Effect of plant essences oils on inhibiting the growth of Aspergillus ochoraceus and reducing Ochratoxin A in barley (Hordeum Vulgare L.)

Chemical fungicide is the most affordable and easiest way to fight against plant diseases, but they increase concerns about endangering human health and residual in the environment. Barley is one of the most important and consumable cereals in the world. Plant essential oils are volatile compounds from plants that have strong antimicrobial properties with phenolic and antioxidant components. The aim of this study was to investigate the four plant essential oil including Savory, Thyme, Rosemary and Fennel on the growth and production of ochratoxin of Aspergillus ochraceus pathogen in barly. In this study, the effect of four plant essential oils (Satureja khuzestanica, Thymus daenensis, Rosmarinus officinalis, Foeniculum vulgare) on the growth pathogen in the petri dishes and the level of ochratoxin A produced by A. ocraceus was investigated in addition, it was studied the essential oils effect on ochratoxin in the culture medium. Measuring of ochratoxin was performed by High Performance thin-layer chromatography. The results of this study showed that the essential oils can significantly decrease the growth of the A. ocraceus and the production of ochratoxin by the pathogen. Savory essence at a concentration of 250 μg/ml inhibits the production of detectable ochratoxin in the medium by preventing the growth of the pathogen. In this concentration, essential oils of Rosemary and Thyme were 79.1% and 53.2% respectively, and the dry weight of the fungi decreased completely. Rosemary essential oil at the highest applied concentration (1000 μg/ml) did not inhibite it was investigated the growth of the pathogen it was investigated, but prevented the production of toxin. Essential oils of Savory, Thyme, Rosemary and Fennel showed fungicidal properties. These essential oils affect the ochratoxin and degrade it in the culture medium.