, 1989; Ward et al., 2008). Most of the biosynthesis pathways of trichothecenes are regulated by Tri5 genes found within the 25-kb Tri cluster (Kimura et al., 2003). Fusarium graminearum-specific Fg16NF/R (Nicholson et al., 1998) and trichothecene strain-specific Tox5-1/2

(Tri5 genes) primer sets were designed (Niessen & Vogel, 1998) to assess FHB outbreaks and the impact of mycotoxic strains on the environment (Wu et al., 2002). Aside from affecting the quality of crops and grains, FHB outbreaks are a source of toxigenic trichothecene contaminants that cause neurotoxicity, severe toxicoses, vomiting, food/feed refusal and immunosuppression in humans and animals (Vasavada & Hsieh, 1987; Edwards learn more et al., 2001; Lutz et al., 2003; Leslie & Summerell, 2006). Thus, controlling the spread of FHB in crops, in particular FHB associated to F. graminearum outbreaks, is crucial to prevent the negative impact of mycotoxin accumulation in food and feed. Many scientists regard biological control as a promising environmental approach (Pal & McSpadden, 2006) and a practical option to combat Fusarium AG14699 pathogenic strains (Vujanovic, 2008).

Most biocontrol agents studied as well as commercially available biopesticides use beneficial bacterial strains and necrotrophic mycoparasitic fungi, such as Trichoderma harzianum Rifai, against Fusarium (Khan et al., 2006). However, Oxalosuccinic acid their efficiency in controlling Fusarium is limited and the outcomes are disputed. Relatively little information is available on the potential of biotrophic mycoparasitic fungi as biocontrol agents to manage F. graminearum

outbreaks. This could be due to the nature of biotrophic mycoparasites, which have a narrower host-specificity (Cortes-Penagos et al., 2007) as well as difficulties encountered when growing them on artificial or agar media. Although several biotrophic mycoparasites have been reported in association with Fusarium (Gliocephalis, Melanospora, Persiciospora, Stephanoma and Sphaerodes), none was noted to parasitize F. graminearum (Hoch, 1978; Davanlou et al., 1999; Harveson & Kimbrough, 2001a, b; Jacobs et al., 2005). Recently, Sphaerodes mycoparasitica Vujanovic biotrophic mycoparasite was isolated and identified from Canadian fields in association with Fusarium oxysporum, Fusarium avenaceum and F. graminearum (Vujanovic & Goh, 2009). Sphaerodes mycoparasitica was found to be a fusion and haustorial-like biotrophic mycoparasitic fungus of F. oxysporum and F. avenaceum (Goh & Vujanovic, 2010). In this study, S. mycoparasitica is reported, for the first time, as a biotrophic mycoparasite of 3-ADON- and 15-ADON-producing F. graminearum strains. This biotrophic mycoparasite is also an efficient suppressor of growth and reducer of the amount of DNA of mycotoxigenic F. graminearum strains in dual-culture mycoparasite–Fusarium assays.