NEMATICIDAL ACTIVITY OF WILD PLANT EXTRACTS AGAINST SECOND-STAGE JUVENILES OF NACOBBUS ABERRANS
Nacobbus aberrans affects the production of crops of economic importance such as chili pepper, tomato, and bean. To control this nematode, it is of interest to study environmentally friendly strategies. In this regard, the aim of this work was to evaluate the in vitro effect of ethanolic extracts (500 ppm) from 20 wild plants (foliage tissue) against second-stage juveniles of N. aberrans. At 24, 48, and 72 hr, the extracts of Verbesina sphaerocephala, Cosmos sulphureus, and Senecio salignus showed the highest immobility effects, respectively (P≤0.05). At 72 hr, after replacing the extracts with water, C. sulphureus had the highest mortality rate (79.45±5.03%). Other extracts with significant nematicidal effects (P≤0.05) were Witheringia stramoniifolia (73.57±8.07%), Tagetes lunulata (73.12±7.40%), S. salignus (71.25±5.02%), and Lantana camara (70.15±11.07%). Since several phenolic compounds have been reported to be nematotoxic, the total phenolic (TPC) and flavonoid (TFC) contents in the plant material were determined. T. lunalata and C. sulphureus recorded the lowest and highest TPC, respectively (P≤0.05); in turn, Dodonaea viscosa recorded the highest TFC, and the Ximenia parviflora recorded the lowest (P≤0.05). In some cases, the abundance of these compounds resulted in a significant nematicidal effect as it occurred with the W. stramoniifolia, C. sulphureus, Asclepias linaria, and Nicotiana glauca extracts. Plant material with significant toxic effects could be assessed at the field level and incorporated into the soil as organic amendments to create suppressive environments against N. aberrans.