Discovered and published 4 new genera and 102 new species of plant and soil nematodes, besides 42 known species redescribed with additional characters, which are published in reputed journals. Explored and established biocontrol potential of predatory soil nematodes against plant parasitic nematodes. Screened and established biocontrol potential of plant growth promoting rhizobacteria, Paenibacillus spp. for root-knot nematode as well as disease complex caused by root-knot nematode and F. oxysporum f. sp. lycopersici.  Developed a model to elucidate systemic resistance induced by Paenibacillus spp. in plants against root-knot nematodes. Evaluated about 6,000 germplasm accessions of various crops viz., pulses, cereals, vegetables and medicinal plants for source of resistance to root-knot nematodes and elucidated mechanism of resistance in resistant accessions of different crops. Among identified resistant accessions to Meloidogyne incognita, 3 of cowpea, (Vigna unguiculata), EC723686; EC724523; EC725122 and 2 of lentil (Lens culinaris), IC559673; IC559890 have been registered by Plant Germplasm Registration Committee of Indian Council of Agricultural Research. Evaluated some medicinal plant materials for their potential against fungi and nematode. Established efficacy of peony (Paeonia suffruticosa) root-bark against R. solani and root-knot nematodes. The antimicrobial compound in peony root bark, isolated in chloroform and identified as “paeonol” by mass spectrometry,¹H NMR, and ¹³C NMR analyses, that inhibited the growth of Rhizoctonia solani and causing mortality to root-knot nematodes. Reported several new host plants to various plant parasitic nematodes. Developed effective salvaging technique for nematode infected vegetative propagules under exchange of exotic planting material. Published 107 research papers on my research out puts in the peer reviewed journals and have authored a book on Nematode taxonomy, edited two books, technical bulletins and training manuals. Delivered several invited lectures in Scientific meetings/conferences, universities and research institutes, and have been reviewer of several research papers published in international journals.