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ThesisItem Open Access Variability and Integrated Management of Spot Blotch of Wheat Caused by Bipolaris sorokiniana (Sacc.) Shoem.(University of Agricultural Sciences, Dharwad, 2017-07) Ashwini, R.; Patil, P.V.Laboratory and field experiment were conducted at Department of Plant Pathology, College of Agriculture and Main Agricultural Research Station, Dharwad to study the variability and integrated management of spot blotch of wheat. Roving survey conducted in Dharwad, Belagavi, Gadag, Bagalkote and Vijayapura districts during rabi, 2017-18 indicated low severity of spot blotch disease. Variability study in 14 isolates of B. sorokiniana through morphological and cultural characters, pathogenic ability and SSR markers had showed high distinction. Colony colour ranged from whitish black to black. On the basis of pathogenicity, 14 isolates were grouped into two different pathotypes (P1 and P2). Similarity coefficients were ranged from 0.53 to 0.98 representing less than 53 per cent genetic variability among isolates. Under in vitro studies, captan at 0.3 % (86.29 %), hexaconazole, propiconazole and tebuconazole at 0.025 %, 0.05 %, 0.1 % (100%), hexaconazole 5 % + captan 70 % WP, carboxin 37.5 % + thiram 37.5 % WP and tebuconazole 50 % + trifloxistrobin 25 % WG at 0.05 %, 0.1 %, 0.2 % (100%), multineemore at 1.0 % (54.81 %) recorded maximum inhibition of mycelial growth. Trichoderma harzianum + Pseudomonas fluorescens + Bacillus subtilis (3.3 g each/l) concentration, panchagavya (20 %) inhibited 80.44 and 30.29 per cent spore germination, respectively. In Integrated disease management, among the eight spray schedules evaluated under field condition, two sprays of hexaconazole 5 % EC (0.1 %) with 15 days interval reduced the spot blotch severity by 13.40 per cent with highe st grain yield (13.33 q/ha), biomass (8.33 t/ha) and BC ratio (1:1.94). Hexaconazole 5 % EC (0.1 %) was most effective in managing spot blotch disease.ThesisItem Open Access Studies on Leaf Blight of Turmeric Caused by Alternaria alternata (Fr.) Keissler(University of Agricultural Science, Dharwad, 2017-09) Savar, Izazahammad; Virupaksha Prabhu H.ThesisItem Open Access Studies on Yellow Mosaic Disease of Soybean [Glycine max (L.) Merrill](University of Agricultural Science, Dharwad, 2017-09) Gaddeppa; Ashtaputre, S.A.ThesisItem Open Access Epidemiology and Management of Foliar Fungal Diseases of Greengram (Vigna radiata (L.) Wilczek)(University of Agricultural Sciences, Dharwad, 2017-07) Hulikatti, Vidya; Benagi, V.I.ThesisItem Open Access Studies on Bacterial Blight of Sesame Caused by Xanthomonas campestris pv. sesami Sabet and Dowson(University of Agricultural Science, Dharwad, 2017-09) Praveenkumar; Palakshappa, M.G.ThesisItem Open Access Studies on Collar Rot of Brinjal Caused by Sclerotium rolfsii Sacc.(University of Agricultural Science, Dharwad, 2016-12) Wahid, S A.; Kamanna, B.C.Brinjal (Solanum melongena L.) is one of the important vegetable crop. Collar rot of brinjal caused by Sclerotium rolfsii Sacc. is serious soil borne disease. A study on this was undertaken at the University of Agricultural Sciences, Dharwad during kharif 2015-16. Survey revealed that disease incidence ranged from 2.33 to 24.25 per cent. Highest mean disease incidence (9.75 %) was recorded in black soil. Dhruva hybrid showed high mean disease incidence of 11.52 per cent. . Significantly highest per cent disease incidence of 59.75 was recorded in plants of 15 days old in pot culture studies to know susceptible stage of brinjal. None of the genotypes were found resistant to collar rot pathogen. Among the six systemic fungicides tested under in vitro difenconazole, tebuconazole, hexaconazole and propiconazole at 0.1 per