It’s been a while, but a number of pesticide manufacturers have unveiled new chemistry set to be rolled out in the spring. CPM looks at what they have to offer and rounds up other technical news.
It’s fast-acting, and that’s a key element of a T2 fungicide.
By Tom Allen-Stevens and Lucy de la Pasture
Two new SDHI-based fungicides are set to bring more choice and potentially better control of key wheat diseases for growers in 2017. What’s more, there’s a new mode of action on septoria in the pipeline that may be in commercial use in 2019.
Bayer has launched Ascra Xpro – the first wheat fungicide formulation to combine two SDHIs, bixafen and fluopyram, with the company’s azole, prothioconazole. Meanwhile, Syngenta has now introduced Solatenol, it’s brand new SDHI (benzovindiflupyr), which will be available also formulated with prothioconazole (PTZ).
Ascra is targeted at the main flagleaf timing on wheat, although two treatments are allowed per season. With 65g/l of each SDHI and 130g/l of azole, this is a slightly lower dose of bixafen and PTZ than you’d deliver with 1 litre of Aviator, but the recommended rate of 1.2 l/ha brings that up, and of course there’s also the fluopyram.
“Fluopyram is the first benzamide SDHI,” notes Bayer’s Will Charlton. “It translocates through the leaf very quickly and has a different binding pattern to bixafen. This has a useful effect against less sensitive septoria strains, although it’s still the 80% dose of azole that provides the resistance-management element.”
Source: 5 AICC trials 2016; T1 overspray Tracker 1.0 + Rubric 0.2 + CTL 1.0 l/ha
The result, says Bayer, is a 6% improvement in disease control over Adexar (fluxapyroxad+ epoxiconazole) and up to a 20% improvement in curative situations. “That means you get a 0.3t/ha yield advantage using Ascra over Adexar at the main T2 spray timing,” states Will Charlton.
What’s more, the new product can be mixed with multi-site fungicides, such as chlorothalonil (CTL). “We still feel T0 and T1 are the best places to use multi-sites, but trials have shown it’s not a problem to add CTL to Ascra at the T2 timing.”
Extensive trials, carried out by both Bayer and independent providers have established the benefits over Adexar, explains Bayer field marketing manager Jennie Watson. “The yield increase is the average over 50 trials for the past four seasons. 70% of 42 growers who tried Ascra in 2016 improved their yield.”
The relative performance of different SDHIs against strains of septoria created in the lab with mutations to the SDHI binding site. Green indicates complete control, while red suggests performance is impaired. Colours in between indicate intermediate performance. Bixafen and fluopyram have complementary performance.
The key, she says, is the speed with which fluopyram moves within the leaf. “It’s fast-acting, and that’s a key element of a T2 fungicide.” The two SDHIs have also been shown in lab tests to have a complementary performance on different septoria isolates mutated to confer resistance to SDHIs.
Syngenta’s bringing two formulations of its new SDHI to market. It’ll be available as a mixture with 75g/l of Solatenol plus 150g/l of PTZ at a recommended rate of 1 l/ha. It’ll also be sold as a straight, delivering 100g/l of active ingredient (now approved as Elatus Plus) with a full recommended rate of 0.75 l/ha, but this will always be available as a twin pack with an additional product with a different mode of action, and should never be applied on its own.
Delivering what Syngenta claims is “powerful, consistent and complete” performance, it’s approved for use as a single application on all winter and spring cereals (except oats). The main target is winter wheat and growers should use it at the T2 spray timing, advises Syngenta’s Iain Hamilton. “Solatenol wasn’t included in official fungicide performance trials until 2016, but was included to benchmark its performance in 2014 and 2015. On septoria, Solatenol plus PTZ is aligned with Adexar on both control and yield.”
On rusts, it edges ahead, he claims, with a number of independent trials showing it has as good or better control on both yellow and brown rust. “Solatenol plus PTZ was the one that persisted longest in yellow rust trials at ADAS Terrington, for example.” Details on how it should be mixed with Bravo (CTL) have yet to be released, but there’s no drop-off in efficacy, he adds.
Over the past three seasons, Solatenol plus PTZ has been compared with Adexar and Aviator over 120 trials, using field rates of 75-80%, reports Syngenta’s James Southgate. “ST02 delivered an average yield increase of 0.29t/ha over Aviator, and demonstrated an average yield advantage over Adexar of 0.13t/ha.”
