Prevalence, polyphasic identification, and molecular phylogeny of dagger and needle nematodes infesting vineyards in southern Spain

The occurrence and geographic distribution of longidorid nematode species inhabiting the rhizosphere of grapevine plants in southern Spain were investigated. Nematode surveys were conducted on 77 vineyards during the spring seasons of 2006, 2007 and 2008 in the main Andalusian grapevine-growing areas, including the provinces of Cadiz, Crdoba, and Huelva. Morphological and morphometrical studies identified two Longidorus and nine Xiphinema species, viz.: Longidorus alvegus, L. magnus, Xiphinema adenohystherum, X. hispidum, X. index, X. italiae, X. lupini, X. nuragicum, X. pachtaicum, X. rivesi, and X. turcicum. Overall, frequencies of infestation were, in decreasing order: X. pachtaicum 90.8%, X. index 30.3%, X. italiae 13.2%, L. magnus 11.8%, X. hispidum 7.9%, X. lupini 3.9%, L. alvegus and X. rivesi 2.6%, and X. adenohystherum, X. nuragicum and X. turcicum 1.3%. Xiphinema hispidum, X. lupini, L. alvegus and L. magnus were compared with nematode type specimens and are reported for the first time in Spain. Furthermore, the male of L. alvegus is described for the first time in the literature. Molecular characterisation of these species using D2-D3 expansion regions of 28S rRNA, 18S rRNA and ITS1-rRNA was carried out and maximum likelihood and Bayesian inference analysis were used to reconstruct phylogenetic relationships among these species and with other longidorids. The monophily of the genera Xiphinema and Longidorus was accepted and the genera Paralongidorus and Xiphidorus were rejected by the Shimodaira-Hasegawa test based on tree topologies.