As part of this year’s Cereals event (11-12 June) at Heath Farm, Leadenham, The Arable Group (TAG) is running a series of demonstration trials comparing winter wheat varieties. There are also a number of plots looking at the relative merits of alternative cereals, such as spring and winter malting and feed barley, naked and conventional winter oats and spring wheat.

Below is a weekly diary from TAG consultant, Chris Nottingham, highlighting the main developments at the site (stand no.102).

Latest report

3 June 2008: Crop growth improves in response to rain but disease held in check by fungicides

Crop growth has improved greatly during the week, particularly in the spring crops, following the significant rainfall seen since Monday.  The appearance of the spring crops is much better this week and both the spring barley and spring wheat have reached full flag leaf emergence.  The winter barley is in the grain filling stage, while the ears are fairly well emerged on most winter wheat varieties.  Panicle emergence is under way in the winter oat plots.

As suggested last week, the spring wheat plot has improved greatly in appearance following the rain, mainly because the yellowed leaf 4 has disappeared in to the canopy as the flag leaf has fully emerged and expanded.  The upper three leaves remain green and healthy.  A flag leaf fungicide will be applied to this plot when the weather allows.

Since there is heavy band of rain crossing Lincolnshire today (3 June), the T2 for the spring wheat will probably be applied later this week.  The spring barley has also responded to the rain and the awns are on the point of emergence, so it too will receive a T2 fungicide later this week.  The barley canopy remains largely free from disease.

Winter barley plots are now in the grain filling phase.  The recent rain will have been very beneficial in terms of the yield potential for these plots and, more importantly, commercial winter barley crops on the surrounding limestone brash soils.  Disease levels remain very low in the three winter barley varieties, despite a slightly stretched T1 to T2 interval, which reflects the relatively low disease pressure during the dry conditions seen during much of May. 

Panicle emergence is under way in the winter oats which also remain disease-free (see photo below).  The Dalguise plot is slightly ahead of the Hendon in development and the height difference between these two types of oat is marked, as expected.

Ear emergence is almost complete in many of the winter wheat varieties although Alchemy remains the slowest variety, with ear emergence just beginning.  Flowering is either under way or will start shortly in the earliest wheat varieties.  Although wheat blossom midge presents no threat to these demonstration plots, a pheromone trap has been positioned in the middle of the wheat plots, for interest.  Several of the ears of the variety Battalion have a twisted look, although this only results from the scurs (‘awns’) on top of the ears of this variety temporarily catching in the top of the old flag leaf sheath (see photo below).  Most of the other wheat plots are not showing this or have moved past this stage, although a few ears in the Glasgow plot are behaving in a similar fashion.

Disease remains absent from the upper three leaves of the wheat varieties although septoria symptoms are expected to increase lower in the canopy, especially on leaves not covered by the recent T2 application.  Mildew has not developed yet in any of the varieties but was treated earlier in the programme.  Yellow Rust should be well under control from the T2 fungicide.  The leaf tipping and flecking symptoms seen in some varieties in the last couple of weeks has not developed any more during the last week and if anything are slightly less obvious now.

The first marquees and stands are just starting to appear, as the transformation of the site begins in preparation for the Cereals 2008 event next week.

27 May 2008: May rain benefits crops – but increases disease pressure

Light rain last weekend has been followed with another 20mm falling at the Cereals site between Monday and Tuesday, the first significant rain in the area since late April.

Crop growth has continued steadily with the spring crops showing the fastest development the flag leaf is now emerging on both the spring wheat and spring barley. The winter barley is well in to ear now, while the winter wheat and winter oats vary between mid booting to early ear emergence.

Spring crops faced the biggest struggle in May’s dry conditions, with the spring wheat plot (variety Paragon, see photo below) displaying the worst condition of all the plots at the TAG site. The symptom displayed below is mainly a yellowing of the tip, or sometimes up to half of leaf 4. There does not appear to be any disease association, but rather a physiological response to May weather. A fungicide was applied to this plot at full leaf 3 emergence and following the rain it is likely that this plot will look significantly better by next week.

The spring barley (varieties Waggon and Tipple) look in better condition overall than the spring wheat. There is some physiological spotting in the base of the canopies of both varieties with occasional symptoms of rhynchosporium also on the lower leaves. A fungicide was applied at early stem extension which should keep any disease in the lower canopy, despite the rain. The spring barley is also likely to appear in better condition in a week’s time.

