Diversity of pathogen populations causing Fusarium head blight of wheat in uruguay

Abstract

Members of the Fusarium graminearum species complex (FGSC) are the primary pathogens causing Fusarium head blight (FHB), Fusarium graminearum is the main pathogen of FHB and can produce various mycotoxins in wheat, in particular type B trichothecenes. This review presents information on the Fusarium species and chemotypes diversity associated to FHB in wheat in Uruguay. In surveys performed in 2001 and 2002, Fusarium graminearum was the most frequently isolated species (76 %), while other non FGSC species were also identified. Among species from FGSC Fusarium graminearum sensu stricto was the most frequently isolated (97 %), while F. cortaderiae and F. austroamericanum were also identified. The predominant chemotype was 15ADON (95 %), followed by 3ADON (3 %) and NIV (2 %). Isolates identified as F. graminearum sensu stricto were characterized according to the levels of DON production, the aggressiveness on different wheat cultivars, the ability to form perithecia on wheat straw. The sensitiveness to the fungicide tebuconazole of FGSC isolates was evaluated. Most isolates showed high sensitivity levels, but a few resisted higher levels of fungicide. Lower sensitivity seemed to be tied to species since F. cortaderiae isolates showed the highest MIC values.