Control of Seed-Borne Fungi by Selected Essential Oils

Abstract

Seed-borne pathogens reduce the quality and cause infections at various growth stages of horticultural crops. Some of the best-known are fungi of genus Alternaria, that cause destructive vegetable and other crop diseases, resulting in significant yield losses. Over several years, much attention has been paid to environmentally-friendly solutions for horticultural disease management regarding the environmental damage caused by chemicals. For example, plant extracts and essential oils could be alternative sources for biopesticides and help to control vegetable seed-borne pathogens. This study aimed to evaluate essential oils’ influence on the growth of seed-borne fungi Alternaria spp. The microbiological contamination of vegetable seeds (carrot, tomato, onion) was determined by the agar-plate method. The essential oils’ impact on the growth of fungi was evaluated by mixing them with PDA medium at different amounts. The hydrodistillation was used for extraction of thyme and hyssop essential oils, and common juniper essential oil was purchased. The investigation revealed that the highest contamination of carrot and tomato seeds was by Alternaria spp. fungi. Furthermore, the highest antifungal effect on Alternaria spp. growth was achieved using 200–1000 μL L−1 of thyme essential oil. Meanwhile, the antifungal effect of other investigated essential oils differed from low to moderate. Overall, essential oils expressed a high potential for fungal pathogens biocontrol and application in biopesticides formulations.