Currently nanotechnology has extensive application in the medicine and agriculture field, food industry and in many other areas. According to research, the activity of many metal ions and nanoparticles is similar to that of fungicides. The aim of the research presented in this paper was to determine the effect of selected plant conditioners against fungal pathogens of herbs as well as of orchard plants which can also affect human being. The fertilisers containing nanoparticles of silver and copper as well as ions of boron and zinc (in mixture): Viflo Cal S Viflo, Viflo Chitosol Silver, Viflo Miedź-Bor and Cynk Viflo Zn, and isolates K 425 of Colletotrichum dematium and K 651 of Phomopsis diachenii were taken to the study. The percent of fungi colony growth inhibition on PDA medium containing metal nanoparticles and ion in three various concentration was adopted as the criterion of evaluation of fertilisers. In vitro experiment showed that the effect of studied conditioners on the colony growth and sporulation of P. diachenii and C. dematium was different. Only Viflo Cal S at the highest studied concentration of 1 g·cm-3 totally inhibited the mycelial growth of P. diachenii and caused dying of fungus cells. None of the tested preparations were fungicidal for C. dematium. Cynk Viflo Zn, Viflo Miedź-Bor independently of the concentration as well as Viflo Chitosol Silver at the concentration 0.125 g·cm-3 and 0.05 g·cm-3 stimulated the growth of C. dematium.