Author Description

"Root-knot nematodes (RKNs) (Meloidogyne Goeldi, 1887) are plant endoparasites that induce galls on roots and cause severe economic damage to a wide range of plants worldwide. They were first recorded from New Zealand by Kirk in 1908. However, they are a difficult group taxonomically and the identification and distribution of RKN in New Zealand is not well documented. Correct identification of RKN to species level is an important component of crop and pasture management, especially for developing resistant varieties and effective crop rotations. It is also important for international trade and biosecurity. The present study was conducted with the objective of identifying the RKN species in New Zealand, summarising the work done, and indicating the areas where future research is needed. Nematodes were isolated from cultivated fields, pastures and orchards. Seven RKN species were characterised using both morphological and molecular approaches. PCR-based molecular analyses confirmed the presence in New Zealand of some highly polyphagous apomictic RKN species. Analyses using sequences of SSU, ITS and LSU allowed consistent discrimination between Meloidogyne fallax, M. hapla, M. minor, M. naasi, and M. trifoliophila, and also distinguished them from M. incognita, M. javanica, and M. hapla. In contrast, they did not separate M. incognita, M. javanica, and M. hapla, respectively. A properly designed survey, using additional sequences in a molecular study, is now needed to clarify whether other RKN species are present in New Zealand, possibly on indigenous plant species. This study also confirmed that M. hapla infects kiwifruit in New Zealand. Keywords: D2-D3 region of large subunit (LSU) 28S rDNA gene, molecular phylogeny, Meloidogyne spp., morphology, nematode identification, perineal patterns, plant-parasitic nematodes, potatoes, root-knot nematodes, PCR, internal transcribed spacer (ITS) region of rDNA, isozyme patterns, kiwifruit, white clover, tomatoes, small subunit