April Week 4
Leaf layer tested: Top 2 leaf layers. Either Leaf 3 & 4 or Leaf 4 & 5.
Summary
It has been busy week for T1 applications across the country and reassuringly Leaf 3, the target leaf layer for this spray, was in a protectant situation for Yellow Rust and Septoria tritici at all but two National Snapshot locations where it has emerged.
However, despite recent dry weather, Septoria was detected in the lower leaf layers at nearly all the National Snapshot locations highlighting the importance of applying a fungicide to protect the newest leaves from disease lurking in the lower part of the crop. Some warm weather and rainfall could easily see this disease transferred to the critical leaf layers without appropriate fungicide applications.
Yellow rust is now present in 5 of the 26 crops tested reminding us of the importance to check your crop for this disease particularly given the recent cool and dry conditions.
Septoria tritici:
Protectant scenario on Leaf 3
Whilst Septoria tritici has been detected on the lower leaf layers at all but three of the National Snapshot locations, this has only transitioned to ‘early stage infection’ in Leaf 3 at one site in Devon so far. At the remaining locations where Leaf 3 has been tested, eight of the sites have Crop Check scores between 4 and 12 indicating that they are still in a protectant scenario but that there are fungal spores present that could germinate if conditions are favourable. Spores are more likely to germinate in warm, wet conditions so recent dry weather will have limited the opportunity for these spores to germinate but with a change in the weather this disease could quickly develop.
Septoria detected on lower leaf layers in September drilled crops
Established latent Septoria tritici is being detected on the second newest leaf layer in nearly all the September drilled crops tested reminding us that drilling date remains one of the most important factors in determining disease levels. Septoria is now visible on Leaf 5 in September drilled Extase at Malshanger Estate in Hampshire highlighting that even the most resistant varieties are more vulnerable when drilled early.
Early stage and established infection detected in Devon
Unsurprisingly, the one National Snapshot field where we have detected Septoria tritici in Leaf 3 is at our South-West site at Taleford Farm, Ottery St Mary in Devon in a crop of Gravity drilled on 1st October with a weak Septoria tritici resistance rating of 4.9. Leaf 3 has a Crop Check score of 24 putting it in the ‘early-stage infection’ category highlighting the need to apply a fungicide urgently to ensure infection does not progress any further on this critical leaf layer. Leaf 4 has a Crop Check score of 95 indicating that it has established latent infection and is likely past the point of even the most curative fungicide activity.
Yellow rust:
Yellow rust incidence and severity continues to build.
After a clutch of results last week, the disease has now been found in five National Snapshot fields in a range of varieties including, Skyscraper (7), Extase (8), Gravity (6) and Gleam (5).
This reflects field observations with yellow rust visible in a number of susceptible varieties. At last week’s CropDoctor tour the disease was present at every site, particularly close to The Wash at Long Sutton, Lincolnshire.
Greg says where T1s are still to be applied a strong yellow rust protectant is advisable. “Positive National Snapshot results are being returned from east and west alike, reflecting field reports. A strong Septoria active with good protection against yellow rust is a sound strategy and there isn’t anything better than Ascra (prothioconazole + bixafen + fluopyram), especially as it will protect against the stem-based complex too,” he notes.
April Week 3
Leaf layer tested: Primarily leaves 5 and 4, leaf 3 at some sites
Summary:
With temperatures picking up and a fair number of heavy dews, so disease levels are picking up too.
Septoria tritici infection in leaves 5 and 4 has climbed steadily from last week and is widespread.The Septoria tritici found only in Scottish regions last week is now being detected in many English counties.
But yellow rust is also a potential threat in some varieties. This includes Graham, however it is at a site close to The Wash, a yellow rust hot spot.
The disease isn’t as widespread as Septoria tritici, and yellow rust CropCheck scores vary considerably but it is interesting that the disease is in eastern and western regions in equal measure.
Eyespot continues to linger in crops, the disease more widespread than of recent seasons.
Septoria tritici:
With leaves 5 and 4 now exposed for some time, infection has built on a week of warm weather.
Leaf 5 infections for most varieties and sites are currently in the late-stage infection category with CropCheck scores ranging between 54 – 100, the exception being Cranium (5.7) at Long Sutton, Lincs. It was drilled in December and it probably hasn’t had the same length of exposure as other varieties.
Leaf 5 infection is visible in more than half of our National Snapshot varieties, most notably with Dawsum (6.1) at Halfhead Farm, Stone, Staffordshire and Wolverine at Fawley Court, Herefordshire (5.7) with 41.70 and 21.42% respectively. Both varieties are not particularly resilient to the disease and being September drilled it will reduce their ratings accordingly.
It is no surprise to see leaf 4 infections ranging more widely. This includes a number of varieties in the protectant scenario, Cropcheck scores of 1 – 20.
But it doesn’t include Extase (7.3) with high CropCheck scores at Malshanger Estate, Hampshire and Fawley Court, perhaps more evidence that plant resistance only ‘kicks in’ as it matures.
Of those varieties with high leaf 4 CropCheck scores the disease is only visible in Skyscraper (4.6) at Halfhead Farm. Again, a September drilling date is a likely factor. Project lead Greg Hanna believes it is behaving more like a 4.
