Acta Agronómica (Apr 2012)
Efecto in vitro de aceites esenciales de tres especies de Lippia sobre Moniliophthora roreri (Cif. y Par.) Evans et al., agente causante de la moniliasis del cacao (Theobroma cacao L.) In vitro effect of essential oils of three Lippia species on Moniliophthora roreri (Cif. and Par.) Evans et al., causative agent of moniliasis of cocoa (Theobroma cacao L.)
Abstract
Se evaluó el efecto antifúngico in vitro de cinco aceites esenciales (AEs) (AE1, AE2, AE3, AE4 y AE5) extraídos de Lippia origanoides, L. citriodora y L. alba sobre aislados de monilia (Moniliophthora roreri) obtenidos de frutos de cacao infectados provenientes de San Vicente de Chucurí, Santander, Colombia. Las plantas de Lippia fueron colectadas en cinco localidades colombianas. Los aislados de monilia (M1, M2, M3, M4 y M5) fueron caracterizados por su morfología, germinación y crecimiento en medios de cultivo. La actividad antifúngica de diferentes concentraciones de los AEs fue evaluada contra el aislado M2 y la cepa de M. roreri (ATCC 64239), para determinar su efecto sobre la germinación y la inhibición del crecimiento micelial. Los AEs estudiados inhibieron 100% de la germinación y del crecimiento micelial cuando fueron utilizados en concentraciones de 800 - 1000 µg/ml. Concentraciones de 200 µg/ml también mostraron efecto sobre los aislamientos fúngicos, siendo los AEs obtenidos de L. origanoides (AE2 y AE3) los más activos. Estos estaban compuestos principalmente por timol, p-cimeno, g-terpineno, acetato de timilo, carvacrol, b-mirceno, trans-b-cariofileno. Diferencias significativas (P The in vitro antifungal effect of five essential oils (EOs) (EO1, EO2, EO3, EO4 and EO5) extracted from Lippia origanoides, L. citriodora and L. alba on isolates of Monilia (Moniliophthora roreri) was evaluated. Lippia plants were collected at five locations in Colombia, and monilia isolates were obtained from infected cocoa fruits collected in San Vicente de Chucurí, Santander, Colombia. The fungi strains (M1, M2, M3, M4 and M5) were characterized by morphology, germination and growth in culture media. Antifungal activity of different concentrations of EOs was evaluated against the M2 and the isolated strain of M. roreri (ATCC 64239) determining their effect on germination and mycelial growth inhibition. The five essential oils studied inhibited 100% germination and micelial growth when they were used at concentrations from 800 to 1000 µg/ml. Concentrations of 200 µg/ml also showed an effect on fungal isolates, being the EOs obtained from L. origanoides (EO2 and EO3) the most active. These were mainly composed of thymol, p-cymene, g-terpinene, timilo acetate, carvacrol, b-myrcene, trans- b-caryophyllene. Significant differences (P < 0.05) on susceptibility were observed between the two fungal strains studied, being generally more susceptible the isolated M2 that the ATCC strain. The EOs of L. origanoides are candidates for use as biofungicides possible to control the moniliasis. Future studies oriented to determinate the in vivo antifungal activity of these EOs and its major components are required.
