Effects of Essential Oils and Plant Extracts on Hatching, Migration and Mortality of Meloidogyne incognita

Abstract

The nematicidal activity of the essential oil/pure components and plant extracts of naturally grown aromatic plant species against hatching, migration and mortality of the root knot nematode Meloidogyne incognita was investigated. The pure components carvacrol, thymol, and linalool at 1, 2 and 4 mg liter-1 concentrations were the most toxic against M. incognita second-stage juveniles (J2s) followed by terpineol and menthone. Hatching was completely inhibited at low concentrations (2, 4 mg liter-1) of carvacrol, thymol, and linalool. Clove extracts (1 mg liter-1) of Allium sativum significantly reduced hatching activity to below 8%, followed by flower extracts of Foeniculum vulgare which reduced hatching to below 25%. These extracts were also toxic against J2s of M. incognita (LC50 43) followed by leaf extracts of Pinus pinea, Origanum syriacum, Mentha microcorphylla, Eucalyptus spp. and Citrus sinensis with an estimated LC50 of 44, 50, 65, 66 and 121 ppm respectively. Flower extracts of F. vulgare had the highest effect on J2 mortality in sand (86%). The highest concentration of essential oils (6%) was detected in leaf extracts of Origanium syriacum. Over 30 major components were identified in all the plant extracts tested.