Chemical Compositions and Nematicidal Activities of Essential Oils on Meloidogyne hapla (Nematoda: Tylenchida) Under Laboratory Conditions

To evaluate the efficacy of natural nematicides for the control of root-knot nematode in strawberry greenhouses, commercial essential oils were examined by 24-well culture plate bioassay for their nematicidal activities against second-stage juveniles and eggs of Meloidogyne hapla. Based on the mortality of M. hapla juveniles at a concentration of 125 μg/mL, the most active essential oil was Alpinia galanga (100%), followed by Carum carbi (22.3%), Eugenia caryophyllata (9.4%), Cinnamonum zeylanicum (7.2%), Mentha pulegium (2.4%), and Foeniculum vulgare (2.1%). Moreover, A. galanga significantly reduced hatching at 7, 14, and 21 days after treatment. The volatile constituents identified in the A. galangal oil were methyl cinnamate (87.4%), 1,8-cineole (4.4%), β-pinene (2.5%), α-pinene (2.2%), and p-cymene (1.1%), as major constituents. Results of this study show that A. galangal essential oil and its major constituents may serve as an environmental friendly agent of a promising natural nematicide to control Meloidogyne spp.