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The infestation of barley grains by fungi of the genus Fusarium was studied on malting barley from Kromei'iz (360 samples) and one sample from Kojet!n in Czech Republic. Most frequent species in the season 1997-1998 were: F. culmorum (over 70% of the isolates), F. poae (over 20% of the isolates), F. avenaceum  (over 2%). Much less frequent were: F. stilboides  v. stilboides, F. aqaeductum v. aqaeductum, F. merismoides v. merismoides and F. gigas. The isolates of F. culmorum were highly pathogenic when barley was artificially inoculated; those of F. poae had low pathogenity. Five varieties of spring barley at growth stage 1-5 on the Feekes scale reacted to F. culmorum as follows: I) Tolar (most resistant), 2) Akcent, Lumar and Rubfn (intermediate), 3) Krona (most susceptible). An application of fungicides on a plot inoculated with F. avenaceum  and F. graminearum increased the yield of grain by 0.46 to 1.71 t/ha. Most effective fungicides against the pathogens were: metconazole, tebuconazole and prochloraz. The effect of the combination tebuconazole + triadimefon + prochloraz was found to be most effective. For determi­ nation of six trichothecene mycotoxins in fungal mycelium, macroconidia and spring barley, high resolution capillary gas chro­ matography with electron capture detection was used. Only toxin T-2 and nivalenol (NIV) were detected in fungal mycelium, and a low level of NIV was found in spring barley, variety Rubfn (lower than legislated limit- 2 mglkg of cereals).

An effective and fast method for determination of deoxynivalenol (DON) in cereals and flours has been developed. The immunoaffinity column was used for the isolation of DON from wheat, corn, rice and flour extract. The determination was carried out by using the HPLC/UV method. The limit of detection was 0.02 mg/kg. The recoveries for the assay range 0.1 to 2 mg/kg were generally higher than 80%, ranging from 83 to 96% with an average relative standard deviation of 3.8%. The trueness of the method using the DON test -HPLC column was established by use of certified reference material CRM 379. The certified value was 0.67 mg/kg. The result obtained from three replicates was 0.68 ± 0.05 mg/kg. The corresponding confidence interval at 95% probability ranged from 0.63 to 0.73 mg/kg. A comparative study of the DON test TM -HPLC/UV and the Mycosep 225 -GC/ECD methods was carried out. Six naturally contaminated wheat samples were analysed by both methods. Linear regression analysis demonstrates that DON test TM -HPLC is a statistically significant predictor of the GC/ECD method using the Romer Mycosep 225 column.