An Evaluation of the nematicidal potential of five botanicals in the management of meloidogyne Spp on tomato (Solanum Lycopersicum)

Abstract

In Ghana, information on plants antagonistic to nematodes is scanty compelling farmers to rely on synthetic chemicals which are effective but pose an environmental threat. This work aimed to evaluate the effect of aqueous leaf extracts of Khaya senegalensis, Tectona grandis, Azadirachta indica, Vernonia amygdalina and Bryophyllum pinnatum plants for the control of Meloidogyne spp. In evaluating the botanicals, a laboratory, field and pot experiments were conducted. The first experiment evaluated the effect of extracts from fresh leaves of K. senegalensis, T. grandis, A. indica, V. amygdalina and B. pinnatum on eggs hatchability and nematicidal activity against second stage juveniles of Meloidogyne spp in the laboratory. Results show that lower egg hatch and higher juvenile mortality occurred in the extracts and was concentration dependent. A. indica at 25% gave the lowest mean egg hatch of 2.33 and highest juvenile mortality of 65.16. The second experiment was carried out to evaluate the effect of aqueous leaf extracts of K. senegalensis, T. grandis, A. indica, V. amygdalina and B. pinnatum applied tosoil as drench on tomato plants. Although the botanicals were effective in the laboratory and pot experiments, they were moderately effective in the field.. The third experiment was carried out to evaluate the application of leaf extracts of K. senegalensis, T. grandis, A. indica, V. amygdalina and B. pinnatum as mulch and soil admixture on growth and severity of nematode infection on tomato plants. The results indicated that K. senegalensis, T. grandis, A. indica, V. amygdalina and B. pinnatum applied as soil-admixtures were more effective in controlling Meloidogyne than applied as mulch.