Deciphering the Identity of the Root-knot Nematode Meloidogyne enterolobii Infecting Guava (Psidium guajava L.) Through Morphological and Molecular Tools

Root-knot nematode Meloidogyne enterolobii has emerged as a major constraint to guava (Psidium guajava L.) cultivation in tropical regions, particularly in association with the guava wilt-nematode disease complex. Accurate identification of the nematode species is essential for understanding its distribution and developing effective management strategies.

Soil and root samples were collected from guava orchards affected by wilt symptoms in Tamil Nadu. Adult females were dissected from infected roots and examined for perineal pattern morphology, while second-stage juveniles (J2) were analysed for key morphological and morphometric characters. Molecular identification was performed using species-specific primers with amplification of the ITS and COI regions, followed by sequencing and phylogenetic analysis.

The perineal pattern of adult females was oval with a high dorsal arch and absence of lateral lines, characteristic of M. enterolobii. J2 exhibited a hemispherical head, slender tail with a rounded terminus and stylet length ranging from 14.5-16.2 μm. Molecular analysis confirmed the identity of M. enterolobii and the ITS and COI sequences were deposited in GenBank under accession numbers PX667703-PX667705 and PX658232-PX658234, respectively. Phylogenetic analysis showed close clustering of the isolates with reference M. enterolobii sequences.