In this issue... Busting the resistance page 8 The full picture on stubborn strains
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EXTRA JANUARY ISSUE . EXTRA JANUARY ISSUE . EXTRA JANUARY ISSUE . EXTRA JANUARY ISSUE
In this issue...
Busting the resistance page 8 Cornish care page 18
The full picture on stubborn strains Getting Real Results in a disease hotspot
Scrutinising costs page 11 Protecting chemistry page 5
Opinion
3 Forward - Introduction from this issue’s sponsor.
Volume 23 Number 1 4 Talking Tilth - A word from the editor.
January 2021 Technical
Editorial & Advertising Sales
PO Box 4856, Shrewsbury, Editor Tom Allen-Stevens Protecting Chemistry - Follow the science
Shropshire. SY1 9NX
5
Technical Editor Lucy de la Pasture However trade deals play out, expect IPM to play an increasing role
Tel: (01743) 861122 in crop protection programmes.
E-mail: tom@cpm-magazine.co.uk Writers Tom Allen-Stevens
angus@cpm-magazine.co.uk Charlotte Cunningham Septoria management - Behind the lines of resistance
8
Design Brooks Design For years, growers have been on the backfoot with septoria, fighting
Advertising Copy a pathogen that’s grown in strength as its population has evolved.
Brooks Design, 24 Claremont Hill, Bus. Dev. Manager Charlotte Alexander
Shrewsbury, Shropshire. SY1 1RD
Publisher Angus McKirdy 12 Spotlight on costs - Take care of the pennies…
Tel: (01743) 244403 A delve into some of the key considerations when it comes to being
E-mail: fred@brooksdesign.co.uk efficient with variable costs, as well as advice from the experts.
To claim two crop protection BASIS points, send an email to
assistant@basis-reg.co.uk, quoting reference CP/100659/2021/g. 15 Canopy management - HAD shown a benefit?
Healthy area duration (HAD) can deliver robust data on the impact
To claim two NRoSO CPD points, please send your name, NRoSO member
of disease.
number, date of birth and postcode to angus@cpm-magazine.co.uk
Reader registration hotline 01743 861122 Innovation
*the claim ‘best read specialist arable journal’ is based
on independent reader research, conducted by the 18 Real Results Pioneers - Kernow know-how
National Farm Research Unit 2014 The south west of England is a hotspot for cereal diseases, but has
the potential for some of the highest yields in the UK.
CPM Editorial, advertising and sales offices are at 1 Canonbury Shrewsbury SY3 7AG.
Tel: (01743) 369707. CPM is published eleven times a year by CPM Ltd and is available free of
charge to qualifying farmers and farm managers in the United Kingdom. 21 Digital Direction - An eye in the sky
In no way does CPM Ltd endorse, notarise or concur with any of the advice, recommendations or Digital technology is helping global agriculture break down the
prescriptions reported in the magazine. If you are unsure about which recommendations to follow, barriers of progress.
please consult a professional agronomist. Always read the label. Use pesticides safely. CPM Ltd is not
responsible for loss or damage to any unsolicited material, including photographs.
legacy recommendations set out in the of the most advanced biological controls, smart
European Commission’s Green Deal. And, farming tools, assurance technologies like
finally, there will be further pressure on the blockchain and seeds and traits.
industry to justify the need for crop protection Our commitment remains steadfast in the
products and antibiotics. conventional crop protection (CP) sector, where
These drivers will force lasting changes to our pipeline is arguably the richest in the world.
Not only are we developing revolutionary products,
Partners on the road farm management, centring on building health
and resilience into soil, animals, people and we are also working closely with regulatory bodies
to change businesses. to ensure market access. Our new-generation
Together with our partners BASF are fungicide, Revystar XE, received approval in
Three things are shaping the UK’s farming’s travelling the same road as the farmers we record time and we anticipate approval for our
future. The first the impact that leaving the EU ultimately serve. new grassweed herbicide Luximo in 2021. The
will have on the agrifood sector, trade, and Within BASF we create chemistry for a pipeline for the potato, fruit and vegetable sectors
farming’s support mechanisms. The second is sustainable future and we are committed to is equally strong, and we will introduce hybrid
how the COVID-19 pandemic will change food reducing CO2 emissions on farm, preserving wheat around the middle of this decade, a
supply chains and consumers’ food buying biodiversity, minimising the use of natural potentially game-changing innovation.
and eating behaviours. The third is how resources and ensuring farmers’ capacity to Importantly, the journey that we are on is not a
agriculture can positively contribute to produce sufficient, safe, nutritious and affordable lone one, we are working closely with our partners,
addressing the world’s climate crisis. food for all. Such transformation requires a advisors and farmers from all over the UK to
Whilst there are still many unknowns affecting holistic approach, ambitious targets, openness ensure that the decisions we take, the investments
business decision-making, primary producers to new technologies and collaboration. we make and the products that we create are what
have firm indicators of the direction of travel. We have been on this path of change for agriculture needs to address its immediate and
Agricultural production will have to positively some years, having invested in technologies that long-term challenges.
contribute to the growth of the natural economy we know farmers will need to adopt a true
Neil Kay is BASF Agricultural Solutions
and Net Zero targets. Support payments –– Integrated Pest Management (IPM) approach.
business director for UK and Ireland.
despite leaving the EU –– will centre on the Our investments have been in the fields of some
crop production magazine january 2021 3
our lives in ways few of us this transition and you’ll find it’s on the experience of growers
could ever have imagined. a clear invitation to farmers to and advice from experts.
