A complex of Fusarium spp. causes Fusarium head blight (FHB) on wheat and also on barley. Infection with FHB results not only in yield loss, but also causes depreciation of the harvested product due to the accumulation of toxins such as deoxynivalenol produced by Fusarium spp. The flowering time is a very susceptible period for primary infection. One reason might be that during this period spores can get into the opened wheat florets where they may later cause infection.Initial symptoms of infection of a wheat ear are visible whitening and drying of individual spikelets or entire parts of the ear. If the florets became infected shortly after blooming, grains are often not formed, while other infected spikelets have grains with various deformities, shrunken and with pinkwhite coloration (Klem & Tvarůžek 2005).The main aim of experiments was detection of Fusarium species on wheat grains by using of the PCR methods. A quite different situation was found in the occurrence of the fourth species -F. poae. In the years 2005 and 2006 it was only detected in 10%, resp. 2% of the samples, compared to markedly higher occurrences in the previous years. A comparison of the current weather development with the long-term mean at the Troubsko locality suggests that years with a relatively long, wet and cold start of the growing season and warmer end of vegetation (late May-July) will favour F. graminearum.