Screen house experiment to determine the effect of the aqueous leaf extract of Jatropha on the control of Meloidogyne javanica infections on tomato (Solanum lycopersicum) was conducted at Federal College of Agriculture, Ishiagu in 2016. UC82B tomato was used as the test crop. The test crop was planted in pots filled with 5 kg sterilized soil. Each pot was inoculated with 3000 M. javanica eggs collected from the infected roots of begonia plant. The aqueous extract was used at three

more »

... of 150, 300 and 450 g/l and applied to each pot with water as the control. The parameters evaluated were plant height (cm), number of leaves at 50% anthesis, stem girth (cm), fruit weight (kg), number of galled roots and root gall index at harvest. The leaf extracts increased significantly (P<0.05) the plant height, number of leaves, stem girth and fruit weight. There were significant (P<0.05) reductions in the number of galled roots and root gall indices with increase in the concentrations of the leaf extract. The extract at 450 g/l showed better potential in the control of M. javanica infections on tomato and could therefore be recommended to tomato farmers for trial under field conditions.