Characterization of Root-knot Nematodes (Meloidogyne spp.) Associated with Abelmoschus esculentus, Celosia argentea and Corchorus olitorius

Vegetable crops are highly susceptible to a wide range of pests and diseases among which are the root-knot nematodes (Meloidogyne species). Traditionally, identification of Meloidogyne species had been based on use of morphological characters such as the perennial pattern. In recent times, accuracy of nematode identification using only morphological tools has been challenged due to similarities in morphological characters of some nematode species. The aim of this study was to identify the root-knot nematodes associated with some vegetable crops cultivated on Covenant University farm, Ota, South-west, Nigeria using molecular tools and to determine the population densities of Meloidogyne spp. on the selected vegetable crops. Plant-parasitic nematodes were extracted from soil and roots of Abelmoschus esculentus, Celosia argentea and Core horus olitorius cultivated on Covenant University farm. The nematode species were identified and counted under a compound microscope. The molecular characterization of the Meloidogyne species was done using single adult female nematodes and eggs which were picked out for DNA extraction and amplified with specie-specific primers through Polymerase Chain Reaction (PCR) and separated on 0.5% agarose gel. High population of plant- parasitic nematodes was recorded on the vegetable crops cultivated on covenant university farm. Also significantly higher population (p<0.005) of Meloidogyne spp. were found in association with C. argentea and Corchorus olitorius than those recorded on Abelmoschus esculent us from the vegetable farm. The molecular characterization of the Meloidogyne species from the farm indicates Meloidogyne incognita as the nematode species associated with the vegetable crops.