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ThesisItem Open Access Studies on Production of Oil Based Formulation of Trichoderma and Their Efficacy of Foliar Diseases of Groundnut(UAS, Dharwad, 2011) Ahamed Mujtaba V.; Shripad KulkarniIsolation of Trichoderma harzianum, maintenance of pure culture, mass production and preparation of oil based formulations were carried out at Institute of Organic Farming and field experiments and studies on shelf life and field evaluation of different oil based formulation against rust and late leaf spot of groundnut were carried out during kharif 2010 at MARS, University of Agricultural Sciences, Dharwad, Karnataka. Among the several diseases affecting the groundnut crop, foliar disease cause heavy loss in yield. These include late leaf spot [Phaeoisariopsis personata (Berk. and Curt.) V. Arx] and rust (Puccinia arachidis Speg.). Results of in-vitro studies of present investigation on shelf life reveals that among various oil based formulations Canola oil + Glycerol based formulation (3.00 x 106 cfu/ml) was found to be the best formulation with highest shelf life, followed by Paraffin oil based formulation (2.00 x 106 cfu/ml). In in-vitro evaluation of different Trichoderma oil based formulations against pathogenic propagules of rust and late leaf spot causing fungi indicated Paraffin oil + Neem oil based formulations to be superior with 4.79% and 3.67% uredospore germination and conidial germination, respectively followed by Neem oil based formulation with 5.68% and 4.59% germination against 92.27% and 95.60% uredospore and conidial germination in control. Among different oil based formulations tested for the management of both rust and late leaf spot, Canola oil + Glycerol based formulation was found to be most effective in reducing the incidence of both rust and late leaf spot with PDI of 11.70 and 12.64, respectively compared to rust and late leaf spot with PDI of 35.62 and 38.45 in untreated check. Similar trend was also observed with respect to groundnut pod yield, treatment with Canola oil + Glycerol oil based formulation had shown maximum pod yield of 22.22 q per ha.ThesisItem Open Access Biochemical Factors Governing Interactions in Rice Genotypes Against Pyricularia grisea (Cooke) Sacc.(UAS, Dharwad, 2011) Sowmya H.M.; S.K. PrashanthiRice blast caused by Pyricularia grisea (Cooke) Sacc. continues to be a serious constraint to rice production in both tropical and temperate regions. Roving survey carried out during kharif 2010 in Karnataka showed that blast severity ranged from 20.17 to 58.72 per cent disease index. Field screening of 210 genotypes against blast showed that, seven genotypes viz., Casebatta, Jasmine -85, Siddasala, IR-64, Diamond Sona, Vajram, MGD 101 were resistant to both leaf and neck blast. Fifty five genotypes were resistant and eighty five genotypes were moderately resistant to leaf blast. Influence of blast on different biochemical components present in resistant, moderately resistant and susceptible genotypes at different stages of blast infection was investigated. Total phenol, Orthodihydroxy-phenol, total sugar, reducing sugar and non reducing sugar content was more in resistant and moderately resistant varieties compared to susceptible genotypes at all the stages of infection but they decreased slightly during neck blast stage. Accumulation and increase of phenol content in resistant genotypes was quick and more compared to moderately resistant and susceptible genotypes. Total amino acid content was more in resistant genotypes compared to susceptible genotypes. Total amino acid content increased from before disease initiation stage to neck blast stage. Protein content was more in susceptible genotypes compared to resistant and moderately resistant varieties and it decreased from before initiation stage to neck blast stage rapidly. Decrease of protein content from before disease initiation stage to peak stage was maximum in resistant varieties than moderately resistant and susceptible varieties. Isozyme study on peroxidase activity indicated significant variations among resistant, moderately resistant and susceptible genotypes. Phenylalanine ammonia lyase activity was more in resistant genotypes compared to moderately resistant and susceptible genotypes.ThesisItem Open Access Studies on Molecular Variations in Puccinia arachidis Speg. Causing Rust of Groundnut(UAS, Dharwad, 2011) C.B. Tashildar; S.S. AdiverAn investigation was carried out to study morphological and molecular variation in Puccinia arachidis Speg. Five isolates were collected from different varieties grown in MARS, Dharwad and ten isolates from other locations. Morphological variation was studied by considering uredospore morphology. Molecular variation was studied by PAGE technique using selected isozymes and RAPD technique using ten random primers. In morphological variation, the dimension of uredospores of all isolates was in the range of 21-26 × 18-21 μm. Nearly all spores had light cinnamon colour and globose to ovoid shape. The pits on the surface of the spores were observed in Annigere, Bellary, Jalgaon and Kolhapur isolates only. The echinulations were scarce to fine in all isolates. A teleospore measuring 30.64 x 19.33 μm was found in the Gadag isolate. This is a rare occurrence and needs further study. PAGE analysis of Peroxidase revealed two distinct groups in Dharwad isolates. Dh-86, Dh-101, GPBD-4 and JL-24 isolates formed one group whereas and TAG-24 isolate