The spores of pathogens arrive at the surface of the fruit during the growing period when the natural resistance is high. The decay is initiated after a mechanical damage or decrease of apple resistance due to ripening (Dennis 1983). Spores of Penicillium species are present in the soil, on the fruit surface, in the air of the store etc. Its preferred hosts are pomiferous fruits. This species is responsible for blue mould rot, a major postharvest disease of apples worldwide (Baert et al., 2007; Schovánková and Opatová; 2011).