A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>

Date: September 2008
Source: ProMED-mail Rapporteur Susan Baekeland <grolleyog@tele2.fr>

There is quite a bit of smut in maize fields. It looks like a type of smut to me; it is called "Charbon" by locals. A farmer said that only certain varieties of maize are susceptible to this fungus disease and that they have not had an outbreak here in this area for several years. He does not think it is toxic for cattle.

I saw something very similar in Kenya, and also here. The fungus is at the bottom of the flower that is at the top of the maize plant. It is at the leaf junctions on the flower stem above the cobs, which do not seem to be affected. It is either head smut or boil smut.

--
Susan Baekeland
ProMED-mail Rapporteur
Normandy, France
<grolleyog@tele2.fr>

[Smuts are a group of fungi causing symptoms of spore-filled galls on a number of cereal hosts. They usually attack the plant's reproductive components rather than the leaves or stems.

Boil smut of maize is caused by _Ustilago saydis_ and attacks any above-ground growing part of the plant to form blisters or galls containing black spores. Mature galls can grow as large as 20 cm in diameter. The yield of affected cobs is very low, and they may be toxic to livestock but are eaten by people in South America as a delicacy. Spores can be spread by wind, seed, clothes or farm machinery and can survive in the soil for many years. Disease management includes plant hygiene measures and seed treatment with fungicides. For more information on boil smut, see recent ProMED-mail post no. 20080909.2817.

Head smut caused by _Sphacelotheca reiliana_ can affect both maize and sorghum. In maize, it infects the young seedling then grows through the plant, replacing reproductive tissues (ears and/or tassels) with masses of spores. Distortion is common, and leafy structures may replace the plant's flowering components (phyllody). The fungus survives in the soil and may also be seed-borne. Cool weather and dry seedbed conditions favour this disease. Disease management includes cultural techniques and the use of clean seed and resistant varieties.

Maps
France:
<http://worldatlas.com/webimage/countrys/europe/lgcolor/frcolor.htm>
Departments of France:
<http://bonjourlafrance.net/france-map/map-of-france-departments-2.htm>
Normandy:
<http://www.discover-normandy.info/pics/normandy_map.gif>

Pictures
Boil smut symptoms on maize:
<http://plantclinic.cornell.edu/FactSheets/corn%20smut/fruit.htm>  (ear),
<http://plantclinic.cornell.edu/FactSheets/corn%20smut/flower.htm>  (flower),
<http://www.inra.fr/hyp3/images/6037071.jpg>  (stem), and
<http://www.inra.fr/hyp3/images/6037073.jpg>  (leaf)
Head smut symptoms on maize:
<http://www.dpi.qld.gov.au/images/Biosecurity_GeneralPlantHealthPestsDiseaseAndWeeds/Maize-HeadSmut-350.jpg> 
(flowers),
<http://www.inra.fr/hyp3/images/6036192.jpg>  (ear) and
<http://cril.cimmyt.org/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=658&g2_serialNumber=2> 
(leaf)

Links
Boil smut information:
<http://plantclinic.cornell.edu/FactSheets/corn%20smut/smut.htm>,
<http://www.inra.fr/hyp3/pathogene/6ustmay.htm>,  and
<http://www.ext.vt.edu/pubs/plantdiseasefs/450-706/450-706.html>
Head smut information:
<http://www.inra.fr/hyp3/pathogene/6sphrei.htm>
Head smut management:
<http://cat.inist.fr/?aModele=afficheN&cpsidt=2781661>  and
<http://www.cimmyt.org/english/docs/proceedings/africa/pdf/24_Njuguna.pdf>
Information on both smuts:
<http://www.dpi.qld.gov.au/cps/rde/dpi/hs.xsl/26_4718_ENA_HTML.htm>
_U. maydis_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=169566>
_S. reiliana_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=195976>
- Mod.DHA]