Inhibitory effect of some plant essential oils against strawberry anthracnose caused by Colletotrichum nymphaeae under in vitro and in vivo conditions

Plant essential oils have been widely used against several plant pathogens due to their antimicrobial effects. In this study, inhibitory effects of three essential oils including lemon grass (Cymbopogon citratus L.), Sage (Salvia officinalis L.) and lavender (Lavandula angustifolia L.) were explored against Colletotrichum nymphaeae, causing strawberry anthracnose under in vitro and in vivo conditions. Furthermore, qualitative parameters of strawberry fruit including weight loss, firmness, total soluble solids, ascorbic acid, antioxidant activity (DPPH) and total phenol were measured exposed to those EOs after 8 days storage. In vitro tests indicated that the three EOs were able to inhibit the mycelial growth of C. nymphaeae in both contact and vapour phases significantly compared to control. Among the three tested EOs, C. citratus had the lowest median effective concentration (EC50) value against the pathogen (12.97 ppm). Under in vivo condition, the higher concentrations of EOs, reduced fruit decay development significantly compared to untreated control. Overall, C. citratus EO was the superior in reduction of the mycelial growth of the pathogen and decay of fruits compared to other EOs. In addition, EOs preserved fruit-quality traits such as firmness, total soluble solids (TSS) and juice chemical properties (ascorbic acid, antioxidant activity and total phenol), while they had no any effect on weight loss of strawberry fruits. This study demonstrated that the application of C. citratus EO has a potential to reduce strawberry anthracnose disease, without any negative effect on the qualitative traits properties of strawberry fruit.