Current status of root knot nematodes (Meloidogyne spp.) in Tamil Nadu
P Suresh, K Poornima, M Sivakumar and S Subramanian
The present study was conducted to identify the current status of root knot nematodes in Tamil Nadu. Totally 20 districts were surveyed (2015-2016) for presence of root knot nematodes from various crop ecosystems and it revealed seven species viz.,Meloidogyne incognita, M. javanica,M. arenaria, M. hapla, M. graminicola, M. enterolobii (Syn: M. mayaguensis) and M. naasi. Among these species, M. incognita was present in all districts of Tamil Nadu that were surveyed. M. incognita, M. javanica, M. arenaria, M. graminicola and M. enterolobii were present in tropical and sub tropical regions and M. hapla and M. naasi were present in temperate regions especially in the Nilgiris. M. incognita populations were found mixed with M. javanica in some samples collected in tropical areas, while M. hapla populations weremixed with M. incognita and M. naasi in certain temperate regions. Incidence of M. naasi seems to be first report from India and it was spotted from Orange Jessamine (Cestrum aurantiacum)belonging to solanaceae family and grown as a hedge plant in the Nilgiris. M. enterolobii is an emerging problem in guava and has been reported first from Tamil Nadu in recent years and wide spread now across the Country. Meloidogyne spp. are usually differentiated by posterior cuticular pattern (PCP) and stylet length of second stage juveniles.