There are so many co-design the future. If you’re How to assess the health
aspects that are someone with innovative flair, of a crop canopy is an
tragic about it. this could be just the right time integral part of growing a
But you also marvel at to step forward. successful crop, so we’ve
the human endeavour It has to be said, these are explored how scientists have
–– the remarkable breadcrumbs of hope, small developed healthy area
resilience of health gestures in a world that’s been duration (HAD) as a trusted
Sowing seeds workers in coping with turned upside down. But in tool. Then we’ve looked at
the pandemic and the times of adversity the small the Real Results achieved in
of change? extraordinary achievements gestures become the big on-farm trials by Cornwall
of scientists in creating a opportunities. When so much grower Mike Hambly, who
vaccine. Rarely has necessity has changed, and so much farms in a part of the UK that’s
As someone who didn’t had to mother invention to such more has to change, that’s the both a disease hotspot and an
manage to get a single an extent, and there must be point where those with a truly area with great potential to
wheat seed in the ground for few moments in history that so progressive mindset can make boost yield. Finally, we’ve
harvest 2020, I have a huge many individuals have stepped their mark. looked at the exciting
amount of hope for the Skyfall up to the challenge, applied That’s why we’re pleased to opportunities offered by
and KWS Extase currently their talents and delivered be working in association drones as digital technology
sitting in my fields. results that are as awesome with BASF, who have kindly breaks down the barriers
They’re not the best of crops, as they are humbling. sponsored this Special Issue of progress.
nor best of seedbeds –– you And there are some very of CPM. Within the arable So as I walk around my
can live with one bad autumn, persuasive drivers of change. sector, we face some particular farm, there’s not a great
but to get two on the trot, Climate change is one that’s challenges, and in such deal of comfort I can draw
especially when there’s a easy to shy away from –– a period of change and from land lying sad from its
moratorium on early drilling to even if you accept the scientific uncertainty, you cannot weather onslaught. Nor from
avoid blackgrass, that’s really prediction of gloom and rely simply on what has a year that’s brought with it
punishing. Indeed, a quarter doom that will result as world worked before to deliver the such upset. But I can plan.
of the farm’s planned cropping temperatures notch up another sustainable solutions of I have the seeds in the
area still hasn’t been drilled degree, you wonder if there’s the future. ground, I have good soil,
–– two wet autumns have much you can do as an So we’ve looked at a few and I’m in an industry with
exposed some shocking individual to stop it. Yet we are key issues growers will be plenty of individuals who
drainage issues that need to farmers, operating in the only grappling with this year. share my passion for
be addressed. industry that can provide the We can’t promise you’ll find innovation. We’ve been
Or should they? You do solutions to this potential crisis. the answers in these pages, invited to step up and usher
wonder whether this is Nature’s Surely this is an invitation to but what we hope is that they in an era of positive change,
way of forcing a rethink. So is instigate change we should lay the groundwork for those so 2021 looks like it will
it the right course of action to all embrace? with a positive mindset to bring great opportunity.
diligently attend to drains Then of course there’s Brexit. find the solution, both for
originally installed in the For UK farmers in particular, themselves and for their
post-war drive to increase 2021 marks the start of a industry.
production? Perhaps it’s time transition during which the Starting with regulation,
for Nature to reclaim the wet only certainty is that direct we’ve brought together some
field corners and lost ponds. payments will fall away. It’s of the recent changes and
Maybe the field boundaries, hugely unsettling, especially what they mean for policy
straightened and narrowed for when among the few targets direction. Fungicide resistance
efficient arable production, set for rural enrichment is one is an evolving and increasingly
large machines and tramlined that will see 30,000ha of UK important issue, and we’ve
sprayers can play a different land every year locked up in summarised the latest Tom Allen-Stevens has a
role in an agriculture focused trees while conversely the US findings from across Europe 170ha arable farm in Oxon
on IPM, carbon capture and is pledging to double food on the current nature of that currently looks as
soil improvement. production. septoria isolates in UK and though it’s sprung a leak.
It’s not just the weather But look through Defra’s Ireland. Keeping a lid on tom@cpm-magazine.co.uk
shock that’s forcing a rethink. Path to Sustainable Farming costs is crucial for the arable @tomallenstevens
COVID-19 has touched all of that tracks its roadmap through business and we’ve drawn
4 crop production magazine january 2021
Follow the science
for a larger toolbox
“ Sustainable
farming is about
doing more with less.
Get it wrong and rather
than find the solution,
we export the
problem.
”
Technical
Protecting chemistry Photo: Bosch
However trade deals play existing EU legislation on plant protection
products (PPP) has lifted and shifted into
out, expect IPM to play UK legislation. There’s room to manoeuvre,
an increasing role in crop and arguably more than the UK had as a
member state of the EU. But there’s no room
protection programmes. to dumb down nor relax existing regulation in
CPM explores the political any way. To be clear, BASF wants the current
strong regulatory framework to remain.”
and regulatory landscape.
Efficient regulatory body
By Tom Allen-Stevens The UK’s in a good place as far as this is
concerned –– Rob points to the inherent
strength of the Chemicals Regulation
Whatever course regulation takes now the Division (CRD) which will continue to
UK has completed its exit of the European oversee product approvals and renewals.
Union, if decisions are made on the basis “CRD was always the most efficient
of scientific evidence, there’s a bright regulatory body when we were part of the Rob Gladwin wants the current strong regulatory
future for UK arable farmers. EU, and is very well respected for following framework to remain.
That’s the view of Rob Gladwin, head of the science. There have been quite a few
technical management for BASF Agricultural changes at Defra since Brexit, and CRD has Rob notes that this could result in
Solutions UK and Ireland, and he has good suffered, but overall staff levels throughout divergence from EU policy for some specific
reason to be optimistic. “International trade the department have increased.” products, and this will pivot on how the
is clearly the area where most uncertainty So growers can expect the regulatory political arguments play out on both sides
lies. But in trade decisions, whether with process to remain robust and largely mirror of The Channel. “The obvious contender
the EU or with other world partners, it’s what happens on the continent. In theory it here is glyphosate.”
more important than ever that we follow may be quicker, he suggests, as there’s less Politics will therefore inevitably have an
the science,” he says. “Science-based admin involved with gathering the evidence important role to play, he reasons, which is
decisions are far more defendable and carry needed over a smaller geographic area why the savvy grower or agronomist should
greater credibility with the WTO, as well as –– that could even mean UK growers get bear the political landscape in mind when
with consumers.” certain new products first. But decisions on making decisions.
