Climatic analysis of the distribution of Fusarium graminearum, F-pseudograminearum and F-culmorum on cereals in Australia

The distributions of Fusarium graminearum (Gibberella zeae), F. pseudograminearum (F. graminearum Group 1) and F. culmorum from cereals in Australia were determined from published survey data and accessions to culture collections. The distributions were analysed in terms of climate, using the climate matching system BIOCLIM. F. graminearum was found mostly in warm temperate to subtropical areas with moderate to high summer rainfall, where mean temperature of the warmest quarter was greater than 18.7degreesC and rainfall of the warmest quarter was greater than 195 mm. This appeared to be due to the effect of climate on production of maize, the host from which most records were obtained. F. pseudograminearum occurred throughout the main cereal growing areas and its occurrence did not appear to be limited by climate within the Australian grain belt. The distribution of F. culmorum on cereals was more limited than that of F. pseudograminearum. In the southern winter rainfall zone, F. culmorum was restricted to sites with mean summer temperatures less than about 22degreesC and annual rainfall greater than about 350 mm, whereas in the northern summer rainfall zone F. culmorum was restricted to areas with mean summer temperatures less than about 24.5degreesC and annual rainfall greater than about 625 mm.