Occurrence and prevalence of nematodes in yam fields from four community-based farming scheme locations in Ogun State, Nigeria
Nematodes is one of the major biotic constraints affecting profitable yam production throughout Nigeria. They affect yams both in the field and in storage thus threatening food security and economic deprivation to growers and their households. The research work identified the types, frequency and population of nematodes associated with Dioscorea rotundata grown by the Farm Practical Year Programme Trainees of the Federal University of Agriculture, Abeokuta in four Community-based Farming Scheme locations, namely Isaga-Orile, Iwoye-Ketu, Ode-Lemo and Odogbolu in Ogun State. Soil samples were taken and assayed for nematode populations. Results showed that 26 Nematodes genera were found in the four locations ranging from 11 to 3201 individuals/250 g soil. Genera of plant-parasitic nematodes recovered included Scutellonema, Meloidogyne, Pratylenchus, Paratylenchulus, Trichodorus, Helicotylenchus, Hoplolaimus, Tylenchorhynchus, Aphelenchus, Xiphinema, Ditylenchus, Rotylenchulus, Rotylenchus and Aphelenchoides while the free-living nematode genera found included Aulolaimoides, Cephalobus, Cylindrocorpus, Lotonchus, Monhystera, Oncholaimus, Paraplectonema, Prismatolaimus, Dorylaimus, Tylencholaimellus, Tylencholaimus, and Tyleptus. Out of the twenty-six nematodes encountered, Meloidogyne spp. Scutellonema spp. and Pratylenchus spp. were mostly encountered in the soil and the only three recovered from the tubers which mean that these three nematodes are of economic importance to yam production. Farmers are therefore advised to go into yam production with management measure of nematodes putting the three key nematodes in mind, in order to avoid yield loss.
Keywords: White guinea yam; Meloidogyne spp.; Scutellonema spp.; Pratylenchus spp.