Abstract
The aims of this study were to assess the antimicrobial efficacy of the leaf essential oil and the leaf extracts of
R. montana
against
Botrytis cinerea
,
Fusarium oxysporum
,
Verticillium dahliae,
Aspergillus oryzae
and
Fusarium solani.
The oil (1.000 µg/disk) and the extracts (1.500 µg/disk) revealed a remarkable antifungal effect against the tested plant pathogenic fungi with a radial growth inhibition percentage of 40.0-80.0 % and 5.0-58.0 %, respectively along with their respective MIC values ranging from 100 to 1100 µg/mL and 250 to 3000 µg/mL. The oil had a strong detrimental effect on spore germination of all the tested plant pathogens along with the concentration as well as time-dependent kinetic inhibition of
Fusarium oxysporum
. Also, the oil exhibited a potent
in vivo
antifungal effect against
Botrytis cinerea
on tomato plants. Experiments carried out in plant revealed that the essential oil was slightly effective in suppression of gall formation induced by
Agrobacterium tumefaciens
on bitter almond. The results of this study indicate that the oil and extracts of
R. montana
leaves could become natural alternatives to synthetic fungicides to control certain important plant microbial diseases. The GC-MS analysis determined that 28 compounds, which represented 89.03 % of total oil, were present in the oil containing mainly 1-butene, methylcyclopropane, 2-butene and caryophyllene oxide.