Comparative Analysis of the Effects of Some Selected Leaf Extracts on Growth Characteristics of Tomato Plant Infected with Meloidogyne incognita

Abstract

This study evaluated the comparative effects of leaf extracts of Vernonia amygdalina (bitter leaf), Polyalthia longifolia (false ashoka), and Jatropha curcas (jatropha) on the growth characteristics of tomato plants infected with Meloidogyne incognita, a root-knot nematode known to significantly reduce crop productivity. The experiment was conducted using a completely randomized design, with treatments consisting of the three plant extracts and an untreated control. Key growth parameters assessed included leaf length, shoot height, leaf width, leaf shade, and plant girth. The results revealed that all treated plants performed better than the control, indicating the effectiveness of the leaf extracts in mitigating the adverse effects of nematode infection. Among the treatments, Vernonia amygdalina showed the highest improvement in shoot height and plant girth, suggesting strong growth-promoting and nematicidal properties. Polyalthia longifolia recorded the highest values for leaf length and leaf width, indicating its potential in enhancing foliage development. Jatropha curcas exhibited moderate effects across most parameters but was less effective compared to the other extracts. Statistical analysis showed that the differences among treatments were significant (p < 0.05), confirming the reliability of the observed effects. In conclusion, the study demonstrates that Vernonia amygdalina and Polyalthia longifolia are particularly effective in improving the growth performance of tomato plants under nematode stress. These findings highlight the potential use of these plant extracts as eco-friendly alternatives to chemical nematicides in sustainable tomato production systems.