Tilletia controversa kuhnis a wheat fungus present in the Pacific Northwest. It takes on policy significance because China applies a zero tolerance on TCK spores resulting in a ban since 1974 on shipments from the Pacific Northwest. Until the summer of 1996, China accepted shipments of U.S. wheat from the Gulf coast, even if they contained traces of TCK and negotiated price discounts with the shippers to cover the cost of decontamination before the affected wheat was unloaded. But in June 1996, China rejected cargoes of U.S. wheat with traces of TCK. China and the United States since have exchanged scientific teams as part of an effort to resolve the problem.