The antifungal activity of essential oils against Phoma exigua var foveata, was investigated by analyzing its inhibitory effect on the gangrene of potato tubers. The results showed that mycelium growth and spore germination of Phoma was suppressed by treatment with essential oils, and the inhibitory effect strongly correlated with the concentration of essential oils used in this study. The effectiveness of post-harvest treatment with essential oils was studied for induced resistance to Phoma rot in tubers of two potato varieties (Kolobok and Sante). The results showed the fungicidal effect of cumin and lavender essential oils against phomosis at concentrations of 0.1, 0.2, and 0.4, significant inhibition of mycelium growth (18.1-100%), and viability of conidia (12.8-100%) compared to the control. Moreover, both oils at a concentration of 0.4% caused 100% inhibition of mycelium growth and spore germination. Treatment with oils at a concentration of 0.01-0.04 l/t significantly reduced the degree of damage to tubers infected with phomosis. However, cumin essential oil at a concentration of 0.04 l/t had the greatest effect 97.1% compared to lavender oil 95.4%.