Occurrence, Diversity and Abundance of Nematode Pests of Pineapple (Ananas comosus) in Two Local Government Areas of Rivers State, Nigeria

Plant-parasitic nematodes (PPNs) contribute to yield losses in pineapple production. Limited studies have been conducted on plant-parasitic nematodes on pineapple despite reports of PPNs infecting it. A survey was conducted in Obio-Akpor and Ikwerre Local Government Areas (LGAs) of Rivers State to determine the occurrence, abundance and diversity of PPNs associated with pineapple. A total of 60 composite samples were collected from the two LGAs. Nematodes were extracted from soil and root samples using the modified Baermann technique and identified using standard procedures. Data were processed using relative frequency of occurrence (RFOC), relative importance values (RIVs), diversity indices, nematode population was calculated and analysis of variance. The most occurring plant-parasitic nematodes were Pratylenchus, Helicotylenchus, Meloidogyne, Scutellonema and Tylenchulus. In Obio Akpor LGA, Helicotylenchus with RFOC 33.3% was the most occurring nematode pests, while Pratylenchus was the most important plant-parasitic nematode (RIV 33.8%). In Ikwerre LGA, both Helicotylenchus and Pratylenchus have the same occurrence (RFOC 33.3%) with Pratylenchus being the most important nematode pest. Pratylenchus species with RIV of 52.4% were the most important PPNs associated with pineapple in both Obio-Akpor and Ikwerre LGAs. Dominance and Shannon- Weiner indices among the PPNs are 0.58 and 0.86, respectively. In Ikwerre and Obio-Akpor LGAs, Aluu (1530) and Rumuekini (630) pineapple farms have the highest population of PPNs, respectively. Ikwerre LGA (2,150) pineapple farms had more PPNs than Obio-Akpor LGA (660). Nematode pests are associated with pineapple in the two LGAs and could be contributing to yield losses.