cent and 0.15 per cent concentrations inhibited cent per cent growth of S. rolfsii. Among the five contact fungicides mancozeb at 0.3 % concentration recorded maximum inhibition (60.25 %) of S. rolfsii followed by captan at 0.3 per cent concentration (55.19 %). Combi-products fungicides viz., thiram 37.5 % + carboxin 37.5 % WP and hexaconazole 4 % + zineb 68 % WP at 0.1, 0.2 and 0.3 per cent concentrations inhibited cent per cent o growth of S. rolfsii. Among six bioagents Trichoderma harzianum recorded maximum inhibition. Among thirteen botanicals, parthenium leaf extract recorded maximum inhibition (64.57 %). Among the different treatment combinations tested under pot conditions the combination of seedling dip with thiram 37.5 % + carboxin 37.5 % WP @ 2 g/l + application of FYM @ 200 g/pot + soil application of Trichoderma harzianum @ 4 g/kg followed by soil drenching with thiram 37.5 % + carboxin 37.5 % WP @ 2 g/l on 0, 15, 30, and 45 days after transplanting recorded the least per cent disease incidence (12.04 %).ThesisItem Open Access Studies on Yellow Mosaic Disease on Mungbean [Vigna radiata (L.) Wilczek](University of Agricultural Science, Dharwad, 2017-07) Rekha A.S.; Patil, M.S.A study on Mungbean yellow mosaic virus (MYMV) disease involving survey of four districts (Belagavi, Dharwad, Haveri, Gadag) in kharif 2016 and summer 2017, molecular characterization, host range, seed transmission, screening of advanced breeding lines and disease management was carried out during 2016-2017. During kharif 2016, the highest incidence (16.12 %) was in Haveri and the least (11.7 %) was in Gadag. During summer 2017, highest incidence (22.54 %) was in Dharwad and the least (20.73 %) was in Belagavi. The coat protein gene of MYMV (642 bp) was amplified using specific primers. PCR amplification, sequencing and construction of phylogenetic tree showed that MYMV Dharwad isolate was 99 per cent homology with different isolates of Horsegram yellow mosaic virus (HYMV). Therefore, MYMV of Dharwad isolate is the close relative of HYMV. MYMV was transmitted to seven crop plants except bhendi namely soybean, pigeonpea, blackgram, horsegram, frenchbean, cowpea, fieldbean and three weed hosts viz., Ageratum conyzoides, Corchorus trilocularis and Sida acuta and these hosts acts as collateral hosts. Studies revealed that MYMV was present in MYMV infected seeds and detected seed borne nature. Twenty-one of 24 advanced genotypes screened against MYMV during summer 2016 showed resistant reaction. Among different modules tested for the management of Mungbean yellow mosaic disease, adoptive module (M3) including seed treatment with Rhizobium (5 g/kg), border crop of maize (3 lines), yellow sticky trap (20/ha), Verticillium lecani (5 g/l), Triazophos (1.5 ml/l) at 30 DAS and spray of neem oil (5 ml/l) at 45 DAS recorded least disease incidence (8.94 %) and lowest whitefly population (2.20 whiteflies) with highest yield of 11.61 q/ha with B: C ratio of 3.00. Hence, adoptive module is best for management of yellow mosaic disease.ThesisItem Open Access Morphological and Physiological Studies on Grape Powdery Mildew Caused by Uncinula necator (Schw.) Burr.(University of Agricultural Science, Dharwad, 2017-07) Nadumani, Parashuram; Adiver, S.S.Studies on grape powdery mildew caused by Uncinula necator (Schw.) Burr, was carried out at Department of Plant Pathology, College of Agriculture, Vijayapur and farmer field, Hittinahalli during Rabi 2016-17. The survey during 2016-17 revealed that, the disease was noticed in varying intensities in three districts; maximum disease severity was in Vijayapur (50.18 PDI and 24.17 PDI) followed by Bagalkote (27.18 PDI and 10.47 PDI) and Belagavi (20.00 PDI and 8.23 PDI) was recorded least disease severity during