A study was conducted to find out the effect of three plant aqueous extracts against root-knot nematode (Meloidogyne javanica). In laboratory assays eggs and second-stage juveniles of M. javanica were exposed to aqueous extracts from leaves of milkweed (Calotropis procera), castor bean (Ricinus communis) and seeds of fennel (Foeniculum vulgare). The result of the laboratory experiment showed that all the extracts increased the percent inhibition of egg hatching with castor bean (85.5%) recording the highest the least inhibition was found in fennel (63%). Most mortality of second-stage juveniles was observed in leaf extracts of milkweed (86/6%), at the end of 48 h incubation. Aqueous extracts were evaluated at different concentrations (60 to 250 ppm) which was applied as soil drench one day after transplanting the tomato seedling. The number of M. javanica juveniles, root-knot index and number of egg masses per gram root were reduced by all treatments. In the pot, milkweed extracts showed the highest reduction in root-knot nematode infection. The application of extract of plants as a natural pesticide for future use against nematodes is highly promising. Plant extracts are a source of cheap and effective nematicides of root-knot nematode.

Keywords: Aqueous extract, castor bean, fennel, milkweed, Meloidogyne javanica