How the misidentification of a pathogen can cause an emergency response – a real life case study of an Australian grain export incident

In February 2004, a shipment of Australian wheat was rejected by an importing country that alleged the grain contained ustilospores of Tilletia indica. This allegation caused all wheat trading and shipments from Australia to be stopped. At this time, Australian wheat was worth A$4 billion and provided 14% of the world's export demand1. How did this misidentification occur? And why is correct identification of pathogens so important when trading with other countries?