Major seed-borne diseases of wheat in Northern Europe: impact … · 2015-07-09 · vHigh risk (high certainty of loss); vmedium risk (authorisations could be lost, but there is some

SASA © Crown Copyright

Major seed-borne diseases of wheat in Northern

Europe: impact and control

Valerie Cockerell, Official Seed Testing Station, Scotland

ISTA Seminar 2015, Montevideo, Uruguay


Outline


Northern Europe


0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

1000

hec

tare

s

United Kingdom

Sweden

Norway

Lithuania

Latvia

Ireland

Finland

Estonia

Denmark

Wheat Area In Northern Europe


Seed-borne diseases: Seedling blight v Microdochium majus/M. nivale

v Stagonospora nodorum

v Fusarium spp. (Fusarium graminearum)


Microdochium majus/nivale

Cabi Crop Compendium,2015


Microdochium spp Microdochium nivale

Microdochium majus


Stagonspora nodorum


Fusarium graminearum


Seed-borne diseases: Tilletia spp.

Tilletia contraversa Tilletia tritici (syn. caries)


Why these seed-borne diseases?

Thick fur to protect it from the cold temperatures


Impact

v Tilletia spp

– Up to 50% yield losses recorded

– 100% grain rejected for human consumption

– Quarantine issue (T. contraversa)

v Seedling diseases

– Seedlings do not emerge or die back

– Reduced yield due to lower plant stand up to 40% losses recorded

– Re-sowing required


Microdochium and S. nodorum incidence in wheat seed samples, OSTS Scotland, harvest years 2013 & 2014

0

10

20

30

40

50

60

70

80

90

100

Incidence Less than10%

More than10%

More than50%

Incidence Less than10%

More than10%

More than50%

Microdochium 2013 Microdochium 2014

Staganospora nodorum 2013 Staganospora nodorum 2014


Tilletia incidence

v In seed for advisory testing to OSTS Scotland

2013

23% contaminated

21% less than one spore per seed

2% greater than 1 spore per seed

2014

13% contaminated

11% less than one spore per seed

2% greater than 1 spore per seed


Tilletia spp incidence (2)

v Only tested for in certified seed if organic. Convential seed treated with fungicides as routine during multiplication

v Sweden all certified seed tested rarely a problem although

T. contraversa found in 5-6 field inspections 2011/12

v Norway rarely a problem, even with only 50% of seed treated


Management: Seed testing


Microdochium & S. nodorum methods Agar Plate Assay Quantitative/Qualitative Real-

time PCR

Paper method (total Fusarium/Microdochium and Staganospora nodorum)


Tilletia spp. methods Filter Method Quantitative/Qualitative Real-

time PCR

Centrifugation Method


Tilletia spp. standards

Country Standard/Seed treatment threshold

Statutory/Advisory

Denmark 10 spores/g statutory

Norway 1 spore detected advisory

Sweden 1 spore detected statutory

UK 1 spore per seed advisory


Seedling blight standards Country Standard/Seed treatment

threshold Statutory/Advisory

Denmark 15% (30% spring)( total) statutory

Norway 15% (5% S. nodorum) advisory

Sweden 30% (total) statutory

UK 10% (total advisory


Fungicide Seed Treatments Available 2015 UK

Product Active Ingredients Bunt Tilletia caries

Soil-borne bunt Tilletia caries

Microdochium seedling blight

Fusarium seedling blight: F. graminearum

Septoria seedling blight Phaeosphaeria nodorum

Carboxin/thiram J L J L J Clothiadin1/prothioconazole J J J J L Difenconazole/fludioxonil J J J J L Fludioxonil J J J J L Fludioxonil/flutriafol J J J J L Fludioxonil/tefluthrin1 J J J J J Fluquinconazole J L L L L Fluquinconazole/prochloraz J J L J L Ipconazole J J J J L Ipconazole/imazalil J J J J L Prothioconazole J J J J L Prochloraz/triticonazole J J J L J Silthiofam L L L L L


Five most popular products Product Active Ingredients UK 2010 Scotland

2010 UK 2012 Scotland

2012 Carboxin/thiram Clothiadin1/prothioconazole 22% 30% 13% Difenconazole/fludioxonil Fludioxonil 9% 8% 7% Fludioxonil/flutriafol Fludioxonil/tefluthrin1 Fluquinconazole Fluquinconazole/prochloraz 9% 9% Ipconazole Ipconazole/imazalil Prothioconazole 24% 13% 25% 19% Prochloraz/triticonazole 13% 45% 14% 42% Silthiofam 12% 12% Fluoxastrobin/prothioconazole 8% 6% Untreated 4% 4% 2% 3% Total hectares treated 96% 96% 98% 97%

1Insecticide Source: Pesticide Usage Survey Report Arable Crops in the UK 2010 & 2012; Pesticide Usage in Scotland Arable Crops and potato stores 2010 & 2012.


