A. Lyubenova1, M. Nikolova2 and S. B. Slavov3,4
1 Agricultural Academy, Department of Agrobiotechnology, AgroBioInstitute, 1164 Sofia, Bulgaria
2 Bulgarian Academy of Sciences, Institute of Biodiversity and Ecosystem Research, Department of Plant and Fungal Diversity and Resources, 1113 Sofia, Bulgaria
3 University of Forestry, Department of Plant Protection, Faculty of Agronomy, 1797 Sofia, Bulgaria
4 Agricultural Academy, Department of Functional Genetics, Abiotic and Biotic Stress, AgroBioInstitute, 1164 Sofia, Bulgaria
Lyubenova, A., Nikolova, M. & Slavov, S. B. (2024). Impact of Origanum vulgare subsp. hirtum (Link) Ietswaart derived extracts and essential oil on plant pathogens from genus Phytophthora. Bulg. J. Agric. Sci., 30(5), 833–838
In the present study we evaluate the potential of essential oil and extracts obtained from Greek oregano (Origanum vulgare ssp. hirtum (Link) Ietswaart) to inhibit the mycelial growth of economically important plant pathogens from genus Phytophthora. The metabolite profiles of the essential oil, exudate, extract and methanolic polarity-based fractions were analyzed by GC/MS. The inhibitory activity of the essential oil and extracts against P. nicotianae var. nicotianae, P. rosacearum, P. citricola, P. plurivora and P. cryptogea was evaluated in an in vitro bioassay. Carvacrol (55.48%), p-cymene (11.06%) and γ-terpinene (15.04%) were the most abundant in the essential oil composition. In the acetone exudate and non-polar fraction, the main compound was carvacrol (48.15% and 50.34% respectively). In least amount carvacrol was found in the methanolic extract (13.24%) and completely absent in the polar fraction, where carbohydrates were the most abundant. All Phytophthora isolates responded to extracts and essential oil treatments with a decline of the vegetative growth to a different extend. A complete inhibitory effect was observed with P. nicotianae var. nicotianae in the essential oil, nonpolar fraction, acetone exudate and methanol extract variants, while the mycelial growth of P. cryptogea and P. plurivora was inhibited to a moderate degree. P. rosacearum was the most tolerant among tested oomycete representatives in these variants. We conclude that the economically important Phytophthora species, investigated in this study are susceptible to the impact of essential oil, methanol extract, the methanol’s non-polar fraction, and acetone exudates of the aromatic plant O. vulgare subsp. hirtum. Essential oil, methanol extract, acetone exudate and non-polar fraction of Greek oregano are rich of carvacrol and could find further application in different sustainable crop protection systems.