Wheat trials in Ireland are suggesting that BASF‘s new SDHI fungicide, Xemium, which is on track to be launched next season, could be the strongest of all the recent fungicide additions against septoria.

Carlow, where Teagasc‘s Oak Park trials site is located, has received over 130mm rainfall in May and June, creating high septoria pressure. Untreated plots of Cordiale were virtually defoliated on a press tour of the plots organised by BASF last week.

But in both a Teagasc-funded single treatment trial used by HGCA in its fungicide performance analysis and BASF-funded programme trials carried out by Teagasc, similar doses of a Xemium product formulated with epoxiconazole visually appeared greener and more free from septoria than rival SDHI fungicides, Aviator Xpro and Seguris.

All three SDHI fungicides were a step up from straight triazole fungicides for septoria control, said John Spink, head of crop science for Teagasc. “The Aviator looks slightly better than the Seguris, and that other stuff [Xemium] does seem quite good, doesn’t it?” he said.

Xemium, the brand name for the range of fungicides BASF will launch containing the active ingredient fluxapyroxad, would be the first truly systemic SDHI fungicide, Peter Hughes, BASF cereal fungicide manager said.

“This movement within the plant means that Xemium can reach and control disease in parts of the plant that other molecules cannot reach.”

That was demonstrated in a BASF laboratory test where each of the three SDHI fungicides were applied near the base of the leaf. While both the isopyrazam-containing Bontima and Aviator Xpro only controlled brown rust in the treated part, Xemium also prevented disease on the untreated part to the leaf tip.

“But one of the most exciting things is that you don’t get all the active ingredient moving to the leaf tip. Instead you get a depot of active ingredient where it is applied that continuously releases active ingredient over time, so you get good protection over the leaf.

“It is the chemical that wants to be everywhere.”

As well as excellent protectant activity that movement in the plant also provided fluxapyroxad with curative activity over and above epoxiconazole, Mr Hughes said.

In inoculated and mist-irrigated ADAS trials at Rosemaund last season, Xemium was still giving good curative control of septoria 16-20 days after inoculation when infections on epoxiconazole-treated plants had taken off.

“It is unquestionably the most active fungicide on septoria, and it also highly active on the entire barley disease spectrum. It will bring BASF fungicides into the premier league of barley fungicides.”

A range of Xemium fungicides are on track to be launched next spring. Fluxapyroxad had been approved by the Chemicals Regulation Directorate’s Advisory Committee on Pesticides, Mr Hughes said. “We’re just waiting for publication of the setting of a maximum residue limit in Europe, which we expect later this year.”

Xemium fungicides

• Contains fluxapyroxad

• First true systemic SDHI fungicide

• Irish trials suggest exceptional septoria control

• BASF claim excellent barley disease control

• Likely to be available next spring