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<http://www.promedmail.org>
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International Society for Infectious Diseases <http://www.isid.org>

[1] Iowa
Date: Fri 29 Aug 2008
Source: Agriculture Online [edited]
<http://www.agriculture.com/ag/story.jhtml?storyid=/templatedata/ag/story/data/1220034624847.xml>

Sudden death syndrome (SDS) has infected Iowa soybean fields and is quickly robbing producers of profit potential, according to a report from the Iowa Soybean Association (ISA).

SDS, though not a new pest to Iowa, is expanding into areas where it has never been seen before. This year [2008] it seems to be appearing in fields planted through late May, crop-watchers say. The disease tends to be most severe on well-managed soybeans with high yield potential. It can also be found in fields known to be infested with the soybean cyst nematode (SCN); research has shown that SCN cysts can carry the SDS pathogen.

Sudden death syndrome is caused by a fungal pathogen that enters the root within 4 days of germination. It is believed the pathogen remains in the root and crown area until the soybean plant enters the reproductive stage when it releases a toxin that moves throughout the plant, quickly killing the leaf tissue. Management options include planting varieties highly resistant to SCN and with greater resistance to SDS. The disease cannot be managed with fungicides.

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[2] Minnesota
Date: Tue 26 Aug 2008
Source: Agri News [edited]
<http://webstar.postbulletin.com/agrinews/292550132887837.bsp>

Sudden death syndrome has been found in Minnesota soybean fields and farmers are asked to submit suspicious plants to the University of Minnesota for testing. SDS began showing up in southern Minnesota fields 3 weeks ago. It has been confirmed in fields near Waseca, Mankato, New Ulm, and Lamberton so far this season [2008].

SDS typically appears when pods start filling, extension plant pathologist specialist Dean Malvick said. He said the disease will probably show up in fields for the next week or so. The odds of it appearing in the areas of central Minnesota where it has been dry are pretty low. Malvick suspects the disease may be more widespread. He needs help from producers to determine the disease's spread throughout the state.

SDS is found in the soil and it moves in much the same way as soybean cyst nematode. Farmers should clean their equipment between fields to avoid spreading the disease. Yield losses associated with SDS vary, but can be significant, Malvick said. Unfortunately, there's not much farmers can do at this point in the season to protect yield.

[Byline: Janet Kubat Willette]

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[The fungus _Fusarium virguliforme_ has been described as the causal pathogen of SDS in North America and _F. tucumaniae_ in South America. Any stress factor, but in particular soybean cyst nematode (SCN; _Heterodera glycines_), is reported to exacerbate symptoms.
Yield losses may be more than 80 percent, depending on variety and timing of infection. For more information on SDS please see previous ProMED-mail report no. 20070904.2909 and links below.

Map of US states:
<http://www.census.gov/geo/www/us_regdiv.pdf>

Pictures
Photo collection of SDS symptoms:
<http://www.ent.iastate.edu/imagegal/plantpath/soybean/sds/>
_H. glycines_:
<http://www.apsnet.org/online/feature/microbe/image/scn2.jpg>

Links
Information on SDS:
<http://www.ces.ncsu.edu/depts/pp/notes/Soybean/soy007/soy007.htm>,
<http://www.ces.purdue.edu/extmedia/BP/BP-58-W.pdf>,
<http://ohioline.osu.edu/ac-fact/0044.html>, 
and <http://www.ca.uky.edu/agc/pubs/ppa/ppa37/ppa37.htm>
Publication on taxonomy of SDS causal pathogens:
<http://www.mycologia.org/cgi/content/full/95/4/660>
_F. virguliforme_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=489315>
_F. tucumaniae_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=489463>
Information on soybean cyst nematode:
<http://www.soybeans.umn.edu/pdfs/DC3935.pdf>. - Mod.DHA]