Species Composition, Frequency, and Pathogenicity of Root-Knot Nematodes (Meloidogyne spp.) on Vegetable Crops

Abstract

Species composition, frequency, and pathogenicity of root-knot nematodes (Meloidogyne spp.) on vegetable crops were investigated to assess their diversity, distribution, and impact on host plant health. Field surveys were conducted across major vegetable-growing regions, and infected plant roots exhibiting characteristic gall formation, stunting, and chlorosis were collected for nematode extraction and identification. Species-level characterization was performed using morphological traits of perineal patterns and second-stage juveniles, supplemented with molecular confirmation through PCR-based assays targeting rDNA regions. Results revealed the presence of multiple Meloidogyne species with varying frequency across vegetable crops, indicating differential host preference and environmental adaptability. M. incognita was the most frequently encountered species, followed by M. javanica and M. arenaria, showing distinct distribution patterns among crop hosts. Pathogenicity assessments demonstrated significant variation in virulence, with highly aggressive populations causing severe root galling, reduced root biomass, and marked decline in plant growth and yield. Infection intensity was positively correlated with nematode population density in soil, highlighting the role of inoculum load in disease severity. The study also indicated that mixed-species infestations exacerbated host damage compared to single-species infections. These findings emphasize the importance of accurate species identification and monitoring of population dynamics for effective nematode management. Integrated approaches combining resistant cultivars, crop rotation, and soil health improvement are essential for mitigating losses caused by Meloidogyne spp. in vegetable production systems.