EN
The aim of this study was the evaluation of the oilseed rape colonisation by Alternaria genus fungi and the determination of mycotoxins produced by them. The seeds of Lisek cultivar were collected from untreated plants and four objects which were treated at the budding stage (BBCH 58–59) and at the late flowering stage (BBCH 68–69) with fungicides Amistar 250 SC and Caramba 60 SL. After harvesting, the seeds were evaluated for the colonization by fungi of the genus of Alternaria and the content of the two alternaria toxins: alternariol (AOH) and alternariol monomethyl ether (AME). The most frequently occurring species was A. alternata. The level of colonization of the seeds by Alternaria fungi depended mainly on the weather conditions prevailing during the growing season. Higher content of AOH and AME was observed in the seeds which were colonised the most by the fungus of Alternaria.