In vitro Antifungal Effects of Plant Essential Oils Against Some Fungal Disease Agents Causing Internal Rot of Dried Pepper Fruits

Fungal disease agents that cause internal fruit rot in agricultural products before and after harvest cause serious quality and yield losses. At the same time, the mycotoxins they produce in foods pose a health risk for consumers. In this study, it was aimed to isolate fungal disease agents that cause internal rot symptoms in dried pepper fruits grown in Hatay province and sold in local bazaars, to identify by morphological and MALDI-TOF methods, and to determine the antifungal effects of different plant essential oils against the most common disease agents. Alternaria alternata and Aspergillus niger were determined as the most common fungal disease agents following the result of isolations, morphological and MALDI-TOF diagnostic studies from fruit samples showing signs of disease. Antifungal effects of different vapor doses of essential oils of different thyme (Thymus vulgaris L., Tymbra spicata L. and Origanum syriacum L.), fennel (Foeniculum vulgare Mill.), laurel (Laurus nobilis L.) and eucalyptus (Eucalyptus camaldulensis Dehnh) were investigated against fungal disease agents in vitro conditions. The highest antifungal activities (100% inhibition) against fungal isolates were displayed by essential oils of Thymbra spicata (2.0-4.0 mu l Petri-1), Origanum syriacum (4.0 mu l Petri-1) and Thymus vulgaris (4.0-6.0 mu l Petri-1). Eucalyptus camaldulensis (16.0-40.0 Petri-1) exhibited the lowest antifungal activity against tested fungal isolates. In addition, the antifungal properties and EC50 values of essential oils were also determined. Plant essential oils showed antifungal effects against the tested fungal isolates in a dose-dependent manner. The results showed that plant essential oils might be applied as biofumigants in dried agricultural products.