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November 13, 2007
Source: The Irish Independent [edited]
<http://www.independent.ie/farming/maize-harvest-hit-by-eyespot-disease-and-poor-pollination-1217664.html>

Poor pollination and disease problems have hit maize yields in the south and east. As a result, it has been an average rather than a bumper harvest. Despite farmers and contractors enjoying excellent harvesting conditions, the early indications are that crop yields are not as strong as expected.

Tim O'Donovan of Teagasc [Irish Agriculture and Food Development Authority], Moorepark, explained that some crops in the south and east had been badly hit by the poor weather during pollination, while eyespot had infected crops in coastal areas. However, Mr O'Donovan claimed that the feeding value of these crops may not be
significantly reduced. He pointed out that the crops had high sugar levels and that this would be retained in the feed where the maize was harvested later than normal and run-off reduced. The vast majority of the crop has been cut in the south, while 10-15 percent remains to be harvested in the northeast.

[Byline: Declan O'Brien]

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ProMED-mail
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[Eyespot on maize is caused by the fungus _Kabatiella zeae_ (synonym _Aureobasidium zeae_), which was first described from Japan in 1959. It has also been reported from Europe, North America, Argentina, and New Zealand. Leaf symptoms are lesions with a light coloured centre and a brown margin surrounded by a yellowish halo giving the characteristic 'eyespot' appearance. The pathogen causes early drying out of the leaves and leads to considerable destruction of photosynthetic leaf area resulting in yield reduction. The disease may develop on sheaths and outer husks, but lesions are more concentrated on leaves approaching maturity. The fungus can cause severe shrivelling of the ears. In extremely infected plants, kernel infections may also develop. Severe disease will commonly predispose the host plant to stalk rots. Eyespot lesions may be confused with genetic spotting common in many inbred maize lines.

Host susceptibility is highest at 10-12 deg C (50-53.6 deg F), therefore eyespot mostly spreads during the cold rainy seasons. The fungus is specific to maize and can overwinter in plant debris. Spores are dispersed by rain and wind, and the disease may be carried over in stubbles from the previous years maize crop. Disease management includes deep ploughing, which causes plant debris to decompose, crop rotation, and fungicide treatments. Hybrid maize lines with reduced susceptibility are available.

The name 'eyespot' is descriptive of the symptoms and does not imply a particular pathogen. Thus there are diseases with the same name on a range of hosts, for example wheat and sugarcane, which are caused by fungi in different genera.

Maps of Ireland:
<http://www.fishing-ireland.de/karte.html> and
<http://healthmap.org/promed?v=53.2,-8.2,5>

Pictures
Eyespot, whole maize plant:
<http://www.inra.fr/internet/Produits/HYP3/images/6033157.jpg>
Leaf symptoms:
<http://www.inra.fr/internet/Produits/HYP3/images/6033153.jpg> and
<http://www.invasive.org/images/768x512/1265065.jpg>
Maize disorders, including genetic leaf spots:
<http://www.public.iastate.edu/~ccblock/photos/corn4.htm#Spots>

Links
Disease information with links to more pictures:
<http://www.inra.fr/internet/Produits/HYP3/pathogene/6kabzea.htm> and
<http://www.extension.iastate.edu/Publications/PM963.pdf>
First description of _K. zeae_:
<http://ci.nii.ac.jp/naid/110002751580/>
_K. zeae_ taxonomy:
<http://www.speciesfungorum.org/Names/SynSpecies.asp?RecordID=282710>
List of maize diseases and pathogens:
<http://www.apsnet.org/online/common/names/corn.asp>
Molecular diagnostics of fungal pathogens of maize:
<http://www.patentstorm.us/patents/5800997-description.html>
TEAGASC:
<http://www.teagasc.ie/>. - Mod.DHA]
 

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