Rob believes current chemistry will approvals will still relate closely to the EU “Whether it’s the EU Farm to Fork Strategy
continue to face tough scrutiny and new process and CRD will have no influence or Defra’s Path to Sustainable Farming, the
products to replace it will be limited, but over this, he points out. common thread that runs through them is
points to the opportunities available through “The big question is whether the scientific sustainable agriculture, and that’s got to be
a wider set of tools to address the opinion from CRD will follow through to a good thing. At BASF, we want to see
challenges faced by growers. on-farm practice or will politics kick in, cultural control and precision technology
as part and parcel of crop protection going
▲
“As we move into this new era, all the as it does in the EU?”
crop production magazine january 2021 5
Protecting chemistry
redundant if all the sprays you want to use
have lost their approval.”
Nor should policy allow new technologies
to get a “free ticket”–– Rob’s keen that
products such as biologicals undergo a level
of scientific scrutiny that follows the true
aims of the Precautionary Principle, to
engender trust from growers and confidence
from consumers.
Use of technology, such as drones, should be part “Conversely, there’s a danger the bar Many agronomists and growers practice aspects
and parcel of crop protection going forward in will be set too high, making it prohibitively of IPM, but maybe aren’t recording decisions
conjunction with best use of chemistry. expensive for all but the largest multinationals, taken in a systematic way.
as we’ve seen with GM, which wouldn’t help
forward in conjunction with best use of the UK grower. following a more sustainable path, and
▲
chemistry.” that helps in negotiations –– both with
Rob sees it as an overall enlargement Use of drones Government and internationally.”
of the toolbox available to growers, with “CRD must also be given the leeway in The pivotal aspect is to demonstrate this,
artificial intelligence (AI) and technology legislation to keep pace with technology. and growers may be practising more IPM
helping a move towards true integrated A good example is the use of drones for then they realise, he suggests. “Many
pest management (IPM) systems. “But spot spraying, that has clear potential decisions on what to apply to a crop involve
sustainable farming is about doing more with benefits for reducing pesticide use and IPM but they’re not recorded as such. The
less. Get it wrong and rather than find the minimising operator exposure. It’s widely choice of a more disease-resistant variety,
solution, we export the problem. With the used in many countries around the world, the decision to delay drilling, attention paid
current direction of policy, this is a big but it’s classed as aerial spraying under UK to good soil health, monitoring nutrient levels
threat,” he warns. “Many agronomists and law and prohibited,” he notes. and state of the crop canopy –– these are all
growers practice aspects of IPM today, The NFU is working hard to ensure UK just as important as the choice of product
but perhaps don’t see it in that context legislation keeps growers on a level playing itself and rate applied. They demonstrate
and certainly aren’t recording decisions field with those they’re competing with that reaching for the can was the final
taken in a systematic way. across the globe, assures vice president decision, not the first.”
“Product withdrawals must also keep Tom Bradshaw. “It’s probably the biggest The NFU is working on an IPM plan for
pace with innovations. A digital tool that challenge we face, apart from the weather. the cereals sector which will be launched
gives you accurate information on when to “IPM’s no golden ticket, but it does in the coming months and will involve a
spray has great potential benefits. But it’s indicate growers are committed towards revamped, interactive version of crop
Necessity drives a natural approach
IPM comes as second nature in the horticulture Measures include the use of moth traps to
sector, believes Worcestershire apple and hop accurately assess thresholds and mating
producer Ali Capper, but few are given credit for it. disrupters to slow down the growth of pest
“Regulators and consumers may perceive they populations, ensuring they never reach the
see the bigger picture, but in reality they think in threshold. “These methods are not cheap but
boxes. Farmers think holistically –– they have to using them forces you to think differently –– you
as they take so many factors into consideration only spray as an absolute last resort.
to balance the many different challenges and “Speciality crop producers also have to think
ecosystems they work with.” very carefully about the soil and the effect on the
Ali chairs the NFU horticulture and potato board environment because with perennials like tree fruit
and has seen across the sector how speciality there’s often no rotation, so no reset if a particular Farmers think holistically says Ali Capper, as they
crops producers in particular have adopted IPM management practice doesn’t bring the desired take so many factors into consideration to
measures. “The difficulty is that the products we result,” she adds. balance the many challenges and ecosystems
apply are classed as minor use. So the crop Hop growers are currently in the third year of they work with.
doesn’t always generate enough data in a a farmer-led study, co-ordinated by Innovative
particular climatic region to support a product Farmers, looking at the effects of reducing the fruit quality benefits, according to the results of an
renewal,” she explains. bare soil between bines. “We’ve established there AHDB-funded study.”
This means growers have to apply for an are soil health benefits and there’s anecdotal But such strategies work best when applied as
expensive EAMU for a product that’s approved evidence to suggest there are pest and disease part of a wider toolbox of measures that includes
for broad-acre crops. What’s more, new product benefits, too,” reports Ali. careful use of chemistry, Ali notes. “Resistance
approvals are often very much more expensive “Apple growers are looking at the effect of management is also important, and there are
and more specific, she says. “So there’s a real establishing wild flowers between rows. There are many new ideas and technologies coming through.
economic and commercial imperative behind benefits for soil health and pollinator population. But it doesn’t help for regulators to apply siloed
adopting IPM, as well as the environmental What’s more, the increased diversity of the insect thinking to something that’s part of a much
benefits.” population reduces pest pressure and there are larger system.”
6 crop production magazine january 2021
Protecting chemistry
protection management plans. “There’s an However, Tom believes there’s an
obligation on growers to take this seriously opportunity for forward-thinking farmers
–– if you’re applying insecticides for BYDV to co-design the regulation they live with.
without using some sort of threshold Farmer-led innovation has the potential to
prediction, that’s simply irresponsible,” help the process.
he notes. “As new technologies come forward,
Nor does he support any dumbing down offering the prospect of a larger toolbox, a
of UK legislation or a move away from the sensible approach would be to authorise
EU’s Precautionary Principle. “The correct these through regulation and develop their
interpretation and implementation of this is use through farmer-led trials,” he suggests.
critical, but deal or no deal, the direction the
EU takes will continue to have an impact on Farmer-led research Tom Bradshaw believes there’s an opportunity for
how consumers view PPP. We need the trust “We’re not talking about side-stepping a
forward-thinking farmers to co-design the
of the public in the practices we follow on trusted independent authority that would
regulation they live with.
farm and the way we produce their food. gather the core data –– that must continue to
So we may yearn for less regulation and a underpin the approval process. But there are
speedier approvals process, but it must be clear benefits for both consumer and grower range of field conditions.
robust and transparent.” in farmer-led research being part of the way “That’s just for one tool added to the
new technologies are adopted.” toolbox. Apply farmer-led innovation across
Rob agrees it’s an increasingly valuable a range of existing and new technologies
part of the process. “The reason Real and you greatly increase the data available
Results has been such a success is for how they interact. The process is
that it engages growers. It was through measured and balanced, delivering the
the initiative that they gained a full year of checks required for positive change, and
real-world experience with Revystar XE it’s transparent, trusted by growers, giving
(fluxapyroxad+ mefentrifluconazole) before it it a multiplier effect and greater public
was released commercially. So the growers confidence in the underlying technologies.
