Incidence of plant-parasitic nematodes in natural and semi-natural mountain grassland and the host status of some common grass species

A plant-parasitic nematode survey was undertaken in mountainous pastures of southern Spain. Sixty-three species of plant-parasitic nematodes distributed over 25 genera were associated with pastures and grasslands in southern Spain. Paratylenchus species (P. microdorus, P. similis, P. nanus and P. ciccaronei) were the most abundant and prevalent plant-parasitic nematodes found. Pratylenchus neglectus and P. thornei were widely distributed in 55 and 41% of sites, respectively. Amplimerlinius globigerus, Helicotylenchus digonicus, H. dihystera, H. tunisiensis, Merlinius brevidens, M. microdorus, Rotylenchus unisexus and Scutylenchus quadrifer were found in more than 10%, of the fields, on occasion at densities of more than 200 per 100 cm(3) of soil. A further 49 species of plant-parasitic nematodes were identified and reported. A pot experiment, using a range of grasses and forage legumes adapted to the zone, ascertained the host status of the most abundant plant-parasitic nematodes. Helicotyenchus digonicus, M. microdorus and P. neglectus populations were maintained or increased by all grasses or legumes tested. In general, grasses were better hosts of P. neglectus and P. thornei than the pasture legumes tested. Medicago minima reduced P. thornei densities after 3 months of growing.