Recent Advances and Developments in the Nematicidal Activity of Essential Oils and Their Components against Root-Knot Nematodes

Abstract

The Meloidogyne genus is widely recognized for its significant economic and scientific importance within the group of plant-parasitic nematodes. The chemical management of nematodes presents its challenges and heavily depends on employing soil fumigants containing toxic and costly nematicides. However, plant-derived essential oils offer promising alternatives, demonstrating a wide range of biological activities that affect nematodes through a range of mechanisms, including disrupting their nervous systems, inducing detrimental effects on plasma membrane permeability, penetrating the gelatinous matrix of nematode eggs, and disturbing intracellular redox status. Most of the extracted essential oils were predominantly sourced from the Lamiaceae family (32%), followed by Asteraceae (11%), Apiaceae (9%), and Poaceae (8%), and with genera Thymus, Mentha, Ocimum, Artemisia, Cymbopogon being the most common. The nematicidal activity of EOs primarily arises from their chemical groups, such as terpenes, phenylpropanoids, and organosulfur compounds. Among these, geraniol, carvacrol, limonene, eugenol, thymol, and pinene demonstrate the strongest nematicidal potential. The assessed EO efficacy was evaluated against 6 species belonging to the genus Meloidogyne. This review also provides knowledge of synergistic and antagonistic interactions of EO components. Synergistic interactions were identified between carvacrol and geraniol, as well as geraniol and eugenol, whereas binary combinations of carvacrol, γ-terpinene, and o-cymene exhibited reduced efficacy. Understanding how specific compounds interact can lead to the development of more potent and effective final products.