Effect of Maerua angolensis and Tabernaemontana elegans leaf meal extracts on Meloidogyne incognita second-stage juvenile hatch and viability

The study examines the nematicidal effect of five leaf-meal extracts of Maerua angolensis and Tabernaemontana elegans on hatching and viability of second-stage juveniles (J2) of Meloidogyne incognita in in vitro assays. At all exposure times, J2-hatch inhibition and mortality caused by all plant extracts was significantly higher compared with the pluronic gel + deionised H2O 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 H2O extracts of M. angolensis and T. elegans caused the highest J2 hatch inhibition (65.5 and 62.7%, respectively). After 72 h exposure, the partitioned-DCM and MeOH/DCM extracts of M. angolensis and the partitioned-deionised H2O extract of T. elegans had caused the highest J2 mortality (49.7, 48.1 and 48.3%, respectively). The results suggest that the compound of T. elegans causing J2 mortality may be either different in type or concentration to those in M. angolensis.