Deal or no deal, the direction the EU takes on the
themselves already know a substantial This accelerates the uptake of IPM and
Precautionary Principle will continue to have an
amount about best use of the product at pace of change towards a truly sustainable
impact on how consumers view PPP.
the correct dose and right time over a agriculture,” he concludes. ■
No clear answers on biostimulant use in barley
Initial results from a set of spring part of the season.” Spring barley treatments compared
barley trials suggest a robust Andrew notes there were low
8.2 0
fungicide programme provides levels of both ramularia and
8
the best form of defence against rhynchosporium seen across the 7.8
0.5
ramularia and delivers a yield benefit three sites. “Ramularia is still 1
Ramularia (%)
7.6
Yield (t/ha)
even when disease levels are low. something of a mystery. The plant 7.4 1.5
A range of biostimulant and may be infected early on, but 7.2
2
nutrition products were tested by expression of the disease is related 7
Scottish Agronomy in trials funded to plant stress. We think it’s triggered 6.8
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
2.5
Untreated Arizona Arizona Bridgeway Seamac Chitosan Sulphur Copper Proline Bridgeway
by Mains of Loirston Trust in the by bright, dry conditions followed by fb T2 + Arizona fb T2
Revystar Arizona
quest to find a non-chemical heavy rainfall,” he explains. Yield (t/ha) Ramularia (%)
alternative to chlorothalonil (CTL). “Spring barley undergoes a lot of
These were applied at the two stress around the T1 timing, with Source: Scottish Agronomy, 2020; cv Laureate; Only treatments (3) and (9) are statistically
significant from untreated; Arizona applied at 1.5 l/ha; Bridgeway – 2.0 l/ha; Seamac PCT –
main spray timings at three sites herbicide, growth regulator as well 2.5 l/ha; Chitosan (BioActive KitoSea) – 4.0 l/ha; Sulphur (UPL Liquid) – 5.0 l/ha; Cuprokylt
in the Scottish Borders, Fife and as fungicide to contend with. CTL (liquid copper) – 2.0kg/ha; all treatments were applied at both T1 and T2 apart from (3) Arizona
Aberdeenshire. has always done a good job at 1.5 l/ha fb Revystar XE 0.75 l/ha + Arizona 1.5 l/ha, (9) Proline 275 (prothioconazole) 0.2 l/ha
“Revystar XE performed best, in a protecting the leaf against infection, + Arizona 0.75 l/ha fb Proline 0.35 l/ha + Arizona 1.5 l/ha, (10) Bridgeway 2.0 l/ha fb Brideway
programme with multi-site fungicide but the trial is really exploring 2.0 l/ha + Arizona 1.5 l/ha. Ramularia levels and green leaf area assessed 08/07/20-21/07/20.
Arizona (folpet), with a standard whether we can replace the T1
azole-based fungicide programme fungicide with an alternative apply other ways to help the crop across the trials where it had been
not far behind,” reports Andrew treatment that helps with the perform.” applied at the later spray timing.
Gilchrist of Scottish Agronomy. stress. But none of the biostimulant or “Revystar is certainly a useful
“But I’m surprised there was little “We now have varieties offering nutrition products delivered a result product at T2. That’s probably down
response to the biostimulant and a 15-20% higher yield than that was statistically different from to its persistence to keep the plant
nutrient treatments –– the principle previous mainstays, with good untreated. However, despite the low protected through the long run-in
that they help a plant that’s suffering disease scores, so this should be a level of disease, Revystar delivered following treatment,” Andrew
stress was not borne out, despite situation where you can cut back a yield response, while green leaf concludes. Trials are set to
the drought experienced in the early on the fungicide chemistry and area was also significantly higher continue for the next two years.
crop production magazine january 2021 7
Behind the lines “ Septoria
is a pathogen that
of resistance will continually seek
to out-manoeuvre
growers.
”
Technical Septoria
management
For years, growers have been chlorothalonil, will the selection pressure to agree a clear picture of just how the
on the backfoot with septoria intensify?” pathogen is developing.
Jonathan notes something of an Rosie’s brought together the data to help
control, fighting a pathogen “anomaly” in the 2020 performance curves explain recent shifts in the efficacy of SDHIs.
that’s grown in strength as that suggests Ascra Xpro (bixafen+ “Strobilurin fungicides went from hero to zero
fluopyram+ prothioconazole) has recovered in just over a year in the early 2000s in the
its population has evolved. some of its lost efficacy. “But Revystar XE UK. For azoles it’s been a much more
CPM gathers the intelligence (fluxapyroxad+ mefentrifluconazole) does gradual shift. With SDHIs, there’s an erosion
look promising –– it’s turned back the clock of efficacy, but it’s nowhere near field failure
to give growers a credible in terms of efficacy. It’ll be interesting to see at the moment,” she says.
advantage against their foe. how it develops.” Adaptation –– whereby an isolate mutates
to one that is less sensitive to SDHIs –– was
By Tom Allen-Stevens Higher performance first noted in net blotch and septoria in 2012.
