With the current market incentive to maximise cereal cropping, more Scottish growers will need to get to grips with soil-borne disease take-all this autumn and take some decisions now to reduce its impact on cereal drillings.

Take-all attacks cereal crop roots, restricting water and nutrient uptake and leading to patches of stunted plants and whiteheads. These contain smaller, shrivelled grains that reduce yield and quality.

The disease is damaging to second and subsequent cereal crops and AHDB literature estimates that it affects half of UK wheat crops, with average yield losses of 5-20%.

Development is very much dependent on conditions and is encouraged by warm winters and wet springs. When followed by a dry summer, symptoms are most severe as compromised root systems struggle to take up moisture.

Historically, it has been thought of as an English problem, stretching into the Borders but no further north. However, with climate change and shifts in autumn and winter conditions, one seed specialist is warning that take-all is set to have greater impact across southern Scotland.

Frontier seed business development manager, Jim Knight, said that one thing apparent from the company’s demo days in June was an increased level of take-all.

He said: “It’s not surprising following the very mild autumn and winter and the dry run up to harvest is now exacerbating symptoms. The shift in autumn and winter conditions we’re seeing in Scotland should certainly now be putting it on the radar of growers beyond the Borders and into southern Scotland.”

With wheat priced at £260 per tonne for harvest 2022 and harvest 2023 futures not far off this level, the incentive is there to maximise wheat area.

He said this would mean more second wheats and continuous cereals, which are at significant risk of take-all.

The main cultural controls for take-all are rotation – taking a one-year break from susceptible crops – and delayed drilling into late October as inoculum levels fall relatively quickly after harvest.

But with the wheat market where it is and later drilling being unworkable in the North, many growers have largely ruled out these measures.

One grower only too aware of this predicament is McGregor Farms' arable manager, David Fuller. Based at Coldstream Mains in the Borders, the business has 3600ha of arable crops in the Tweed valley on river alluvial sandy clay loams, with rotation set according to whether the ground is light enough to grow potatoes.

Take-all causes most damage on light soils and this high-risk scenario is avoided by being able to slot potatoes, peas and OSR in between wheats so all are first wheats.

Mr Fuller said: “We‘re lucky to have the vining pea group but we’re limited on break crop options for the heavier land, where to maximise profitability the focus is on OSR and wheat.”

In total, the business grows 1700ha of winter wheat, with 20% of these being second wheats on heavier land, but he emphasised the importance of getting crops in early, in the right conditions.

His aim is to maximise wheat drilling in September and get second wheats drilled in the last week of September to first week in October.

“Down South they’d be mortified to drill before mid-October, but we need to shut the gate by then as we just can’t rely on getting the right conditions beyond early October,” he pointed out

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First wheats average just over 10t/ha with second wheats doing just a tonne less. Mr Fuller added that attention to detail was key to getting the best out of them and on his list of things to get right are cultivations, nutrition, variety, and seed treatment.

Following a single pass with a Simba SL non-inversion cultivator, crops are drilled with a 12m Horsch Pronto universal drill at 300-400 seeds/m2. Although non-inversion tillage leaves infected soil near the surface, it also makes for a much firmer seedbed which discourages fungal growth and on balance has a greater impact on disease, he believed.

With nutrition, the objective is vigorous development of roots. Because triple superphosphate (TSP) is highly immobile, a small amount is drilled into the ground with the seed so it’s close to developing roots and the plant can find it quickly.

Biostimulant Nutri-Phite PGA is applied post-emergence to energise rooting and nitrogen is applied as early as possible after February 15.

For take-all he says the only specialist fungicide seed treatment that provided bona fide control was Latitude (silthiofam). “At our drilling rate of 180 kg/ha, Latitude is costing just under £35/ha this autumn and with wheat at £250/tonne it only needs to increase yield by 0.15 tonne/ha to pay for itself.

“Without it, we could be down 0.5 to 1.0 tonnes/ha in second wheats, so it always pays a healthy return on investment.”

On varietal choice, he said that Gleam and LG Skyscraper had performed consistently for McGregor Farms as first and second wheats.

Jim Knight added that choosing the right variety was an easy thing for growers to get right as there are now plenty that suit the region and rotational position. In addition to tried and tested Gleam and LG Skyscraper, he suggested soft feed wheat varieties RGT Bairstow and KWS Colosseum for this autumn.

“They grow particularly well in southern Scotland and those keen to try out something new should also look at Champion, which topped the recommended list for yield.

“Whatever variety you choose for the second wheat slot, Latitude seed treatment is a must. In manufacturer, Certis Belchim’s trials in medium take-all risk situations, it consistently delivered an average yield increase of 0.55 tonnes/ha over crops drilled with just a single purpose dressing.

“With forward prices for harvest 2023 at £230/tonne, that would equate to a return just over £100/ha in additional gross margin. The ‘gold standard’ to mitigate take-all, boost root development and establish successful second wheats is Latitude, plus Vibrance Duo (fludioxonil + sedaxane). Together they add more than the sum of the two parts,” he argued.