Ascra Xpro, from Bayer, builds on the excellent performance from its existing SDHI fungicide Aviator Xpro by adding a second complementary SDHI active ingredient, fluopyram, to bixafen and the azole prothioconazole.

The combination has given 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. 

As importantly that translated into an average yield boost of 0.3t/ha over market-leading competitor products, such as Adexar (fluxapyroxad + epoxiconazole) in 2016. That’s worth around £40/ha in extra margin to the grower at current wheat prices of around £140/t.

The boost in performance is due to the complementary activity of the active ingredients, explains 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.”

This added up to 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 0.3t/ha compared with Adexar.”

That confirms results across five contrasting seasons, including the high pressure year of 2014, when the average yield response in favour of Ascra was 0.39t/ha, Mr Charlton says. “Overall, Ascra has yielded more than Adexar in nearly 70% of 55 Bayer and independent trials in that period. It shows Ascra performs consistently whatever the weather and the season throws at you.”

Another key to Ascra’s performance is the backbone of an 80% dose of prothioconazole in the recommended rate of 1.2 L/ha, he says. “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 competitor products, creating a more sustainable level of disease control.”

Mr Charlton stresses the prothioconazole helps Ascra combat resistance development in Septoria. “It’s having the two modes of action together that’s important, not having two SDHIs in the product. 

“Bixafen and fluopyram are different types of SDHI – bixafen is a pyrazole-carboxamide and fluopyram a benzamide. So 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.”

It’s also possible to mix Ascra with a multi-site fungicide if desired. “Our trials have shown there is a neutral to positive impact from mixing in a multi-site at T2. However, the use of multisites will have the greatest benefit earlier in the season.”

The product is formulated in the same Leafshield system as Aviator, which ensures easy spraying and protects growers’ investment even if it rains within minutes of an application.

Ascra also helps wheat plants cope in drier conditions, through the combined physiological benefits from bixafen and fluopyram, which Bayer is calling Xpro Plus. This results in greener leaves, bigger roots and hardier plants and has given a yield boost in the absence of disease of 0.52t/ha over untreated plots across nine ADAS trials in four years, says Mr Charlton. 

Ascra is fully approved and will be widely available through the distribution network next spring.