Nematicidal Effect of Organic Extract Metal Complex on Meloidogyne incognita Infecting Groundnuts (Arachis hypogea)

Abstract The control of plant parasitic nematodes is constantly associated with environmental pollution problems which emanates from the ability of synthetic nematicides to bind strongly to different soil types owing to their hydrophilic nature. This research attempted to determine the nematicidal potential of copper, iron and zinc salts complexed with methanolic extract of Enantia chloranta on Meloidogyne incognita infecting groundnut plants on the field. Carbofuran, a synthetic nematicide was used as a reference standard. The experiment was a randomised complete block design which was conducted in two raining seasons (2017 & 2018). Two grams (2 g) of each of the metal salts were reacted with 300 ml of E. chloranta methanolic extract. Good nematicidal activity was displayed by E. chloranta crude extract copper complex (ENCT/CuSO4) close to the value obtained with carbofuran (CBFN), iron and zinc salt complexes (ENCT/FeSO4 and ENCT/ZnSO4) were also significantly (p<0.05) effective. Toxicity of the metal salt complex to M. incognita was dose dependent. Vegetative growth and yield was significantly (p<0.05) higher in plants treated with the highest concentration of the metal complex solution. Significantly lower nematode population was seen at harvest in the roots of treated plants as opposed to the untreated plants. This research has demonstrated that the E. chloranta metal complex is a promising nematicidal substance.