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Date: June 3, 2008
Source: Journal Gazette-Times-Courier [edited] <http://www.jg-tc.com/articles/2008/06/04/features/farm/doc4845f44fb36ff145665837.txt>

Unusual winter wheat disease

One specific problem that some wheat growers are seeing in our area [Coles County, Illinois] is a fungal disease called _Cephalosporium_ stripe. This is a fairly dramatic-looking disease when it shows up. The fungus is a true vascular pathogen. Unlike many vascular diseases that produce toxins and various compounds that gum up the vascular system of a plant and then cause wilting, _Cephalosporium_ actually grows in the vascular tissue.

The leaf symptoms of _Cephalosporium_ stripe can occur from jointing to heading. Growth of the fungus in the vascular tissue causes the dramatic leaf symptoms because nutrients are unable to reach infected portions of the leaf. The symptoms are generally one to 4 long yellow stripes per leaf.
The stripes are quite bright and often extend the full length of the leaf and sometimes even continue down the leaf sheath and stem. As the leaf ages, the yellow stripes eventually turn reddish brown, and gradually the leaf withers and dies. Plants are typically stunted or dwarfed and produce characteristic white, poorly filled heads with shriveled kernels.

Most typically, _Cephalosporium_ stripe is found first in low wet areas of the field. Fluctuating winter temperatures, wet soil, and continuous cropping of cereals and grasses favor its development. In highly infested areas of the field, incidence can be as high as 80 per cent resulting typically in a 50 per cent yield reduction.

Managing this disease and reducing the inoculum for disease development in subsequent years can be accomplished by rotating to a non-host crop (corn or legumes) for at least 2 years and by managing crop residue and grassy weeds. When rotation with a non-host crop is not practical, removing or plowing under residue to a depth of below 3 inches [7.5 cm] will help decompose crop residue and manage the fungus. Although some differences in susceptibility are noted, resistant varieties are not available.

[byline: Sharon Kuhns]

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communicated by:
ProMED-mail
<promed@promedmail.org>

[_Cephalosporium_ stripe is caused by _Hymenula cerealis_ (previously _Cephalosporium gramineum_). The disease is known to affect wheat, barley, oats, rye, and many other grass species, which can serve as pathogen reservoirs. Affected plants are usually randomly scattered through the crop. Tillers have a single distinct bright yellow stripe on each leaf, which extends onto the leaf sheath. All leaves on a tiller usually show symptoms but not all tillers on a plant show symptoms. The vascular tissue at the nodes is frequently discoloured. Tillers can ripen prematurely and produce whiteheads with shrivelled seeds. The fungus enters host plants through wounds such as root injuries due to, for example, frost or root feeding insects. Heavy, wet soils and low pH favour the disease. The fungus can survive on straw residue for 3 to 5 years and is the only true vascular parasite known to attack wheat. Survival is enhanced by fungal production of antibiotic substances. There are no chemical control methods for this pathogen and disease management relies on cultural practices and use of varieties with reduced susceptibility. The disease can be a problem during repeated planting of certain high yielding but susceptible cultivars.

Maps
USA:
<http://www.mapsofworld.com/usa/usa-road-map-enlarge-view.html>
and <http://healthmap.org/promed?v=40,-97.6,4>
Illinois:
<http://mapsofworld.com/usa/states/illinois/illinois-county-map.html>
Pictures of _Cephalosporium_ stripe on wheat:
<http://scarab.msu.montana.edu/Disease/DiseaseGuidehtml/Img0022.jpg>  (whole plant), <http://www.omafra.gov.on.ca/english/crops/field/news/croppest/2006/08cpo06a6f2.jpg>
(leaf), and
<http://www.hgca.com/hgca/wde/IMAGES/Ceph30.JPG> (ear)
Links Information on _Cephalosporium_ stripe of wheat:
<http://pnw-ag.wsu.edu/smallgrains/Cephalosporium%20Stripe.html>,
<http://www.omafra.gov.on.ca/english/crops/field/news/croppest/2006/08cpo06a6.htm>,
and via
<http://www.hgca.com/hgca/wde/diseases/Cephal/Cephhost.html>
_H. cerealis_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=202160>.
 - Mod.DHA]

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