What concerns him, though, is the effect The progression of mutation development in
a series of low disease years will have had net blotch was faster than in septoria but by
In 2016, AHDB fungicide performance on perceptions of fungicide strength and 2016, mutations in septoria had also started
monitoring began to pick up a worrying efficacy. “The data suggest the protectant to increase significantly in the UK and Irish
change. The flagship products growers activity of prothioconazole has plateaued at population.
and agronomists rely on for managing about 40%. Revysol is showing a much “Fairly early on, one mutation –– C-H152R
Septoria tritici were showing a notable higher level of performance, but growers –– was identified with a relatively high ED50,”
drop-off in performance. could currently be putting less of an
Ever since the new generation SDHIs had insurance margin into fungicide programmes
been introduced there had been warnings without realising it. The background
that resistance was inevitable, and the population is more resistant than it was the
monitoring work had already tracked the last time we had a bad year for septoria.
decline of azole efficacy. But no one was With the loss of the most active multisite,
sure how soon the performance of newer chlorothalonil (CTL), we’re also more reliant
chemistry would be affected, nor how on just two modes of action, offered by the
quickly it would tumble. SDHIs and the azoles.”
“There was a distinct shift in sensitivity So just what is the current picture on
in the septoria population, reflected in the resistance for these two key groups?
performance of the main SDHI/azole Dr Rosie Bryson is head of technical project
fungicides over two years,” notes Jonathan management for BASF across Europe. Every
Blake of ADAS. “Over the past two years, year, the company collects septoria isolates
however, field efficacy within the fungicide from across the continent as well as from the
performance trials appears to be fluctuating. UK and Ireland and tests them to assess
“What’s unclear is how much we can rely how the population is shifting in its sensitivity Jonathan Blake in unclear on how much growers
on the current chemistry we have –– how to the chemistry, she explains. The data can rely on the current chemistry and wheat
robust are the genetics in the wheat varieties and the understanding of complementary genetics to keep deliver an effective defence
currently grown, and how is the septoria independent work and findings are shared against septoria.
population shifting? And with the loss of and discussed between European scientists
8 crop production magazine january 2021
Septoria management
SDHI + azole protectant activity over time
With SDHIs, there’s an erosion in efficacy, says
Source: AHDB, 2020; Librax contains fluxapyroxad+ metconazole; Elatus Era – benzovindiflupyr+ prothioconazole.
Rosie Bryson but it’s not field failure.
Rosie explains. This is the dose needed in while the impact on other SDHIs depends
lab tests (in vitro) to kill half of the isolates in on their intrinsic efficacy” adds Rosie. in a similar manner and as such are cross
a particular sample –– the higher the ED50, What’s interesting is how the changes in resistant. But in 2016, Dr Bart Fraaije at
the more resistant the isolate. sensitivity of the septoria population have Rothamsted Research discovered
“C-H152R was found to have a high level developed over time. This is usually something rather odd during monitoring
of insensitivity to all of the SDHIs, and this illustrated through frequency distribution work he was carrying out. He found two wild
was at first alarming. But it currently curves arranged according to ED50 value. type isolates with no SDHI mutations that
accounts for a small percentage of the “For azole-related mutations you see a showed a high degree of resistance to
population in the field and we believe there’s gradual shift to the right over time. With fluopyram.”
a fitness penalty meaning it’s adapted to SDHIs, the shift has been quicker, but Strong cross-resistance was confirmed
SDHI chemistry, but doesn’t survive the you get a bimodal distribution curve,” between fluopyram and isofetamid, but
winter well.” she explains. importantly not with other SDHIs. The
The UK and Ireland have a more resistant “The population has shifted to one that’s conclusion reached was that this is a
population than mainland Europe as a result more resistant, but the key point is that it resistance mechanism outside of the target
of the generally wetter weather, higher hasn’t become more severe. If that had site of conventional SDHIs. “We therefore
resulting incidence of septoria and more happened, you’d expect to see a third have two different mechanisms of resistance
frequent sprays applied. Two mutations ‘hump’ in the distribution curve with high at play for SDHIs in the field, but target site
dominate the population –– C-T79N and ED50 values. So we’re not seeing a killer resistance is by far the dominant one. That
C-N86S make up around 68% of isolates, mutation, just an increase in frequency.” means using two SDHIs together is not an
with C-H152R accounting for about 4%. Rosie notes that the resistance mechanism effective resistance management strategy for
“The two dominant isolates have an generally found to SDHIs is target site septoria,” notes Rosie.
impact, and efficacy of SDHIs varies meaning mutations at the fungicide target A small number of double mutations in a
–– BASF tests have shown Xemium reduce the sensitivity of the isolate to the single isolate have also been identified,
(fluxapyroxad) is not significantly affected, SDHI molecule. “All commercial SDHIs react which have the effect of raising ED50 values.
“We’re monitoring these developments, but
ED50 of Zymoseptoria tritici towards Xemium – UK and Ireland again incidence is currently very low. So
current best practice of using an SDHI at no
more than two timings, always mixed with at
least one other mode of action, is still the
best advice to retain the efficacy of this
valuable chemistry,” she advises.
So what about the azole element of
Revystar XE? Similar tests have been carried
out across Europe to assess the sensitivity of
septoria isolates to Revysol notes Dieter
Strobel, responsible for technical market
development of cereal fungicides.
“During product development, we had
already established Revysol has an
extremely high level of efficacy against
septoria –– even on those isolates that were
less sensitive to prothioconazole (PTZ),”
he notes.
Source: BASF internal data, 2020.
“We have found populations with a
▲
crop production magazine january 2021 9
Septoria management
Frequency distribution of ED50 of Zymoseptoria tritici
2012-2016
While the efficacy of prothioconazole in the field
has continued to decline, Revysol has not, notes
Dieter Strobel.
So why is this? Dieter points out the target
site of demethylation inhibitors (DMI) –– the
group of fungicides to which the azoles
belong –– is an enzyme commonly known
2017-2020
as CYP51. The most common form of
resistance to DMIs is when small mutations
occur and accumulate so that the azole
binding to the target site is reduced.
“Research has shown that Revysol has a
much higher binding affinity to the septoria
CYP51 than conventional azoles –– on
average it is 100 times more powerful.
What’s more, a very low concentration of
Revysol is needed for CYP51 inhibition
in vitro.”
He refers to this as effective binding,
which increases efficacy at one point in time.
