New mix to tackle yellow rust threat

A new tank mix aims to give growers a cost-effective way to target this year’s heightened yellow rust threat.

The mix – of epoxiconazole with the three active ingredient fungicide Cherokee – will also target Septoria tritici with extra fungicide active ingredients, said Syngenta cereal disease specialist Rod Burke.

Aimed mainly for use at the spring T1 spray timing, the mix was designed to protect the first of the top three yield-building leaves, said Mr Burke.

“With the recent discovery of a virulent, new race of yellow rust, it will be particularly important to protect against the disease in the early part of this season,” he added.

“But in addition to that, there is also the issue in the industry about protecting triazole fungicide performance against Septoria tritici. So it makes sense for growers to tackle both issues.

In many situations, straight Cherokee would be the product of choice, said Mr Burke. A full dose of 2 l/ha targets disease with the equivalent of full rate cyproconazole plus full rate propiconazole and 1.5 l/ha of Bravo.

The new mix was aimed at growers thinking of using epoxiconazole but wanting to fortify it. As well as adding three ingredients to epoxiconazole, it also brought complementary activity.

Testing had shown that cyproconazole moved at a faster rate in the leaf, so it would reach yellow rust infections in unsprayed parts of the leaf quickly, said Mr Burke.

In addition, the Bravo component in Cherokee provided an all-important different mode of action against Septoria tritici to triazoles for resistance management, he added.

“In many situations, growers add Bravo to epoxiconazole anyway, so there’s no extra tank mixing involved. With its robust triazole content, Cherokee also brings a plant growth regulator effect.”

In trial plots, 2.0 l/ha of Cherokee applied at growth stage 31 reduced lodging from 21 to just 9%. Its strong rust activity, anti-resistance against Septoria tritici and good value made it a good option for adding to epoxiconazole.

“With Septoria tritici able to reduce yield up to 3 t/ha, and yellow rust capable of yield losses of twice this, it makes sense that growers have robust strategies in place for these diseases.”

Suggested dose rates for the new tank mix are 1.25l/ha of Cherokee plus 0.25-0.4l/ha of epoxiconazole.

The new tank mix adds to an alternative tank mix option of Cherokee + prothioconazole – also designed for higher pressure rust and Septoria tritici situations – announced by Syngenta last year.