Survey of 'Fusarium' species associated with crown rot of wheat and barley in eastern Australia

'Fusarium' species associated with crown rot were isolated and identified from 409 wheat, barley or durum wheat crops from the eastern Australian grain belt between 1996 and 1999. 'Fusarium pseudograminearum' was almost the only species isolated from crops inQueensland and New South Wales. 'F. pseudograminearum' was also the most common species in Victoria and South Australia, but 'F. culmorum' was frequently isolated in these states. 'F. culmorum' accounted for more than 70% of isolates from the Victorian high rainfall (>500 mm) region and the South-East region of South Australia. 'F. culmorum' comprised 18% of isolates from the Victorian medium rainfall (350-500 mm) region, and 7% of isolates from each of the Victorian low rainfall region and the Mid-North region of South Australia.'F. avenaceum', 'F. crookwellense' and 'F. graminearum' were isolated very infrequently. The proportion of 'F. culmorum' among isolates of 'Fusarium' from districts in Victoria and South Australia was strongly correlated with climatic conditions around the end of the growingseason, especially with rainfall in November.