Its efficacy on rust is particularly noticeable on milling wheats, he says. “Rust is a con artist and tricks the plant into keeping nutrients and proteins in the leaf to feed it.. Trials show you not only get a yield advantage over Adexar with Solatenol plus PTZ, but a lift in protein levels, too, as a result of its efficacy on rust.”
Tests on leaf movement reveal Solatenol has a well balanced acropetal translocation and persistent properties, giving it a blend of curativity, and long-lasting protection says Syngenta’s Jason Tatnell. “Solatenol is more metabolically stable and more potent than other leading SDHI’s, resulting in longer-lasting, more even protection..”
Solatenol’s been welcomed by many in the industry. “It’s as good as the best, but that doesn’t mean it’s necessarily a major step-on from Adexar or Aviator,” notes NIAB technical director Bill Clark.
Independent Bucks-based agronomist Luke Cotton reckons Solatenol may hit the Aviator market, but will fit well in the T2 slot as an alternative to Adexar or Librax (fluxapyroxad+ metconazole). “It brings to the table everything Aviator lacks, especially on yellow rust, and does appear to have the edge on the disease over Adexar. But we’ll have to see how it’s priced before making a judgement on how it’s best used in the field.”
Dow AgroSciences will be rolling out Arylex, its new auxin broadleaf-weed herbicide, for its first full commercial season in 2017. Formulated as Pixxaro (halauxifen-methyl+ fluroxypyr) it’s more effective under a wider range of field conditions across a broader spectrum of weeds than Starane (fluroxypyr), claims Dow. A formulation with florasulam is expected later in 2017.
It’s part of what the company’s UK managing director Toni McEwan calls “innovation beyond expectation”. “We have a very exciting innovation pipeline, uniquely suited to UK farmers,” she says.
This includes two further new active ingredients that will be rolled out after Arylex. Due for launch next year is Isoclast (sulfoxaflor), which controls sap-feeding insects in cereals, fruit and vegetables. Tests show that even at low use rates, it offers good knockdown and residual control, is effective against insect pest populations resistant to other insecticides, and has minimal impact on beneficial insects, says Dow.
But perhaps raising more interest in the trade is what Dow’s calling its new “game-changer” fungicide, Inatreq, due for release in 2019. “It acts on a new target site for cereals, so finally there’s something new against cereal pathogens,” says Dow’s Will Corrigan.
Just what this target site and mode of action are remain tightly under wraps, with an update expected in the New Year. “Its efficacy in trials is shown to be very strong, and research done to date shows that isolates found to be resistant to current actives are susceptible to Inatreq.”
David Ellerton of Hutchinsons says he’s looking forward to having another option in the fungicide armoury. “We’re in desperate need of a new mode of action in cereals. Septoria isolates resistant to SDHIs have already been found and the efficacy of azoles continues to ebb away.”
Bill Clark sees it as a probable addition to the fungicide mix. “It’s really exciting to have a new mode of action on cereal pathogens. It will help the general resistance picture, but this is another single-site acting fungicide, so we’ll need to look after it carefully.”
Deltamethrin MRL lowered
Commonly used insecticide, deltamethrin, has been undergoing a review process that has seen its Maximum Residue Level (MRL) reduced in some crops.
The legislation change was announced on 13 Oct, and will come into force on 7 May, 2017. The new MRL for deltamethrin applies to wheat, rice and beans only – where the legal concentration of the active has been reduced from two parts per million (ppm) to 1ppm.
With the benefit of regulatory foresight and extensive consultation, the impact of the change to the MRL on wheat has been such that the treatment of grain with deltamethrin remains a valuable option.
“Deltamethrin-based K-Obiol is one of relatively few products that can be applied directly to grain. The product is already well within the newly prescribed MRL limits, meaning application rates will stay the same,” says Dave Ross of Bayer.
This legislation only applies to treated grain – the residual levels of product applied to the fabric of the grain store, up to two months before grain goes in, won’t be affected, he clarifies.
“Grain store pests can be split into two categories – primary and secondary,” explains Ken Black, rural hygiene manager for Bayer. “Primary pests can attack whole unbroken grains, while secondary pests attack only damaged grain, dust and milled products. It’s important to be aware of both to ensure the correct control measures are used.
“Traditionally the most damaging pest to stored grain is the grain weevil, with the females burrowing into the grain, laying their eggs and the larvae then eating their way out, hollowing the kernels out so they’re in effect more like ‘Rice Crispies’ in appearance than quality, saleable grain.
