Abstract: The experiment was aimed to know differential sensitivity of four Pestalotiopsis spp., P. funerea (Eriobotrya japonica), Pestalotiopsis sp. (Rhaphiolepis umbellata), P. photinia (Photinia glabra) and P. breviseta (Viburnum awabuki), to the five phytoalexins isolated from three Rosaceae plants. The names of two kind biphenyl phytoalexins accumulated in E. japonica (loquat), R. umbellata and P. glabra (photinia), were aucupurin and eriobofuran, 4`-methoxyaucuparin and rhaphiolepsin, 2`-methoxyaucuparin and 4`-methoxyaucuparin, respectively. Four Pestalotiopsis spp. showed different sensitivity to the phytoalexins tested. P. funerea was less sensitive to aucuparin in comparison with the other fungi. The less sensitive fungi to eriobofuran was obtained with P. photiniae., P. breviseta was unable to germinate in the medium containing rhaphiolepsin in concentration of 10 ppm and 50 ppm. Of the five phytoalexins tested, 2`-methoxyaucuparin was less toxic to the fungi.