Occurrence and distribution of Tylenchulus semipenetrans Cobb in Nagpur mandarin orchards of Vidarbha, Maharashtra

Survey of Nagpur mandarin orchards was conducted to determine the occurrence, distribution and population density of plant parasitic nematodes in Vidarbha region of Maharashtra. A total of 119 orchards were sampled from six Talukas viz., Nagpur, Kalmeshwar, Katol. Narkhed, Parseoni and Warud. Fourteen plant parasitic nematode species were found associated with Nagpur mandarin. Tylenchulus semipenetrans was the most abundant and widely distributed throughout the region followed by Basiria graminophila and Rotylenchulus reniformis. T. semipenetrans recorded highest absolute frequency (80.7%), absolute density (2212 nematode/250 cc soil) and prominence value (1990.8). High, medium and low populations of T. semipenetrans were obsewed in 52,13 and 16% of the orchards. The maximum (3049 nematodes/250 cc soil) population of T. semipenetrans was obsewed in Kalmeshwar followed by Katol (3033 nematodes/250 cc soil) and the minimum population (267 nematodes/250 cc soil) in Parseoni Taluka. The population of T. semipenetrans was obsewed more in trees showing initial decline than in trees of advanced stage of decline. It was obsewed that the trees of 11–15 pears of age supported maximum population of T. semipenetrans compared to younger or older trees.