Additional information on Meloidogyne ethiopica Whitehead, 1968 (Tylenchida: Meloidogynidae), a root-knot nematode parasitising kiwi fruit and grape-vine from Brazil and Chile

Abstract

Abstract A root-knot nematode parasitising kiwi fruit (Actinidia deliciosa) in Rio Grande do Sul State, Brazil and grape-vine (Vitis vinifera) in Chile, is identified as Meloidogyne ethiopica Whitehead, 1968. The species is redescribed from this new material and compared with the type description of M. ethiopica and another population of the species from Kenya. The female has an oval to squarish perineal pattern with a moderately high to high dorsal arch, smooth, widely spaced striae, and no 'shoulders'. The head region is set off with an elevated squarish labial disc, usually marked by annulations, and the stylet is 12-15 μm long, the cone usually being slightly curved dorsally and the shaft gradually widening posteriorly to near the junction with the rounded stylet knobs. The DGO is 3.0-5.0 μm behind the knobs. The male has a high, rounded head cap which is continuous with the body contour and has a distinct labial disc, almost circular to hexagonal in shape, and distinctly separated from the medial lips. The stylet is robust, 23-27 μm long with a straight cone and a cylindrical shaft widening slightly near its junction with the basal knobs which are smooth, round to pear-shaped and backwardly sloping. The stylet length of the second-stage juvenile is 11-14 μm, the DGO is 2.0-3.0 μm behind the knobs and the tail length is 52-72 μm. Biochemically, the esterase phenotype E3 ( Ki3) is species-specific and is the most useful character for differentiating M. ethiopica from other species. Reproduction is by mitotic parthenogenesis, 2n 36-38. In a differential host test, populations of M. ethiopica reproduced on tomato, tobacco, pepper and watermelon. No reproduction occurred on cotton or peanut. Using the PCR-RAPD analysis to compare populations from Brazil, Chile and Kenya, a low proportion of polymorphic fragments (about 17.7%) was detected and the isolates clustered together with high bootstrap support (100%), thus confirming that all three populations are very similar and apparently conspecific.