Evaluation of nematicidal activity of the essential oil of Homalomena occulta (Lour.) Schott rhizome and its major constituents against Meloidogyne incognita (Kofoid and White) Chitwood

In a screening program for new agrochemicals from Chinese medicinal herbs and wild plants, essential oil of Homalomena occulta (Lour.) Schott rhizome was found to possess strong nematicidal activity against the root-knot nematodes, Meloidogyne incognita (Kofoid and White) Chitwood. The essential oil of H. occulta rhizome was extracted via hydrodistillation and investigated by gas chromatography-mass spectrometry (GC-MS). A total of 39 components of the essential oil were identified. Linalool (47.7%) was the major compound of the essential oil of H. occulta followed by 4-terpineol (16.5%) and α-terpineol (11.2%) and 87.3% of the total components were monoterpenoids. The essential oil possessed strong nematicidal activity against M. incognita with a LC50 value of 156.43 μg/ml. α-Terpineol and 4-terpineol exhibited toxicity against M. incognita with LC50 values of 103.41 μg/ml and 115.17 μg/ml, respectively while linalool had a LC50 value of 180.36 μg/ml.