Influence of volatile oils on the in vitro growth of Phytophthora infestans

Abstract

Modern agriculture depends on a wide variety of synthetic fungicides, which are continually widespreading, resulting in human and environmental pollution. These chemicals used in excessive doses can give rise to abnormal chromosomes and degeneration within the mitotic cycle. In this sense, the development of alternative strategies, based on non-chemical fungicides for late blight management, becomes imperative. Thus, the aim of this study was to find several indigenous plant species that show antifungal activity against the pathogen Phytophthora infestans . The bio base of the experiment consisted of indigenous plant species, namely Mentha piperita L., Pinus sylvestris L., Acorus calamus L., Salvia officinalis L., and Rosmarinus officinalis L. The plant material was subjected to the extraction method using vapor entrainment, aiming to obtain volatile oils. The in vitro testing of the antifungal activity of the extract was achieved using the Kirby-Bauer disc (d) diffusion method. The negative control was sterile distilled water and the positive control was the commercial substance Mancozeb. The obtained results showed that the mint volatile oil had a significant antifungal effect, totally inhibiting the growth and development of the oomycete. In the case of the volatile oils extracted from the other four species, the most intense antifungal activity was achieved by calamus volatile oil. The results revealed that the obtained volatile oils (100% concentration) have fungicide (mint) and fungistatic (calamus, pine buds, sage and rosemary) effect, influencing the growth as well as the development of the oomycete P. infestans .