The more forward winter wheat varieties are at early ear emergence these include Timber, Humber and Einstein with Duxford and Battalion not far behind. Most of the rest of the varieties are at the late booting stage with the Alchemy and Viscount fractionally behind this.

Septoria pressure should increase now that the rain has arrived although the winter wheat should be well protected by the T2 flag leaf fungicide, which was applied on 22nd May. Septoria symptoms remain most obvious on leaf 5 which is starting to senesce some early signs of leaf spotting can now be seen on leaf 4 in some varieties which may be septoria. Yellow rust symptoms have not developed greatly during the week and should now be controlled by the T2 fungicide. The T1 fungicide included a mildewicide which continues to give protection against development of this disease. By contrast in some commercial crops mildew levels have increased in the last 7 – 10 days and thickening canopies and recent rain will encourage development of this disease.

The pale or yellow flecking reported in some winter wheat varieties last week remains visible and tipping of (mainly) leaf 2 is now quite common across the plots. The main varieties affected are JB Diego (see photo below), Monty, Battalion and Zebedee, and to a lesser extent Timber, Alchemy, Robigus and Viscount. There is no disease associated with these symptoms.

 

 

 

19 May 2008: Growth steadies in cooler temperatures, soils slowly dry and disease levels remain low

After the surge of growth seen last week, development in all crops slowed in response to the cooler temperatures this week.  So winter wheat is now approaching full flag leaf emergence, while the winter barley is at the awns emerged to early ear emergence stage.  Spring crops are still in the early stem extension phase.

All the winter wheat varieties are between growth stage (GS) 37 – 39, except for Timber which is at early booting stage.  Alchemy remains one of the slower developing varieties, as can be seen in commercial crops.

In the winter barley, awns are visible on all varieties and Pelican remains the most forward variety, with the majority of ears also visible.  In the winter oat plots, meanwhile, the flag leaf is emerging, with the variety Dalguise slightly ahead of Hendon. 

The tip of leaf two is just visible in the spring wheat plots while the spring barley plots are between GS 31 and 32.

Septoria development in the winter wheat remains confined to the lower canopy, reflecting the situation in many of the winter wheat crops in south Lincolnshire.  The current dry conditions – the area escaped the rainfall seen in other parts of the country last week – will be helping to reduce septoria spread up the canopy.

Yellow rust is slightly more obvious in the Robigus this week, but only in the lower canopy.  There is no disease to be seen in the winter barley (see photo above) or oats and the spring crops have had a T1 fungicide applied, prior to the development of any disease.

The winter wheat T2 fungicide will be due over the next few days once the flag leaf is more fully emerged on most varieties.  The T1 to T2 interval will be approaching three weeks at this point, which is a longer period than looked likely a week ago.  The priority for the wheat T2 application will be to eradicate any active disease, to prevent further yellow rust development in the Robigus in particular and to add septoria and brown rust (should it start to develop) protection to the flag leaves.

A slight flecking symptom can be seen in some winter wheat varieties now, including Monty (see photo), Humber and Duxford.  This may be a response to the current weather conditions and drying soils, although recent herbicide applications may have contributed.  However, no ‘complicated’ tank mixes have been applied to the winter wheat with most applications being sequenced.

The winter barley has received its T2 application to top up disease protection, with brown rust perhaps the most likely disease to develop in the current conditions.

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12 May 2008: Growth accelerates rapidly and yellow rust makes a comeback

A much warmer week saw the speed of crop growth accelerate rapidly, with the winter wheat producing a new leaf while the quickest developing crop, the winter barley, moved from growth stage (GS) 32 to flag leaf fully emerged or beyond.

The flag leaf is now visible on all winter wheat varieties, but in most of these it is yet to unfurl to any degree.  Timber has leapt to the front of the queue, with its flag leaf fully emerged on many main stems (see photo below), while Alchemy is among the slowest developing varieties.

The fastest growing crop this week is the winter barley, moving from scarcely GS 32 through to flag leaf emerging (Flagon) or fully emerged (Saffron), or in the case of Pelican, which has always been the most forward variety, the boots swelling stage.  Winter oats have moved on to GS 33 while the spring barley and wheat has also grown fast, with their canopies closing and stem extension beginning.

Disease levels in the winter wheat remain low overall, although yellow rust symptoms have returned to the Robigus, showing on the tip of leaf four on a low number of plants (see photo below).  Septoria tritici symptoms can be found on the tip of leaf five now on several of the more septoria-susceptible varieties.  Mildew has yet to develop in any of the wheat varieties.

