''Tilletia controversa'' is a plant pathogen. It is a

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...

known to cause the smut disease TCK smut in soft white and hard red

winter wheat Winter wheat (usually '' Triticum aestivum'') are strains of wheat that are planted in the autumn to germinate and develop into young plants that remain in the vegetative phase during the winter and resume growth in early spring. Classificatio ...

s. It stunts the growth of the plants and leaves smut balls in the grain heads. When the grain is milled the smut balls emit a fishy odor that lowers the quality of the flour. TCK smut exists in the western and northwestern United States, but is not considered a major problem. The disease took on policy significance because China applied a

zero tolerance A zero tolerance policy is one which imposes a punishment for every infraction of a stated rule.zero tolerance, n.' (under ''zero, n.''). The Oxford English Dictionary, 2nd Ed. 1989. Retrieved 10 November 2009. Italy, Japan, Singapore China, Indi ...

on the presence of TCK spores, resulting in a ban from 1974 to 1999 on shipments from the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Tho ...

. Until the summer of 1996, China accepted shipments of U.S. wheat from the

Gulf Coast The Gulf Coast of the United States, also known as the Gulf South, is the coast, coastline along the Southern United States where they meet the Gulf of Mexico. The list of U.S. states and territories by coastline, coastal states that have a shor ...

, and negotiated price discounts with the shippers to cover the cost of decontamination if traces of TCK were found. Then in June 1996, China rejected all cargoes of U.S. wheat with traces of TCK. The November 1999 U.S.-China Agricultural Cooperation Agreement removes the ban and allows imports of U.S. wheat and other grains that meet a specific TCK tolerance level, thus improving the competitiveness of U.S. wheat with

Canadian Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

and Australian exports.

References

External links

Index FungorumUSDA ARS Fungal Database
* Fungal plant pathogens and diseases Wheat diseases Ustilaginomycotina Fungi described in 1874 {{fungus-plant-disease-stub