Eco-friendly management of the citrus nematode Tylenchulus semipenetrans using some aromatic and medicinal plants

Abstract

Tylenchulus semipenetrans is among the most damaging obligate plant parasitic nematodes (PPNs) in citrus. The use of chemical nematicides has successfully been used to lower the population of T. semipenetrans, but the repetitive use of these compounds can be environmentally harmful requiring the implementation of ecological strategies. The present study aimed at assessing the biological control potential of Essential Oils (EOs) of seven aromatic and medicinal plants (AMP), Rosmarinus officinalis, Thymus vulgaris, Laurus nobilis, Verbena officinalis, Foeniculum vulgare, Moringa oleifera, and Chamaemelum nobile against the citrus nematode T. semipenetrans in terms of juvenile J2 mortality and eggs hatch inhibition. Obtained results showed that all EOs exhibited high toxicity against T. semipenetrans. Indeed, the juvenile J2 mortality (ranging between 4% and 23% after 24 h of incubation), and eggs hatch inhibition (varying between 0% and 69% after 48 h of incubation) increased with increasing EOs concentration and incubation period reaching 100% of mortality after 96 h and complete eggs hatch after 144 h of incubation at EOs concentration of 20 μl/ml. In addition, the efficiency of EOs varied significantly between the seven AMP species. Indeed, R. officinalis and T. vulgaris were highly active on T. semipenetrans inducing 100% of J2 mortality recorded after 72 h of incubation at 15 µl/ml, and complete eggs hatch inhibition regardless of the EOs concentration and incubation period. As a result of this study, EOs of the AMP studied, particularly R. officinalis and T. vulgaris, could be used as healthy nematicidal products that are highly effective against T. semipenetrans.