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Rapid Disease Detection

National Snapshot project

May week 4 results

May Week 4 2021

Leaf layer tested: Top 4 leaf layers

Summary: With wheat crops at or close to GS39 at most sites, the Septoria tritici that bubbled up on leaves 5 and 4 at the beginning of May has remained there. No infection is present on leaf 3 at any of the UK sites. At Long Sutton, Lincs, Septoria tritici has spread to leaf 2 of Graham, but at low levels.

It is more good news for growers. The Septoria tritici threat to the all-important flag leaf is low and the rain just arrived in time to revive crop fortunes.

That is certainly the case at G H Hoyles Ltd, Long Sutton. After 82mm of rain during May David Hoyles describes the turnaround in crops as ‘remarkable’.

With decent temperatures and plenty of solar radiation he believes wheat yields will be above the farm average - something he wouldn’t have believed back in April. “With the weather and the lack of disease we’ve managed to hang on to a lot of tillers, crops have really filled out now,”

He will be looking to keep crops green for as long as possible, and doesn’t mind a late harvest. It still could go back the other way. A repeat of June 2012 saw dull, cool conditions blunt yield prospects after a promising spring, and just a mile from The Wash, Fusarium is always a concern.

CTM James Wilkins believes the physiological benefits of SDHIs means there is a case for inclusion in T3 sprays - providing only one has been used earlier in the season.

He notes that trials have highlighted that for every day green leaf area is maintained in the upper canopy post GS39 it can be worth as much as 0.45t/ha.

And those greening benefits don’t mean a compromise with Fusarium control. “Aviator (prothioconazole + bixafen) delivers a sufficient dose of prothioconazole to manage Fusarium, plus you’re getting enhanced foliar control and greening benefits from bixafen. It could be worthwhile, especially given wheat potential, grain prices and the risk of late foliar disease.”

Septoria tritici:

Over the last week there hasn’t been any great change in Septoria tritici pressure. Across all sites, latent infection is still low in leaves 5 and 4, with no great evidence of the disease moving further up the canopy.

A possible exception is Long Sutton, where leaf 2 of Graham (6.8) is carrying Septoria tritici. It is low at 0.361 ng/ul and leaves 4 and 3 are clean. Leaf 5 is still holding on to some infection, but minimal at 0.259 ng/ul.

On the Suffolk/Essex border at Ovington Hall, Septoria tritici infection in leaf 4 of Insitor (6.8) now stands at 0.705 ng/ul, not a significant rise from last week of 0.195 ng/ul. Again, the benefit of late drilling is being seen. Leaves 4 – 1 of Parkin (5.5) – sown a month later - are currently free of the disease. 

Skip to the opposite side of the country, and at Cornwall it has gone slightly the other way.

Penryn farmers Oliver Bromley of Treluswell Mount Farm and Jason Chapman of Pencoose Farm are working together to compare Graham and Extase (8.0). Leaf 4 of Graham has dipped from 1.017 ng/ul to 0.838 ng/ul. At Pencoose farm, leaf 4 of Extase is carrying just 0.447 ng/ul, the leaves above it all clean. Where they differ is in development. Extase is significantly further on at GS51-59.

Even in Ireland Septoria tritici isn’t concerning Mick Marmion of Greenpark, Dunshaughlin, Co Meath or CTM James Byrne, despite may rainfall six times the monthly average.

Bennington (6.0) and Conros (5.0) are not particularly resilient against the disease so to find leaf 4 with moderate infection ng/ul 2.349 and 6.290 respectively for late May is considered unusual

For James Byrne it highlights how cool April and May have been. “It looks like May 2021 will set a rainfall record, but it has been extremely cool. Apart from the last few days of the month temperatures have ranged between 8 – 13 °C. The disease hasn’t cycled as we would normally expect to see,” he notes.

Yellow rust:

Yellow rust is only present at one site in the UK in leaf 4 on a crop of Skyscraper. However, over in Ireland at Greenpark, Dunshaughlin, Co Meath,  Bennington is now carrying yellow rust on all leaves tested. James Byrne puts it down to variety susceptibility.  “Bennington is a highly susceptible variety so it is no surprise, indeed the surprise is we didn’t see it earlier in the season.”

A 29th September drilled crop of Graham in Ireland is also carrying levels of yellow rust in Leaf 1, 2 and 3.


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 To download as PDF click here.

May week 3 results

May Week 3 2021

Leaf layer tested: Top 3 leaf layers

Summary: There’s been no progression with the Septoria tritici found in leaves 5 and 4 at a number of sites last week. Septoria tritici pg/ul levels remain low in both leaves, and no disease is present in leaf 3 at any site.

Local weather station weather data from our site at Hinton Waldrist, Oxfordshire reveals that the temperature remained below 15°C on all but one day throughout May. Ideally, wet or humid weather coupled with temperatures of 15-20 °C form ideal cycling conditions but temperature have been more akin to March than May. It explains why leaves 3, 4 and 5 remain clean in untreated Barrell (4.2) and Skyscraper (5.2) at the Hinton Waldrist trial site.

