A large-scale survey of the natural occurrence of trichothecene mycotoxins in major cereals harvested in the Czech Republic was conducted during the years 1999–2001. In total, 198 cereal samples representing various wheat, barley, and rye cultivars were examined for deoxynivalenol (DON) using gas chromatography with electron capture detector (GC-ECD). Four years later, in 2005, the list of target analytes was fairly extended, 65 wheat and barley samples were analysed for seven trichothecene mycotoxins – deoxynivalenol (DON), nivalenol (NIV), fusarenon-X (Fus-X), 15-acetyldeoxynivalenol and 3-acetyldeoxynivalenol (ADONs), HT-2 toxin (HT-2). and T-2 toxin (T-2) by high performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Trichothecenes represented mainly by DON were detected in almost all grain samples, its mean levels were the highest in the year 1999 which was characterised by very humid conditions during the growing season. The maximum concentration set in Commission Regulation EC (No. 856/2005) for DON (1250 µg/kg) in unprocessed cereals was exceeded only in two of all the samples analysed.

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Erysiphe azaleae, a powdery mildew growing on deciduous Rhododendron species is reported from the Slovak and Czech Republics. A detailed description is given and its distribution in Europe is discussed.

 1 ÚVODHouby rodu Fusarium jsou významnými patogeny obilnin, u nichž způsobují onemocnění klasů (běloklasost -fuzáriová hniloba klasů), kořenů a pat stébel i odumíráním klíčních rostlin [1]. Nepříznivě ovlivňují výnos i kvalitu produkce [2]. K infekci může docházet kdykoliv během vegetace, pokud je vlhké či deštivé počasí. Nejvýznamnější je napadení klásků, které jsou nejvnímavější v době květu nebo počáteční fázi voskové zralosti obilek [3]. Napadené obilky představují nebezpečí pro člověka i hospodářská zvířata. Důvodem je produkce toxických sekundárních metabolitů, tzv. mykotoxinů, poškozujících např. zažívací ústrojí, imunitní systém aj., některé mají karcinogenní

Eighty‐four grass species and cultivars were inoculated with populations of puccinia poae‐nemoralis Otth and Puccinia poarum Nielsen from Zubri; 25 species were infected. Twenty species (Poa species only) with high rust: sporulation may be considered to be the real hosts of those rusts. The largest number of host species may be classed with the tribe Poae.