Source: BASF internal data; ED50 values shown for Xemium for field isolates of septoria collected in UK and Ireland. This is the property Revysol exhibits during
in vitro tests, he explains, and is measured in
relatively high adaptation to Revysol. But fungicide at flag leaf and half of them were the ED50 values. Revysol’s ability to bind
▲
while the efficacy of PTZ in the field (in vivo) then shaded for 3-4 weeks with septoria more tightly, attributed to the unique shape
has continued to decline, Revysol has not. In levels assessed 55 days after application. and flexibility of the molecule itself, allows
vitro testing, carried out by both BASF and The level of infection in the shaded plots it to overcome a mutation that may thwart
independently, has indicated a further shift in treated with PTZ was found to be around half conventional azoles, he argues.
the sensitivity of isolates to PTZ over the past compared with where the crops were left But Dieter notes that Revysol also has
three years, but by comparison the ED50 exposed to sunlight. There was very little very low solubility –– put it on a leaf and
values for Revysol show it has maintained infection in the Revysol plots, with the although it’s taken up quickly by the plant
its superior efficacy.” shading making little difference. tissue, there’s very little translocation. “So
As with SDHIs, the level of resistance in Another observation has come from as well as a low concentration required for
the UK and Ireland populations is generally profiling ED50 values of populations and effective binding, the low solubility means
higher than it is across the rest of Europe, comparing these across azoles. Work Revysol retains its efficacy over time.
but the level of resistance specifically to carried out at Aarhus University has noted “This is important because septoria takes
Revysol across Europe is significantly lower the sensitivity of Danish and Swedish several weeks to develop in the leaf tissue.
than to other azoles, reports Dieter. populations of difenoconazole and During this time, the concentration of other
One interesting observation has been a tebuconazole correlates well with Revysol. azoles dilutes as they move in the plant
difference noted in field isolates tested in This contrasts significantly with PTZ and xylem.” Couple this with the low degradation
France to those gathered in the UK. “Tests epoxiconazole –– here the data confirmed of Revysol, found in the field studies, and
indicated higher sensitivity of the French what BASF has found, that there’s very poor this explains the relatively high in vivo
population to PTZ in vitro than when it was correlation with how Revysol performs. performance, he says.
tested in the field. But whereas Revysol “But field efficacy work carried out as part That’s all very well for mutations, but what
worked very well in both environments, the of the same study shows very different about other forms of resistance found in
PTZ seem to struggle more in France which results from the in vitro tests,” says Dieter. the septoria population? These include
is surprising. We believe higher levels of UV “Here Revysol performs significantly higher over-expression, efflux pumps and
radiation could be the difference.” than all other conventional azoles. There’s detoxification –– all mechanisms expressed
Shading tests carried out at ADAS no doubt there are isolates that are highly by septoria isolates that are not specific to
Rosemaund this year have confirmed the adaptive across Europe, but Revysol still the azole used.
difference. Plots were given a single dose of works in the field.” “Firstly, the presence of very low
10 crop production magazine january 2021Septoria management
concentrations of Revysol due to its poor
solubility gives it an advantage as the Field performance of azole fungicides over time
molecule is less likely to be affected by
those pathogen resistance mechanisms,”
he notes.
Field efficacy (%)
“What’s more, the proportion of isolates in
the European population that exhibit these
forms of resistance is currently quite low,
and they’re believed to carry a fitness
penalty. We are monitoring for this and can
very quickly identify any substantial
changes.”
Dieter believes this very robust
performance in both in vitro and in vivo tests
gives Revysol an extra degree of resilience Source: Aarhus University; treatments applied at 2x half dose; Rubric contains epoxiconazole; Proline – prothioconazole; Juventus –
when it comes to resistance –– not only does metconazole; Folicur – tebuconazole.
the new azole currently have substantially
better efficacy, it’s likely to retain a relatively mixing it with other modes of action,” mode of action, she notes. “There are
high level of performance. he notes. varieties with good resistance to septoria, but
“When we started with Revysol, we set out Rosie echoes this advice. “With the the genetics need protecting, just as much as
to find a molecule with a good regulatory loss of CTL it’s important to have effective the chemistry. What’s more, you get a good
profile as well as a high level of efficacy. But partners in the tank-mix so they protect response from effective chemistry with even
the more we work with it, the more surprises each other. Revysol is different from the most resistant varieties.
it reveals about its performance. However, epoxiconazole as it has the properties “While we’ll continue to monitor
that’s no reason to be relaxed when it comes to deal with a more complex septoria populations, septoria is a pathogen that will
to stewardship –– it’s more important than population than in the past, but it continually seek to out-manoeuvre growers.
ever to look after chemistry with good still needs protecting as much as The strongest line of defence will always
efficacy, which means applying it at the the SDHIs.” be to use the best tools available,”
appropriate dose, optimum timings and Using plant genetics is effectively another concludes Rosie. ■
Beware the hidden Cougar when selecting for disease
Look across the new AHDB Recommended List of encouraged to take your foot off the septoria
winter wheat varieties and you’ll see quite an control, and that’s when varietal resistance
impressive line-up of disease scores for Septoria becomes exposed and the pathogen finds a way
tritici, especially among the clutch of new Group 3 round it. Before you know it, lesions are appearing
winter wheats. on a variety that should have a septoria score
But there’s some essential information missing of 7.4.”
from the RL, according to independent plant It’s a problem growers are all too familiar with
breeder Bill Angus, that he feels might make you when it comes to yellow rust, he points out. “There
want to question how much you’re going to rely are a lot of varieties currently in commercial use Bill Angus points out there are a lot of wheats on
on those healthy scores. that rely on Hereford or Timaru for their apparently the AHDB Recommended List that depend on one
“It’s their pedigree,” he says. “Six out of the high scores. Yet the Hereford yellow rust race is set of genetics for their resistance to septoria.
eight Group 3 varieties are derivatives of Cougar already making inroads into the UK population.”
as is Group 4 (soft) variety RGT Saki. That’s a lot of But Bill doesn’t dismiss the value of varietal “Three is a good number, and avoid those with
wheats that depend on one set of genetics for resistance. “Breeders are generally doing a good the same or similar pedigrees. Graham, Costello
their resistance to septoria.” job of bringing stronger disease resistance into and Theodore might make a good mix for
What’s more, I suspect that Cougar itself relies their lines without compromising yield, and that’s example, although you can run into problems
on major gene resistance, he points out. “The not easy. You’re dealing with a Rubik’s cube of with varieties that don’t ripen at the same time or
problem with major genes is that when they traits and every time you try to bring another in, have different heights. So try a small area first,”
capitulate, they go big time. As a grower, you’re you multiply up the muddle which makes it even Bill advises.
