Effect of essential oils on fungal growth and fungal infections

Letessier, Murielle Paule (1993) Effect of essential oils on fungal growth and fungal infections. MSc(R) thesis, University of Glasgow.

Abstract

Investigations were made on the effect of hyssop and oregano essential oils on plant diseases. This involved an examination of the effect of the oil on infection of barley and apple with powdery mildew and broad bean with rust, and on mycelial growth of Pyrenophora avenae and Pyricularia oryzae. Germination of Botrytis fabae conidia and Uromyces viciae-fabae uredospores, in the presence of the oils, was also studied. The effects of the main components of the essential oils were also tested in several in vitro and in vivo experiments. The in vivo experiments yielded various results which were not significantly different from controls. Thus, preinoculation treatment of broad bean and apple with oregano oil increased infection with rust and powdery mildew, while post-inoculation treatment of barley and pre-inoculation treatment of apple with hyssop oil, and a post-inoculation treatment of apple with oregano oil, all reduced powdery mildew infection. In addition, both ?-pinene and isopinocampheol controlled barley powdery mildew infection. Suspensions of 0.4% and 0.04% oregano oil completely inhibited mycelial growth of P. avenae and P. oryzae. This inhibition was shown to be due to vapours of the oils. Combinations of components of hyssop oil containing isopinocampheol slowed down growth of P. oryzae and inhibited growth of P. avenae. Thymol, and especially carvacrol, both components of oregano oil, reduced mycelial growth of P. avenae and P. oryzae considerably. Suspensions of hyssop oil reduced germination of conidia of B. fabae and uredospores of U. viciae-fabae, while oregano oil reduced germination of B. fabae conidia. Thus, although the two essential oils examined here were powerful inhibitors of fungal growth in vitro, the oils possessed very little activity on the plant.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Additional Information: Adviser: Dale Walters
• Keywords: Plant pathology.
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: Supervisor, not known
• Date of Award: 1993
• Depositing User: Enlighten Team
• Unique ID: glathesis:1993-72640
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Jun 2019 11:06
• Last Modified: 26 Jul 2021 15:35
• URI: https://theses.gla.ac.uk/id/eprint/72640