Why We Shouldn’t All Be Rushing to Cut Fungicide Costs with Extase

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Despite KWS Extase’s untreated yield of over 10.6t/ha in the latest Recommended List, genetics and chemistry will have to live in partnership for some years to come.

KWS Extase’s 8.1 for Septoria resistance combined with an untreated yield of 10.6t/ha in 2020/21 RL has got many growers and advisers alike dreaming of cutting back fungicides significantly, but it’s really not as simple as that, says KWS UK country Manager Will Compson.

“Breeding for greater disease resistance and functional traits is an inevitable direction of travel as a result of ongoing loss of actives, the effects of climate change and the need to farm in a more environmentally-friendly way in the future.

“Plus it’s a real testament to breeders and modern genetics technology that we have arrived at a point in time where we have something like Extase with such high levels of disease resistance without the yield or grain quality compromises of previous years.

“But I don’t think it’s time to park up the sprayer just yet.”

KWS’s own SPP (sowing for peak performance) breeding initiative is putting the future needs of growers right at the heart of its development of future varieties, but its focus is more on establishing how genetics, data and chemistry can work to best effect in the future rather than making one area redundant, he says.

“There is a lot to consider before advising rates of fungicides should be reduced or specific timings such as T0 or T2 be cut out and much of this revolves around being responsible to other growers and taking a longer term view of things.

“Even with a variety like Extase with its high levels of Septoria resistance, you might get away with it one year, but you could have serious issues the next. With the variety largely predicted to be the most popular wheat at drilling 2020, it’s important growers take heed of this.

“Don’t forget Extase is also the highest yielding milling variety on the current RL bar none, so it is a variety that does respond to investment, although this is likely to be less than with other varieties due to its high threshold of untreated performance in the first place.

“With a robust spray programme the yield response from Extase is likely to be in the region of 0.5t/ha to 1.0t/ha rather than the 1.2 – 2.0t/ha seen in other varieties.”

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Whilst there is little evidence Extase will benefit from heavy duty spray programmes, growers need to be mindful of leaving it too exposed in years with a heavy disease threat, says KWS senior researcher at KWS Nick Bird.

“There are a number of ways a wheat variety can put up its own defences, but septoria is very good at adapting. It’s a tough one to tackle.”

“We’ve narrowed down the specific regions responsible for fighting septoria and found the precise location of Stb6 (Septoria tritici blotch) – a major gene found to confer resistance – but unfortunately this is now only effective against a very small proportion of the UK septoria population.

“Extase has a fair degree of genetic strength built in, as we’ve combined this with a whole host of other genes known to confer resistance and it’s this combination that offers the stability of control and overall resilience.

“Breeding for resistance takes time and if the genetics are abused, the resistance won’t last as long as it needs to.”

“Once we identify a promising source of resistance it still takes 8-10 years to bring it to market so we really want to make sure Extase stays as robust as possible for as long as possible.”

KWS knowledge transfer manager Dr. Kirsty Richards says the strength of Extase’s genetic base should stand it in good stead for the future, but growers should not see it principally as a low input variety.

“Some varietal disease resistance may rely heavily on a single gene, which is equivalent to using a fungicide with one mode of action. Others, including Extase, feature multi-gene resistance, which is more resilient, but both types benefit from chemical protection.

“In a low risk year, there are definitely opportunities for cutting fungicide spend with Extase.

“But whilst it is very tempting for growers to try to grow resistant varieties very cheaply, that’s not sustainable for protecting genetic resistance as all it does is ramp up the selection pressure on that resistance mechanism.

“Genetics and chemistry must be used responsibly in tandem and this is very much the case with Extase - too much emphasis on either one will break the chain.”

Trials carried out by Bayer and KWS looking at integrate varietal disease resistance with existing chemistry have highlighted the complexities of choosing the best strategy to achieve this, says Beyer’s Gareth Bubb

“Varietal resistance is brilliant, but we need to use it sensibly as a risk management tool. There may be opportunity to reduce inputs on more resistant varieties, such as not applying an SDHI at T1, but cost-savings shouldn’t be the driver.

“One main benefit from varietal resistance is to buy more time around key spray timings and help prioritise fields to treat first.”

There are a number of ways a wheat variety can put up its own defences, but septoria is very good at adapting. It’s a tough one to tackle.
Nick Bird , Molecular Breeder

Independent agronomist Bob Simons definitely says Extase will definitely need treating differently from other high yielding wheats.

“You need to make the most of the variety’s attributes. Extase is very quick growing so you will need to plan for that at the time you drill, taking account of its earlier scheduling and the lower inputs you’re likely to apply.

“You probably wouldn’t need to apply a T0 spray, for example, unless yellow rust is prevalent - Extase currently has an RL score of 9 for the disease so a lower cost triazole should do the job if needed.

“A modest triazole with an SDHI would probably manage most situations at T1 but you would want to use something a bit stronger at T2 and this is probably where you would focus your spend.

“T3 would then be season and situation-dependent with end market being a consideration.”

Will Compson is keen to point out that Extase is not a one-trick pony with its high untreated yield seen as its only virtue.

“Overall, it’s Extase’s combination of flexibility and resilience that means it is most likely to achieve its full yield potential in the real world.

“It’s got the disease resistance without the yield penalty but there’s good quality there too. Plus it’s got good standing power and is early to harvest.

“As a dynamic quality wheat it has also had a great response from millers thanks to a reliable baking performance along with an RL-leading Hagberg number of 297 and specific weight of 78.4 kg/hl and these help make Extase a stand-out variety package.”

Heygates senior grain buyer George Mason says the company is keen to support Extase.

“There are ample opportunities for growers to make a quality premium even at a low protein. Our contracts are for either full spec 13% with fallbacks down to 12% or min 11.5% protein with fallbacks to 11%.

“You can have confidence in the variety to save on inputs, especially for far-flung fields, but you can’t just drill it and leave it. It’s best put in a healthy situation, with inputs carefully planned.

“I find if I invest in a variety, I get more than my money back, and that’s certainly true of Extase.”

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