Published Date: 2012-06-20 22:57:25
Subject: PRO/PL> Fusarium & undiagnosed blight, wheat - China
Archive Number: 20120620.1173738
FUSARIUM AND UNDIAGNOSED BLIGHT, WHEAT - CHINA
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Fri 15 Jun 2012
Source: Agrimoney [edited]
Grain scouts deepened the cloud over Chinese wheat by saying that 5m tonnes may have been lost to disease. "A severe blight may reduce China's winter wheat harvest," the US Grains Council said following a crop tour in the north of the country.
The comments come amid growing fears over the winter wheat crop, of which more than half has already been harvested, and which forms the great bulk of China's wheat output. The downgrade represents the latest in a rash of concerns over wheat harvests [internationally].
Separately, the China National Grains and Oil Information Centre, the official crop bureau, cut by 2.3m tonnes its forecast for the winter crop and the overall wheat harvest. "Output is lower than expected, while quality is also poor," the bureau said.
The main problem has been wet weather which has encouraged fungal diseases such as fusarium, or wheat scab.
[Fusarium head blight (FHB; also called ear blight, scab) of small grain cereal crops (wheat, barley, rye, oats, maize) is caused by several fungal species originally classed into the genus _Fusarium_. FHB causes yield losses of up to 45 percent and reduces the grade of harvested grain. The pathogens are favoured by humid conditions and persist on infected crop residues. Spores are windblown or splashed onto the heads of cereal crops.
Depending on fungal strains involved and environmental factors during plant growth and grain storage, infection may also contaminate the grain with fungal toxins. The total crop may be lost because of toxin levels. Disease management includes timely fungicide applications and crop varieties with reduced susceptibility. However, new FHB strains with increased virulence are emerging.
It is not clear whether the fusarium mentioned in the last paragraph of the article above is also the "blight" referred to at the beginning of the report, or whether additional diseases are considered to be contributing to the problems. Several blight diseases (that is, symptoms of yellowing or bleaching) due to fungi and other pathogens can affect wheat, and the wet conditions described above would favour many of them.
Provinces of China:
Fusarium head blight (FHB) on wheat:
Photo galleries of pathogen symptoms on wheat via:
Information on fusarium head blight of cereals:
http://www.grainscanada.gc.ca/str-rst/fusarium/fhbwc-foc-eng.htm (with pictures)
FHB disease and toxin information:
_F. graminearum_ current species complex and FHB information:
Taxonomy of fungal pathogens via:
Information on selected wheat diseases via:
List of major diseases and pathogens of wheat:
http://www.apsnet.org/publications/commonnames/Pages/Wheat.aspx. - Mod.DHA]