“But the saw-toothed grain beetle is now the most common primary insect pest of grain stores in the UK. The beetles can cause the grain to heat if infestations are heavy, which in turn leads to moulding and even sprouting and both the quality and the weight of the grain may be reduced,” he says.
“Secondary pests like grain mites can be just as destructive because they can build up very quickly and damage the grain by feeding on the germ (the embryo part of the seed), tainting the produce with allergens and spreading fungal spores.”
Ken Black reminds growers that deltamethrin is a long-term grain protectant. “It’ll treat pests when applied, but it can’t kill the larvae if they’re inside the grain. When the larvae eat their way out of the grain, that’s when they ingest the active and are treated.
“Some farmers might see bugs present in the grain even after it’s been treated, and this will be larvae that’s eaten through grain after it’s hatched. It could take up to a month before they all hatch, eat the grain and are ‘knocked down’. So patience is required because, while some grain will be damaged, the risk is far less than if it isn’t treated at all.”
As always, prevention is better than cure, he continues, and cleaning grain stores thoroughly, then treating the fabric of the building up to two months before harvest, will give you the best chance of a pest-free crop.
“If the risk of pest infestation is high, then it’s advisable to treat the grain as a precautionary measure. Then it’s important to monitor weekly using ‘pit fall’ traps, ensuring optimal grain temperature and grain moisture (for long term storage of cereals, this is below 14.5% and 7.8% for oilseed rape).
“Although you should only directly treat grain when the risk of infestation is high, it’s a crucial product in our armoury. But responsible use of chemicals is central to maintaining these vital pesticides,” he adds.
Strategies to avoid BLW resistance
Although grassweeds come to mind when there’s talk of herbicide resistance, broadleaf weeds aren’t immune. Resistance to ALS-inhibiting herbicides, mainly sulfonylureas (SUs), has been identified in the UK, mostly in poppy but also in chickweed and mayweed.
A four-year ADAS project, funded by AHDB, BASF, Dow AgroSciences and DuPont, has demonstrated a need to introduce alternative modes of action and certainly to use ALS inhibitors sparingly across the rotation, believes project leader and ADAS weed biologist, Lynn Tatnell.
This is particularly the case with spring crops or on non-blackgrass land. These may not receive pre-em herbicide stacks aimed at blackgrass, which also control broadleaf weeds. High organic matter soils where pre-em efficacy is reduced are also prone, she explains.
“To many people, broadleaf-weed resistance is a minor issue. Blackgrass and other grassweed problems tend to dominate. But we rely heavily on ALS inhibitors for broadleaf weed control and we know from reports in Europe, where spring cropping and tight rotations dominate, that this is risky. We need to keep our eye on it and not put it on the back burner,” she warns.
Project work confirmed that ALS inhibitors are ineffective across a range of resistant poppy populations and in these situations, there was no point putting the herbicide on – it just didn’t work.
“But in winter wheat, you could see to a line where the non-ALS treatment of flufenacet+ pendimethalin (as in Crystal) followed by MCPA had been applied.”
Similar results were achieved in OSR, comparing imazamox (as in Cleranda) with a sequence of Butisan (metazachlor) and Astrokerb (aminopyralid + propyzamide), says Lynn Tatnell.
The results also showed the value of timing and weed growth stage when using post-emergence treatments. “Early control is key or you’re faced with a challenge and it’s essential to maintain non-ALS herbicides in the programme,” she adds.
Other weeds, such as henbit deadnettle, charlock and fat hen, are likely to develop resistance at some point, and cultural control options are also much more limited for broadleaf weeds than grasses.
“One poppy plant can produce 20,000 seeds which germinate throughout the year and they remain viable in the soil for decades,” she points out.
Iain Ford, business development manager for BASF, hopes the provision of updated management advice will avoid getting into the same situation as we face with blackgrass.
“The project shows we can still obtain excellent control of susceptible and ALS-resistant poppies using well timed applications of other modes of action, such as pendimethalin (PDM), in Stomp Aqua, and picolinafen, in Picona.”
Picona, which contains PDM and picolinafen, is now approved for use on rye and triticale, as well as spring barley and spring wheat, he adds.
Both actives are non-ALS from different low-risk groups and have broad spectrum activity. Picolinafen has additional activity over diflufenican (DFF) on poppy and other key weeds like charlock, cleavers, fumitory and shepherd’s purse, he adds.
AICC agronomist Mike Thompson has been dealing with broadleaf weed resistance for the past five years. Resistant poppy has been identified on a handful of customers’ farms in north Norfolk, where SUs were the only herbicide used.