The winter wheat T1 to T2 interval looks as though it will be very short given the sudden rapid growth, with the T2 flag leaf spray likely to become due towards the end of this week under current conditions, making the interval around two weeks.  Maintaining septoria control and clamping down on the yellow rust in the Robigus are the main priorities for this application.

The winter barley and winter oat plots remain virtually free of disease and the barley T2 will be applied soon when the majority of awns have emerged, giving a more normal T1 to T2 interval of around 4 weeks.  The T1 application was applied relatively early, however, and in many commercial barley crops, the T1 to T2 interval may also be much shorter, as some crops were very slow to begin stem extension.

The spring barley and wheat plots are clean at present, although disease pressure may build now that their canopies have begun to close together.  The T1 fungicide application for both these crops will become due soon.

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5 May 2008: Wheat varieties start to move but visual disease levels remain low

Another warm week has seen all the wheat varieties in the TAG Cereals plots respond and move up a gear in terms of growth. Visual disease levels have changed little, however and septoria remains the only obvious disease on the foliage.

Leaf three is now fully emerged on all wheat varieties, with the most forward varieties moving past growth stage (GS) 32 towards GS 33, with the third node extended by 1cm.

Leaf two is now visible on the main stems of most varieties, although it is most obvious in Monty, JB Diego, Humber and Glasgow, which continue to be the most advanced varieties.

The winter barley plots are between GS 31 and 32, with Pelican the most advanced variety being fully at GS 32. Winter oats are also between GS 31 and 32, while the spring wheat and barley is at the mid to late tillering stage.

Obvious Septoria tritici symptoms remain largely confined to leaf six, although recent rains and higher temperatures will be increasing the pressure from this disease. Yellow rust has yet to be seen again in the Robigus (pictured above) or Glasgow. The threat of mildew development should rise with canopies thickening, warmer temperatures and moist soils, with the most recent rain in the area having fallen overnight on the 4 May. However, there is little sign of mildew so far in any of the plots.

Spraying opportunities during last week (w/c 27 April) were limited by frequent showers and windy days. The ideal T1 fungicide timing in terms of leaf three being opened and presenting a good target for fungicide application occurred at the site late last week.

Application of fungicide was actually possible on 1 May. The rates of the T1 fungicide have yet to be increased given the relatively short delay and the use of a T0 fungicide, which appears to have slowed the spread of disease though the canopy.

Disease levels remain low in the winter barley and winter oat plots, with no sign of mildew developing in either. The barley variety Flagon continues to grow away from the physiological spotting seen earlier on, with symptoms much less obvious now (pictured left).
 

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29 April 2008: Wheat leaf 3 slowly emerging while disease levels remain low

A warmer week saw some commercial crops respond and enter a more rapid growth phase, with final leaf 2 just visible on some of the earlier sown, faster developing varieties.  At the Cereals site, steady crop development has occurred during the week and disease levels remain low overall.  Wheat varieties are approaching the final leaf 3 ‘T1’ fungicide timing.

All wheat varieties at the Cereals site are moving between growth stage (GS) 31 and 32, with final leaf 3 up to half emerged on the main stems of the most forward varieties, which this week are Monty, Humber, JB Diego and Glasgow.  The winter barley and oats are moving towards GS 32, while spring crops are still at the early tillering stage.

As last week Septoria tritici symptoms are visible on leaf 6, the lowest surviving leaf in the canopy, with occasional symptoms on leaf 5.  Rising temperatures during the last week will have shortened the latent phase of this disease, increasing the speed of its spread up the crop canopy and reducing the window for its control as leaf 3 emerges.

Yellow rust symptoms have yet to re-appear in the most susceptible varieties Robigus and Glasgow.  Eyespot symptoms remain common in commercial crops, often in earlier drilled first wheats and second wheats.

The TAG winter wheat ‘T1’ fungicide application will be based on a triazole with the emphasis on strong septoria protection, mixed with chlorothalonil for increased disease protection and as an anti-resistance measure.  A protectant mildewicide, appropriate given the mildew-free canopy at this time, has been added as insurance against the possible development of this disease in the more mildew susceptible varieties such as Solstice, Humber and JB Diego, as temperatures rise and crop canopies thicken.

