Quantitative and qualitative studies on plant and soil nematodes associated with crops of economic importance in Rajasthan.
The results of quantitative estimation of soil samples collected from eight districts of Rajasthan State, India revealed that the wide variety of plant parasitic nematodes are found associated with crops of economic importance i.e. agricultural, horticultural and cash crops. In the Rajasthan State, many scientists are involved in experimental and applied fields, mainly on root-knot (Meloidogyne spp.) and cereal cyst nematodes (Heterodera avenae), because these inflict severe losses in yield and quality of crops of economic importance. Most of these plant parasitic nematodes are ectoparasites and remained attached to the root-system of the plants and suck the juice by piercing their stylet, odontostyle or onchiostyle in roots, which results in the stunting of the growth of plants and yellowing of leaves. In the present study, the following plant parasitic nematode species were found as predominant pests of plants: Hoplolaimus indicus [Basirolaimus indicus], Helicotylenchus sp., Rotylenchulus reniformis, Pratylenchus zeae, Pratylenchus thornei, Pratylenchus neglectus, Hirschmanniella gracilis, Tylenchorhynchus mashhoodi (other species mentioned in the list), Pratylenchoides sp. Rotylenchoides sp. Hemicriconemoides mangiferae, Hemicriconemoides brachyurus, Paralongidorus citri, Longidorus sp., Xiphinema sp. and Trichodorids (Paratrichodorus porosus). Pratylenchoides sp., Rotylenchoidoides sp. and Paratrichodorus porosus and other trichodorids are reported for the first time from Rajasthan. In all, 84 species were identified belonging to 37 genera of 20 families of Orders Tylenchidae (43 spp.), Aphelenchidae (1 sp.), Dorylaimidae (35 spp.), Mononchidae (3 spp.), Triplonchidae (1 sp.) and Isolaimidae (1 p.) Out of 84 species identified during the study, 29 species were recorded for the first time from the State while 14 species were recorded for the first time from India. Besides, 12 species belonging to Order Tylenchida, Dorylaimida and Isolaimida were considered new to science.