Had the weather been warmer, Bayer technical manager, Ben Giles thinks we could be facing much higher Septoria tritici pressure for T2 sprays. But with disease checked a good protectant against Septoria tritici with broad-spectrum properties fits the bill nicely.

The cool weather’s influence isn’t just being seen in lowering disease pressure. Many crops are well behind where they should be for the middle of May and marked differences in development is being seen at some sites.

Generally, most crops are at GS37 but at Callow, Herefordshire, Wolverine is only at GS33. At D J Tebbit Farms, Cambridgeshire, Skyscraper is close to having its T2, as is Extase but Saki could be a week behind. Bayer technical manager, Ben Giles, believes some crops may not catch up despite increasing day length “Leaf 3 emergence in Saki was ten days behind the likes of Skyscraper and Extase. I expect a gap will still exist when they hit full flag leaf emergence.”

Yellow rust remains undetected at all sites except for one site in Scotland and on a crop of Bennington in Ireland.

Septoria tritici:

At Callow, Herefordshire the disease seen last week on leaf 5 in both Wolverine (5.3) and Extase (8.0) has remained broadly static. Currently, leaf 2, 3 and 4 are clear of latent infection.

It is a similar picture elsewhere. At Malshanger Estates, Hampshire, Septoria tritici is now in leaf 4 of September drilled Skyfall (5.8). At 0.234 pg/ul it is low and not concerning farm manager Ian Margettes or Bayer technical manager, Richard Prankard.

Leaf 4 of Graham (6.8) at Long Sutton, Lincs, is also carrying Septoria tritici but again at just 0.19 pg/ul it is not causing alarm. A little further inland at D J Tebbit, Cambridge, and Septoria tritici is present in leaf 5 of Skyscraper (5.1) and Saki 6.5). But only in untreated plots and at low levels – nothing above 0.27 pg/ul.

What is in evidence at Long Sutton is the value in delayed drilling. With a November 6th drilling date, a field of Skyscraper is the latest sown crop of any in the National Snapshot. Despite its susceptibility it has been pretty clean throughout the season, with Septoria tritici pg/ul peaking in the third week of March at just 0.293.

Yellow rust:

Yellow rust remains undetected at all sites in the UK except for low levels detected on Leaf 4 of a crop of Skyscraper in Perthshire.  One of our sites in Ireland with a crop of Bennington now has yellow rust on Leaf 2, 3 and 4 highlighting the weak genetics of this variety.

Alongside the National Snapshot project, we are also sampling untreated yellow rust prone varieties at our demo sites on a regular basis. Despite being untreated, there has been no yellow rust detected on the Zulu, Dunston and Skyfall plots at each site until testing this week , which revealed yellow rust on both Leaf 2 and Leaf 3 in a crop of Dunston at our Eastern site in Long Sutton, Lincolnshire.


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 To download as PDF click here.

May week 2 results

May Week 2 2021

Leaf layer tested: Top 3 leaf layers

Summary: With another week of unsettled weather and most sites at or around GS32, it is good news that test results show leaf 3 still clear of latent disease. However, Septoria tritici continues to ‘bubble away’ on leaves 5 and 4 at a number of sites.

Week 2 results probably reflect the weather variability across the country. Those sites seeing the worst of the ‘May showers’ seeing the greater infection as Septoria tritici infection isn’t restricted to susceptible varieties of September drilling data. It also explains why the disease isn’t being seen in leaves 5,4 or 3 from the South East corner – our sites in Hampshire, Essex, Suffolk and Lincs. Geographical differences in crop development are now apparent as leaf 1, 2 and 3 are now emerged at our sites in Cornwall compared to Perthshire, where leaf 2 is yet to emerge.

Septoria tritici:
Results from the 2 nd week in May show Septoria tritici present on leaf 5 and 4 from west to east. At Callow, Herefordshire both Wolverine (5.3) and Extase (8.0) have the disease on leaf 5. It’s no surprise that it is higher in Wolverine with 3.103 pg/ul recorded, but Extase isn’t far behind at 2.616. In the shadow of the Brecon Beacons the site gets its fair share of wet weather but a September drilling data is also a factor.

Move east to the heart of the midlands and at Quebec Farm, Leicestershire, leaf 4 of Gleam (6.1) is infected with pg/ul of 0.217. Extase (8.0) is faring much better, leaves 5, 4 and 3 all being clean – probably no surprise given the 2-point difference in resistance rating.

Head further north and east into Lothian and Skyscraper (5.1) at Boghall is carrying Septoria in leaf 4 as is Elation (4.1) at Scoughall Farm. Again, varietal resilience is in evidence as Skyscraper is less troubled than Elation at 1.298 pg/ul and 0.369 pg/ul respectively.

Like many, Scoughall farm manager Sandy Dale is awaiting the next set of results keenly. He is hoping to have some rate flexibility with Insitor (6.8) but that depends on whether the disease will move up the plant.

