Arable Fungicides Disease Watch Bayer

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22 September 2017 – As spring arrives so does disease

Welcome to the first edition of Disease watch 2017.

Following a successful first year in 2016 Bayer will again issue a number of Disease watch articles this season. They are designed to keep you informed and ready to tackle diseases infecting arable farms around the country.

Wheat 

Challenging autumn weather resulted in drilling taking place over a protracted period from late March to early June. 

Image above (left) while crops in Southland at still at the end tillering in Canterbury some crops have reached GS32. Image above (right) tiller from a crop of Oakley that has reached GS32 13-09-17.

What impact does this have? 

The main impact is on the infection levels of Septoria leaf blotch. The Bayer team is finding that wheat crops emerged by mid-May are infected with high levels of Septoria leaf blotch (SLB) whereas those crops which emerged later are relatively free of SLB. 

Stop press: SLB is developing very rapidly with May sown crops now developing heavy infections. The Bayer field team is reporting that for some April sown crops the level of infection is the worst they have seen. We are finding this from Manawatu to South Canterbury. This is largely a result of the exceptional rainfall these regions have seen.


At this stage SLB, along with stem base disease caused by either Fusarium species or sharp eyespot are the main diseases being found. There are no records of either stripe or leaf rust reaching my desk, in part this is due to the widespread adoption of Galmano® seed treatment.

Image (top left) Starfire at GS25 showing Septoria leaf blotch infections. Image (top right) Oakley showing SLB lesions with pycnidia clearly visible. Image (bottom left) Oakley showing early signs of sharp eyespot infection. Image (bottom right) stem base browning resulting from infection by either Fusarium species or Monographella nivalis

The Bayer field team has had one unexpected “find” while collecting data for Disease watch - an infection by tan spot. To find tan spot so early in the year is surprising but the sample has been identified and so we can be sure that tan spot is what we are looking at. (Note the amount of crop debris, tan spot spores are released from crop debris and this will have aided infection).

Images (above) Tan spot infection with lesions showing a clear yellow margin. As they develop a dark central spot will develop.

Wheat: T0 and T1 Fungicide options

Most wheat crops are still at the end tillering but there are some forward crops at GS32. 

A T0 application at GS30 can be justified if crops are infected with significant levels of foliar disease, which is the case in many paddocks this spring. Suitable products to apply would be either Prosaro® 1.0 L/ha or Proline® 600 ml/ha. Both of these products would control any Septoria leaf blotch or stripe rust present.

Once crops reach GS32 the importance of applying a robust fungicide increases dramatically as it is at GS32 that final leaf 3 emerges. Protecting leaf 3 from disease attack is important for two reasons. 

The most important is that if leaf three becomes infected it acts as a natural spring board for disease to move up through the canopy leading to rapid and serious disease infection of final leaf two and the flag leaf. As leaf 2 and the flag leaf deliver around 70% of the crop’s yield it is easy to see why they are so important to protect.

The second reason is that in crops with an open canopy leaf 3 can provide 10% of a crop’s yield. Yield well worth protecting.

Again suitable products to apply would be either Prosaro 1.0 L/ha , Proline 600 ml/ha or Aviator® Xpro 1.0 L/ha. Aviator Xpro is an exceptional fungicide for the control of SLB and is likely to be the product of choice in many paddocks this spring.

To illustrate the importance of GS32 fungicides consider this data recently released by FAR. (Source: Arable Update cereals 212). Applying Aviator Xpro at GS32 increased yields and more importantly, profit.

 

Yield increase t/ha
Aviator Xpro applied at GS32

Profit achieved $/ha
(Margin over fungicide cost)

Irrigated wheat crop

1.35

$394

Dryland wheat crop

0.82

$208

At GS32 it could be worth considering the addition of Folpet if using Proline or Prosaro. While Bayer trials have not shown significant yield increases from adding Folpet it does add a different mode of action and therefore may aid the fight against fungicide resistance.

The importance of correct fungicide timing

Now we know what fungicides to apply and why we are applying them, let’s stop to think about one of the most important factors for successful disease control - the time interval between sprays.

