Evaluation of Plant Extracts against Root-Knot Nematodes in Okra
Year: 2026
Type: article
Abstract: Root-knot nematodes (Meloidogyne spp.) are major plant pathogens causing substantial reductions in crop growth and yield. This study evaluated the nematicidal efficacy of selected plant extracts (garlic, neem, marigold, ginger, and turmeric) at concentrations of 1, 2.5, and 5% compared with the chemical nematicide carbofuran, and assessed their effects on nematode infestation, plant growth, and yield of okra (Abelmoschus esculentus). The nematode-inoculated untreated control recorded the highest infection levels, with a gall index of 8.5, 155 egg masses per plant, 1950 soil J2s/100 g, and 475 root J2s/g, together with the lowest fruit yield (75 g/plant). In contrast, garlic extract at 5% showed the greatest efficacy, reducing the gall index to 1.2, egg masses to 15, soil juveniles to 210 J2s/100 g, and root juveniles to 48 J2s/g, representing an 85.9% reduction, while increasing yield to 208 g/plant. The difference in yield between garlic 5% and the absolute control (215 g/plant) was only 7 g, which was lower than the calculated Least Significant Difference (LSD = 15), indicating no significant difference between them. All botanical treatments exhibited a concentration-dependent response, with neem and marigold showing moderate effectiveness, whereas turmeric and ginger were less effective, particularly at lower concentrations where turmeric recorded the lowest yield (90 g/plant). The absolute control produced the highest yield (215 g/plant), confirming the negative impact of nematode infestation. Carbofuran improved yield to 180 g/plant but was less effective than garlic in several parameters. Overall, the results demonstrate that plant extracts, particularly garlic, possess strong potential.
Authors: Nashwa M. Hussein, Faten A. Hamdi
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W7160763023