At Fawley Court, Extase is about to get its T1 – a combination of Aviator (prothioconazole + bixafen) with Phoenix (folpet). With its high prothioconazole loading it will guard against eyespot – the one weakness in an otherwise impressive range of disease ratings.
Greg feels with the background threat of Septoria tritici, yellow rust and eyespot in the lower canopy, a well-timed T1 will be important this season. “CropCheck scores, and fieldwalking, are highlighting the broad-spectrum threat crops are facing currently. What will be important this season is to fully protect leaf 3 for an effective firebreak as possible to reduce the pressure at T2.”
“It is always better to apply fungicides preventatively than have to firefight later in the season where the return on investment may not be optimised.”
For good measure, some National Snapshot partners are finding mildew in sheltered field areas and headlands. Greg doesn’t feel it warrants the inclusion of a mildewicide to T1 sprays but it is another reason for a prothioconazole base.
Yellow rust:
For the first time this season we are seeing yellow rust in more than a single variety and site. This includes Wolverine (4) at Fawley Court, Herefordshire. Leaf 4 returning a CropCheck score of 70. It isn’t on leaf 5 but that could be due to the presence of Septoria tritici.
Gleam (5) at Folkenham Farms, Sleaford, Lincolnshire also has the disease in leaf 4. This is in the early-stage infection phase. The disease is also present at another Lincolnshire site, this is Graham (7), at G H Hoyles Ltd, Long Sutton. Like Wolverine this is also in the late-stage infection category with a CropCheck score of 97.
There is also a trace of the disease in leaf 4 of Skyscraper (7) at Halfhead Farm, Stone Staffordshire.
It isn’t a surprise for project lead Greg Hanna. He points out that for much of last week daytime temperature hovered around 15°C. “At this temperature the latency period for yellow rust is around 12 days. But bear in mind that for varieties with a lower resistance rating the latent period could be shorter,” he notes.
Again, he considers it another reason to go with prothioconazole at the T1. “Our best yellow rust protectants are Ascra (prothioconazole + bixafen + fluopyram) and Elatus (prothioconazole + benzovindiflupyr). Elatus has the edge on curative activity but it isn’t as strong against Septoria as Ascra, which is why in the majority of cases Ascra is the better option,” he concludes.
April Week 2
Leaf layer tested: Primarily leaves 5 and 4, leaf 3 at some sites
Summary:
With dry weather holding in many areas, Septoria tritici and yellow rust infection in the upper canopy remains low. Apart from a few exceptions, CropCheck scores are all in the protectant scenario.
We’ve added eyespot testing to the National Shapshot programme and our first round of testing reveals the disease is more widespread than in recent seasons. Apart from the South East, eyespot is being found in several varieties within the National Snapshot programme. Both W and R type infections currently being detected.
There is no change in the yellow rust situation. The upper canopy is clean with extremely low CropCheck scores, reflecting observations from the field.
Septoria tritici:
It is only a couple of varieties in Scotland that are carrying troublesome Septoria tritici CropCheck scores.
At Middlebank Farm, Errol, Perthshire the disease is still present in leaves 5 and 4 of Spotlight (4.9). Leaf 5 has a Cropcheck score of 97, leaf 4, 96– late-stage infection.
A little further up the road at Keilor Farm, Septoria tritici has continued to build in Illuminate (5.4). Leaf 5 and 4 now also have CropCheck scores in the 90’s. Many Scottish regions have seen a bit more in the way of rainfall and agronomist Ben Lowe and CTM Grant Reid believe this is the cause.
Elsewhere, regardless of variety rating and drilling date, leaf 4 and 3 CropCheck scores all range in the protectant phase, 1 – 20.
There is still the risk the disease could spread from the base of crops should warm and wet weather arrive ahead of the T1 timing. But we probably need to see a number of rain events for leaf 3 to come under serious threat.
Project lead Greg Hanna suggests growers should remain vigilant but a good preventative T1 should suffice this season. “If leaf 4 remains clean it will reduce the risk of transfer onto leaf 3. But we saw last year how quickly Septoria tritici can take hold in the right conditions, so I wouldn’t ease up in preventative strategies. Firefighting is costly and has limited effect.”
One following that mantra is agronomist Steve Wood. Despite current CropCheck scores, he feels Extase 7.3 at Malshanger estae, Hampshire, is carrying more Septoria tritici this season. January, February and March have been exceptionally mild, and that is probably a factor but there is also the question of whether Extase is losing some of its resilience. However, it was drilled early so it is behaving more like a high 6 than a 7.
Both Steve and Bayer CTM Richard Prankerd expect adult plant resistance to ‘kick in’ at stem-extension, currently leaf 3 is emerging.
The variety responds to fungicides so if the run up to T1 is warm and humid it will get Silvron (prothioconazole + tebuconazole + bixafen + fluopyram), if it is dry Steve will drop back to Skyway (prothioconazole + bixafen +tebuconazole). There is no sign of eyespot in the crop but it has been noted quite widely in the region.