Whenever you start your wheat fungicide programme, whether it is at GS30 (T0) or GS32 (T1), do not exceed 28 days between your first fungicide application and subsequent fungicide applications until you finish your fungicide programme. In fact, ideally the interval between fungicides will not exceed 25 days.

Barley

Images (above) barley crops are showing a wide variation in growth stages

At this time of year Scald, and to a lesser extent, net blotch are the diseases you would expect to find, along with isolated cases of leaf rust, when you walk your barley paddocks and that is exactly what the Bayer team is finding. 

Scald is very common this spring and aggressively developing. Net blotch and leaf rust are being found but much less frequently. 

Image (above left) aggressive scald infections can be found in many crops. Image (above right) as well as scald leaf rust can be found in barley crops.

No examples of Ramularia leaf spot (RLS) have been seen but don’t relax, it will be growing unseen in your crops.

In fact, in one image of a crop infected with scald that we have received there is just a hint some RLS might be showing. If you think you might have seen it this year we would love to know. We are including an image from 2016 to show you the disease symptoms to look out for.

Image (above) Ramularia leaf spot infection from 2016

Barley: T0 and T1 Fungicide options

The best approach to control scald, net blotch and leaf rust in early spring is to use Delaro®, a powerful and cost-effective fungicide containing generous amounts of prothioconazole and trifloxystrobin. Adopting Delaro allows you to keep Aviator Xpro available for later season disease control when it is needed for Ramularia leaf spot control.

Considering the levels of scald being found across large parts of the country it is likely your barley crops will benefit from a application of Delaro 600 ml/ha application at GS30. Follow this with a second Delaro application 25-28 days later at GS31-32. At GS31-32 increase the Delaro rate to 750 ml/ha.

The Essential Disease planner.

Have you received your copy of the Essential Disease Planner? Packed full of illustrations of the common arable diseases found in New Zealand and of information about how to effectively control them. It is a “must have” for arable farmers.

Download one now or view it as an e-book from this website or, if you would like a hard copy, drop Neil a request giving your postal address and we will send you one (neil.waddingham@bayer.com).

The next Disease watch will be issued in early October by which time we will be thinking about flag leaf fungicides to autumn and winter planted cereal crops and about GS31-32 applications to spring planted cereals.

Should you have any questions, feedback or if you have a photo you'd like to submit, please get in touch with me directly or contact your local Bayer Crop Science representative.For information regarding Bayer fungicides, please contact your local agrochemical supplier, or your local Bayer Crop Science representative.

Kind regards,

Neil Waddingham Customer Marketing – Arable and SeedGrowth

Email: neil.waddingham@bayer.com

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14 November 2016 - Developing disease & what to look out for

Welcome to the latest edition of Disease watch, a season long programme designed to keep you informed and ready to tackle diseases invading arable farms around the country.

After reviewing the latest findings from the Bayer Sales and Development teams, it is apparent that there is an aggressive development of Septoria leaf blotch and wheat leaf rust on the lower North Island. In Canterbury, the ones to watch are Ramularia leaf spot and scald. Find out what the disease threat looks like in your region below.

Wheat - Lower North Island

A recent trip to the Bayer fungicide trial at the Aorangi Plant and Food Centre near to Fielding revealed that Septoria leaf spot had been developing rapidly during the past three weeks. Where left uncontrolled, Septoria is now severely affecting the flag leaf with leaf two already almost dead.

Considering these leaves account for 70% of yield production we expect the Aviator® Xpro programmes we are testing to deliver very profitable returns.

Image: Septoria aggressively infecting wheat at Aorangi Research Centre. Note that leaf 2 has been very severely affected.

Leaf rust is also developing quickly. In fact, due to the very heavy rain experienced in the Manawatu recently, a lot of the leaf rust spores have been washed off making the disease harder to see. But don’t be fooled, it is still there and will recover.

Interestingly, the Bayer team came across some symptoms that had them scratching their heads; a general yellowing in patches, but without recognisable symptoms - see photographs below. This was later identified as the over wintering stage of leaf rust - occurring in November!

