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International Society for Infectious Diseases <http://www.isid.org>
[1]
Date: Thu 24 Apr 2008
Source: Farmers Weekly Interactive [edited]
<http://www.fwi.co.uk/Articles/2008/04/24/110263/tag-weekly-cereals-2008-trials-diary.html>
The cool and showery conditions seen in Lincolnshire during
April [2008] have encouraged the development of _Septoria
tritici_ in 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.
To date, brown rust has shown few signs of appearing, while a
series of recent frosts has continued to suppress mildew.
Meanwhile, Robigus [variety] was displaying yellow rust at a
cereals [experimental] site in early April [2008], albeit later
than some commercial crops in the area which saw yellow rust
develop during March [2008].
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.
Few other diseases have featured so far [in wheat crops].
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.
[Byline: Paul Spackman]
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[2]
Date: Fri 25 Apr 2008
Source: Farmers Guardian, ADAS report [edited]
<http://www.farmersguardian.com/story.asp?sectioncode=20&storycode=17961>
Winter wheat -- yellow rust is sporulating actively on untreated
Robigus in the east. New lesions of _Septoria tritici_ are
developing on leaf 3 of more susceptible varieties. Brown rust
remains at low levels in Alchemy and other susceptible varieties
and is mainly on leaf 3.
Eyespot is being reported very widely in wheats. There are some
very severe lesions causing damage to the lowest green leaves on
some tillers. Fusarium is causing browning of leaf sheaths and
some sharp eyespot is present.
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[3]
Date: Tue 22 Apr 2008
Source: Farmers Weekly Interactive [edited]
<http://www.fwi.co.uk/Articles/2008/04/22/110239/crop-watch-t1-fungicides-going-on-in-the-south-as-t0-delays-continue.html>
On the Wiltshire/ Dorset border, Dan Dines said the 1st T1
sprays had gone on. "Septoria is the main disease threat in
wheat. Both yellow and brown rust are notable by their absence
thus far. Eyespot is present in some fields, and mildew can be
found in a small number of crops. Fungicide treatments should be
based on diseases present/disease risk."
Lincolnshire-based Ruth East said crop growth had also been
slowed due to cold weather, but there was plenty of disease
about that would need treating. "_Septoria tritici_ is abundant
on the lower leaves of susceptible varieties, a well timed,
robust T1 [fungicide] will be needed to control it, because if
temperatures increase the disease
will take off."
But further north in Northumberland, frustration was growing as
showery weather continued to disrupt planned spraying
programmes. Robert Sullivan said, "Disease levels in general are
low in the crops, with septoria being really the only disease
apparent, although there are signs of eyespot on some crops."
[Byline: Paul Spackman]
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[4]
Date: Tue 22 Apr 2008
Source: The Irish Independent [edited]
<http://www.independent.ie/farming/time-to-apply-the-t1-to-winter-wheat-1354804.html>
During my tour around the country [Ireland] last week [14-20 Apr
2008], what struck me was a general lack of septoria lesions on
the upper leaves of wheat. The only wheat variety, which has
plenty of disease was Consort. However, don't be fooled into
thinking that there is no disease in cleaner varieties, as
normally there is plenty of septoria at the base of the crop
just waiting for its chance to spread upwards.
Mildew was absent and I failed to spot a crop with any level of
the disease. However, I did spot eyespot on my travels and, if
it is present on a crop, then it should be addressed with the T1
fungicide. There are many fungicide options available at T1 that
can be used effectively and represent value for money.
Wheats in a rotational position that are susceptible to Take-all
(2nd wheats after a break crop, or 3rd wheats after ley) may
require attention now.
[Byline: Michael Hennessy]
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[Cereal diseases of the septoria complex are appearing in both
the UK and Ireland. They can be caused by the fungi
_Mycosphaerella graminicola_ (previously _Septoria tritici_) and
_Phaeosphaeria nodorum_. These pathogens cause blotches on both
leaves and glumes.
Eyespot (also called strawbreaker) caused by the fungus
_Oculimacula yallundae_ is also being reported from both the UK
and Ireland. Sharp eyespot caused by the soil-borne fungus
_Ceratobasidium cereale_ appears to be emerging in the UK only.
Take-all is reported to appear in Ireland. It is a fungal
disease causing severe yield loss of up to 50 percent in cereal
crops. _Gaeumannomyces graminis_ var. _tritici_ causes the
disease in wheat and barley; other pathovars affect different
cereal and grass hosts.
Several fungal species originally classed into the genus
_Fusarium_ can cause blight diseases on cereals. They are still
commonly referred to as fusarium although some of the pathogens
have since been re-assigned to different genera. Leaf rust, also
called brown rust, on wheat is caused by the fungus _Puccinia
recondita_, and
stripe (yellow) rust is caused by _P. striiformis_ var.
_striiformis_. Both these rusts affect leaves reducing the
photosynthetic potential of the plant. Powdery mildew of wheat
is caused by _Blumeria graminis_ and affects all aerial parts of
the host.
