Taking the unusual step of applying a T3 ear fungicide in spring barley can boost the crop’s yield by approaching half a tonne per hectare, new trial results conducted by Syngenta in Hampshire have shown.

Carried out across six spring barley varieties last year, the work examined the effects of following an already-robust SDHI fungicide programme at T1 and T2, with a T3 tank mix of Amistar + prothioconazole applied to the ear.

While the core T1 and T2 programme of isopyrazam + cyprodinil on its own gave a substantial yield increase of 2 t/ha over untreated across the six varieties, following this with the T3 spray boosted average yield by a further 0.45 t/ha. Results also showed a specific weight improvement of around 0.5 kg/hl from the June-applied T3 spray – taking average specific weight to over 67 kg/hl.

“Although we have seen in other work that T1 and T2 sprays of the isopyrazam + cyprodinil fungicide Cebara significantly boosts yield, a T3 fungicide isn’t often used in spring barley,” says Syngenta field technical manager, Iain Hamilton. “So the purpose of the trial was to see what extra effects this might have.

“The extra 0.45 t/ha produced equated to about a two to one return on investment on the T3 fungicide cost. With grain prices under pressure, increasing spring barley yield, even of a malting crop, can bring a welcome income boost – while increasing specific weight can improve grain marketability,” he adds.

“Interestingly, the whole programme, from T1 to T3, was applied over the course of a month. People sometimes think spring barley is so rapidly-growing that it doesn’t benefit from tightly-spaced fungicide inputs. But this suggests otherwise. Also, recommended doses for the T1 and T2 treatments were used, so it wasn’t as if earlier sprays had been skimped on,” he notes.

The main diseases noted in the trial were Rhynchosporium and brown rust, says Mr Hamilton, and where the T3 treatment of Amistar + prothioconazole was applied, green leaf area tended to improve and grain nitrogen content tended to reduce. “Low grain nitrogen may be needed for brewing, depending on the specific end market,” he adds.

Rhynchosporium tends to build from the bottom of the crop, says Mr Hamilton, but brown rust can suddenly strike during the summer. And although it isn’t always possible to predict future disease pressures at the time of spraying, a T3 will top up earlier foliar sprays and protect ears during grain-filling, he explains.

When considering T3 fungicides in barley, Mr Hamilton urges growers to check labels fully for the latest application timing of the products to be used, especially with malting barley, where he says the latest timing may be earlier than on feed crops.