To ensure that your crops are protected apply Aviator Xpro now at GS39-45. Then, to ensure you don’t get caught out by leaf rust infecting during December, follow up with an application of Proline® + a strobilurin fungicide or Prosaro® + a strobilurin fungicide at full ear emergence.

Illustrated below is the performance of Aviator Xpro. Contrast a two spray Aviator Xpro programme where the flag leaf is very healthy and fully intercepting sunlight for yield production with untreated crop where the flag leaves are already losing green leaf area to Septoria leaf blotch infection.

Image above (left): untreated wheat with Septoria infecting the flag leaf. Image above (right): crop treated with Aviator Xpro at GS31-32 and GS39.

Barley- Mid-South Canterbury

2016 is proving to be an interesting year in this part of the world for barley growers. Scald has been present all spring and has continued to develop when not adequately treated. The surprise has been the amount of net blotch present and the early development of Ramularia leaf spot. In addition powdery mildew can be found.

The fungicide approach you take to control these diseases will vary depending on whether you are treating winter planted barley now at ear emergence or spring barley now which will be around the end tillering to GS30.

Image above: Net blotch developing on spring barley. Bayer SeedGrowth trial, Lincoln.

Image: Ramularia leaf spot developing during October in South Canterbury.

For winter barley most crops will have received their GS39 application and this will help protect against scald, net blotch and Ramularia leaf spot.

If powdery mildew is present, it is likely to be in the base of the crop and is unlikely to now cause economic yield losses.

The question is, should a later application of Aviator Xpro be made?

This can be justified for high yield potential crops as this application, which can be made until 56 days prior to harvest, will help suppress Ramularia.

Image: Ramularia leaf spot, disease in the early stages of establishment. Mid-Canterbury November 2016.

Now is the important time to apply a fungicide to spring barley as the open nature of the crop means the lower leaves are important for yield production. As the target at this time is largely scald and net blotch, an application of Delaro® will fit the bill.

This should then be followed with an application of Aviator Xpro at GS37-39.

Last edition's mystery photo:
In the last edition, the Bayer team was puzzling over a disease that was difficult to identify. Before sending it away for testing, we predicted that it might be a mixture of net blotch and physiological leaf spotting.

The lab results are in and the mystery has been solved. If you suspected it was the spot form of net blotch, you'd be right.

Let us know what you think this edition's mystery photograph might be.

Image: Last edition's mystery photo.

Image below: this week’s mystery photograph. Is it Ramularia leaf spot? We will know soon as it is being identified.

mystery disease

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Wheat and Barley - Southland

Like other parts of the South Island, scald is developing rapidly in both wheat and barley throughout Central Otago and Southland.

Treatment options are outlined throughout this Disease watch update, just make sure that the growth stage of the crop matches the treatment plan.

Image: Very aggressive scald attack on an untreated barley crop in Southland.



Wheat - Mid-South Canterbury

Septoria leaf blotch is present in many crops but at present is mainly on the lower leaves. However, the prevailing changeable weather is ideal for disease transfer and development so growers will need to remain vigilant.

Now is the time to ensure you do not let Septoria develop from the bottom of your crops. If you do, yields will suffer as there is a very long time between now and harvest.

Image below: While Septoria leaf spot can easily be seen in the crop, at the moment it is confined to the lower leaves. Without adequate control now, it is poised to spread quickly.

Septoria leaf blotch in lower leaves

Image below (left): Now an uncommon disease to find, stripe rust is still present in Canterbury and will continue to attack if left unprotected. Image below (right): An impressive infection by powdery mildew.

Images below: Take-all symptoms, characterised by blackened stem bases and roots and stunted patches in the crop are now starting to show. (These photos were actually taken on the lower North Island 9-11-16).

Image below (left): Sharp eyespot is a stem base disease caused a soil dwelling fungus. Unless the infection level is very high sharp eyespot doesn’t result in dramatic yield losses Image below (right): Stem base browning, caused by the pathogen Monographella nivalis, can be difficult to conclusively identify without microscopic identification

If you would like to receive these updates directly to your inbox, make sure you sign up to receive updates below.

