Essential Oils as Potential Alternatives to Synthetic Fungicides for the Control of Two Fusarium Head Blight Pathogens

Abstract

Fusarium head blight of cereal, caused by fungi of the genus Fusarium spp., reduces yield and accumulates mycotoxins. The increasing resistance of pathogens to synthetic fungicides encourages the search for natural alternatives. This work aims to determine the chemical composition of essential oils (EOs) of caraway, sage, and pine and to evaluate their antifungal activity against Fusarium graminearum and Fusarium culmorum. The composition of EOs was determined by gas chromatography and gas chromatography–mass spectrometry, and activity was assessed by agar dilution to determine mycelial growth inhibition and EC50, with the effect evaluated by two-way ANOVA. Caraway EO, belonging to the carvone chemotype (carvone 57.57%, limonene 35.86%), had the highest antifungal activity (EC50 = 727 ppm), sage EO (cis-thujone 29.59%, camphor 21.74%) had an average activity (EC50 = 1017 ppm), and pine EO, rich in α-pinene and δ-3-carene, had the lowest activity (EC50 > 3000 ppm). The antifungal activity was determined by the compounds’ chemical nature, not by their amount. Low EO concentrations (125–250 ppm) elicited a biphasic response, promoting mycelial growth (zero effect point ≈ 269–295 ppm); therefore, insufficient dosage could increase the risk of mycotoxin contamination. Carvone-rich caraway EO exhibited the highest antifungal activity among the oils tested and is worthy of further investigation as a potential tool for sustainable control of Fusarium head blight in cereals.