In vitro bio-efficacy of plant essential oils against major fungal and bacterial diseases of cauliflower

The study was conducted to evaluate the in vitro efficacy of seven plant essential oils against major fungal and bacterial pathogens causing significant diseases in cauliflower: Sclerotinia sclerotiorum (stalk rot), Alternaria brassicicola (alternaria leaf spot) and Xanthomonas campestris pv campestris (black rot). The essential oils tested included Mentha arvensis, Eucalyptus hybrid, Rosmarinus officinalis, Melia azedarach, Syzygium aromaticum, Tagetes minuta and Cinnamomum camphora, evaluated at concentrations ranging from 25 to 250 ppm using poisoned food technique for fungi and inhibition zone assay for bacteria. Results showed varied inhibitory effects among the oils. C camphora demonstrated the highest mycelial growth inhibition against S sclerotiorum (83.06%) and A brassicicola (82.50%). For the bacterial pathogen, X campestris pv campestris, S aromaticum exhibited the maximum inhibitory effect (34.33 mm inhibition zone) followed closely by M azedarach and C camphora. These findings highlight the potential of certain plant essential oils as promising bio-fungicides and bio-bactericides, offering eco-friendly alternatives for the sustainable management of cauliflower diseases, thereby, reducing reliance on synthetic chemicals and addressing residue concerns.