Abstract:
Antifungal effects of 7 different active components (cinnamaldehyde, citral, carvacrol, linalool, thymol, menthol, perillyl alcohol) from plant essential oils against
Fusarium graminearum (
F.g.) were compared by the method of inhibiting mycelial growth
in vitro. Citral, carvacrol, and thymol were selected due to their lower EC
50 values and formed a compound with each other, respectively. The compound composed of carvacrol and thymol was considered the most excellent pairing with the best inhibitory effect against
F.g. in vitro. Additionally, the mass ratio of carvacrol and thymol in the compound was optimized and finalized the formulation of natural compound fungicide. Results showed that when the mass ratio of carvacrol and thymol was 1∶2, the fungicide had the best antifungal effect against
F.g. and the synergistic index (S.I.) is 1.45, which showed a synergistic effect. The possible antifungal mechanisms of carvacrol and thymol compound were also analyzed. The prepared natural compound fungicide could change the permeability of
F.g.’s cell membrane, reflected by the change in conductivity. Furthermore, the effects of the prepared natural compounded fungicide on wheat coleoptiles against
F.g. were studied. It could significantly inhibit the growth of lesions on wheat coleoptiles. When fungicide (200 μg/mL) was administered to wheat coleoptiles infected by
F.g., the control rate of the protective group and the curative group were 79.08% and 84.54%, respectively. This research provided a theoretical guidance for developing natural compound fungicides with precise efficacy. The possibility of further application of active components of plant essential oils was also discussed.