.

[1] Net blotch, barley - Australia (South Australia)
[2] Septoria, wheat - United Kingdom
[3] Anthracnose and holcus spot, maize - USA (Iowa)

[1] Net blotch, barley - Australia (South Australia)
Date: Thu 3 Jul 2008
Source: ABC News (Australian Broadcasting Corporation) Rural News [edited] <http://www.abc.net.au/rural/news/content/200807/s2293187.htm>

Disease hits SA barley crops

South Australian (SA) grain growers fear a wipeout from a fungal disease that takes hold of barley crops. The South Australian Research and Development Institute says the disease, called net blotch, could cut crops yields by a third.

Farmer Brian Tiller, from the state's mid-north, says the only weapon against it is monthly spraying, a costly exercise when returns aren't guaranteed. "I've already sprayed 500 acres (202 ha) and I'm just looking whether I am going to spray more," he says. "As long as you're going to get a yield at the end of the day it's all right, but if you're going to put it on and don't end up getting the rain to get the costs at the end, I'm not sure where you draw the line."

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[2] Septoria, wheat - United Kingdom
Date: Tue 1 Jul 2008
Source: Farmers Weekly Interactive [edited]
<http://www.fwi.co.uk/Articles/2008/07/01/107733/crop-watch-west-neil-potts-looks-to-next-years-harvest.html>

_Septoria tritici_ has proved extremely challenging this year [2008] with many crops carrying higher levels of the disease than might have been expected given the level of [fungicide] input applied. The trend emerging is that early-drilled crops with a septoria rating of 5 or less are a lot dirtier [carrying more disease] than the same varieties drilled later or varieties with a better resistance score drilled at the same time.

This is perhaps not altogether unexpected, but the differences are more marked than usual, so one could be forgiven for questioning the curative activity of some materials applied at T2 [growth stage]. For 2009, disease resistance will more than ever figure as a key consideration in varietal choice, particularly for the September drillings.

[Byline: Neil Potts]

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[3] Anthracnose and holcus spot, maize - USA (Iowa)
Date: Thu 3 Jul 2008
Source: Ottumwa Courier [edited]
<http://www.ottumwa.com/local/local_story_185230531.html>

Area farmers brace for lackluster year

Farmers are facing more concerns than just wet weather. Iowa State University Extension Southeast Iowa field specialist Mark Carlton said 2 crop diseases have been discovered in some area fields -- anthracnose and holcus spot. "These are mainly on corn crops," he said.

Anthracnose is a fungus that survives on crop residue. Add in high humidity levels and rainfall, the fungus will spread, eventually knocking the lower three or four leaves off the corn plants. "It could lead to stock rot later on in the summer or fall ... it can be a serious problem," Carlton said. "We would have a small to moderate yield loss if severe."

The other disease -- holcus spot -- is caused by a bacterium that also thrives in corn residue and splashes up on the leaves.

And there's also worry about pests.

[Byline: Scott Niles]

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[Net blotch of barley is caused by the fungus _Pyrenophora teres_ and affects only domestic and wild barleys (_Hordeum_ spp.). The disease causes necrotic areas on leaves leading to significant losses of up to 20 percent to barley yield around the world. There are 2 types of this fungus: the net type caused by _P. t._ f. _teres_, and the spot type caused by _P. t._ f. _maculata_. The fungus survives between seasons on barley residue, volunteer barley plants, some grasses, and seed. Disease management includes cultural practices to remove pathogen reservoirs, fungicide applications, use of clean seed, and planting of resistant cultivars.

Cereal diseases of the septoria complex are caused by the fungi _Mycosphaerella graminicola_ (previously _Septoria tritici_) and _Phaeosphaeria nodorum_. These pathogens cause blotches on both leaves and glumes reducing the photosynthetic ability of the host and causing yield losses.

Anthracnose leaf blight and anthracnose stalk rot of maize are caused by the fungi _Colletotrichum graminicola_ and _Glomerella tucumanensis_. _G. tucumanensis_ also causes red rot of sugarcane.

Holcus spot of maize is caused by the bacterium _Pseudomonas syringae_ pv. _syringae_ . This pathogen also causes diseases of, for example, tomato, citrus, mango, and apricot. Other pathovars also exist which can affect different hosts.

For further information on the diseases mentioned please see links and previous ProMED-mail posts listed below.

Maps
Australia:
<http://www.ga.gov.au/image_cache/GA4073.jpg>
and <http://healthmap.org/promed?v=-25.7,134.5,4>
South Australia:
<http://www.ozhorizons.com.au/sa/map.htm>
UK:
<http://www.lib.utexas.edu/maps/europe/united_kingdom.gif>
and <http://healthmap.org/promed?v=54.5,-2,5>
USA:
<http://www.mapsofworld.com/usa/usa-road-map-enlarge-view.html>
and <http://healthmap.org/promed?v=40,-97.6,4>
Iowa:
<http://www.mapsofworld.com/usa/states/iowa/iowa-map.html>

Pictures
Net blotch on barley:
<http://plantpathology.tamu.edu/Texlab/Grains/Barley/Images/barley1.jpeg>  and <http://www.inra.fr/hyp3/images/6034311.jpg>
Net blotch, spot form:
<http://www.dpi.qld.gov.au/images/Biosecurity_GeneralPlantHealthPestsDiseaseAndWeeds/Barley-SpotForm-OfNetBlotch-168.jpg>  
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)
Anthracnose leaf blight, maize:
<http://cril.cimmyt.org/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=409&g2_serialNumber=2> 
Anthracnose stalk rot, maize:
<http://cril.cimmyt.org/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=481&g2_serialNumber=2>
Holcus spot on maize:
<http://www.lgseeds.com/lg_tech2/images/holcusspot.gif>

Links
Information on net blotch of barley:
<http://www.inra.fr/hyp3/pathogene/6pyrter.htm>,
<http://www.sac.ac.uk/consultancy/cropclinic/clinic/diseases/netblotch> and <http://www.ipm.ucdavis.edu/PMG/r730100311.html>
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 maize anthracnoses:
<http://ohioline.osu.edu/ac-fact/0022.html> and <http://nudistance.unl.edu/homer/disease/agron/corn/CoAnthrac.html>
Information on holcus spot of maize:
<http://www.lgseeds.com/lg_tech2/holcusspot.asp>
Taxonomy of all fungal pathogens via:
<http://www.indexfungorum.org/Names/Names.asp>
Taxonomy of bacterial pathogens via:
<http://www.bacterio.cict.fr/search.html>
Growth stages of cereals:
<http://www.grdc.com.au/GRDC/ResearchSummaries/CMAttachments/cropmonitoringv2.pdf>.
Mod.DHA]

[see also in the archive:
Fungal diseases, cereals - UK, Ireland: update 20080428.1460 Bacterial diseases, tomato - Europe 20080227.0789 Red rot, sugarcane - India: (Orissa) 20080201.0401
2005
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Leaf rust, Septoria spp., wheat - Kazakhstan: corr. 20050825.2509 Leaf rust, Septoria spp., wheat - Kazakhstan 20050823.2488
2004
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Barley net blotch, spot type - Uruguay: 1st report 20041130.3198 Citrus blast disease - Turkey: 1st report 20041113.3073

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