Different susceptibility of two Botrytis cinerea strains to supercritical CO2 plant extracts

Botrytis cinerea is an airborne plant pathogen with a necrotrophic lifestyle. As a generalist, B. cinerea has no host specificity and infects over 500 plant species. There are many studies about phenotypic and genotypic diversity of B. cinerea strains from different regions of the world. Two different morphological strains of B. cinerea were previously isolated also in Slovenia from buckwheat. The morphological diversity of B. cinerea is also reflected in different susceptibility to plant extracts. We tested the susceptibility of two B. cinerea strains derived from buckwheat grain to eleven extracts of plant species Humulus lupulus, Nepeta cataria, Taraxacum officinale, Achillea millefolium, Calendula officinalis, Chamomilla recutita, Helichrysum arenarium, Hypericum perforatum, Juniperus communis, Sambucus nigra and Crataegus sp. obtained by supercritical fluid extraction using CO2 (SFE-CO2). The resistance profiles showed that strain II of B. cinerea was generally susceptible to the action of these SFE-CO2 extracts, whereas strain I was more resistant. The concentration-dependent antifungal activity of the extract of chamomile and sandy everlasting indicates their possible use as a fungicide for both strains of B. cinerea.