The genus Cylindrocladium includes phytopathogenic species that affect many crops around the world. In Argentina, it has been found to cause the black spot of yerba mate (YM) (Ilex paraguariensis), producing defoliation and large crop yield losses. I. paraguaiensis, a small tree native to South America, has economic and social importance since its leaves and branches are used to prepare a popular infusion called “mate”. In search of natural strategies to control the black YM spot, the objective of this work was to evaluate the use of peppermint (Mentha x piperita), oregano (Origanum vulgare ssp. hirtum) and marigold (Tagetes minuta) essential oils for Cylindrocladium sp. (Cy) control. The essential oils (EOs) were characterized by GC-MS. Cy 14-day culture grown in YM agar medium was used as inoculum; a 4 mm disc was placed at the center of the Petri dish. For each EO treatment, two EO-embedded paper discs were placed near the edge of the Petri dish. Discs with sterile water were used as control. The fungus colony diameter was measured on days 5, 7, 10 and 15. Conidium production was analyzed on day 15. The assays were made in three replicates and the results analyzed using the Kruskal–Wallis test. Oregano EO (OEO) was composed mainly of trans-sabinene hydrate and thymol, marigold EO (MEO) of dihydrotagetone and verbenone, and peppermint EO (PEO) of menthol and menthone. OEO and PEO inhibited fungal growth, showing significant differences with the control from day 5 to 10. However, on day 15, only OEO showed statistical differences (p=0.0188), suggesting that PEO could reduce the inhibition effectiveness with time. MEO showed no fungal growth inhibition. Conidium production resulted in 7.27 x 10⁶ conidia in the control while no conidia were observed in the OEO and PEO treatments. These results demonstrate the effectiveness of OEO and PEO as natural control agents against Cy.