Authors : T.I. Olabiyi , E.E.A. Oyedunmade , G.J. Ibikunle , O.A. Ojo , G.O. Adesina , K.A. Adelasoye and T.A. Ogunniran
Abstract: Laboratory experiments were conducted on the effect of leaf extract of some weeds on root knot nematode, Meloidogyne incognita and also on the chemical compounds in the leaf extract of some weeds. Leaf extracts were obtained from Sida acuta Burm F., Euphorbia hirta Linn Andropogon gayanus Kunth, Phyllanthus amarus Schum and Thomm and Cassia obtusifolia L. weeds. Distilled water and ethanol (95%) were used as the extraction media for nematode bio-assay and phyto-chemical analysis experiments, respectively. Concentrations of each leaf extract of the weed were 5, 10, 15 and 20% (w/v). Approximately, 100 M. incognita juveniles were dispensed into each Petri-dish containing the graded weed extracts, while M. incognita juveniles that were dispensed into distilled water only served as control. Each treatment, including the control, was replicated 10 times. M. incognita juvenile mortality rate increased with an increase in test plant extract concentrations and exposure time. In 15 and 20% (w/v) concentrations of Euphorbia hirta, Phyllanthus amarus and Cassia obtusifolia and 20% (w/v) concentration of Sida acuta and Andropogon gayanus, there was 100% M. incognita juvenile mortality by the 7th day. The result of phyto-chemical analysis revealed that Euphorbia hirta contained tannins, saponins, flavonoids and alkaloids; Andropogon gayanus contained saponins, flavonoids and alkaloids; Cassia obtusifolia contained tannins, flavonoids and alkaloids; Phyllanthus amarus contained tannins, saponins, flavonoids and alkaloids while Sida acuta contained tannins, saponins, flavonoids and sterols chemical compounds.
T.I. Olabiyi , E.E.A. Oyedunmade , G.J. Ibikunle , O.A. Ojo , G.O. Adesina , K.A. Adelasoye and T.A. Ogunniran , 2008. Chemical Composition and Bio-Nematicidal Potential of Some Weed Extracts on Meloidogyne incognita under Laboratory Conditions. Plant Sciences Research, 1: 30-35.