then left relying on the variety’s background harder to line up the ones you want. “But the crucial aspect is not to rely on varietal
resistance. But since the major gene has always “It’s up to the grower and agronomist to look resistance for disease control –– protect the
masked what the minor genes are contributing, behind the headline figures and question the genetics just as you protect the chemistry. It used
you have no idea whether your variety will then be agronomics of a variety on its pedigree before to be the case that many growers ignored varietal
moderately resistant or completely exposed.” making a choice.” disease resistance and relied too heavily on the
Bill’s concerned that in just the same way as Another strategy he favours for those growing chemistry for control. Now we’re in danger of
growers are losing their choice of chemistry to feed varieties is to plant a mixture. “It’s a good going too far in the other direction. The wise
fight septoria, they’re losing the diversity in their idea to spread your risk, and growers who make grower makes good choices with both their wheat
genetics. “The problem is that it’s not as obvious their choices carefully have found they get a varieties and the chemistry they use to ensure they
as an active ingredient losing its approval. You feel number of benefits. perform,” he concludes.
crop production magazine january 2021 11“ It’s about
spending better
–– not necessarily
less.
”
Take care of the
pennies…
Technical
Spotlight on costs
As growers seek to boost and have been benchmarking against this One of the main things Pat has done is
profit by reducing their for years. to invest in soil health. “Soil is the most
“Benchmarking gives us the opportunity valuable asset on farm and while I don’t
outgoings, CPM delves to challenge what we’re doing and how proclaim to be an avid direct driller, I’ve
into some of the key we’re performing, as well as flagging up always had a good understanding of
any potential issues within the business.” the impact machinery and cultivations
considerations when it can have.
comes to being efficient Value for money “With rainfall having such an effect on
Having worked as an independent whether we have a profitable year, I started
with variable costs, as well agronomist for many years, Pat says good thinking about how the amount of rainfall
as advice from the experts advice is essential when it comes to keeping impacts the number of machinery working
an eye on costs. “It’s important to remember
about how to spend that it’s not always about reducing your
on fungicides. spend, but more about getting true value for
that money. Benchmarking is a good way of
By Charlotte Cunningham evaluating this, but peer-to-peer learning is
so important too.”
Looking at costings on Low Melwood
Farm, Pat estimates about 60% of the total
As UK agriculture moves quickly into production expenditure is apportioned to
the biggest period of change in over fixed costs, however, the annual total can
50 years, one thing that is certain is that fluctuate dramatically depending on the
to remain afloat, it’s going to be crucial weather. “Interestingly, through collecting
for businesses to ensure they remain data over the years, we’ve found that the
competitive and viable. biggest influence on both our fixed and
However, this isn’t a new notion for variable costs is rainfall –– we can actually
grower, Pat Thornton, who has been using plot our costings against the rainfall data
benchmarking and data gathering to keep and see a direct correlation.
a lid on variable costs at his 150ha farm in “So because we’re such a small farm,
North Lincs for some time. “Analysing our I had to start thinking about what we Benchmarking gives Pat Thornton the opportunity
costs is actually something my grandfather could do in light of this to prevent such to challenge what the farm is doing and how
introduced,” he explains. “More recently, volatility and ensure we remained a they’re performing.
we began using the Farm Business Survey viable business.”
12 crop production magazine january 2021Spotlight on costs
Trial work has shown that even varieties with high disease resistance – like KWS Extase – can still have
a good yield response to a fungicide (Source: NIAB, 2020; untreated on left; assessed 15 July).
days that are available. So changing our this has been a really helpful way of
approach was very much a risk-management building a better picture of individual Bill Clark says fungicides are not just about
strategy that allowed me to essentially buy field data.” protecting against disease, but also for insuring
time in a year of heavy rainfall.” Having access to this data also means against yield losses.
As well as making use of the Farm that better decisions can be made when it
Business Survey, Pat has also been comes to variable cost, he adds. “I’ve found
variable costs being a risk-management
involved in BASF’s Real Results that variable costs are very recognisable
expenditure, rather than something that just
programme which he says has been and can be the obvious place to cut when
needs to be reduced. Basically, every
incredibly beneficial. “Being a part of this it comes to keeping your outgoings down.
penny I spend from T1 needs to give me
programme has allowed me to get involved However, in terms of crop protection
an investment on return.
with the YEN project and yield mapping. spend, by the time I get to a traditional T1
“So the advice from me is that rather
Sometimes, our ability to be early adopters timing, I’ve probably spent about a good
than just looking to cut costs, instead,
of technology is limited by our size, however, half of my production costs, so I then see my
make sure you’re using the best chemistry,
applied at the ideal time, at the optimum
rate and the benefits will speak for
A strategic approach themselves.
In the South, farm manager, Robin Aird, is also “This is what we’re trying to practice and
seeing the benefits of being more strategic as a result, we’re becoming more resilient.
with costings on the 1400ha Charlton Park We have a lot of data and for us, it’s about
Estate. “We grow around 1200ha of arable using that data to see what the impact is
crops here, on a low input/average output on the bottom line.”
system –– largely due to our soil type Arguably, one of the largest variable
preventing us from reaching some of the costs for arable growers is fungicides.
higher yields.” As traditionally regional disease pressures
The soil is a shallow silty clay loam over have become more nationwide, it’s fair to
limestone, which runs wet in the winter and dry With lower yielding soils, Robin Aird budgets for say their importance has increased across
in the summer, which naturally has an impact margin, rather than chasing high unrealistic the board, however, according to Bill Clark,
on both costs and likely crop performance. “I’d yields. technical director at NIAB. “A lot of people
rather budget for likely yields and grow to that, think fungicide usage is about disease
and then, if we get rain at the right time that grow for, looks at the most resistant varieties and that they’re applying it just to protect
boosts things, it’s a bonus. For me, I prefer to suited to that market, and then bases his against disease. However, the way I look
think about margin rather than just chasing fungicide programme around how robust it is. at it is that it’s actually insuring against
high yields that often aren’t feasible for us.” “KWS Extase and KWS Siskin are examples of yield loss.”
