Plant-Parasitic Nematode Genera Associated with Date Palm in Central Iraq

A survey of plant-parasitic nematode genera associated with roots of mature date palm trees was conducted in central Iraq to study their occurrence, population density, and geographical distribution. This study in Baghdad, Babil, Diyala, Karbela, Najaf, and Wasit governorates was conducted from 2019 to 2023, during the months from October to April. A total of 150 soil and root samples were gathered from 46 fields, and plant-parasitic nematodes were extracted and morphologically identified to genus level. Eleven genera of plant-parasitic nematodes were detected in the declining order of frequency: Tylenchorhynchus spp. (20%) in Baghdad, Babil, Diyala, Karbala, and Najaf; Meloidogyne spp. (17.3%) in Baghdad, Babil, Diyala, Najaf, and Wasit; Paratylenchus spp. (16%) in Diyala and Najaf; Helicotylenchus spp. (12%) in Baghdad, Diyala, Najaf, and Wasit; Tylenchus spp. (12%) in Baghdad, Babil, Diyala, Najaf, and Wasit; Aphelenchoides spp. (6.7%) in Babil, Diyala, Karbala, and Wasit; Pratylenchus spp. (4%) in Baghdad, Diyala, Najaf, and Wasit; Ditylenchus spp. (3.3%) in Babil and Najaf; Hoplolaimus spp. (1.3%) in Diyala; and Heterodera spp. and Scutellonema spp. (0.7% each) in Diyala. Population density was low in Baghdad. High population density was recorded for Meloidogyne spp. (37,625 J2/1,000 cm³ of soil) and the lowest population density occurred with Paratylenchus spp. (20 nematodes/1,000 cm³ of soil) in Diyala (Al-Jadidah). This appears to be the first report of occurrences of plant-parasitic nematodes of date palm in central Iraq.