The Vectorial Role of The Earthworm In Plant-Parasitic Nematode Dispersal

Plant-parasitic nematodes (PPNs) pose a significant threat to global agriculture, resulting in substantial annual crop yield losses. Although largely immobile in soil, PPNs exploit earthworms as biological vectors for dispersal across farmlands. This study investigated the complex interactions between earthworms and PPNs, specifically examining how earthworm burrowing, feeding, and casting behavior facilitates or impedes nematode migration. Specimens of Lumbricus terrestris were extracted from three soil types — swampy, semi-dry, and dry — within the Kolo Creek area of Ogbia Local Government Area, Bayelsa State, Nigeria. Following dissection, gut contents were analyzed using the Baermann funnel method for nematode identification and quantification. Results indicated the presence of PPNs across all soil environments: 23 individuals (51%) from swampy land, 17 (37%) from semi-dry land, and 5 (11%) from dry land. A one-way Analysis of Variance (ANOVA) confirmed that these differences were statistically significant (P < 0.05), indicating that soil moisture significantly influences earthworm vectorial capacity. These findings underscore the role of earthworms as vectors in dispersing economically important PPNs. An understanding of this relationship is vital for developing sustainable agricultural management strategies that effectively control PPN infestations while preserving the beneficial ecological services provided by earthworms.