As part of this year’s Cereals Event (13-14 June) at Vine Farm, near Royston, The Arable Group (TAG) is running a winter wheat demonstration variety trial on stand no.305.

The varieties are arranged in quality order from Hereward to Gladiator. TAG consultant David Parish, and consulting group colleague Alison Barnett, are reporting on the development of the trials on a weekly basis. See below for the latest and previous reports:

7 June 2007: Mildew moving in for Cereals 2007

mildew on wheatWarm moist weather has favoured mildew development in a number of varieties this week and the disease is now far more noticeable.

Cordiale is the worst sufferer, showing visible signs on the flag leaf, but even leaf two is affected on other varieties.

Leaf two has also succumbed to brown rust in the known susceptible varieties Alchemy, Claire, Robigus, Solstice and Zebedee, but Septoria tritici remains at low levels across all varieties, with the exception of Xi-19 – it’s showing more than 10% infection on leaf three.

Having just started flowering, Xi-19 is lagging behind all other varieties which are now at the peak flowering stage.

There’s no doubt that 2007 has been another ‘different’ year in terms of weather pattern and consequent disease pressures, so it will be interesting to see how the varieties perform in this year’s TAG trials. With 59 variety trials across 23 sites TAG is well placed to assess varietal performance nationwide and, with the information available within 24 hours of harvest, TAG will always have the latest variety information to hand.

Growers requiring independent and impartial variety information this summer should contact TAG at tag@thearablegroup.com

Variety Leaf emergence Mildew leaf 3 (%) Brown rust leaf 3 (%) Septoria leaf 3 (%)
Group 1 milling wheat
Hereward

65
Flowering half-way

8
2% on leaf 2
10
Malacca

65
Flowering half-way

Trace 2
Xi-19

61
Flowering started

10
6% on leaf 2
Trace 15
2% on leaf 2
Solstice

65
Flowering half-way

5
1% on leaf 2
4
2% on leaf 2

2

Group 2 milling wheat
Cordiale

65
Flowering half-way

10
6% on leaf 2
4% on flag leaf
Trace 4
2% on leaf 2
Einstein

65
Flowering half-way

1%
Trace on leaf 2
Trace
Group 3 biscuit wheat
Robigus

65
Flowering half-way

6
15% on leaf 2
5
4% on leaf 2
4
Claire

65
Flowering half-way

2 6
3% on leaf 2
3
Zebedee

65
Flowering half-way

2 10
3% on leaf 2
2
Group 4 feed wheat
Glasgow

65
Flowering half-way

2 5
Alchemy

65
Flowering half-way

1 10
2% on leaf 2
2
Timber

65
Flowering half-way

Trace Trace
Brompton

65
Flowering half-way

5
2% on leaf 2
Gladiator

65
Flowering half-way

Trace 4

Crop Details:

  • Sown 17 October 2006

Fungicide treatments:

  • T0 Cherokee 0.5 l/ha 23 March
  • T1 Tracker 1.0 l/ha + Bravo 1.0 l/ha 20 April
  • T2 Opus 0.75 l/ha + Comet 200 0.3 l/ha + chlorothalonil 1.0 l/ha 16 May

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30 May: Septoria increasing after Bank Holiday deluge

Septoria winter wheatWith an impressive 60mm (2.4 inches) of rain falling at the Cereals Event site during the Bank Holiday weekend, the drought conditions of April have been effectively corrected.

It’s not only the risk from septoria that is steadily increasing, due to continued rain splash and high humidity; the actual levels of this disease in the crop have increased with septoria now present on leaf three in a number of the varieties on show. Particularly of note is the presence of septoria on Alchemy – rated as resistant to the disease.

The return to more humid conditions is also favouring the development of mildew, with the disease being present up to leaf two on Robigus.

The brown rust infection encouraged by the earlier dry, warm conditions is now stable on most varieties. However it can still be seen as far as leaf two on the known susceptible varieties Alchemy, Claire and Zebedee.

Ears are completely emerged on all the varieties under test.

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23 May: Improved yield potential following rains

flag leaf sprayingAfter 67mm (2.65 inches) rain during the last two weeks, the T2 flag leaf fungicide was finally applied (see below for details), just under four weeks after the T1 treatment.

This much-needed wet weather has helped ‘wash-in’ the nitrogen, which should improve the yield potential, although it also brings with it an increased risk from septoria.

Septoria tritici is now present on all the varieties with Claire, Solstice and Timber showing the highest levels of infection. Timber’s resistance rating of 7 looks questionable, given the relatively high levels of the disease it’s carrying.  Hereward and Malacca, meanwhile, are showing typical stress spotting, which on Hereward is now present as far up as leaf three.

Brown rust levels have declined following fungicide treatments and the onset of cooler weather which does not favour the disease. It can now be found only on the known susceptible varieties, Alchemy and Zebedee.

