Effect of <i>Maerua angolensis</i> and <i>Tabernaemontana elegans</i> leaf meal extracts on <i>Meloidogyne incognita</i> second-stage juvenile hatch and viability
The study examines the nematicidal effect of five leaf-meal extracts of <i>Maerua angolensis</i> and <i>Tabernaemontana elegans</i> on hatching and viability of second-stage juveniles (J2) of <i>Meloidogyne incognitain in vitro</i> assays. At all exposure times, J2-hatch inhibition and mortality caused by all plant extracts was significantly higher compared with the pluronic gel + deionised H<sub>2</sub>O treatment. Percentage J2-hatch inhibition and mortality increased with increasing exposure time for all extracts of both plants. After 21-days exposure, the partitioned-deionised H<sub>2</sub>O extracts of <i>M. angolensis</i> and <i>T. elegans</i> caused the highest J2 hatch inhibition (65.5 and 62.7%, respectively). After 72 h exposure, the partitioned-DCM and MeOH/DCM extracts of <i>M. angolensis</i> and the partitioned-deionised H<sub>2</sub>O extract of <i>T. elegans</i> had caused the highest J2 mortality (49.7, 48.1 and 48.3%, respectively). The results suggest that the compound of <i>T. elegans</i> causing J2 mortality may be either different in type or concentration to those in <i>M. angolensis</i>.