10th U6+ Consortium of African Universities International Conference

Plant-parasitic nematodes (PPNs) are significant constraints to finger millet production in Kenya, yet their diversity and distribution in the major growing regions remain poorly characterized. This study assessed the community composition, frequency, and diversity of PPNs associated with finger millet (Eleusine coracana) in Kapsowar ward, Elgeyo-Marakwet County. Soil and root samples were collected from twenty farms along an altitudinal gradient from the uplands to the escarpment. Nematodes were extracted from 100 cc soil samples, morphologically identified to genus level, and community diversity indices (richness, Shannon H', Simpson D, and evenness E) were calculated. Ten PPN genera were identified, with Helicotylenchus (29.5%) and Hoplolaimus (21.0%) being the most dominant. Meloidogyne and Filenchus occurred at intermediate frequencies (14.0% each), while Pratylenchus (4.0%), Criconema (4.75%), and rare genera (Xiphidorus, Paratylenchus, Trichodorus, Hemicycliophora) occurred at lower frequencies. Diversity varied considerably across farms; species richness ranged from 2 to 6 genera per farm, Shannon diversity (H') ranged from 0.45 to 1.63, and evenness from 0.65 to 0.94. Farms in upland areas exhibited greater diversity (H' > 1.30; S ≥ 5), while lower altitude farms showed reduced diversity (H' < 1.00; S ≤ 3). The presence of economically important genera—particularly Meloidogyne javanica and Pratylenchus spp., which have established tolerance limits of 0.65 J2/g and 1.70 nematodes/g soil, respectively—indicates significant pathogenic potential. This study documents a diverse PPN community in finger millet ecosystems, with spatial heterogeneity in community structure. The dominance of spiral and lance nematodes, coupled with the presence of lesion and root-knot nematodes, underscores the need for region-specific integrated pest management strategies to mitigate yield losses in this staple crop.