Should you have any questions, feedback or if you have a photo you'd like to submit, please get in touch with me directly or contact your local Bayer Crop Science representative.

For information regarding Bayer fungicides, please contact your local agrochemical supplier, or your local Bayer Crop Science representative.


Kind regards,

Neil Waddingham Customer Marketing – Arable and SeedGrowth

Email: neil.waddingham@bayer.com

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Second edition header

18 October 2016 - A critical time for disease control

Welcome to this edition of Disease watch, a season long programme designed to keep you informed and ready to tackle diseases invading arable farms around the country.

Wheat - Southland

With crops at GS32 final leaf three has emerged. Protecting leaf three is important for two reasons: it is one of the yield producing leaves and secondly, if disease is allowed to develop on leaf three, when the flag leaf emerges it does so at the same height in the canopy as the infected leaves and direct transfer of Septoria leaf blotch takes place.

With the prevailing wet weather, warm conditions and active Septoria on the lower leaves it is shaping up to be a challenging year for any crop not adequately protected from disease.

Wheat - South Canterbury

Like other regions of New Zealand, crops in South Canterbury are showing a high incidence of Septoria leaf blotch.

While it is mainly the lower leaves infected at the moment, sporulating lesions are very easy to find (see left hand image) and the disease is now moving up on to leaf three (see image below).

In addition, low levels of leaf rust and tan spot are being reported. It pays to look carefully for these as these diseases can develop rapidly under the right climatic conditions.

South CanterburyWheat

Wheat - Mid Canterbury

David Parker, Regional Sales Manager for Mid-Canterbury, examining a Prosaro treated crop as part of Disease watch.

Unlike the untreated crops we have been examining for these updates, this crop is very clean of disease.

Check out the stem base shot of this crop.

It isn’t just Septoria that is attacking wheat this season in Mid-Canterbury as this image shows. This is the most aggressive mildew infection Bayer has seen for a long time on a winter wheat crop.

(Below) Not strictly a disease but Barley Yellow Dwarf Virus (BYDV) is now showing. Note the bright yellow and also purple leaves. This virus can attack wheat, barley and oats.

Wheat - Manawatu

Wheat - Manawatu

Untreated wheat in Manawatu showing an aggressive Septoria leaf blotch infection. Note the emerging flag leaves in the centre of the image.

The flag leaf is critical for yield production and in this crop they are emerging at the same level as infected leaves. A “perfect storm” scenario for disease development! All it needs is moisture, some wind and disease will be transferred throughout the canopy.

(Below) Certainly not what Bayer staff expect to see in mid-October. Wheat in full flower with Septoria crawling all over the upper leaves. This clearly illustrates the disease threat that is out there this season.

Manawatu Wheat in ear

Disease control in wheat

In situations such as this, adopting a three spray programme utilising Aviator Xpro at GS32 and GS39 followed by Proline + a strobilurin fungicide at GS60-69 will provide excellent control of SLB as well as late infections of leaf rust. Click here to see the recommended Bayer spray programme for wheat

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Barley - Southland

With crops reaching awns emerging and with plenty of moisture, warm conditions and scald throughout the canopy it is critical that you apply a robust fungicide now. This fungicide will also control Ramularia leaf spot – perhaps the most devastating late season disease of barley.

Barley Southland

Barley - South Canterbury

Scald is the predominant barley disease throughout South Canterbury although leaf rust is starting to be found and net blotch can be a problem, especially for second year barley crops. This shows a typical scald lesion that is still actively producing spores - the greyish green, “water soaked” appearance is typical of active lesions. Spores from lesions such as these are able to wash down the leaf to lodge in the leaf axil. Here they germinate and the subsequent lesions are able to kill the entire leaf.

Barley - Mid Canterbury

It is evident that scald is widespread throughout the South Island this year.

The crop held aloft (below on left) has been treated with Delaro and now approaching GS39, is just at the right stage to receive an application of Aviator Xpro as a T2 fungicide to protect against scald and Ramularia leaf spot.