Mildew has become a little more noticeable during the week and can be found on leaf three on Claire and, somewhat surprisingly, Cordiale.

Most of the varieties now have the ears emerging, with the exception of a few backward varieties that include Alchemy, Claire and Zebedee where the boots are only just splitting open.

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16 May: Varietal brown rust resistance ratings up for review
 
brown rust on wheatMuch-needed rain in the east of the country has delivered a welcome respite from the near drought conditions of April, but has delayed application of the T2 spray we expected to make this week, says TAG’s David Parish.  However, all varieties are now in boot and the most forward (Cordiale, Einstein and Glasgow) are splitting.

The fungicides applied to date continue to keep brown rust largely at bay, although Alchemy’s leaf 3 is starting to succumb.  More to the point, a review of variety brown rust ratings will be required this summer.  A number of those currently rated as brown rust resistant – Robigus and Timber, for example – are showing obvious signs of the disease.

As the rain will favour septoria spread up the plant, fungicide protection of the upper leaves is now essential; indeed, Septoria tritici is already present on all varieties.  Claire and Solstice are showing the highest levels, but look closely at Hereward – it’s displaying its typical stress spotting, which can easily be mistaken for Septoria.

Don’t be complacent about yellow rust, even if – as in TAG’s Robigus plot – it appears to have dried up.  The current spell of cooler, wetter weather will encourage its return.  Keep monitoring the situation.

The T2 application will now take a slightly different character to that discussed in report no.2. Due to the increased threat of Septoria, the triazole rates will be increased. The strobilurin element will be maintained in the mix to add further brown rust protection

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8 May 2007: Mildew moving in but rust still being held

Septoria winter wheatWeeks of fine weather came to an end this week, but in the TAG variety trials the rapid crop growth continues – with mildew starting to make an appearance.

Flag leaves have emerged on all varieties, with the exception of Claire.  Einstein stands out as being the most forward, its boots visibly swollen.

The wet weather probably hasn’t yet had time to make a difference to disease levels, but with plenty of Septoria inoculum in the crop, the current showery weather is likely to favour its spread up the plant.  The disease is present at low levels on all varieties, with many varieties now showing signs of it on leaf 4.  Claire again stands out from the crowd with evidence of relatively high infection.

The TAG fungicide programme seems to have kept brown rust largely under control, even thought it is present in most varieties and particularly active in Alchemy, which joins Zebedee and this week’s poor performer, Claire, in showing signs of the disease on leaf 4.

TAG continues to keep an eye on progress of yellow rust in the susceptible variety Robigus, but little’s changed over the past week.

By the time next week’s diary is published – dependent on good spraying weather – the T2 fungicide application discussed in report 2 should have been applied.

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1 May 2007: T0 fungicides running out of steam
brown rust on wheatThe warmest April for 350 years has ensured rapid crop growth over the past week, TAG’s David Parish reports, but it’s also pushing the capabilities of T0 applications to their absolute limit.

As reported last week (see below), Septoria tritici is present on all varieties but continues to remain at low levels. Claire, however, is displaying surprisingly high levels. Brown rust is also present in most varieties, being particularly active in Alchemy, but the fungicide programme appears to be keeping it under control.

Susceptible Robigus has finally succumbed to yellow rust, with the disease visible at up to 10% infection on leaf four in some areas of the plot.

Without exception, the flag leaf is now emerging on all varieties, although it ranges from just tipping in some varieties to 50% emerged in others – Hereward, Cordiale and Claire. This is likely to force growers to focus on their T2 sprays sooner rather than later – the aim should be to apply at 60% flag leaf emergence, GS 37-39.

Considering the current high pressure from brown rust and relatively low incidence of septoria, we are planning an application of a triazole plus strobilurin fungicide mix for T2. The strobilurin adds brown rust protection whilst the triazole gives curative activity. Although septoria is at a low level it shouldn’t be forgotten, the triazole offers both curative and protective activity against this disease.

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23 April 2007: T0 fungicides holding back yellow rust

Yellow rust has so far been kept at bay, even on the susceptible variety Robigus, reports TAG from its variety trial at this year’s Cereals site.

Applying 0.5 l/ha of Cherokee as a T0 treatment on 23 March appears to have countered the yellow rust threat completely. Unfortunately the same can’t be said for brown rust which, showing consistency with other reports, is now ubiquitous across all varieties, particularly Alchemy where it has spread onto leaf four.

septoria triticiSeptoria is present on all the varieties in the trial. At present, there is no relationship between the variety’s septoria resistance score and the level of disease actually found in the crops.

Mildew is present only on the older leaves of the variety Cordiale.

Most of the varieties are now at GS32 (second node) with leaf three fully emerged. Leaf two is just emerging. The most advanced varieties are Robigus and Gladiator, where leaf two is at 20% emergence.

See FWi’s Crop Watch for reports on a range of crops from agronomists around the UK.