The T1 fungicide is targeted at ‘final leaf’ 3 which is the first significant leaf to contribute to crop yield, given that the canopy has up to this point remained sufficiently disease-free to grow effectively.  Yield contribution increases with each subsequent leaf, i.e leaf 2 and flag leaf.

However, yield contribution from lower leaves (leaf 4 or lower) may increase where canopies are more open, for example following slug grazing or other establishment issues last autumn.  T1 fungicide application will start in a few days once leaf 3 has opened more on side tillers to present a better spray application target. 

The T1 fungicide has already been applied to the winter barley and disease levels remain low.  As the winter oats approach their T1 fungicide timing at GS32 the canopy is just starting to join together.  This will increase disease pressure, although there is little sign of any mildew yet.

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Previous reports

21 April 2008: Septoria is the main disease after cool and damp weather

The cool and showery conditions seen in Lincolnshire during April have encouraged the development of Septoria tritici in all wheat varieties.  The development of eyespot is also a concern in commercial crops, but few other diseases have featured so far.

Most wheat varieties are moving on past growth stage (GS) 31, with final leaf 3 beginning to emerge in the faster developing wheat varieties, noticeably Timber, Humber and Einstein.  The winter barley and winter oats are at GS 31.  Spring cereal crops are at the 3 leaf – first tiller stage.

April’s weather has been in stark contrast to the high temperatures of the same month last year, which was warm enough to encourage an unusually early brown rust epidemic.  To date, that disease has shown few signs of reappearing, while a series of recent frosts has continued to suppress mildew. 

Septoria tritici is present on all wheat varieties with obvious visible infection on final leaf 6, with some symptoms on leaf 5.  Development of this disease will have been checked to some extent by the cool temperatures.  Meanwhile, Robigus was displaying yellow rust at the Cereals site in early April, albeit later than some commercial crops in the area which saw yellow rust develop during March.

Eyespot, or general stem-based browning symptoms, is present in many commercial crops and the ongoing development of eyespot is of concern if current weather patterns continue.

Disease levels in winter barley and winter oats remain low.  There is some physiological spotting present in winter barley, most noticeably in the variety Flagon.

The TAG winter wheat ‘T0’ fungicide application, based on a triazole + chlorothalonil combination, has been applied to control yellow rust and slow the development of Septoria tritici.  The winter barley ‘T1’ fungicide has also been applied, prior to the development of disease.

Septoria tritici in the lower canopy of wheat variety Solstice   Physiological spotting in barley variety Flagon.

 

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TAG Variety Plots at the Cereals 2008 site

Alternative cereals	Winter wheat
Paragon Spring milling wheat	Duxford Group (4*)	Alchemy Group 4
Waggon Spring feed barley	Solstice Group 1	Glasgow Group 4
NFC-Tipple Spring malting barley	Battalion Group 2	Humber Group 4
SW Dalguise Conventional winter oats	Einstein Group 2	JB Diego Group 4
Hendon Naked winter oats	Robigus Group 3	Monty Group 4
Flagon Winter malting barley	Viscount Group 3	Oakley Group 4
Pelican 6-row winter feed barley	Zebedee Group 3	Timber Group 4
Saffron 2-row winter feed barley

* Duxford – currently listed as group 4 feed wheat on the Recommended List.  Undergoing further tests for suitability for ukp bread wheat for export

• Crop Details: Sown 11th October 2007

  Fungicide treatments:

  Winter wheat:

  • T0: Cherokee 1.0 l/ha (9 April 2008)
  • T1: Proline 0.5 l/ha + Chlorothalonil 1 l/ha + Talius 0.18 l/ha (1 May 2008)
  • T2: Opus 0.8 l/ha + Chlorothalonil 1 l/ha + Comet 250 0.30 l/ha (22 May 2008)

  Winter barley:

  • T1: Fandango 1.0 l/ha + Talius 0.1 l/ha (9 April 2008)
  • T2: Fandango 0.75 l/ha (14 May 2008)

  Winter oats:

  • T1: Cabaret 0.25 l/ha + Talius 0.125 l/ha (1 May 2008)
  • T2: Planned this week

  Spring barley:

  • T1: Fandango 0.75 l/ha + Talius 0.125 l/ha (14 May 2008)
  • T2: Planned this week

  Spring wheat:

  • T1: Opus 0.5 l/ha + Chlorothalonil 1 l/ha + Talius 0.125 l/ha (14 May 2008)
  • T2 Planned this week

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