Ascra strengthens barley fungicide arsenal

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Stronger activity against key barley disease threats Rhynchosporium, net blotch and Ramularia is the benefit of fluopyram approval in barley, claims manufacturer Bayer. 

Ascra (prothioconazole + bixafen + fluopyram) is approved for one application per season for both winter and spring varieties. Independent and Bayer farm trials with its Forward Farmer group delivering mean yield responses of 0.3 t/ha in winter barley varieties and 0.2 t/ha benefit in spring varieties, when compared to previous standard Siltra (prothioconazole + bixafen).  

The company also claims improved protection against Rhynchosporium and net blotch when compared to Revystar (mefentrifluconazole + fluxapyroxad) and equal Ramularia control. 

Full MAGB approval for malting varieties 

Importantly, Ascra also has full MAGB approval for malting varieties and a cut-off date of GS61, ideal for those targeting premium markets. “Often the ideal Ramularia timing for spring crops is GS49 (first awns visible) and fortunately both Siltra and Ascra can be used here,” notes Bayer’s Greg Hanna. 

Ascra has been in trials with SRUC and Prof Fiona Burnett feels it is particularly useful in net blotch and Rhynchosporium situations. She puts this down to the higher loading of SDHI. “We’ve seen a slight slide in SDHI performance against net blotch resulting in higher rates being needed to maintain control. Ascra’s high SDHI loading is bolstering activity,” she notes.  

For Ramularia control she considers the best options are Ascra, Siltra and Revystar, although she advises that control is largely based on their azole components. Also, she welcomes the news that there has been no shift in the efficacy of prothioconazole, given that it is the cornerstone of most barley programmes.  

In SRUC spring barley trials, Ascra has shown to give a slight uplift in yield over Siltra, which could be down to physiological properties. “We know that plant stress is a factor in Ramularia infection, so any benefit in plant health is helpful. Much of the SDHI family have these additional properties, which we saw with strobs. Also, research has also shown that healthier plants photosynthesise more efficiently,” she adds. 

Dr Tom McCabe of Teagasc agrees that Ascra’s SDHI loading is a benefit in barley disease control programmes. 

He considers Rhynchosporium the major winter barley threat in Ireland and throughout much of the UK. A polycyclic disease crops can be exposed to multiple infections and research has shown that this trash-borne disease can be spread by infected seed.  

There’s probably no better place than Ireland to test fungicides for wet weather diseases, and Ascra has proved a consistent performer in Teagasc winter barley Rhynchosporium trials, with yield responses of 0.3 t/ha over Siltra and Revystar.  

He sees Ascra as a flexible option, suiting both key timings but particularly useful as a winter barley T1 application. “Barley is a sink capacity crop so ear numbers are vital for yield. The T1 is all about tiller protection and retention. That SDHI loading is also giving an uplift to net blotch control, and with a good dose of prothioconazole it is effective against mildew too,” he notes. 

But he says Siltra is still performing well, the addition of fluopyram just giving growers more options. Also, he isn’t opposed to prothioconazole being used twice in winter barley programmes, but would be if used at the T0. Here he would prefer to see cyprodinil or spiroxamine applied.  

Bayer’s Scottish technical manager Grant Reid sees the approval of Ascra in barley welcome with fungicides so critical to disease management. “Barley genetics have got better in recent years but we don’t have any equivalent to Extase in barley varieties. Its Septoria rating is also matched with good scores for rusts, mildew and Fusarium 

“Of 27 recommended winter barley varieties, just six get a score of seven for Rhynchosporium, and of these all are rated below six for net blotch. In spring varieties only four have a Rhynchsporium rating of six or better. Fortunately, Ascra is a very strong all-round fungicide delivering effective control across the spectrum,” he concludes. 





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