Plant parasitic nematodes associated with cassava in the west senatorial district of Rivers State, Nigeria

Nigeria, though not listed among the five highest yield per hectare producers of cassava is the world’s largest producer of the crop while Thailand is the largest exporting country of dried cassava. Plant parasitic nematodes (PPNs) are severe pests contributing to poor growth and yield of the crop. Effective management of PPNs depends on identification and determination of their distribution and population over time and space. This study was conducted to determine the occurrence and population of PPNs in cassava from four Local Government Areas (LGAs): Ahoada East, Ahoada West, Asari-Toru and Degema of Rivers West Senatorial District, Rivers State, Nigeria. Multistage random sampling method was adopted to collect a total of 57 samples from cassava monoculture farms across the four LGAs in the senatorial district. Plant parasitic nematodes were extracted from roots and soil of cassava using standard procedures. Data were processed using descriptive statistics. Five genera of plant parasitic nematodes were encountered in the study: Meloidogyne spp., Pratylenchus spp., Gracilacus spp., Helicotylenchus spp. and Scutellonema spp. The frequencies of occurrence (FOC) of the PPNs in root samples were 57.78%, 31.1%, and 8.89%, for Meloidogyne spp., Pratylenchus spp., and Gracilacus spp., respectively. A similar trend in occurrence of PPNs was also observed in the soil samples. However, Gracilacus species were the most abundant in roots (22.5/10 g roots) and soil (28.75/200 ml soil) of cassava across the four LGAs. Meloidogyne species occurred most frequently while Gracilacus species was most abundant among the plant-parasitic nematodes of cassava in the study area.