Additional information on Meloidogyne inornata Lordello, 1956 (Tylenchida: Meloidogynidae) and its characterisation as a valid species

Abstract

Abstract A root-knot nematode parasitising yakon (Polymia sonchifolia) in São Paulo State, Brazil, is identified as Meloidogyne inornata. The species is redescribed from this material and compared with the original description of M. inornata. The female perineal patterns have a distinct, high, dorsal arch composed of smooth to wavy striae, similar to Meloidogyne incognita. The female stylet is 15.0-17.0 μm long with the cone generally slightly curved dorsally and with well developed knobs. DGO is 3.5-4.5 μm. Males have a high, rounded, head cap that is continuous with the body contour and has a large, round, centrally concave, labial disc raised above the medial lips. The head region is never marked by incomplete annulations and the stylet is robust, 20.0-25.0 μm long, with a straight cone, cylindrical shaft with several small projections and pear-shaped, backwardly sloping knobs. The stylet length of second-stage juveniles is 10.0-13.0 μm, DGO is 2.5-3.5 μm, tail length is 35.0-58.0 μm and c = 6.7-13.9. Biochemically, the esterase phenotype I3 (= Y3) is species-specific and is the most useful character for differentiating M. inornata from other Meloidogyne species. Reproduction is by mitotic parthenogenesis, 3n = 54-58. In a soybean test, cv. Abura was susceptible and cv. LA411219 was highly resistant. As the type material is lost, a neotype female is formally designated.