Occurrence, abundance and community diversity of plant-parasitic nematodes in vegetable production fields across selected local government areas of Gombe State, Nigeria

Abstract

Plant-parasitic nematodes (PPNs) are among the major biological constraints limiting vegetable production worldwide because they reduce plant growth, yield, and quality. Despite the economic importance of vegetable farming in Gombe State, Nigeria, information on the occurrence and diversity of PPNs remains limited. This study investigated the distribution, population density, relative abundance, frequency of occurrence, and diversity of plant-parasitic nematodes associated with cultivated vegetable fields across five major vegetable-producing Local Government Areas (Akko, Balanga, Dukku, Yamaltu Deba, and Kaltungo) in Gombe State. Soil samples were collected from farmers' fields and processed using the modified Whitehead and Hemming tray extraction technique. Recovered nematodes were identified to genus level using standard morphological keys. Thirteen genera of plant-parasitic nematodes were identified during the survey. Meloidogyne was the dominant genus, recording the greatest relative abundance (20.4%), highest population density (464.4 nematodes per 200 g of soil), and occurrence in all surveyed locations. Akko exhibited the greatest nematode diversity, whereas Dukku recorded the lowest diversity indices. Shannon diversity values ranged from 2.15 in Dukku to 2.62 in Akko. Chi-square analysis showed that most genera were uniformly distributed across the study area (P >0.05), although Helicotylenchus, Heterodera, Hoplolaimus, Rotylenchulus, and Tylenchulus varied significantly among locations (P < 0.05). The widespread occurrence of economically important genera, particularly Meloidogyne, indicates a considerable threat to vegetable production in Gombe State. The findings provide baseline information that will support the development of sustainable and integrated nematode management strategies aimed at improving vegetable productivity in northeastern Nigeria.