AHDB’s fungicide performance trials show that the new generation SDHI from Bayer offers good broad spectrum control of septoria and rusts.

It also reveals that, of the approved actives tested, it is the top performer for yield when looking at brown rust.

While there is no published AHDB data for the SDHI in a mix, Niab director of agronomy Stuart Knight says the data for the straight give farmers and agronomists an idea on how well it performs against the main foliar disease of wheat.

See also: New wheat fungicide provides three-pronged attack

Septoria

Three straights were tested at a range of doses: Myresa, which is the newest azole from BASF, the next generation SDHI Vimoy, and Corteva’s Peqtiga.

Looking at the results, Peqtiga gave the highest level of septoria control. Bayer’s new fungicide, Vimoy, was similar to Myresa – both of which have good activity against the disease, especially as protectants.

In terms of yield, Myresa and Vimoy are similar at full rate, while Peqtiga offered a bit more.

“Last season, all three were doing a good job in what was a high pressure situation,” says Stuart.

However, farmers would normally apply them with a partner product and the two mixtures tested (Univoq and Revystar) gave better control than the straights, showing the value of having a partner product.

Rusts

Starting with yellow rust, good control was obtained from Vimoy and Myresa, but Elatus Plus and mixtures (Univoq and Revystar) were most effective

This was reflected in the yields, with Elatus Plus being the top performer, and Vimoy ahead of Myresa. Again, as with septoria, the mixes offered better control.

Finally, with brown rust, Peqtiga was the weakest of the straights, with Elatus Plus, Myresa and Vimoy all similar and giving a high level of control.  

However, when looking at yields, Vimoy was the highest, ahead of the second best, Myresa.

He says it is not clear why there was a yield advantage.

However, in practice, fungicides should be applied as mixes to gain the best disease control and to reduce resistance risk.

Rosalind O’Hare, Bayer campaign manager for combinable fungicides, points out that the SDHI is being sold in a co-pack with Proline.

While it is a little behind the best on septoria, the mix partner brings yellow rust control up to the level of Elatus Era.