“I’ve switched to PDM pre-em and DFF or Picona post-em. It’s not a crisis to see resistance in poppies but it’s important to know you have it, so you can make an informed decision. Poppies are prolific and persistent – once you let them seed, you have them for life.”
Practical guidelines
Actionsto minimise risk of resistance include:
- Using ALS inhibitors in mixture, sequence or rotation with herbicides with different modes of action
- Adopting cultural control methods including non-cereal rotations, competitive crops and cultivations
- Investigating cases of poor weed control and keeping good spray records
- Early detection of resistance – cultural control efficacy is limited and seeds are very persistent
- Seed testing where resistance is suspected
- Removing small patches of persistent weeds to prevent spread.
25% off crop production conference tickets
The role of technology and science is critical to the future health of the agricultural sector and key issues that’ll impact on crops and cropping in the short and medium term will be discussed at the biennial, two-day conference, organised by the Association of Applied Biologists (AAB). Crop Production in Southern Britain takes place at the Peterborough Arena (formerly the East of England Showground), Cambs, on 15-16 Feb 2017.
Held jointly with the British Crop Production Council (BCPC) and supported by Adama it’ll bring together ground-breaking papers from some of Britain’s leading experts, say organisers.
AAB/BCPC has teamed up with CPM to offer readers an exclusive opportunity to attend either or both days of the conference at a 25% discount off the full registration fee. The first 50 readers to book tickets at www.aab.org.uk can attend both days for £150, or either day for just £90. The price includes proceedings for the whole conference, coffees/teas and lunch.
The first day of the conference will be on Crop Protection and the second day on Crop Production. Highlights of a packed programme include papers on:
Crop nutrition and soil management – two papers by Ron Stobart describe the impact of cultivations on soil structure and yields and the effect of cover crops. Dick Godwin of Harper Adams will summarise the research on the impact of three different trafficking systems. In addition, there are two further papers on cover crops. There’ll also be additional papers on approaches to soil testing and in using coated phosphate fertilisers.
Biostimulants – The results of Agrii trials over the past few years.
Insect pests – a paper by Caroline Nicholls of AHDB on the impact on winter OSR of cabbage stem flea beetle will be followed by a paper from Sacha White on the integrated control of this insect.
OSR diseases – Julie Smith of ADAS will describe the physiological processes that determine the yield responses to fungicides in OSR. Four papers from the University of Hertfordshire describe identifying the risk of severe stem canker and the identification and evaluation of new disease resistance genes.
Disease control – Caroline Young of ADAS will be discussing fungicide management strategies to minimise the development of resistance and Paul Gosling of AHDB will describe the cost of septoria leaf blotch in wheat to the agricultural sector. Avice Hall of the University of Hertfordshire will discuss the lessons for field-scale crops from integrated disease control in horticultural crops.
Grassweed control – The emphasis is on cultural control and best practice with a total of seven papers including those by Dr Stephen Moss of Stephen Moss Consulting, Richard Hull of Rothamsted and Tudor Dawkins of Procam.
New herbicides – two new active ingredients will be described.
Plant breeding – A paper by Penny Maplestone of the British Society of Plant Breeders will describe current breeding objectives and the potential of new breeding techniques. Louise Ball of Defra will describe the current and possible future regulatory background for plant breeders. Two speakers from NIAB will demonstrate how new breeding techniques are being used in wheat and spring faba beans.
Panel discussion on the future of rotations – Poul Hovesen will describe the benefits of the longer term rotations adopted by the Salle and Holkham Estates in Norfolk. A panel consisting of a business consultant, a distributor and a member of the pesticide industry will give their views before the audience joins the discussion.
HSE CRD workshop – HSE CRD are seeking views on opportunities to improve labels, stewardship, IPM uptake, and other practicalities. HSE CRD also want to listen to views on the opportunities and risks for pesticide regulation following an exit from the EU.
These are a just a few of the papers that bring together the latest research relevant to UK arable crops, claims conference organiser Jim Orson.
“We have again brought together with this programme a level of scientific and economic insight into crop technology that’ll prove invaluable to both forward-thinking farmers and advisers. If you’re searching to peak into the future of crop protection and also for answers to get the best from the 2017 crop, we don’t think there’s a better place to find them,” he maintains.
Delegates received 10 BASIS points for attending the previous conference and BASIS points will be awarded for attending this conference. To qualify for the 25% discount, go to the online registration page at www.aab.org.uk, and confirm that you’re a CPM reader in the status box provided.