foliage (vegetative) and fruiting stage respectively. The pathogen produced conidia in chains and they were ellipsoid or ovoid to cylindrical. They were non septate and hyaline in nature which measured about 29-42×12-20 µm. Maximum conidial germination was observed at 24 hrs after incubation. Temperature range of 20 to 25 0C, relative humidity of 80 to 85 per cent and slightly acidic pH (5.0 -6.0) were found congenial for conidial germination of U. necator. The maximum per cent conidial germination (45.50 %) was recorded in indole acetic acid (IAA) fallowed by gibberellic acid (GA) (36.50 %). Least conidial germination was observed in ethylene (9.66 %). Phenol content was higher in diseased leaves (4.61 mg/g) and fruits (3.71 mg/g) as compared to the healthy leaves (3.95 mg/g) and fruits (3.30 mg/g). The reducing sugars (3.25 mg/g and 74.51 mg/g) total sugars (4.74 mg/g and 84.75 mg/g) and protein (7.41 mg/g and 2.57 mg/g) contents were higher in healthy leaves and fruits as compared to the diseased leaves and fruits. Azoxystrobin 23 EC (99.66 %) was shows highest inhibition of powdery mildew of grape caused by of U. necator followed by hexaconazole 5 EC (98.00 %) and Chlorothalonil 75 WP (43.33 %) shows least inhibition under in vitro conditions. Azoxystrobin 23 EC at 0.05 per cent found to be the best fungicide recoding least incidence (4.00 %) followed by hexaconazole 5 EC (6.67 %) and propiconazole 25 EC (10.00 %) at 0.1 per cent after four spray under in vivo conditions.ThesisItem Open Access Isolation, Characterization and Use of Bacteriophages Against Bacterial Wilt of Brinjal [Ralstonia solanacearum (SMITH) Yabuuchi et al.](University of Agricultural Science, Dharwad, 2017-10) Amrutha Lakshmi M.; Byadgi, A.S.A major constraint in brinjal production is bacterial wilt disease caused by Ralstonia solanacearum. An attractive option is the use of bacteriophages, (viruses) that specifically kill bacteria. The present investigation on isolation and characterization of bacteriophages against bacterial wilt of brinjal was carried out at Department of Plant Pathology, University of Agricultural Sciences, Dharwad during 2016-17. Five isolates of R. solanacearum from brinjal were collected during survey covering four districts of northern Karnataka, cultured and confirmed for their biochemical and molecular identity using specific primer pairs Rs-sp and fliC which showed their genetic uniformity. The bacteriophages were isolated from raw water of municipal sewage treatment plant, pond and river water, rhizosphere and phylloplane samples of brinjal plant. The plaque forming units (PFU) assay was conducted to understand plaque morphology. Among the nine phage isolates, three phages against R. solanacearum viz., Rsab1, Rsab2 and Rsab3, having clear plaques were obtained with titre value of 2.40 x 105, 2.60 x 105 and 0.50 x 105 PFU ml-1and diameter of 12.10, 3.01 and 8.20 mm, respectively. From host range analysis, phages were found to be non-effective against other tested bacteria Escherichia coli, Staphylococcus aureus, Pseudomonas fluorescens, Xanthomonas axonopodis pv. citri and X. a. pv. punicae and have a broad lytic activity on R. solanacearum isolates. The chloroform sensitivity test showed that the phages were insensitive to the chloroform. The genetic diversity of isolated phages was confirmed by Randomly Amplified Polymorphic DNA (RAPD). In vitro UV sensitivity test showed pregelatinised corn flour (1%) as phage formulation. In rhizosphere stability studies, persistance of formulated phages was observed up to 16th day. In glasshouse studies, sole application of phage mixture on one month old seedling was found better in comparison to standard chemical check (Copper oxy Chloride (0.3 %) + Streptocycline (500 ppm)).
