Potential of some Essential Oils to Control Meloidogyne Javanica on Eggplant

Abstract

Nematicidal activities of eight essential oils (Castor oil, Bitter almond oil, Sweet almond oil, Watercress oil, Ginger oil, Frankincense oil, Mint oil, Camphor oil) at four different concentrations were assayed against Meloidogyne javanica and the Oxamyl nematicide on the egg hatching, J2 mortality percentage, disease parameters of eggplant (egg masses, numbers of nematode galls, eggs /plant and number of J2 / 250 cm3 soil), plant growth parameters (shoot fresh weights and shoot dry weights and root fresh weight) as well as PPO and POD defense enzymes activities. All the essential oils at the applied concentrations suppressed egg hatching after 7 days, and J2 mortality after 72 hours’ exposure. There was a progressive decrease in egg hatching with rise in oils concentration. The highest concentration that gave the highest egg hatching reduction and J2 mortality was 1000 ppm. However, Ginger oil showed the highest reduction percentage in nematode galls (88.3%), egg-masses (89.5%), eggs /plant (92.2%) and number of J2 / 250 cm3 soil (90.2%), also gave the highest increased of shoot fresh weight (46.1%), shoot dry weight (62.8%), root fresh weight (42.2%), as well as POD enzyme activity (0.562) and PPO enzyme activity (0.487). This was followed by Watercress oil, then Castor oil while the treatment with Mint oil was of the least effect on reduction rate in nematode galls as compared with Oxamyl nematicide and untreated infected control. In conclusion, the essential oils showed effectiveness in reducing egg hatching and J2 mortality with ginger oil being the most impactful in reducing damage and promoting plant growth.