Title of Article: Studies on the Distribution of Plant-parasitic Nematodes Associated with Pineapple in Delta, Imo and Cross River states of Nigeria Authors: Fisayo Daramola and Steven Afolami

Background: Plant-parasitic nematodes are important pests of horticultural crops causing damage and significant reduction in the crop yield of pineapple. A survey was conducted to determine the types, frequency and population distribution of plant-parasitic nematodes associated with pineapple in some pineapple-producing states in Nigeria. A total of 30 farms were sampled from Delta, Imo, and Cross-River States using the Agricultural Development Project in each state as a pilot to locate representative farmlands in the States. Soil samples for the survey with were collected from the rhizosphere of the pineapple plants with the aid of a soil auger to a depth of about 15 cm and within a 25 cm radius from the base of the pineapple plants. Vermiform nematodes were extracted from 200g each of the composite samples using a modified Baermann extraction tray set-up. Objective: To provide an update on the diversity and population distribution of plant-parasitic nematodes associated with pineapple in Delta, Cross River and Imo states of Nigeria. Result: Fourteen species of Plant-Parasitic Nematodes (PPN) were found associated with pineapple from the fields surveyed as follow: Pratylenchus brachyurus, Meloidogyne incognita, Rotylenchulus reniformis, Helicotylenchus dihystera, Scutellonema brachyurum, Tylenchus sp., Hoplolaimus pararobustus, Criconemoides limitaneum, Paratylenchus minutus, Gracilacus sp., Hemicycliophora sp., Aphelenchus sp., Aphelenchoides sp. and Xiphinema nigeriense. The most prominent phytophagus nematode found in association with pineapple on all the fields was P. brachyurus with frequency ratings of 100%, 92% and 87% from Delta, Imo and Cross-river states respectively. Meloidogyne sp., Pratylenchus reniformis and Rotylenchulus reniformis were also frequently encountered in the three states. Grasilacus sp. was recorded on pineapple for the first time in Nigeria. Conclusion: The study indicated a widespread distribution of PPN on pineapple in south-south and south-east Nigeria which could be a factor responsible for low yields recorded in some pineapple fields. Therefore, there is an obvious need for pineapple farmers to control plant-parasitic nematodes for improved crop yield.