Richard says growers need to be mindful of rates after last season. “We saw some very low T1 rates last year and when the weather turned late foliar disease bubbled up. With resilient varieties like Extase there is some leeway with products and rates but we have to be mindful of what might lie ahead. We also must ensure we apply all fungicides at rates where the mixture partners protect each other.”
Eyespot
Eyespot is present from Scotland through to Herefordshire.
This includes Skyfall (7) at Hay Farming, Holbeach St Marks, Lincoln. Skyfall is understood to carry the Pch1 resistance gene. However, it is a second cereal which is a risk factor.
Although distribution is fairly even between W and R types, DNA/mg figures for W type eyespot infection is significantly higher. This type is generally more visible early in the season and this concurs with reports from our National Snapshot partners. But the R type is also being detected – less visible it can be overlooked warns Greg.
At Scoughall Farm, East Lothian, the disease is visible in Skyscraper (4) and Sandy Dale is looking at a robust dose of prothioconazole at the T1. Last year he went with a prothioconazole-based T1 and that looks likely again this season. It’s also a strong yellow rust option, useful with the number of Sea Haars the farm experiences.
Further north, eyespot is visible in Spotlight (5) at Middlebank Farm, Errol, Perthshire. Agronomist Ben Lowe is also looking at a prothioconazole-based approach, probably Ascra (prothioconazole + bixafen + fluopyram) with Folpet but he will make a final decision nearer the time.
Spotlight will get a tebuconazole T0 to keep yellow rust in check, and with low Septoria tritici CropCheck scores he expects to remain in a preventative position at T1. But GS32 is two weeks away and a lot can change with the Scottish climate.
Yellow rust:
There is still no change in the yellow rust situation, leaves 4 and 3 remain clean of infection. The disease is visible in the base of a number of varieties but cool weather ahead of Easter has helped keep it in check. T0 sprays should also help keep the disease in check until the T1 timing.
April Week 1
Leaf layer tested: Primarily leaves 5 and 4
Summary:
With dry weather predominating much of the country, disease pressure remains low on newly emerged leaves. We’re only in the second week of April but is it looking like it could be another dry one.
A week on and leaf 3 is emerging in the most forward varieties. However, November drilled Cranium (5.7) at G H Hoyles, Long Sutton, Lincs is still tillering.
Yellow rust CropCheck scores remain low, although reports of visible disease have increased from the first week of the month.
Septoria tritici:
Graham (6.4) and Gravity (4.6) at Taleford Farm, Ottery St Mary, Devon, are our most forward National Snapshot varieties. Drilled on October 1st leaf 3 is out and it is no surprise that both carry very low CropCheck scores.
That reflects widely what is happening elsewhere.
At Extase at Malshanger Estate, Hampshire, Leaf 5 has a CropCheck Score of 90 but leaf 4 is just 1. Visual symptoms are still to express on leaf 5, but it is expected given its September drilling date.
The same can be found at J P Clay, Fawley, Herefordshire. Leaf 5 in Extase (7.3) and Wolverine (5.7) are carrying high Septoria tritici infection but leaf 4 is clean. Mark Wood is still weighing up T1 options but some eyespot is visible in Extase, so he is likely to go with a product with a good prothioconazole loading.
Leaves 5 and 4 of Extase at Ovington Hall, Sudbury, Essex are also clean with CropCheck scores of 1. For James Nott, he too has a range of diseases on his radar. Extase’s eyespot rating means it will get Ascra (prothioconazole + bixafen + fluopyram) at the T1 as James wants a robust dose of prothioconazole to check the disease. Gleam and Insitor will follow suit for the same reason.Although yellow rust hasn’t been particularly evident – qPCR results or visual symptoms – crops did get a tebuconazole T0 and with Gleam and Insitor both being rated 5, andadditional activity from Ascraat T1 is welcome. James is considering Univoq at T2, which will widen T3 choices to possibly include an SDHI. With hindsight, he wished he’d have held Aviator (prothioconazole + bixafen) back last season when late Septoria tritici ‘bubbled up’. It’s a logical route where Fusarium and late foliar protection is desired.
The biggest transformation has occurred at Scoughall Farm, East Lothian. Both Saki (5.1) and Skyscraper (4.6) have moved from red to green. Where the previous leaves tested were in a curative scenario for Septoria, Leaf 4 has now emerged and holds a CropCheck score of 1 putting this leaf layer in a protectant scenario.
But we have got Septoria tritici in leaf 4. Gleam (5.5) and Graham at Cocked Hat Farm, Sowerby, North Yorkshire, have CropCheck scores of 28 and 16 respectively. Graham is in a protectant scenario but Gleam is at the early-stage infection phase.Both were drilled in October so it could be that these caught a few more showers. This could also be the explanation for infection in Spotlight (4.9) and Illuminate (5.4) in Perthshire. At Middlebank Farm, rain was recorded for four days running from Sunday 3rd, this and with leaf 4 still to emerge being more probable causes.
Yellow rust:
Leaf 4 has emerged with Saki (8) at Scoughall Farm, East Lothian and its CropCheck score has fallen into line with every variety in the National Snapshot programme. The infection found in leaf 5 during the first week of April has still to express itself and its CropCheck score has fallen considerably too.