As part of his financial strategy, Robin says varieties that have proved to work particularly Although the risk of loss is often
the key things are working a year ahead, trying well for us.” correlated with disease, it’s crucial to look
to home-save seed as much as possible, and While home-saved seed and variable rate at the bigger picture and think about local
not scrimping on herbicides. “I don’t put a fertiliser application have also played a role in disease pressures, seasons, and historic
ridiculously robust programme on, but where reducing costs, the most influential element performance data, he adds. “Identifying
I do invest is in a good pre-em. overall is prioritising spending, he adds. your main risk has certainly become more
“To reduce high inputs, I do tend to drill a “I recommend a good strong T1 application, difficult as disease pressures have become
little later and also make use of resistant though the weather before application will heterogeneous –– for example, there are
varieties to give us a helping hand. Septoria is influence just how strong that needs to be. plenty of growers in the West who had
one of our biggest threats, but this seems to You may also be able to drop the T3 spray, never seen yellow rust and now it’s
definitely help.” depending on the market. becoming more prevalent.
When it comes to balancing variety choice “I always try to keep the market in mind “However, it’s crucial to monitor and be
with chemistry in order to be cost efficient, through the whole production cycle and when aware of your local risk as this will directly
Robin says he selects the market he wants to I budget, I’m realistic but competitive.” impact yield potential.”
While developments in plant breeding
▲
crop production magazine january 2021 13Spotlight on costs
Looking to specific fungicides, know now what the pressure is going to
resistance is one of the greatest be like next spring.”
challenges facing growers at present, he There are also a lot of varieties with high
adds. “Resistance is a big deal. Triazoles disease-resistance scores available to
are drifting in the level of control they those wanting to cut costs, adds Bill.
provide, and even some of the mainstream “There’s quite a large handful of low-risk
products that were brilliant three years ago varieties whereby if you cut the spend
are now just very average.” and mess up, you don’t lose too much. The
According to Bill, the problem with this is advice from me is that if you want to cut
that efficacy is deteriorating quicker than costs, do it where the risk is small.”
new products are coming to market. “If Fungicides also have a role in protecting
you’ve seen Alice in Wonderland, you’ll be the disease-resistance genes of “low-risk”
familiar with the Red Queen scene, where varieties, while on higher risk varieties, it’s
both Alice and the Queen are running crucial to spend to protect the crop, he
quickly but not actually going anywhere warns. “We have a points system where
with the famous line ‘you have to run just to we look at the yield responsiveness of a
stand still’. Translated into the situation that variety. If they’re not very responsive, we
fungicides find themselves in, the new recommend spending half the amount you
products that are coming through now are usually would. It’s important to remember
just compensating for the loss –– or that your insurance on a Ferrari is going to
reduced efficacy –– of older ones. It seems be more than it would be on a Renault
every time we get something new, it only Twingo. You can afford to spend more if
lasts for a few years.” the potential loss is greater.”
So how do you balance using fungicides And in high-risk situations, Bill says
Revystar XE (fluxapyroxad+ mefentrifluconazole)
to protect yield losses, against the Revystar is head and shoulders above
contains a new azole that appears to have
pressure of declining efficacy, and turn everything else for septoria control.
greater efficacy than others on the market.
it into a formula for budgeting? “Arguably, the SDHI part is under a bit
of pressure because of the selection of
now mean that many varieties are now Best products resistance, but the combination of products
▲
armed with a good level of resistance in Bill believes the best way to get the most is fantastic.”
their DNA, they’re still giving yield effects from chemistry and expenditure comes For septoria control, Bill recommends
with a fungicide application, adds Bill. down to using the best products available. using it at T1 and T2. “The only chink in
“For example, Theodore, KWS Extase and “Even if you don’t spend more, but just the armour is yellow rust and you have
LG Astronomer are all varieties which on use better products, then you’ll be getting to be careful with this. It can offer good
paper have such good disease resistance, better control and more for your money. control at a high enough rate, but a lot of
that you might expect them not to respond “For example, when Revystar was people this year just added tebuconazole
to fungicide usage. However, what we launched, a lot of people complained that to bring it up.”
have seen is that they do –– in terms of it was too expensive, but pound-for-pound, Bill suggests that while other chemistry
green leaf area retention, which is not it’s better than anything else on the has declined in terms of efficacy, the same
relatedto disease. market.” pattern hasn’t yet emerged for Revystar, so
“When you have no disease, but a With this pound-for-pound comparison in he recommends making use of it now while
big difference in green leaf area –– mind, Bill also says that optimising newer it’s at its best. “If you’re going to spend
due to fungicide usage –– it begs the chemistry can prove to be much more £40 on a flag leaf spray, you might as well
question: Why? cost-effective. “Older products are often spend that £40 on the best product you
“We don’t have an explanation yet, but cheaper, but you would have to put them can buy. You’re almost guaranteed to get
there were similar observations 20 years on at a higher dose, which would increase a higher level of control from a newer
ago with strobilurins, which were well your expenditure. product, and right now, there’s nothing
known for greening and delaying “Eventually that wouldn’t be enough, rivalling Revystar.” ■
senescence. We see these effects with and you couldn’t apply the products at a
new SDHIs and triazoles –– which would high enough dose to get the same level
include Revysol –– but don’t yet have of control as some of the more recent
a good handle on how they work.” products. It’s about spending better ––
Evidence of the non-disease effects of not necessarily less.”
SDHI/azoles has been seen in trials this But for those who are looking to reduce
year, says Bill. “I was really interested in their costs, being clever with timings may
seeing how long varieties held onto their be a way of slimming things down, he
green leaf, and in the case of Extase, I’ve adds. “If you can get the timings right, you
been to trials where there’s no disease risk, can afford to adjust down. Even at T1, if
but when a fungicide programme was you’re too late or too early it can really put
applied, a yield response of up to 2t/ha pressure on the flag leaf spray.
Resistance is a major problem for growers at the
was seen and the greening levels were “So while it’s important to plan ahead,
moment – particularly in triazoles.
completely different.” make judgements in real-time. We don’t
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