This study aims to investigate the composition of the leaf essential oil and
the total phenolic and flavonoid contents as well as the antioxidant
activity of the n-hexane, ethyl acetate, and methanol extracts of Vaccinium
myrtillus leaves collected from two different locations (Mu?la and Mersin,
Turkey). In addition, the antifungal activity against Sclerotinia
sclerotiorum (SS), Fusarium oxysporum f sp. melonis (FOM), Fusarium
oxysporum f sp. cucumerinum (FOC), and Rhizoctonia solani (RS) and the
bioherbicidal activity against Taraxacum officinale and Rumex crispus were
evaluated for the first time. The methanolic extract inhibited mycelium
growth of SS, FOM, FOC, and RS in a dose-dependent manner. No significant
difference was observed in antifungal activity between the two different
collection sites. In the bioherbicidal activity tests, the methanol extract
of the fruits completely suppressed the root-shoot development of Taraxacum
officinale, while also significantly inhibiting the root-shoot development
during the seed germination of Rumex crispus compared to the control group
at 3 mg/mL concentration for both locations. Based on the results of the
GC/MS analysis, the major constituents identified in the leaf essential oils
collected from the Mu?la and Mersin locations were ?-pinene (29.16%/15.75%),
eucalyptol (22.19%/26.46%), linalool (12.66%/25.27%), and linalyl acetate
(7.43%/2.71%). The total phenolic and flavonoid contents of the plant
extracts for the Mu?la and Mersin samples were determined as (42.80-157.58
GAE/g extracts), (29.38-151.44 GAE/g extracts) and (10.52-37.88 QE/g
extracts), (14.81-44.18 QE/g extracts) respectively. In addition, the plant
exhibited significant antioxidant activity. These findings indicate
quantitative differences in the chemical composition of the essential oils
between the two geographical locations. These findings are significant as
they provide insights for the development of new natural antifungal agents
with potential applications in agriculture.