Rawat, ShilpiPatil, Prashant2022-02-102022-02-102021-09https://krishikosh.egranth.ac.in/handle/1/5810182020Tomato (Lycopersicon esculentum) is an important vegetable in India but its productivity is very low (214.5 q/ha), compared to the developed countries, and this can be attributed to the vulnerability of tomato crop to various diseases including fungal, bacterial, viral and nematode diseases. Among the above diseases, Root-knot nematodes are the major pathogens of vegetable crops and are responsible for causing huge yield losses every year in heavily infected crops. Meloidogyne incognita deteriorates the quality of fruit and thereby causing yield losses of 30 to 40% of tomato crop. The experiment was carried out during the year 2019 and 2020 at Department of Plant Pathology, Collage of Agriculture, G. B. Pant University of Agriculture and Technology Pantnagar. Laboratory study on identification of M. incognita resulted with important findings based on morphological characterization of species. The experiment conducted to study the effect of different inoculum level viz, 250, 500, 1000, 2000, 4000 and 8000 second stage larvae of M. incognita on various growth parameters of tomato showed significant reduction at the inoculums level of 500 J2 per kg of soil and above. Damaging threshold level at inoculum level of 2000 J2 per kg of soil and maximum reduction at 8000 J2 per kg of soil has been observed in tomato cv Pant T-3. Experimental results of in vitro evaluation of compounds on egg hatching of M. incognita showed, rate of egg hatching was directly proportional to time period and inversely proportional to concentration of compounds used. AB+L @ 10.0 per cent concentration at the end of 120 hours exposure period was most effective as compared to other compounds. Similarly, in vitro evaluation of effect of compounds on mobility of J2 of M. incognita showed that immobility of second stage larvae was found directly proportional to time period and concentration of chemical compounds. Among all the treatments, AB+L @ 10.0 per cent concentration caused maximum per cent immobility of second stage larvae. Under glass house condition, among three compounds tested which exhibited nematicidal effect on nematode population and galls clearly revealed that the AB+L were found most effective at 3.0g /kg of infected soil followed by its lower concentration of 2.25g/kg of infected soil. AB at 1.0g/kg of infected soil and lime at 2.0 g/kg soil of concentration perform better than control. With respect to chemical properties i.e. soil pH, organic carbon and available nitrogen on nematode suppression, AB+L increased the soil pH, organic carbon and available nitrogen suppressing the nematode population followed by AB which increases both nitrogen and organic carbon and lime which increased only pH. However, all the compounds at all the concentrations suppressed the nematode population and increase the plant growth as compared to check. Thus, it can be said that Ammonium bicarbonate and Lime (AB+L) has the potential of a nematicide.EnglishThesis