A ProMED-mail post
ProMED-mail is a program of the
Date: 15 Dec 2009
Source: Alberta Farmer Express [edited]
Manitoba's sunflower crop turned out relatively poor this year [2009], as growing conditions led to low yields and caused disease problems in some areas.
Oilseed sunflowers in the Red River Valley and east turned out very poor, with low yields and a lot of head rot and sclerotia, due to excessive moisture, said Earl Schnellert of Agri-Tel Grain. Farther west, the fields fared a little better. Confectionary seed had the same problem, with poor crops in the central and eastern growing regions and better quality farther west, he said.
Some sunflowers are still standing and will be harvested through the winter. While crops did not turn out well overall, the demand is still good said Schnellert. He didn't think the poor season would turn farmers off from planting the crop next spring [2010], with those growers who have sunflowers as a regular part of their rotation keeping them there.
Statistics Canada has pegged Manitoba's 2009-10 sunflower crop at 101 900 tonnes, which would compare with 112 200 the previous year. The tighter supplies will likely cause some processors to bring up more US sunflower seed in order to meet their commitments.
[Byline: P. Franz-Warkentin]
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Communicated by:
[The problem referred to above is most likely the fungus _Sclerotinia sclerotiorum_, although the related species _S. minor_ has been reported to cause similar symptoms on sunflower. The pathogen causes
3 of the most important diseases of sunflower: wilt, middle stalk rot, and head rot. Sclerotinia wilt is caused by sclerotia infecting the roots; it is the most serious of the diseases and can destroy whole sunflower fields. Head rot and middle stalk rot are caused by airborne spores and are above ground diseases; they are usually associated with wet weather periods. The presence of sclerotia (fungal survival structures) in seed can reduce the grade and market value of the crop.
_S. sclerotiorum_, also called white mould, is one of the most nonspecific and successful of plant pathogens, with around 400 known hosts worldwide. The fungus is primarily soilborne and has a complex disease cycle. It can survive in soil as sclerotia and is also spread by infected plant material, mechanical means, and wind-borne spores.
Risk of crop infection depends on the previous disease history of an area as well as weather conditions. Disease management includes cultural practices (such as long term crop rotation with non-hosts and deep ploughing to minimise inoculum) and fungicide applications.
However, fungicides may not be very effective against soilborne fungal pathogens.
In Manitoba, a previous outbreak of sclerotinia on sunflower in 2008 (ProMED-mail post 20081106.3490) may have resulted in increased amounts of available aerial inoculum. Together with humid conditions, this would have favoured the development of head rot in the current sunflower crops.
Maps
Canada:
Manitoba:
Pictures
Sclerotinia wilt on sunflower:
Head rot:
Middle stalk rot:
Sunflower seed contaminated with sclerotia:
Links
Sclerotinia diseases on sunflower:
Sunflower diseases, including sclerotinia:
Information on _S. sclerotiorum_:
_S. sclerotiorum_ taxonomy:
_S. minor_ taxonomy:
- Mod.DHA]
[see also:
Sclerotinia, oilseed rape - Australia: (WA) 20091126.4062 White mould, soybean - USA 20091008.3481 Fungal diseases, soybean - USA 20090817.2912
2008
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Vegetable diseases - UK 20081225.4066
Sclerotinia, sunflower - Canada: (MB) 20081106.3490 Sclerotinia, multicrop - UK 20081008.3187 Fungal diseases, wheat, oilseed rape - UK 20080930.3083 Verticillium wilt & sclerotinia, oilseed rape - UK 20080718.2180 Wheat stripe rust, oilseed rape sclerotinia - China 20080408.1297 Fungal diseases, potato - Bangladesh 20080107.0091
2004
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Sclerotinia blight, peanut - USA (TX) 20041001.2702
2003
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Sclerotinia minor, chickpea - Australia (Qld) 20030625.1565
2002
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Sclerotinia spp., sunflower wilt - Spain 20020706.4677
2001
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Sclerotinia shoot blight, grapevine - Chile 20011103.2724
1999
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Crop diseases - Canada (Manitoba) 19990816.1417]
Topics
Species
