LAUSR

Abstract A survey of plant-parasitic nematode genera associated with certain greenhouse vegetable crops was conducted in Riyadh region, central of Saudi Arabia. In this respect, a total of 349 roots and rhizosphere soil samples were collected from the surveyed plants as follows: tomato, Solanum lycopersicum (140 samples); cucumber, Cucumis sativus (128); aubergine, Solanum melongena (25); sweet pepper, Capsicum annuum (26); green beans, Phaseolus vulgaris (22); and squash, Cucurbita pepo (8). Nematodes were extracted by centrifugal flotation and identified at the generic level using the standard identification keys. Results showed that a total of 18 plant-parasitic nematode genera were found to be associated with the six surveyed plant species. These genera, in a general descending order of occurrence frequency (FO%) were: Meloidogyne (45.8%), Aphelenchus (16.6%), Tylenchorhynchus (12.9%), Aphelenchoides (12%), Ditylenchus (10.3%), Pratylenchus (3.7%), Tylenchus (2.3%), Subanguina , Trichodorus , Tylencholaimus (1.7%, each), Hemicriconemoides (0.9%), Helicotylenchus , Longidorus , Merlinius (0.6%, each), Paratrichodorus , Paratylenchus , Telotylenchus and Zygotylenchus (0.3%, each). Identification of the root-knot nematode species revealed that M. javanica was the most common root-knot nematode infecting the surveyed greenhouse vegetable crops in general, However M. incognita was found in 2% of the examined root samples.