In vitro Evaluation of the Antifungal Activity of Essential Oils of Some Medicinal Plants on Phytopathogenic Strains in the Kisangani Region (DRC)

Abstract

Purpose: The present study evaluates the antifungal activity of essential oils of Curcuma longa and Eucalyptus globulus on strains of Lasiodiplodia theobromae and Pseudocercospora fijiensis in the Kisangani region (DR Congo). Methods: The essential oils were obtained after extraction by the hydro distillation method. The isolation of strains of L. theobromae was made from the fragments of mesocarp taken from the diseased cocoa, previously cut with a Scarpel and then disinfected with bleach water, while the strains of P. fijiensis were obtained by the method of discharging ascospores on agar medium (H2O Agar) and then transplanting on potato dextrose agar (PDA). In addition, inhibition of mycelial growth on a PDA was used as a method to assess the sensitivity of strains to the essential oils of the medicinal plants studied. Results: The results obtained show that the essential oils of the rhizomes of C. longa and the leaves of E. globulus showed a low yield of essential oils (EOs) of 0.50% and 0.48% respectively. However, the EOs of the rhizomes of C. longa and the leaves of E. globulus exhibited inhibitory action on the mycelial growth of strains of L. theobromae and P. fijiensis. Conclusion: The ANOVA test applied to the mean mycelial growth values of these two strains (L. theobromae and P. fijiensis) on the Eos of C. longa showed that the difference is not significant (p-value = 0.47). In addition, there is also no significant difference (p-value = 0.51) between the mean mycelial growth values of these two fungal strains on the essential oil of E. globulus.