Association and Community Structure of Plant Parasitic Nematodes in Horticultural Crops

Abstract

The study aimed to analyze the community structure, occurrence and diversity of plant parasitic nematodes associated with different production blocks of Horticultural Orchard of Biswanath College of Agriculture, with a focus on identifying dominant nematode species. The study was conducted in fruit, floriculture, vegetable and spice blocks during March 2024 to August 2024. During the investigation soil samples were collected from different crop blocks. From each crop block 10-15 subsamples were collected to make a composite sample. Extraction of nematodes from collected soil samples was done by modified Cobb’s sieving and decanting technique followed by Baerman’s funnel technique. The plant parasitic nematodes present in the suspension were identified using taxonomic key and nematode population in each sample was counted three times in a multi chambered counting dish under a stereoscopic binocular microscope and mean was taken. Community analysis of plant parasitic nematodes were done by determining absolute frequency (AF), relative frequency (RF), density (D), relative density (RD) and prominence value (PV) following Norton's methodology. Seven species of plant parasitic nematodes viz., Meloidogyne sp, Helicotylenchus dihystera, Hoplolaimus indicus., Tylenchorhynchus leviterminalis., Xiphinema sp. and Pratylenchus sp., were isolated and identified from soil samples collected from rhizosphere of different production blocks. Analysis of nematode communities revealed that, in fruit block 100% absolute frequency was recorded in case of H. dihystera, H. indicus and T. leviterminalis. In vegetable and floriculture block 100% absolute frequency was recorded in case of H. dihystera, H. indicuas, Meloidogyne sp. and T. leviterminalis. H. dihystera was found to be most prominent in all the production blocks. The findings offer critical insights into nematode ecology and underscore the importance of region specific management practices to reduce the crop losses cause by plant parasitic nematodes in horticultural crops.