SURVEY OF PLANT-PARASITIC NEMATODES ASSOCIATED WITH YAMS IN OGUN AND OSUN STATES OF NIGERIA

A survey was conducted to determine the types, frequency and population of plant parasitic nematodes associated with the soils and roots of Yam (Dioscorea species) in all the Local Government Areas of Ogun and Osun States of Nigeria using random sampling soil and root and pie pan modification of Baerman funnel for plant parasitic nematode extraction. Ten and nine genera of plant parasitic nematodes were encountered both from the soils and root samples from the two States. Plant parasitic nematodes recovered included Scutellonema spp., Meloidogyne spp., Pratylenchus spp., Trichodorus spp., Helicotylenchus spp., Radopholus spp., Longidorus spp., Xiphinema spp., Rotylenchulus spp and Aphelenchoides species. Scutellonema spp., Meloidogyne spp., and Pratylenchus spp were most widely distributed with frequency ratings of 70, 65 and 60% respectively in soil samples from Ogun State and in the root samples the three genera predominated with 60, 55 and 45% frequency ratings respectively. Meloidogyne spp., Scutellonema spp., and Pratylenchus spp were most widely distributed with frequency ratings of 65, 45 and 35% respectively in soil samples from Osun State and in the root samples the three genera predominated with 55, 35 and 35% frequency ratings respectively