Occurrence, distribution and importance of plant parasitic nematodes associated with litchi plantations in North Tripura district.

During March to July, 2007, an extensive survey was conducted in three sub-divisions of North Tripura district for isolation and identification of plant parasitic nematodes affecting litchi plants. Analysis of soil and root samples collected from 70 sites in 14 locations of three sub-divisions showed that nine plant parasitic nematode species within seven genera being associated with litchi plants. The isolated and identified nematode species were Hemicriconemoides litchi, Rotylenchulus reniformis, Meloidogyne incognita, Helicotylenchus dihystera, H. indicus, Hoplolaimus indicus, Tylenchorhynchus leviterminalis, Xiphinema brevicolle and Xiphinema sp. Among them H. litchi, R. reniformis and M. incognita were the most abundant, frequent and prominent nematode species. The population percentage of these three nematodes were 9530.00, 5220.00 and 4100.00, respectively. Out of nine nematode species, R. reniformis, Helicotylenchus indicus, T. leviterminalis and Xiphinema sp. were reported for the first time from Tripura state associated with litchi plants. So, it is clearly indicated that H. litchi, R. reniformis and M. incognita are the most important and harmful nematode species in litchi plantations of North Tripura district.