Plant Parasitic Nematodes Associated with Three African Indigenous Vegetables in Southwest Nigeria

Background and Objective: African indigenous vegetables are rich in nutrients and medicinal properties that are important for health and vitality, but their availability is on the decline partly due to attacks by plant parasitic nematodes, hence field surveys were conducted in 2016 and 2017 to investigate the distribution of plant parasitic nematodes and their interactions with free-living nematodes in fields planted to three African indigenous vegetables in Southwest Nigeria. Materials and Methods: A total of 180 soil samples were taken from 180 farms in all Local Government Areas (LGAs) visited in the four States in Southwest Nigeria. Samples were taken from three vegetable fields in all the LGAs visited. Nematodes were extracted from 200 mL sub-samples; the nematodes were counted and identified under a compound microscope using a pictorial guide. Results: The results showed that 16 genera of plant parasitic nematodes were found associated with Amaranthus cruentus, Solanum macrocarpon and Telfairia occidentalis. Meloidogyne, Helicotylenchus, Rotylenchulus, Xiphinema, Pratylenchus and Hoplolaimus were the most abundant nematode species encountered in vegetable fields in the study areas. The correlation analysis shows an antagonistic relationship between free-living nematodes and plant parasitic nematodes. Conclusion: There is a need to cultivate vegetable crops to suppress the populations of plant parasitic nematodes in Southwest Nigeria.