Single-site cereal chemistry vulnerability caution from UK expert

The release of new single-site cereal chemistry targeting Septoria in wheat and Ramularia in barley comes with a caveat from an expert: “Brilliant. But for how long?”

Global fungicide authority and ADAMA UK Technical Specialist Andy Bailey is reinforcing the need to protect new chemistry by including multi-sites in the tank to protect single-sites from Septoria and Ramularia resistance.

His message isn’t new.

Four years ago, on the first of his visits to New Zealand, Andy gave a stark warning about the threat to wheat and barley from fungicide resistance, which had appeared in the UK almost a decade before it impacted yields in this country. Andy’s advice hasn’t changed regarding the importance of multi-site protectants such as ADAMA New Zealand’s Phoenix^® Fungicide (Phoenix).

Science supports Phoenix to be first in the tank

“We have the science behind us. Multi-site fungicides should be the first thing in the tank. Folpet (the active in Phoenix) is definitely extending the life of single-site chemistry.”

“Resistance to fungicides will continue to be there. It’s all about how long we can keep new single site chemistries. They can be highly effective, but the question is until when?”

Andy says in all resistance the first thing to go is the curative effect. Then doses tend to be increased in some cases to the maximum to achieve field control. “Single-sites are still badly exposed to fungi’s ability to mutate.”

“I tell people; folpet will do the same year after year after year. The new chemistry will do brilliantly well, but then we’ll start to see erosion because it’s still single-site chemistry.”

“It’s a massive challenge for the industry.”

Protecting new chemistry is vital

ADAMA New Zealand Commercial Manager Daren Mabey says the new single-site chemistry on the market in this country, including; Questar, Revystar, Vimoy Iblon, and Caley Iblon can be protected by Phoenix. “What’s important here is to think about the future, to learn from overseas’s experience, and to take action now before we suffer other major crop loss events.”

Phoenix works against Septoria and Ramularia at a cellular level, inhibiting spore germination and cell division as well as reducing energy production in the mitochondria. There is currently no known resistance to folpet anywhere in the world and it has the additional benefit of not inhibiting DMI uptake, ensuring their speed of action and efficacy.

Phoenix is now also approved for use on green feed crops and can be applied up to GS59 (ear emergence) in barley.

First in the tank for Septoria and Ramularia control

While recent drier seasons, particularly in New Zealand’s “cereal bowl” of Canterbury, may have reduced some Septoria pressure in wheat it is still a real risk to yields, especially in the high-value and more susceptible varieties. ADAMA New Zealand says again their advice is to ensure Phoenix is first in the tank. Application at T1, with a DMI such as Bolide^®, is strongly recommended and supported by industry bodies.

If only one spray of Phoenix is being applied in barley, then T2 is the optimum timing. This ensures that leaves 2 and 3 are protected. For best results though, a programmed approach suggests even higher levels of Ramularia control when using Phoenix at both T1 and at T2. These applications maximise the crop’s green leaf area index to maximise yields by promoting healthy spikelet and ear development.

Adding Bolide an excellent solution

ADAMA recommends partnering Phoenix with Bolide or other triazole chemistry as an excellent solution for both Septoria and Ramularia control. Bolide is an all-rounder DMI fungicide, featuring an innovative combination of epoxiconazole and prochloraz. It is taken up via the stem and foliage and translocated upwards and outwards, providing some protection for new growth.