives yields in the crop.

There was plenty of mildew in winter barley crops as we approached the end of March, but we will also inevitably see increased Rhynchosporium pressure during April. There’s also been more net blotch reported in recent seasons in Scotland.

Growth stage for this spray is GS30/31, which will likely be in early to mid-April in Scotland.

Ascra can now also be used in barley crops, including on malting varieties, although it is limited to just one application.

In winter barley I’d suggest using a robust rate because of the higher fungicide response at T1. Ascra at 0.9 L/ha will cover those disease threats, while Siltra (bixafen + prothioconazole) is still available and a good alternative at 0.6 L/ha. Alternatively, Ascra (0.7 L/ha) could be saved for the awns emerging T2 spray in May due to its Ramularia activity.

3. Monitor spring barley crops for disease

Many Scottish growers took advantage of good drilling conditions in mid to later March and drilled spring barley. Hopefully, if it gets some moisture it will get up and away quickly, with warmer temperatures forecast for the end of March.

For those still drilling in April, a reminder that Liberator (flufenacet + diflufenican) has an on-label approval for weed control at 0.3 L/ha, but it is pre-emergence only, unlike the old EAMU.

Depending on speed of growth the first fungicides may be due towards the end of April in earlier drilled crops. In spring barley T1s should be applied at the end of tillering at slightly lower rates than in winter barley.

I’d save Ascra for T2 for the additional Ramularia suppression and go with Siltra at T1 at 0.4 L/ha.

4. High OSR commodity price supports protection from Sclerotinia  

At the current commodity prices for oilseed rape, only a small yield increase is necessary for a good return on investment – just 0.1 t/ha increase brings a return on investment of about £60/ha. It will be worth protecting crops if they have the potential.

Crops will be in full flower in April. Aviator (bixafen + prothioconazole) is a good option for Sclerotinia control – we don’t see the disease every year, but it can hammer a crop of oilseed rape which is not what you want when it’s worth £700/t.

Light leaf spot pressure has increased during spring, which Aviator (0.75 L/ha) will also help take care of around early to mid-flowering.

5. Apply Emerger at least 7 days before potato emergence

Potato growers have it pretty tough currently, with the increased fuel and fertiliser prices not being supported as well by higher crop prices as in cereals or oilseed rape. That might lead to a lower area being planted this season.

Planting will begin in earnest in April. For weed control Emerger (aclonifen) gives good broad spectrum activity on a wide range of broadleaf weeds, while if you have grass weeds

Artist (flufenacet + metribuzin) is a good partner product.

Emerger works primarily through shoot uptake so it is important to get it on early to create the film on the soil surface, through which the weeds grow through and take up the chemical. Ideally apply it within 48 hours of planting, and certainly at least seven days before potato emergence.

With the loss of Vydate (oxamyl) there’s been a lot of interest in our liquid nematicide Velum Prime (fluopyram). Its ease of handling and application through either in-furrow application or overall spray and incorporate are major plus points.

There’s also no harvest interval or restrictions on varieties.

In low to moderate PCN situations it can be used alone, while in higher pressure use at full rate (0.625 L/ha) in combination with the last remaining granular nematicide nemathorin.