First report of root-knot nematode, Meloidogyne enterolobii on watermelon in India

Abstract

Root-knot nematode, Meloidogyne enterolobii is a devastating species of Meloidogyne. This nematode was restricted only to guava. However This paper reports the occurrence of M. enterlobii on watermelon at Perur village, Coimbatore district, Tamil Nadu, India and it is the first record of new host of this species. Soil and root samples showed very high population (536 J, / 250g soil; 123±10 adult female/5g root). Young seedlings of watermelon showed multiple compound galls on the root. Seedlings expressed stunted growth and pale yellow leaves. The species was confirmed by comparing with the original description and using molecular characterization. The morphological characters of adult females, males and second stage juveniles were measured using micrometers. Female nematodes recorded with a average body length including neck 687.8 µm; body width 425.3 µm; stylet length 13.8 µm, stylet knob height 2.8 µm; stylet knob width 4.5 µm; dorsal oesophageal gland orifice 4.90 µm and the distance from the excretory pore to head end 63.45 µm. Morphometric characters of female were similar to that of native population from guava and original descriptions.