Second generation SDHI fungicide chemistry will cost £6-8/ha more than existing standards in wheat, Bayer CropScience confirmed at the launch of its new Xpro range of fungicides.

That was for 1.0 litre/ha of Aviator 235 Xpro, containing new active bixafen plus existing azole fungicide, prothioconazole, compared with a three-quarter dose of a standard triazole fungicide plus 80g/ha of strobilurin, explained Alison Daniels, the firm’s campaign manager for combinable fungicides.

For that investment, growers could expect on average 0.4t/ha extra yield based on 23 independent trials from 2008 and 2009, she said.

Septoria, the key disease in wheat, was controlled around 15% more effectively on the top three leaves, while both yellow and brown rust could be kept off for the season providing the early season fungicide treatments were adequate, she reckoned.

Persistence of activity was “easily three weeks longer lasting” than the best current standard, she said.

James Taylor-Alford, Bayer’s product agronomy support manager, added that the product would be strongly targeted at the T2 flag leaf market,

“Technically it is right at T2. It is the strongest septoria product and most active against rust.”

But to get the best from the product it had to be used at least at that 1.0 litre/ha rate, he stressed. “If you reduce the dose to 60% of the label rate of 1.25 litres/ha, then you’re not getting anything you can’t do with existing chemistry.”

Crops with the moderate to high yield potential were most likely to see significant responses to the new chemistry, he added.

In barley, Siltra Xpro, containing a different ratio of the same active ingredients, the premium would be 12-15% for 0.6 litres/ha compared with a 50% dose of azole fungicide plus 100g/ha of strobilurin, according to the firm’s barley fungicide product manager Phillipa Overson.