In vitro effectiveness of plant extracts on the mortality of root-knot nematodes

Resumen

Objective: To identify plants with nematicidal potential against Meloidogyne enterolobii and Nacobbus aberrans for potential use in sustainable agricultural practices.

Design/methodology/approach: Six aqueous extracts (AEs) from the leaves of Origanum vulgare, Foeniculum vulgare, Dracocephalum moldavica, Thymus vulgaris, Dysphania ambrosioides, and Melissa officinalis were evaluated for the control of second instar (J2) juveniles of Meloidogyne enterolobii and Nacobbus aberrans. The solution obtained was designated as standard (100%) and was diluted with distilled water to concentrations of 25%, 50% and 100%. Sterile distilled water was included as a test sample. Each concentration was repeated four times, using 400 J2/concentration. Mortality observations were performed at 6, 24 and 48 h. A nonparametric factorial analysis was performed using aligned ranks in R.

Results: The factorial analysis of variance for the main effects—P (Plant) and T (Time)—on the mortality of M. enterolobii (Me) and N. aberrans (Na) J2 showed highly significant differences (p ≤ 0.05), as well as a significant P*T interaction effect. All aqueous extracts at 100% concentration caused the highest J2 mortality for M. enterolobii at 24 hours and for N. aberrans at 12 hours using the 25% concentration.

Limitations on study/implications: This study serves as a foundational step for future research and represents the first attempt to propose the use of these plant species for the control of root-knot nematodes through nematicidal activity.

Findings/conclusions: Our results demonstrate, for the first time, the in vitro nematicidal activity of plant extracts of Dysphania ambrosioides, Melissa officinalis, Foeniculum vulgare and Thymus vulgaris against the nematodes M. enterolobii and N. aberrans. These findings support the need for further research under soil conditions and metabolomic studies to identify the active compounds responsible for this effect.