The aim of the present work was to determine the pathogenicity of Fusarium avenaceum, F. culmorum, F. equiseti isolates, obtained from various species of herbs, to lemon balm. Three different tests of pathogenicity were carried out. The effects of Fusarium spp. post-culture liquids and water suspension of conidia on germination of lemon balm schizocarps were studied in laboratory conditions. The effect of Fusarium spp. on shooting up and healthiness of seedlings was carried out in climatic chamber conditions using the method with infested soil. All the isolates of fungi species studied caused necrosis of shoots and roots, regardless of their origins. From among three methods of artificial infection used, the method with Fusarium spp. post-culture liquids secured a fast estimation of pathogenicity the fungi isolates to lemon balm. The studied isolates of Fusarium spp. were recognized as pathogenic to lemon balm on the base of positive results in pathogenicity tests and on the base of their earlier isolation from different organs: schizocarps, roots and the bases of stems, taken from the plantations of lemon balm.

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