Community analysis of soil nematodes in vegetable growing areas of Dhading District, a high hill of Nepal

Abstract

A nematological survey was carried out in the year 2014 from vegetable crops of Dhading district; a high hill of Nepal located at latitude 2752'0.120"N, longitude 8455'0.120"E and altitude 1518m. The entire district covers mainly temperate zone with annual average precipitation and temperature 1683.9 mm and 11.8 – 22.4°C respectively. Thirty soil samples were collected randomly from ten vegetable crops during their flowering time. A total of 23 genera of soil inhabiting nematodes belonging to 7 orders and 14 families were encountered. Of the total population, herbivores were 33%, bacteriovores 35%, fungivores 12%, predators 14% and omnivores 6%. In terms of number of genera varied from 8 to 14 and in terms of abundance the number varied from 64 to 308 per 100cc of soil. Rhabditis was the most abundant genus among bacteriovores, Aphelenchoides among fungivores, Mononchus among predators and Helicotylenchus among herbivores. Meloidogyne sp was the most dominant plant parasitic nematode in terms of both frequency and density occurring in many vegetable crops. The trophic diversity index (TDI) in the sample was 1.07 – 1.30 (1.16 ± 0.06), maturity index (MI) 1.66 – 2.65 (2.22 ± 0.25), plant parasitic index (PPI) 2.49 – 3.0 (2.95 ± 0.11) and channel index (CI) 0.21 – 1.48 (0.82 ± 0.35).