Control of phytopathogenic fungi by the essential oil and methanolic extracts of Erigeron ramosus (Walt.) B.S.P.

Abstract

The efficacy of the essential oil and methanolic extracts of Erigeron ramosus (Walt.) B.S.P. was evaluated for controlling the growth of some important phytopathogenic fungi. The hydrodistilled essential oil was analysed by GC-MS. Thirty one compounds representing 95.3% of the total oil were identified, of which β-caryophyllene (24.0%), α-humulene (14.5%), 1,8-cineole (9.0%), eugenol (7.2%), globulol (7.1%), caryophyllene oxide (5.2%), δ-cadinene (5.0%), α-copaene (4.9%) and widdrol (2.0%) were the major compounds. Thus, the monoterpenes and sesquiterpenes were the predominant portions of the oil. Essential oil and methanol extract of E. ramosus and the derived fractions of hexane, chloroform and ethyl acetate were tested for anti-fungal activity, which was determined by disc diffusion and minimum inhibitory concentration (MIC) determination methods. The oil (1,000 ppm) and methanolic extracts (1,500 ppm) displayed great potential of anti-fungal activity as a mycelial growth inhibition against the tested phytopathogenic fungi such as Fusarium oxysporum (KACC 41083), Phytophthora capsici (KACC 40157), Colletotricum capsici (KACC 410978), Fusarium solani (KACC 41092), Rhizoctonia solani (KACC 40111), Sclerotinia sclerotiorum (KACC 41065) and Botrytis cinerea (KACC 40573), in the range of 49.3–70.3% and minimum inhibitory concentration ranging from 125–500 μg ml-1. The results obtained from this study may contribute to the development of new anti-fungal agents to protect the crops from fungal diseases.