Antifungal efficacy of Juniperus and Pinus essential oils against phytopathogens

Authors: SEMERDJIEVA, IVANKA - Agricultural University Of Bulgaria; SLAVOV, SLAVTCHO - Agrobioinstitute; DINCHEVA, IVAILA - Agrobioinstitute; Cantrell, Charles; ZHELJAZKOV, VALTCHO - Oregon State University

Submitted to: Journal of Natural Pesticide Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2026
Publication Date: 2/16/2026
Citation: Semerdjieva, I., Slavov, S.B., Dincheva, I., Cantrell, C.L., Zheljazkov, V.D. 2026. Antifungal efficacy of Juniperus and Pinus essential oils against phytopathogens. Journal of Natural Pesticide Research. 16:100185. https://doi.org/10.1016/j.napere.2026.100185.
DOI: https://doi.org/10.1016/j.napere.2026.100185

Interpretive Summary: Phytopathogenic fungi are recognized as a major factor for the emergence of widespread crop diseases worldwide, annually reflecting significant economic losses in both agricultural and forestry areas. Synthetic fungicides are currently mainly applied in controlling fungal plant diseases. This pesticide group contributes to more than 35% of the worldwide pesticide market. Biological control of plant diseases could mitigate the negative consequences associated with the intense use of synthetic fungicides. This study evaluated the fungal in vitro activity of the essential oils (EOs) of two Juniperus species (J. sabina L. (Male (M); Female (F)) and J. excelsa M. Bieb.) and four Pinus species (P. heldreichii Christ, P. peuce Griseb., P. sylvestris L., P. nigra J. F. Arnold) on mycelium growth of six economically important plant pathogens: fungi Alternaria alternata, Botrytis cinerea, Diaporthe nobilis (anamorph Phomopsis sp.) Fusarium oxysporum, Rhizoctonia solani, and oomycete organism Phytophthora cryptogea. The EO of female J. sabina (F) was identified as the most effective EO among the examined three Juniperus EOs in inhibiting the mycelium growth of tested plant pathogens. The EO of P. heldreichii expressed the high mycelium inhibition of B. cinerea, D. nobilis, F. oxysporum, and P. cryptogea comparing to the EOs originating from other tested Pinus species.

Technical Abstract: Fungal plant diseases are currently controlled primarily by the application of synthetic fungicides. The overuse of chemical pesticides, including fungicides, induces human health and environmental pollution risks. Plant essential oils (EOs) are a significant source of biologically active compounds, which are proven for their pesticidal (incl. fungicidal) properties with admission to avoid the negative influence of synthetic fungicides. This study evaluated the bio fungicides in vitro activity of the EOs of two Juniperus species (J. sabina L. (Male (M); Female (F)) and J. excelsa M. Bieb.) and four Pinus species (P. heldreichii Christ, P. peuce Griseb., P. sylvestris L., P. nigra J. F. Arnold) on mycelium growth of six economically important plant pathogens: fungi Alternaria alternata, Botrytis cinerea, Diaporthe nobilis (anamorph Phomopsis sp.) Fusarium oxysporum, Rhizoctonia solani, and oomycete organism Phytophthora cryptogea. The EO of female J. sabina (F) was identified as the most effective EO among the examined three Juniperus EOs in inhibiting the mycelium growth of tested plant pathogens. The EO of P. heldreichii expressed the high mycelium inhibition of B. cinerea, D. nobilis, F. oxysporum, and P. cryptogea comparing to the EOs originating from other tested Pinus species.