Barley growers with high yield potential crops or facing high disease pressure should consider switching to new SDHI fungicide, Siltra Xpro, according to Phillippa Overson, Bayer CropScience‘s barley fungicide product manager.

The product, which contains a different ratio of bixafen and prothioconazole to the wheat product Aviator Xpro, delivered an extra 0.25t/ha on average in 2008 and 2009 trials.

“But in certain situations where you can push crops further we’ve seen yield increases of 0.6t/ha over current standard Fandango,” she said.

Growers would be paying around 12-15% premium for a 60% label dose (0.6 litres/ha) of Siltra Xpro compared with a 1.0 litre/ha dose of Fandango.

For that extra outlay, growers could expect to see around 15% better rhynchosporium control and an extra three weeks persistence, 30% better ramularia control and a 20% improvement in net blotch efficacy, on average, she said, based on independent trials results.

In addition, Siltra Xpro maintained around 30% more green leaf area on leaves two and three, which were the important leaves for developing yield in barley, she added.

In the HGCA appropriate fungicide dose trials comparing Siltra Xpro with Fandango and Bontima better disease control had resulted in around 0.35-0.4t/ha for the new product.

But analysis of other independent trials highlighted, as in wheat, that it was the higher yield potential sites where Siltra Xpro delivered the greatest benefits over Fandango, with increases of 0.5t/ha from two sprays versus equivalent rates of Fandango.

On those high yield potential winter barley crops, the firm recommended two sprays of Siltra Xpro, using rates of 0.6 litres/ha followed by 0.4 litres/ha, but suggested growers should remain with two sprays of Fandango where yield potential was lower.

Where disease pressure was high on low-yield potential sites, growers could consider using Siltra Xpro as the first spray, Miss Overson suggested.

Active ingredients

Aviator Xpro – 160g/litre prothioconazole + 75g/litre bixafen

Siltra Xpro – 200g/litre prothioconazole + 60g/litre bixafen

Firefly / Fandango – fluoxastrobin + prothioconazole

Bontima – isopyrazam + cyprodinil

Tracker – epoxiconazole + boscalid