Improved polymerase chain-reaction (PCR) detection of Gaeumannomyces-graminis including a safeguard against false negatives

A previously reported method for polymerase chain reaction (PCR) detection of Gaeumannomyces graminis was modified to simplify it, improve its specificity and decrease the possibility of contamination of the assay. The modified method also allowed discrimination between the G. graminis varieties (tritici and avenae) that are pathogenic to wheat and oats respectively and the variety weakly pathogenic to wheat (var. graminis). An internal positive control for the PCR was also added to the test by including a second pair of primers in the reaction. This positive control has wider application in PCR tests for detection of other fungi.