Volatile Antifungal Activity of Essential Oils Against Fusarium culmorum: the Effects of Concentration and Temperature

The phytopathogenic fungus F. culmorum represents a serious threat to wheat production due to its aggressiveness and ability to survive in soil and plant residues, and as a significant producer of toxicologically important mycotoxins that pose a risk to food safety and human and animal health. In this regard, essential oils are considered potential natural substitutes because of their volatile properties. This study aimed to assess the volatile antifungal activity of five essential oils (anise, thyme, cinnamon, sweet orange, and mountain pine) against mycelial growth of F. culmorum isolate under different concentrations, temperatures, and light regimes. The experiment was carried out in Petri dishes using essential oils at 20 and 100 µL at three temperatures (10, 20, and 30 °C) and under different light regimes. The mycelial growth was measured at 72 and 168 hours of incubation, and antifungal activity was expressed as the percentage growth of inhibition. Thyme, anise, and cinnamon essential oils fully and stably inhibited mycelial growth at all concentrations and temperatures. On the other hand, sweet orange and mountain pine essential oils showed weaker temperature sensitivity with higher dependence on concentration. The effects of concentration and temperature were more conspicuous at the early stage of incubation but lowered over time. These results suggest that volatile antifungal activity is primarily determined by the type of essential oil and indicate their potential to develop natural strategies to control F. culmorum.