Incidence of Root-Knot Nematode on Misai Kucing (Orthosiphon stamineus) in Peninsular Malaysia: A New Discovery

A survey was conducted over one and half years to estimate the occurrence of root-knot nematode infestation on Ortosiphon stamineus (misai kucing) in selected locations around Peninsular Malaysia. Infestations were monitored in ten misai kucing plantation areas in Pulau Pinang, Perak, Negeri Sembilan, Selangor, Johor, Terengganu, and Kelantan. The survey indicated that misai kucing grown on sandy clay-type soil tends to be more susceptible to heavy root-knot nematode infestation. The highest frequency of disease incidence in which almost all the roots of misaim kucing have a knot-like appearance (100%) was reported from the Batu Kurau area. The other two locations, Ipoh and Pantai Baru, had mild infestations, and these were reported as 16% and 4% incidence. The methodology for access the damage caused by the root-knot nematodes in misai kucing, Meloidogyne gall index and its egg-mass index were calculated and these were found in the range of 1-4. The average egg mass from ten randomly selected stunted misai kucing plants from Batu Kurau was recorded as 599.4, with the highest number of 2274 egg mass per plant. Sampled plants showed the significant presence of Meloidogyne incognita. The root-knot nematodes were morphologically identified based on the perineal patterns of females and the head morphology of both Meloidogyne females and males.