SUMMARY
Screening of 55 plant extracts against second stage juveniles of Meloidogyne incognita was conducted. These extracts were obtained from leaves, stems, and roots of 20 native Yucatecan plants, of which 13 species were characterized as endemic. These were Acalypha gaumeri, Ageratum gaumeri, Ambrosia hispida, Bidens alba, Blechum piramidatum, Caesalpinia yucatanensis, Calea urticifolia, Carlowrightia myriantha, Croton chichenensis, Eugenia yucatanensis, Eugenia winzerlingii, Furcraea cahum, Stenandrium nanum, Tephrosia cinerea, Trichilia arborea, Trichilia minutiflora, Randia longiloba, Randia obcordata, Randia standleyana, and Vitex gaumeri. An in vitro nematicidal assay, carried out at 250 and 500 ppm showed that extracts from Calea urticifolia leaves and roots, Eugenia winzerlingii leaves, and Tephrosia cinerea stems were the most active against M. incognita. The plant extracts were evaluated at 0, 50, 100, 200, 300, 400, and 500 ppm to obtain their median effective dose. Results showed that Eugenia winzerlingii leaf extract induced at 300 ppm mortalities of 77% and 84% after 48 and 72 hr, respectively. The activity demonstrated by Eugenia winzerlingii was good enough to propose this plant for further studies at greenhouse and field stages to determine its efficacy in soil.