For further information on the diseases mentioned please see
links and previous ProMED-mail posts listed below.
Cereal disease management can be applied at key decision times
(T0, T1, T2, and T3) to reflect the changing risk as the season
unfolds. T reflects the growth stages referring to tillers
present at a particular time: T0 refers to the coleoptile
tiller, T1 to the tiller developing from the 1st leaf, etc.
Continuous monitoring, as reflected in the reports above, and
early discovery of infection at any stage of the crop cycle is
important so action can be taken to limit the spread of the
pathogen as well as build-up of inoculum.
Maps
UK:
<http://www.lib.utexas.edu/maps/europe/united_kingdom.gif>
and
<http://healthmap.org/promed?v=54.5,-2,5>
Ireland:
<http://www.fishing-ireland.de/karte.html>
and
<http://healthmap.org/promed?v=53.2,-8.2,5>
Pictures
Septoria diseases of wheat:
<http://www.omafra.gov.on.ca/french/crops/facts/90-008f3.jpg>
(leaf) and
<http://www.omafra.gov.on.ca/english/crops/pub811/images/6septf2.jpg>
(ear)
Wheat leaf rust:
<http://www.hgca.com/hgca/wde/IMAGES/brown%20rust1.JPG>
Wheat stripe rust:
<http://www.ars.usda.gov/Main/docs.htm?docid=9918&pf=1&cg_id=0>
and
<http://utextension.tennessee.edu/fieldCrops/wheat/Wheat_photos/Wheat_StripeRust.jpg>
Sharp eyespot on wheat leaves:
<http://scarab.msu.montana.edu/Disease/DiseaseGuidehtml/Img0079.jpg>
Take-all root symptoms on wheat:
<http://www.plantmanagementnetwork.org/php/elements/view.asp?ID=1>
Field with take-all patch:
<http://www.plantmanagementnetwork.org/php/elements/view.asp?ID=223>
Links
Septoria, leaf rust, powdery mildew and other diseases of wheat:
<http://www.aces.edu/pubs/docs/A/ANR-0543/>
Information on septoria diseases:
<http://ipm.ppws.vt.edu/stromberg/smallgrain/biology/wgblotch.html>
and
<http://www.cimmyt.org/Research/Wheat/pdf/septoria_ago99.pdf>
Information on wheat leaf rust:
<http://plant-disease.ippc.orst.edu/disease.cfm?RecordID=1138>
Information on wheat stripe rust:
<http://www.ars.usda.gov/Main/docs.htm?docid=9918&pf=1&cg_id=0>
and
<http://www.oznet.k-state.edu/path-ext/factSheets/Wheat/Wheat%20Stripe%20Rust.asp>
Information on wheat powdery mildew:
<http://ohioline.osu.edu/ac-fact/0010.html>
and
<http://www.hgca.com/hgca/wde/diseases/Mildew/Milhost.html>
Information on sharp eyespot:
<http://ohioline.osu.edu/ac-fact/0011.html>
and
<http://www.hgca.com/hgca/wde/diseases/Sharp%20Eye/Sharhost.html>
Information on take-all:
<http://www.plantmanagementnetwork.org/pub/php/diagnosticguide/take-all/>
and
<http://www.takeall.com/english/default.htm#options>
Taxonomy of all fungal pathogens via:
<http://www.indexfungorum.org/Names/Names.asp>
List of wheat diseases and pathogens:
<http://www.apsnet.org/online/common/names/wheat.asp>
Growth stages of cereals:
<http://www.grdc.com.au/GRDC/ResearchSummaries/CMAttachments/cropmonitoringv2.pdf>.
- Mod.DHA]
[see also in
the
archive:
Fungal diseases, wheat - Canada, USA 20080427.1454
Wheat stripe rust, oilseed rape sclerotinia - China
20080408.1297
Sharp eyespot, wheat - China 20080325.1119
Fungal pathogens, wheat - UK (England) 20080319.1055
Stripe rust, wheat - Denmark: new strains 20080211.0542
2007
----
Seedling blight, cereals - UK 20071130.3860
Stripe rust, wheat - Australia (SA): new strain 20070921.3135
Fungal head blights, wheat - UK 20070816.2674
Take-all, cereal crops - UK 20070808.2578
Fungal pathogens, wheat - United Kingdom: new races
20070523.1652
Rust diseases, bean & wheat - UK: alert 20070512.1515
2006
----
Cereal diseases, fungal - Russia, Kazakhstan 20060816.2298
Leaf rust, wheat - Russia (Irkutsk) 20060815.2287
2005
----
Leaf rust, wheat, resistance change - India 20051201.3462
Leaf rust, Septoria spp., wheat - Kazakhstan: corr.
20050825.2509
Leaf rust, Septoria spp., wheat - Kazakhstan 20050823.2488
2000
----
Take-all disease, wheat - Australia (02) 20001021.1822
Take-all disease, wheat - Australia 20001017.1779]