PLANT-PARASITIC NEMATODES ASSOCIATED WITH DATE PALM TREES (PHOENIX DACTYLIFERA L.) IN THE SULTANATE OF OMAN

Abstract

Surveys were conducted in the Batinah, Interior, Sharqia and Dhahira regions and in the Musandam governorate in the Sultanate of Oman to study the occurrence, population density and geographical distribution of phytoparasitic nematodes associated with date palm. Surveys were conducted during two successive cropping seasons from October to April from 1990 to 1997. A total of 165 soil samples were collected and plant parasitic nematodes were identified from the rhizosphere of date palm. Mixed populations of 32 economically important plant-parasitic nematode species belonging to 17 genera were identified, with fifteen identified to species. Rotylenchulus anamictus was reported for the first time in the Arabian Peninsula, and Helicotylenchus digonicus represents a new record for the Sultanate of Oman. The important parasitic nematodes found in date palm rhizosphere included populations of elicotylenchus multicinctus, which ranged from 22-3960 nematodes/250 cm3 soil with high numbers at Seeb, Barka, and Rustaq; Meloidogyne incognita, ranged from 156-7560 juveniles/250 cm3 soil with high numbers at Quriyat and Buraimi; M. javanica, with 20-4000 juveniles/250 cm3 soil with high numbers at Wadi-Quriyat and Dhank; and Rotylenchulus anamictus with 400-12,600 nematodes/250 cm3 soil with high populations at Adam, Samail, Nizwa, Bahla, Al Hamra, Wadi-Quriyat, Ibri, Buraimi and Wadi Al Tayyin. Additionally, Helicotylenchus sp., Pratylenchus sp., and Rotylenchulus sp. were often observed at varying population levels. Other nematode genera identified were insignificant in most instances, usually occurring in low population densities. The effects of nematode damage on growth, vigor and yield of date palm need to be investigated.