Biodiversity of Plant Parasitic Nematodes in Tea Nurseries and Plantations in Tripura

One hundred and thirty sites at thirteen widely separated tea nurseries and plantations of different age groups were sampled for qualitative and quantitative analysis of plant parasitic nematodes communities during March to October, 2001. A total of 14 species of plant parasitic nematodes within eight genera, were isolated and identified from roots and rhizosphere soil of tea plants. All species of plant parasitic nematodes associated with tea are first records of nematodes associated with tea from Tripura. The most frequently encountered nematode species includes: Helicotylenchus spp., Meloidogyne spp., Pratylenchus brachyurus (Pb), Rotylenchulus reinformis (Rr), Hoplolaimus spp. and Hemicriconemoides mangiferae (Hm), which were detected in 85%, 70%, 68%, 55%, 53% and 41% of the sites. respectively. Nematode communities were analysed by mean abundance, prominence value, importance value and diversity index based on nematode numbers and biomass. Analysis showed that Meloidogyne hapla ranked first in importance value followed by M. incognita, H, dihystera R. reniformis and H. erythrinae. A linear increase in the index of diversity (H’) of the nematode communities with increase in the age of plantation up to eight years was observed and with the further increase in the age of plantation there is a gradual decline in the diversity index. This indicated that with an increase in the age of plantations up to certain age parasitic species have become more abundant. This is a distinct sign of gradual establishment of these species.