Morphometric Taxonomy of Meloidogyne spp. Infesting Vegetable Crops in Sri Lanka via Female Perineal Pattern Analysis

Abstract

Meloidogyne spp. are among the most significant plant-parasitic nematodes in agriculture, necessitating precise identification for effective management. This study aimed to identify and taxonomically characterize Meloidogyne spp. infesting vegetable crops in Sri Lanka using female perineal pattern analysis. A total of 54 root and soil samples were collected from 17 agricultural regions and analyzed at the Horticultural Crop Research and Development Institute (HORDI), Sri Lanka. Single egg-mass cultures were established using a nematode-susceptible tomato variety (KWR), and second-stage juveniles (J2) were used for precise inoculation. Perineal patterns of mature females were prepared following standard protocols and examined microscopically. A total of 101 female nematodes were identified, revealing the presence of M. arenaria (33%), M. javanica (30%), M. incognita (25%), and M. hapla (13%). M. arenaria exhibited forked lateral fields and a low dorsal arch, while M. javanica displayed distinct double lateral incisures. M. incognita was characterized by an angularly oval pattern with a high dorsal arch, and M. hapla showed a concentrated punctation between the anus and tail terminus. Host range analysis indicated that M. hapla had a narrow host range, whereas the other species were oligophagous, with M. incognita affecting a broad spectrum of crops, including tomato, spinach, brinjal, and okra. The study confirmed that M. incognita, M. javanica, and M. arenaria are the predominant Meloidogyne spp. in Sri Lanka’s vegetable-growing regions, with M. arenaria being the most frequently detected. These findings align with previous research and highlight the necessity of targeted management strategies. The results provide a valuable foundation for developing species-specific nematode control measures in Sri Lanka’s agricultural systems.