Contrast this with the untreated crop (below on right) which is heavily infected with scald, even on the upper leaves. If you look carefully towards the bottom left of the image, you will see a number of leaf rust pustules.

What is the below barley disease? The Bayer team is having this scientifically identified but we expect it to be a mixture of net blotch and physiological leaf spotting.

Mid Canterbury Barley

Disease control in barley

For general disease control in barley adopting a two spray programme utilising Delaro at GS32 followed by Aviator Xpro at GS39 will provide excellent control of scald, net blotch and Ramularia leaf spot. Late infections of leaf rust will also be controlled. Click here to see the recommended Bayer spray programme for barley.

Hot off of the press! Aviator Xpro has been granted a shortened withholding period, effective immediately which means it can be applied up to 56 days prior to harvest. This provides far more flexibility and means barley crops that show high yield potential can be protected from Ramularia leaf spot and leaf rust for much longer.

If you would like to receive these updates directly to your inbox, make sure you sign up to receive updates below.

Should you have any questions, feedback or if you have a photo you'd like to submit, please get in touch with me directly or contact your local Bayer Crop Science representative.

For information regarding Bayer fungicides, please contact your local agrochemical supplier, or your local Bayer Crop Science representative.


Kind regards,

Neil Waddingham Customer Marketing – Arable and SeedGrowth

Email: neil.waddingham@bayer.com

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First edition 2016

22 September 2016 - Spring is coming and so is disease

Welcome to the first edition of Disease watch, a season long programme designed to keep you informed and ready to tackle diseases invading arable farms around the country.

Wheat

Wherever the Bayer team is looking at the moment Septoria leaf blotch can be found. This wheat crop at the Aorangi Research Station near Fielding Lower North Island, currently at GS32, is showing significant infection with Septoria leaf blotch (SLB). GS32 is an important time when considering disease control programmes as this growth stage normally coincides with final leaf three emerging.

Wherever the Bayer team is looking at the moment Septoria leaf blotch can be found. This wheat crop at the Aorangi Research Station near Fielding Lower North Island, currently at GS32, is showing significant infection with Septoria leaf blotch (SLB). GS32 is an important time when considering disease control programmes as this growth stage normally coincides with final leaf three emerging.

In situations such as this, adopting a three spray programme utilising Aviator Xpro at GS32 and GS39 followed by Proline + a strobilurin fungicide at GS60-69 will provide excellent control of SLB as well as late infections of leaf rust.

Click here to see the recommended Bayer spray programme for wheat.

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Arable Fungicides Disease Watch Bayer
Low disease pressure - high yield potential with fungicides
As always the Bayer team is finding paddocks which aren’t showing obvious signs of disease at the moment. While it is natural to hope they will stay this way, from a management point of view it doesn’t really matter!

What do we mean by this? Well, in 2015, Bayer conducted three trials in Canterbury, all of which had very low levels of disease and yet all three delivered a profitable yield ($40-200/ha) with a robust, three spray fungicide programme. Click here to find out more about the non-fungicidal physiological benefits of applying fungicides.
Arable Fungicides Disease Watch Bayer

Barley

At this time of year Scald, and to a lesser extent, net blotch are the diseases you would expect to find, along with isolated cases of leaf rust, when you walk your barley paddocks and that is exactly what the Bayer team is finding. Almost without exception crops are infected with scald. Net blotch is also being found and so is leaf rust.

The best approach to control scald is to apply an application of Delaro once your crops reach GS31-32. This should then be followed up 3 - 4 weeks later at GS37-45 with an application of Aviator Xpro.

The Bayer recommended spray programme is available to view here.
Arable Fungicides Disease Watch Bayer

If you would like to receive these updates directly to your inbox, make sure you sign up to receive updates at the bottom of this page.

Should you have any questions, feedback or if you have a photo you'd like to submit, please get in touch with me directly or contact your local Bayer Crop Science representative. For information regarding Bayer fungicides, please contact your local agrochemical supplier, or your local Bayer Crop Science representative.


Kind regards,

Neil Waddingham Customer Marketing – Arable and SeedGrowth

Email: neil.waddingham@bayer.com