Future of Seed Treatment Fungicides v EC 1107/2009

Introduced hazard criteria to the evaluation process, if a pesticide fulfils these it is precludes their approval

– Mutagenic

– Carcinogenic or have Reproductive Toxicity (unless the exposure is ‘negligible’)

– Endocrine Disruptors which cause adverse effects (see below for more details)

– Persistent Organic Pollutants (PoPs)

– Persistent Bio-accumulative and Toxic (PBT)

– Very Persistent / very Bio-accumulative (vPvB)


Future of Seed Treatment Fungicides (2)

Fungicides fall in to three categories:

v High risk (high certainty of loss);

v medium risk (authorisations could be lost, but there is some uncertainty on this, or the disappearance may be over the longer-term

Although highest risk fungicides (epiconazole, carbendazim, tebuconazole) do not include any wheat seed treatment actives, they increase the risk to FHB control by reducing the number of options and increasing the risk of resistance


Fungicide Seed Treatments: medium risk Product Active Ingredients Bunt

Tilletia caries

Soil-borne bunt Tilletia caries

Microdochium seedling blight

Fusarium seedling blight: F. graminearum

Septoria seedling blight Phaeosphaeria nodorum

Carboxin/thiram J L J L J Clothiadin1/prothioconazole J J J J L Difenconazole/fludioxonil J J J J L Fludioxonil J J J J L Fludioxonil/flutriafol J J J J L Fludioxonil/tefluthrin1 J J J J J Fluquinconazole J L L L L Fluquinconazole/prochloraz J J L J L Ipconazole J J J J L Ipconazole/imazalil J J J J L Prothioconazole J J J J L Prochloraz/triticonazole J J J L J Silthiofam L L L L L

All depend on the EU definition of an endocrine disruptor (thiram, prochloraz, fluquinconazole, prothioconazole and triadimenol).


Five most popular products Product Active Ingredients UK 2010 Scotland

2010 UK 2012 Scotland

2012 Carboxin/thiram Clothiadin1/prothioconazole 22% 30% 13% Difenconazole/fludioxonil Fludioxonil 9% 8% 7% Fludioxonil/flutriafol Fludioxonil/tefluthrin1 Fluquinconazole Fluquinconazole/prochloraz 9% 9% Ipconazole Ipconazole/imazalil Prothioconazole 24% 13% 25% 19% Prochloraz/triticonazole 13% 45% 14% 42% Silthiofam 12% 12% Fluoxastrobin/prothioconazole 8% 6% Untreated 4% 4% 2% 3% Total hectares treated 96% 96% 98% 97%

1Insecticide Source: Pesticide Usage Survey Report Arable Crops in the UK 2010 & 2012; Pesticide Usage in Scotland Arable Crops and potato stores 2010 & 2012.


Variety Choice

v Seed-borne Microdochium, Septoria and Fusarium

– Limited to none

v Tilletia caries

Resistant varieties exist but most varieties are susceptible

At least 15 specific resistant genes (Bt) exist against common bunt.

Many virulence race types exist


Anders Bogens, Virulence pattern in Danish races of common bunt (Tilletia caries), 7th ISTA Seed Health Symposium v Using spores from the same variety in field trials express the

risk and rate of epidemic development.

v Virulence in Denmark was found against Bt-1, Bt-2, Bt-3, Bt-4

Bt-5, Bt-7, Bt-8, Bt-10 and Bt-13, but not against Bt-6, Bt-9, Bt-

11 and Bt-12. Using bulk spores in the field trial would only

have identified virulence against Bt-1, Bt-3 and Bt-4.

v Using varieties with different reactions to different bunt

virulence races in a crop rotation will minimise the risk of

disease establishment.


Summary

v Major seed-borne diseases are adequately controlled through chemical or heat treatment

v Seed testing provides information to allow appropriate choice of fungicides

v Wheat is at risk from changes to EU legislation that may lead to a ban of some seed treatment chemicals – leading to a higher risk of resistance to existing chemicals

v Suitable varietal resistance for seed-borne diseases is many years away

v Managing disease through seed testing could. become more important as well as new ways of managing in the field for example Tilletia


Thank you for listening Special thanks to: Marian McNeil Guro Brodal Karin Sperlingson Gillian McLaren

1914-2014


Documents

Major seed-borne diseases of wheat in Northern Europe: impact … · 2015-07-09 · vHigh risk (high certainty of loss); vmedium risk (authorisations could be lost, but there is some