GAUTAM, H RTYAGI, ANKUR2018-12-222018-12-222018-11http://krishikosh.egranth.ac.in/handle/1/5810086248ABSTRACT The present investigation entitled “Integration of soil solarization and beneficial soil microflora for management of Rhizoctonia stem rot of chrysanthemum” was conducted in the laboratories and experimental farm of the Department of Plant Pathology. Among different bio-control agents evaluated under in vitro conditions against the Rhizoctonia stem rot pathogen, T. viride resulted in maximum mycelial growth inhibition (68.8 %) followed by T. harzianum (66.1 %) and T. hamatum with 58.4 per cent inhibition in mycelial growth of the stem rot pathogen, respectively. Among bacterial antagonists, P. fluorescens was found most effective resulting in 56.9 per cent mycelial inhibition followed by B. subtilis (53.5 %). Combination of Trichoderma viride with soil solarization was found most effective with no incidence of the disease and this treatment also reduced the viability of the sclerotia by 99.2 per cent. Combination of neem cake with soil solarization was found most effective with no incidence of the disease and this treatment also reduced the viability of the sclerotia by 93.7 per cent.Soil amendment ofresidues ofmustardcropbefore solarization was found most effective with no incidence of the disease and it also reduced the viability of the sclerotia 100 per cent. Soil solarization resulted increased average maximum soil temperature to 45.9and 44.9 °C, during the years 2016-2017 with an increase of 7.8 and 7.07°C at 5 cm soil depth over unsolarized pots. Treatment combination of soil solarization with green gram was found most effective with 85.6 per cent reduction in the stem rot incidence and also improved plant growth and quality parametersof the flowers. Soil solarization increased the average maximum soil temperature to 41.4, 40.7 and 40.3°C, during the years 2013, 2015 and 2016 with an increase of 7.2, 7.5 and 6.0°C at 5 cm soil depth over unsolarized plots. Soil solarization of the sclerotia of Rhizoctonia stem rot pathogen with transparent polyethylene sheet at 5 cm soil depth for 40 days reduced the viability of sclerotia by 88. 7 per cent. Treatment combination of green gram in the year 2016-2017 with soil solarization was found most effective with 62.5 per cent increasein the spore countof AM fungi with root colonization of 60 per cent. Soil solarization of thesclerotia of the stem rot pathogen with transparent polyethylene sheet at 5 cm soil depth for 40 days increased the incubation period of the disease by 21.2 per cent.Eight native species of AM fungi related to four genera viz., Glomus, Acaulospora, Gigaspora, Scutellospora sp. were isolated from the rhizosphere soil of the chrysanthemum field. Treatment combination of soil solarization with Trichoderma viride formulation and growing of green gram crop was found most effective in all the trials in the years 2013, 2015 and 2016 with 81.7, 85.1 and 85.8 per cent reduction in the stem rot incidence. Treatment combination of soil solarization followed by growing of green gram crop and application of Trichoderma viride formulation improved plant height by 36.3 to 41.7 per cent, increased flower size by 31.8 to 37.8 per cent, increased number of flowers by 27.9 to 38.3 per cent and reduced the time taken to first flowering from 4.0 to 6.0 days in comparison to unsolarized control in different years. Treatment combination of Trichoderma viride formulation and green gram in solarized soil was found most effective in 2013, 2015 and 2016 with an increase of 75, 66.6 and 63.1 per cent inspore population ofAM fungi and 72.1, 72.8 and 72.6 per cent higher root colonization.ennullThesis