However, changes in barley management and increasing potential of new varieties is building the case for a specific seed treatment to reduce its impact and maximise yield.
Take-all is a fungal pathogen that is omnipresent in all UK arable soils and attacks the roots of cereal crops including wheat, barley, rye and triticale.
It can significantly reduce yield by hindering water and nutrient uptake of infected plants and is often most acute in second and third wheats, where inoculum is allowed to build within the soil.
As winter barley is grown almost exclusively as a second cereal behind wheat, the crop is also at considerable risk of infection, but a long-held view is that it is less affected by take-all symptoms, says ADAS plant pathologist and principle research scientist Jonathan Blake.
This is because winter barley yield potential – mostly determined by shoots by shoots/sq m and grains/ear – forms much earlier than in wheat, so when soil temperatures hit 10C+ in late April or early May and take-all bites, there is less yield loss.
This view had been reinforced by AHDB trials investigating the impact of take-all in wheat and barley between 1999 and 2004, which showed little or no yield response to specific seed treatment Latitude (silthiotham) in barley, despite positive effects in wheat.
However, more recent additions to the winter barley Recommended List are setting new benchmarks for yield – particularly hybrid varieties.
Combined with an evolution of winter barley agronomy, where more emphasis is placed on pushing crops earlier in the season for greater biomass, crops are taking more time to fulfil potential.
“Where you have boosted shoots/sq m and grains/ear, you are relying on late-season green leaf area to capture light and fill out the crop.
“As the need for that late season energy has increased, so has the ability of take-all to have an impact on winter barley yield,” explains Mr Blake.
To explore this impact on newer high-yielding varieties, 2010 ADAS trials with two-row types Cassia and Saffron showed 0.5t/ha and 0.9t/ha yield responses, respectively, when seed was treated with Latitude.
Last year, ADAS repeated the experiment at its Herefordshire and Norfolk sites, but this time included four varieties – two-row conventional types Orwell and Craft and six-row hybrids Volume and Bazooka.
At the Herefordshire site, a yield response of 0.5t/ha was recorded on Volume and an average response of 0.24t/ha was observed across all varieties.
Plant root assessments also showed Latitude to consistently reduce take-all symptoms across all varieties and sites.
With winter barley mostly grown as a second cereal and the potential to delay its drilling limited, rotational or cultural methods of minimising the impact of take-all in the crop are reduced.
With this taken into account, along with more recent trials results, Mr Blake says a Latitude seed treatment can play a role in its management.
“Latitude can help maximise yield and it’s in early-sown barley crops are where you are most likely to see a benefit, as infection risk is higher and you tend to have more tillers and more potential.
“Growers may also benefit when it is used on malting varieties, with the added yield helping to dilute grain nitrogen and hit key parameters for malting or brewing uses,” he adds.
The agronomic case for using a take-all specific seed treatment in winter barley is clear, but with the crop often seen as a lower-input option to winter wheat, most growers remain unconvinced of the economic argument.
However, James Barlow of seed merchant ADM Agriculture says putting the potential benefits into pounds and pence per hectare makes a compelling case for investing in Latitude.
The cost of the treatment is about £205/t and in a conventional variety sown at a sensible seed rate, that equates to about £34/ha.
Assuming a feed barley price of £140/t and a yield response of 0.4t/ha, growers would get a benefit of about £56/ha or a return on investment ratio of 1.6.
In hybrid varieties, however, the figures are even more attractive. At lower seed rates, the per hectare cost of the treatment reduced to just £20/ha and the ROI ratio goes up to 2.8.
Mr Barlow says to unlock the high yield potential of hybrids, more investment in inputs such as nitrogen and crop protection is required over conventional varieties and for a relatively low sum of £20/ha, Latitude can help maximise crop performance.
“Latitude has been pigeon holed as a second wheat treatment, but with most barley grown in a second cereal slot, it is just as prone to take-all.
“Hybrids now represent about one-third of the UK winter barley area, so there is a significant proportion of crops that would benefit from treatment,” he notes.