Biocontrol of Carrot Disease-Causing Pathogens Using Essential Oils

Diseases caused by fungal pathogens such as Alternaria spp. damage the commercial appearance of carrots or cause foliage diseases, resulting in significant yield losses each year and are a source of pre- and postharvest rots. European commission encourages the reduction of chemical pesticides. Therefore, the potential of essential oils for alternative plant protection is increasingly discussed. Furthermore, essential oils naturally produced by aromatic plants are rich in secondary metabolites, which possess several biological activities, and their use could be a significant step in environmentally friendly food production. This study aimed to evaluate the Origanum vulgare subsp. vulgare and Origanum vulgare subsp. hirtum essential oils efficacy on Alternaria spp. growth inhibition. A Clevenger-type apparatus was used to extract the essential oils from the fresh material. The Alternaria spp. radial colony growth was evaluated under essential oils concentrations from 200 to 600 µL L^-1. Each essential oil separately was mixed with a PDA medium and Alternaria spp. disk placed in the center of the Petri dishes. Plates were incubated at 25 °C in the dark and evaluated 1, 2, 3, and 7 days after inoculation. The results revealed little difference between the essential oils, and the most effective concentration was 600 µL L^-1 of O. vulgare subsp. vulgare essential oil and 400 µL L^-1 of O. vulgare subsp. hirtum. Our findings can help to control carrot disease-causing pathogens Alternaria spp., but further research is needed.