FREQUENCY AND POPULATION DENSITY OF PLANT PARASITIC NEMATODES ASSOCIATING DATE PALM CULTIVARS IN RIYADH, SAUDI ARABIA

Abstract A survey of plant parasitic nematodes was conducted in the rhizosphere of 30 date palm (Phoenix daetylifera L.) cultivars in Riyadh region, Saudi Arabia. A total of 296 composite soil and root samples were collected and assayed for nematode extraction and identification. Fighteen genera of plant parasitic nematodes were found in the following descending order of frequency: Helicotylencilus (64.9%), Meloidague javanica (52%), Aphelenchus (14.5%), Hoplotaimus (10.8%), Rotylenchulus (7.4%), paratrichodorus (6.4%), Pratylenchus (6.1%), Trichodarus (5.7%), Ditylenchus and Longidorus (3.7%, each), Zygotylencghus (2.7%), Xiphinema (2%), Aphelenchoides (1.7%) and Paralylenchus (0.7%). Date palm cv. Nebut saif was the cultivar most associated with plant nematode genera, followed by cvs. Khalas, Menefi, Barhi and Khudair, whereas cvs. Anbara and Trichodorus on cv. Khashram to 4452/kg soil for Hellcatylenchus on cv. Anbara. Prominence values of the associated nematodes revealed that Helicotylenchus, Tylenchorhynchus, Meioidogyne and Hemicrieonemuides were the most prominent. Only Helicotylenchus and Meloidogyne were found on all surveyed date palm cultivars. This is the first report on the occurrence of Dilylenchus sp., Meloidogyne favanica, Paratrichodorus sp. and Zygotylenchus sp. in the rhizosphere of date palms in Saudi Arabia. Keywords: date palm, frequency, new records, phoenix dacrylfarn, plant patristic nematodes, population density, prominence, Saudi Arabia, survey