Occurrence of barley root knot nematode, Meloidogyne naasi in orange jessamine (Cestrum aurantiacum L.) in Nilgiris, Tamil Nadu, India: A new record

Abstract

A survey was taken up (2015-2016) in the present study to record the root knot nematode species existing in Tamil Nadu in crops such as tomato, brinjal, chillies, carrot, cabbage, potato, beetroot, guava, pomegranate, tea, coffee and some turf grasses. Among the various root knot nematode species encountered, Meloidogyne naasi commonly called the barley root knot nematode or cereal root knot nematode was recorded from the Nilgiris, from a place called Kuruthukuli in roots of Orange Jessamine (Cestrum aurantiacum L.), a common weed plant in Nilgiris. The population occurred as a mixture of M. naasi, M. incognita and M. hapla in the roots of same plant which showed profuse typical and conspicuous tip galls. The perineal pattern was exactly rounded with rough striae and the phasmids are prominent, stylet length of female is12.83µm (11.5 – 14µm), backward sloping knobs with a mean body length of second stage juveniles is 432µm (433 -456µm), tail length of J2 is 61.6µm (56 – 65µm) and stylet length of male is 18.5µm (16 – 19µm). These characters matched with the original description of M. naasi by Franklin 1965 and hence the species was confirmed morphologically. Studies will be made to further confirm the same at molecular level.