A new wheat flag leaf fungicide that promises Scottish growers bigger yields and give them peace of mind, whatever the weather, has been launched by Bayer.
Ascra Xpro builds on the top performance of its existing SDHI fungicide, Aviator235Xpro, by adding a second complementary SDHI active ingredient, fluopyram, to bixafen and the azole, prothioconazole.
This combination gave the best septoria control from a T2 fungicide in Bayer and independent trials, as well as excellent control of the other key diseases, yellow and brown rust, mildew, tan spot and suppression of fusarium inoculum.
With a potent septoria curativity and a raft of physiological properties, that makes it particularly suitable for cooler, wetter conditions experienced in Scotland.
It all translates into an average yield boost of 0.3-tonne per ha over market-leading competitor products, such as Adexar (fluxapyroxad + epoxiconazole), in 2016. That could be worth about £40 per ha in extra margin at current wheat prices of around £140 per tonne.
That's is due to the complementary activity of the active ingredients, explained Will Charlton, Bayer’s fungicide campaign manager.
“Fluopyram distributes through the leaf quickly, increasing curative control of latent disease in the leaf, and adding to the curativity from the other SDHI bixafen. Bixafen and prothiconazole then also help provide the long-lasting activity needed from a flag leaf fungicide to keep the top two leaves free from disease for as long as possible,” he pointed out.
"This gave 6% better septoria control on the top two leaves than Adexar across 14 independent and Bayer trials in 2016. In curative situations, the difference is larger – around 20% better. “Our trials have shown that Ascra is both the most curative and consistent fungicide for septoria control now available. In the trials, yields were raised by an average of 0.3 tonnes tonnes per ha compared with Adexar.”
This confirms results across five contrasting seasons, including the high pressure year of 2014, when the average yield response in favour of Ascra was 0.39 tonnes per ha, Mr Charlton said.
Another key to its performance is the use of an 80% dose of prothioconazole in the recommended rate of 1.2 l/ha, he added. “Trials in the past couple of seasons have shown that prothioconazole is in a class of its own against septoria, consistently outperforming epoxiconazole and metconazole. This means the SDHIs in Ascra have comparatively less work to do in controlling the disease than competitors, creating a more sustainable level of disease control.”
Adding prothioconazole also helps it combat resistance development in septoria as the two modes of action give the disease a double whammy.
“Bixafen and fluopyram are different types of SDHI – bixafen is a pyrazole-carboxamide and fluopyram a benzamide. In laboratory tests there is evidence that they could potentially control different strains of septoria with mutations in the SDHI binding site. But as they still have the same mode of action that cannot be considered a resistance management strategy,” he said.
It is also possible to mix Ascra with a multi-site fungicide if desired and it is formulated using the same Leafshield system as Aviator235Xpro, which protects its efficacy even if it rains within minutes of an application.
Ascra is fully approved and will be widely available through normal distribution networks next spring.