Emergence of gracilacus species as one of the key plant-parasitic nematodes associated with cassava in east senatorial district, rivers state, Nigeria

The type, distribution and population of plant-parasitic nematodes on crops change over time and space. It is pertinent to know their current status to ensure effective management. A survey was carried out to determine the occurrence and population of plant-parasitic nematodes associated with cassava in the East Senatorial District of Rivers State, Nigeria. Multi-stage random sampling method was used to collect soil and root samples from 56 farms growing cassava in monoculture across four Local Government Areas. Plant-parasitic nematodes in samples were extracted using the modified Baermann’s method, then later identified and counted. Data obtained were processed using descriptive statistic. Five genera of plant-parasitic nematodes were found to be associated with cassava namely: Helicotylenchus, Pratylenchus, Tylenchus, Gracilacus and Meloidogyne. Gracilacus with a frequency of occurrence (FOC) 39.3% and Meloidogyne (FOC 44.5%) were the predominant plant-parasitic nematodes in soil and roots of cassava, respectively. Meloidogyne species (FOC 32.7%) and Gracilacus species (FOC 48.5%) were the most abundant in soil and roots of cassava, respectively. The findings of this study gave credence to the emergence of Gracilacus species as one of the key plant-parasitic nematodes associated with cassava in Rivers State.