That is a problem both he and Scottish CTM’s Grant Reid and Craig Simpson share. With many plants at ‘knee height’ and leaves close together the disease could easily splash up into the upper canopy.

But at Keillor Farm, Perth, the earlier troubles with Sundance (7.9) appear to be over, suggests Grant. After high levels of Septoria tritici were seen in emerging leaves in early March, leaf 5 carries a small and leaf 4 none. “I think we are seeing adult resistance kick in.”

Another awaiting week 3 results with interest is Spunhill agronomist Paul Cawood. His North West region saw extensive downpours from May 10 th onwards – the rain was welcome as it has come just in time to save crops dropping leaves and tillers.

But with GS39 approaching he worries that disease levels at T2 could be higher than T1. He also cautions growers not to dismiss the yellow rust threat.

Results from both KWS Extase and Graham in Cornwall, where the flag leaf has now emerged, are showing no latent Septoria infection on Leaf 1 to 3 suggesting that disease detected on Leaf 4 the previous week has not yet transpired into latent infection in the top 3 leaf layers. This result gives agronomist and grower the confidence that as the T2 timing approaches, the critical top 3 leaf layers are in a protectant scenario.

Yellow rust:
Again, no real change in the latest yellow rust situation, with only one site proving positive. This is Skyscraper (8.0) at Boghall, Lothian, where leaves 5 and 4 are carrying light infection – just 0.022 pg/ul in leaf 5, a little higher at 0.13 pg/ul in leaf 5.



To download as a PDF click here.


 To download as PDF click here.

May week 1 results

May Week 1 2021

Leaf layer tested: Top 3 leaf layers, leaves 4 – 2 at some sites.

Summary: The change in the weather has seen a change in Septoria tritici fortunes. In the last week of April, Septoria was present in Leaf 5 at just three sites. One week later and the disease is present in leaf 5 or 4 at all sites, except two. No infection has been detected in leaf 3 at any site, but this could be just a matter of time with further unsettled weather forecast. With the all-important T2 spray approaching making the right fungicide choices is vitally important. With variable crop development, an unsettled forecast and ranging T1 timings the value of Rapid Disease Detection is likely to come to the fore.

Septoria tritici:
With the drought giving way to a spell of wet weather, the value of varietal resilience is being seen at most sites.

At Malshanger Estates, Hampshire, testing revealed no infection in leaves 5 and 4 in Skyfall (5.8) and Extase (8.0) through the latter half of April. Now into May and leaves 4 and 5 in Extase remain that way but leaf 5 of Skyfall is carrying 2.146 pg/ul.

With rain on the radar farm manager Ian Margettes opted for a Skyway (prothioconazole + bixafen + tebuconazole) + Folpet T1 mix on April 29th . That proved welcome as 30mm fell in the following week.

The question now is the possibility of further unsettled weather. He and CTM Richard Prankard await next week’s results with interest to see the threat to leaves 3 and 2. Continued wet weather is likely to see Ian include fluopyram in T2 mixes, but if it turns dry it could be a second Skyway application.

Further along the cost at Penryn, Cornwall, it is a similar picture. Leaf 4 in Extase (8.0) is again showing its resilience with a low reading of 0.257 pg/ul. But Graham (6.8) – not much more than a point behind and drilled on October 26th – leaf 4 is holding 3.697 pg/ul.

For agronomist Richard Tresidder and CTM Matt Siggs the latest results are no surprise and highlight the annual threat for the region. “With crops so short when the rain arrived it didn’t take much to splash the disease up the canopy,” notes Matt.

But mildew is also a slight concern. Although not part of the National Snapshot, Richard has noted it in the crop of Extase. He puts this down to it being forward, and it will need to be addressed as
part of the T2 mix.

At J P Clay Farms in Herefordshire, RGT Wolverine (5.3) is carrying more disease on leaf 5 than Extase (8.0).

It’s is no different away from the south and west. At R H Mason, Wold Newton, East Riding, despite Kerrin (4.8) being drilled in late October, leaf 4 is carrying 1.196 pg/ul. The disease is undetected in leaf 4 of Extase – probably no surprise with the same October 20th drilling date.

And it is probably no surprise to see the biggest change at our Irish sites, nor the value of varietal resilience. At Balyraggert, Co. Kilkenny, September drilled Costello (5.0) is revealing its vulnerability, leaf 4 carrying heavy infection at 20.696 pg/ul. The disease is also present in leaves 5 and 4 of Graham (6.0) but much lower at 2.890 and 2.145 respectively. Given that the disease hardly registered on leaves 5 or 6 during much of March and April it highlights how quickly pressure can build in the right conditions.

Further north at Dunshaughlin, Co. Meath, Conross (5.0) and Bennington (6.0) have also seen a rise in leaf 5 infection. At 5.059 pg/ul Bennington is suffering more but its September 20 th drilling date is probably a factor.

Yellow rust:
Yellow rust remains undetected on all leaves in the upper canopy. This includes highly susceptible Kerrin (4) at Wold Newton, East Riding.



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