New fungicides prove their worth across two seasons

Using new SDHI fungicides gave better disease control and boosted cereal yields for Suffolk grower Charles Mathieson in two contrasting seasons.

He tried the new fungicides in the dry 2011 season and in last year’s wet summer, and they proved their worth across both years in winter wheat and barley.

His initial experience in 2011 was enough to convince him that the triazole-SDHI product Aviator (prothioconazole+bixafen) should be his T2 flag leaf fungicide choice.

“We’d seen a very good yield response from Aviator in the first year, albeit on a limited area,” he says. “And that was in a dry season. So we had confidence in it.”

In that first year, Bayer’s Aviator was compared to another triazole-SDHI newcomer, Adexar, as well as to a triazole/strobilurin.

Having seen the advantage that the SDHIs could bring, he did a split field comparison of Aviator and Adexar in 2012 as part of Bayer CropScience’s “Judge for yourself” initiative.

At the T2 stage, Aviator was applied at 1l/ha to one section, while Adexar was applied at 1.25l/ha to the other. A T3 spray of 0.6l/ha of Prosaro followed at early flowering.

The results showed a small difference in favour of Aviator on a field of Oakley wheat, and equal performance between both products on a wheat field of JB Diego.

“It confirmed what we suspected and what independent TAG trials have found,” comments Mr Mathieson. “The two fungicides are very similar, both offer superior disease control to the triazoles and they bring a yield benefit.

“However, last year the economics were in Aviator’s favour. The equivalent treatment with Adexar was £10/ha more,” he says.

On that basis, he will be using Aviator again in 2013. “These are more expensive chemicals, so the price is important. I will be looking closely at costs before I make the final decision.”

Wheat yields in 2012 were below the farm average at 8.25-8.5t/ha, but not disastrous, and better than many farms in the region, he says.

“If we’d been reliant on the triazoles last year, I think we would have been hammered. There was tremendous septoria pressure and spray windows were few and far between.”

Mr Mathieson says he is unlikely to use one of the newer generation SDHIs at T1, except out of curiosity and on a look-see basis.

“I would be reluctant to spend that amount on the T1 spray, especially as there are other effective options. I prefer to keep them for the T2 timing.”

He has also seen the benefits of a triazole-SDHI product in winter barley, having used Siltra Xpro (prothioconazole+bixafen) for the past two years.

“It did a good job for us in 2011, but we really saw what it was capable of in 2012, which was such a wet year,” he recalls.

(Panel): Judge for yourself

Bayer’s Judge for yourself initiative involved 41 growers and 58 field comparisons, carried out across the country from Scotland to Devon.

Growers were asked to use Aviator on half a field at T2, comparing it to their standard farm practice. Field records and final yield results were then submitted to Bayer so the results could be shared among the group.

The farm results reflected what the company has recorded in its own trials, as well as proving that the 1l/ha rate of Aviator is robust, says Alison Daniels of Bayer.

“Averaging out all the results, the growers saw a 0.8t/ha advantage with Aviator over a triazole/strobilurin mix, and a 0.45t/ha advantage over Seguris (another triazole-SDHI product).”

Furthermore, the 1l/ha rate of Aviator proved to be equivalent to 1.25l/ha of Adexar, she reveals. “If they were both applied at 1l/ha, then Aviator had a 0.2t/ha yield benefit.”

Other observations made about Aviator in a very tricky spraying season were its formulation and rainfastness advantages, she notes.

“Formulations which include adjuvants to make the active ingredients work together are far better than tank mixes, especially when time is short and the weather is being difficult.”

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