Trials back multi-site chemistry in barley resistance battle

ADAMA's concerns regarding Ramularia resistance in barley, and the need for multi-site chemistry, are being backed by recent FAR trials.

The FAR trials show that Ramularia was the main disease present in autumn sown barley and was also prevalent, along with leaf rust, in spring sown barley.

Ramularia is resistant to strobilurins and has, of late, become less sensitive to the SDHI fungicides. The pattern in this country is following the well-documented experience in the UK and Ireland.

In the FAR trials, adding multi-site protectant fungicide Phoenix to Proline^® in a two spray programme gave significantly better control of Ramularia than mixes of triazole with SDHI and, also, the highest yield (FAR Crop Action Edition 134, 14. September 2018). Further trials are planned for 2018/19.

It is an outcome that Adama has welcomed.

Effective tools for resistance management

Over the last two years, the company has been committed to increasing awareness of multi-site chemistry, the issue of resistance, and the need to protect not only yields, but the agrichemicals that generations of cereal growers have relied on.

ADAMA's knowledge, and the combination of the multi-site Phoenix with Bolide, has had notable success in tackling declining Septoria control in wheat throughout New Zealand. The launches of Phoenix and Bolide have been a welcome addition to the Septoria arsenal. Septoria tritici (speckled leaf blotch) is acknowledged to be the number one yield-robbing threat in wheat. Both here and in the UK.

Now, ADAMA's spotlight has been turned on giving support to growers battling Ramularia.

Ramularia resistance development quite rapid

Technical Specialist at Adama UK for fungicides, Andy Bailey, was here as a guest of Adama NZ and talked to agronomists and industry influencers around the country.

He says despite the experience with Septoria, the speed of development of resistance in Ramularia had taken the industry by surprise. “It’s been quite rapid. We now have Ramularia resistance to all key chemical groups. So, we’re in a situation, where we’re struggling to control Ramularia in barley in the UK and Ireland.”

Andy says resistant mutations had been seen in Germany previously, but the spread, and its pace, was unexpected. “Last year, in 2017, the Agriculture and Horticulture Development Board published data from some of their trial sites around the UK, and particularly sites in Scotland, where we actually saw no performance what-so-ever with a tri-azole or SDHI mixtures.

Multi-site protectant Phoenix solution for Ramularia

Ramularia, here in New Zealand, is also a worry for growers and agronomists and a serious threat to yields. Ramularia can cause extensive damage to the upper leaves of spring and autumn barley once crops have finished flowering, resulting in reduced crop quality and yield.

However, the news is not all grim. Andy says multi-site protectant fungicide, Phoenix, is now providing a solution in the UK and Ireland, and helping protect and support existing chemistries.

He also says risks and timings have been identified. “We know that T2 is the absolute optimum in timing for the multi-site. We’re also looking at additional timings earlier, say at T1. Likewise, we know that leaf wetness in the spring is a risk factor for Ramularia.”

In New Zealand Phoenix is already approved for use in barley. ADAMA is confident of adding a label claim for Ramularia in the near future to provide an effective solution to this emerging resistance issue.

NEW: Bolide now registered for Ramularia in barley

Bolide, ADAMA's cereal multi-tasker, was recently approved for Ramularia in barley. It contains two different DMI active ingredients. Epoxiconazole is a tri-azole. Prochloraz is an imidazole. So they complement each other in a mixture at optimised ratios.

Bolide provides broad spectrum control of key cereal diseases comparable to industry standard DMIs and SDHIs and excellent performance against Ramularia. Trial results in New Zealand have confirmed this. Bolide is an ideal option for applications at both T1 and T2. However, the most important time to apply Bolide for Ramularia control is T2 to protect leaves 2 and 3.

Find out how you can combat the growing resistance threat with Phoenix and Bolide!