Antifungal effects of essential oils from oregano and fennel on Sclerotinia sclerotiorum.
OBJECTIVE
The antifungal effects of essential oils of oregano (Origanum syriacum var. bevanii) and fennel (Foeniculum vulgare) were evaluated against Sclerotinia sclerotiorum. Effects of the essential oils on morphological structures of hyphae and sclerotia were studied under light and scanning electron microscopes (SEM).


RESULTS
Inhibitory effects of volatile and contact phases of the essential oils used were determined on hyphae and sclerotia. Both essential oils have a marked antifungal effect against S. sclerotiorum. Soil amendment with essential oils has significant effect on reducing sclerotial viability. Both essential oils significantly inhibited the fungal growth in soil, thereby increasing the number of surviving tomato seedling by 69.8% and 53.3%, respectively. Light and SEM observations on pathogen hyphae and sclerotia revealed considerable morphological alterations in hyphae and sclerotia.


CONCLUSIONS
The significant reduction in the mycelial growth and germination of sclerotia would greatly reduce the pathogen inoculum source. This may influence the rate of disease development in soil.


CONCLUSIONS
Considering the reduction in the number of diseased plants in infested soil amended with essential oils, we concluded that oregano and fennel essential oils could be used as possible bio fungicides alternative to synthetic fungicides against phytopathogenic fungi.
Soylu
S
S
Mustafa Kemal University, Department of Plant Protection, Faculty of Agriculture, Antakya, Hatay, Turkey. soylu@mku.edu.tr
Yigitbas
H
H
Soylu
E M
EM
Kurt
S
S
D000935:Antifungal Agents / Q000494:pharmacology*; D001203:Ascomycota / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D030001:Foeniculum / Q000737:chemistry; D018525:Germination / Q000187:drug effects; D025301:Hyphae / Q000187:drug effects / Q000254:growth & development / Q000648:ultrastructure; D018551:Solanum lycopersicum / Q000382:microbiology; D008855:Microscopy, Electron, Scanning; D009822:Oils, Volatile / Q000494:pharmacology*; D031341:Origanum / Q000737:chemistry; D010935:Plant Diseases / Q000382:microbiology*; D012988:Soil Microbiology
D000935:Antifungal Agents; D009822:Oils, Volatile