formed another group. In other locations, Gadag isolate formed a distinct group. Other isolates formed another group. Polyphenol oxidase analysis too revealed two distinct groups in Dharwad isolates. Dh-86, Dh-101 and JL- 24 isolates formed one group whereas GPBD-4 and TAG-24 isolates formed another group. In other locations too, Jalgaon isolate formed a distinct group. Other isolates formed another group. In case of molecular variation with the RAPD markers, OPD-18 (5’- GAGAGCCAAC-3’) gave highest amplification. RAPD analysis revealed two distinct groups within Dharwad isolates. Dh-86, Dh-101 and TAG-24 isolates formed one group. GPBD-4 and JL-24 isolates formed another group. In other locations, Dharwad and Raichur formed a distinct group. Rest of the isolates formed another group. Isozyme studies with PAGE and RAPD revealed minor variation in the pathogen in spite of insignificant morphological variation; which is useful to understand host-pathogen interaction.ThesisItem Open Access Organic Management of Anthracnose of Chilli Caused by Colletotrichum capsici (Syd.) Butler and Bisby(UAS, Dharwad, 2011) Reena B. Rajput; M.G. PalakshappaChilli, Capsicum annum L. is an annual herbaceous spice/vegetable/cash crop grown in both tropical and sub-tropical regions. Among the fungal diseases anthracnose or ripe fruit rot of chilli caused by Colletotrichum capsici (Syd.) Butler and Bisby is one of the limiting factors in cultivation of chilli. The survey revealed that the highest severity of anthracnose of chilli was recorded in Nalsvadi (46.35%). Plant extracts Ocimum sanctum, Neem Gold (300 ppm), Achook (1500 ppm) and Neem Fighter (10,000 ppm), T. harzianum, commercial bioagent Biocure F and Criyagen F, organic products Neem oil and Neem oil plus butter milk were found highly effective in inhibiting mycelial growth of C. capsici. Highest fungal population before planting and at flowering was noticed in Vermicompost (VC50%) + Farm yard manure (FYM50%) equivalent to recommended dose of nitrogen (RDN) with seedling dip in Panchgavya @ 3%, sulfur @0.2%, panchagavya @ 3%, nimbicidine (0.03% EC) @ 0.25% and VC 50% + FYM 50% equivalent to RDN with seedling dip in cow dung slurry @ 10% + Trichoderma harzianum @ 10g/l, sulfur @ 0.2%, nimbicidine (0.03%EC) @ 0.25%. The highest bacteria population before planting and at flowering was noticed in untreated check (VC50% + FYM50% equivalent to RDN) and VC50% + FYM50% equivalent to RDN with seedling dip in cow dung slurry @ 10g/l + Pseudomonas fluorescens @10g/l, sulfur @0.2%, nimbicidine(0.03%EC) @ 0.25%. Highest germination, seedling growth and vigour index was noticed in(VC50% + FYM50%) equivalent to RDN along with seedling dip in cow dung slurry @10% + Pseudomonas fluorescens 10g/l, sulfur @ 0.2%. The field trial results indicated that VC50% + FYM50% equivalent to RDN with seedling dip in cow dung slurry @10% + Pseudomonas fluorescens 10g/l, sulfur @ 0.2% recorded least per cent disease index and per cent infection in first and second picking and yielded(4.38q/ha).ThesisItem Open Access Studies on Sorghum Ergot Caused by Claviceps africana Frederickson Mantle and de Milliano(UAS, Dharwad, 2011) Shivakumar R.; A.R. HundekarErgot (sugary disease) caused by Claviceps africana has become major constraint particularly in the cultivation of sorghum hybrids and hybrid seed production. The survey data indicated that average disease incidence of 6.6% and severity of 17.56 PDI was recorded in Northern Karnataka. The maximum incidence of 12.02% and severity of 25.94 PDI were observed in Belgaum district followed by Dharwad, Gadag, Haveri and Raichur. Isolation and morphological studies confirmed that C. africana as causal organism of the disease. The pathogen attained maximum growth on 12th day of incubation in T2 broth. T2 agar and Kirchhoff’s agar media were the best for colony growth and sporulation. The maximum dry mycelial weight of C. africana was observed at 200C (114 mg) and it was least at 400C (12 mg). In vitro cent percent inhibition of mycelial growth was observed with Hexaconazole 5% EC, Captan 70% + Hexaconazole 5% and Hexaconazole 4% + Zineb 68%. Adusoge at 10 per cent was found most effective among plant leaf extracts. In vitro cent percent inhibition of mycelial growth was observed with Achook 0.15% EC, Neem Extra Power 10000 ppm and Nimbicidine 0.03% EC @ 15% concentration. The sorghum grain yield loss of 38.47% due to ergot disease was observed with unsprayed treatment over five sprays of Hexaconazole @ 1ml/l. Yield loss due to ergot disease decreased with increased number of Hexaconazole sprays. Hexaconazole 5% EC @ 1 ml/l, Propiconazole 25% EC @ 1 ml/l and Captan 70% + Hexaconazole 5% @ 2 g/l were found effective in reducing the incidence and severity of the disease and thereby increasing the sorghum grain yield. Hexaconazole @1 ml/l was found most effective. None of the plant leaf extracts was effective to as that of Hexaconazole. None of the genotype showed resistant reaction against the disease among the ten genotypes screened under artificial condition.ThesisItem Open Access Studies on Root Rot/ Wilt of Soybean(UAS, Dharwad, 2011) Sangeetha T.V.; Shamarao JahagirdarSoybean Glycine max (L.) Merill is protein rich oilseed crop. It is considered as a golden bean, miracle bean and wonder crop of the 20th century because of its characters and usage. Wilt/root rot is caused by Sclerotium rolfsii, Rhizoctonia sp. and Fusarium sp. are major constraints in soybean production. Isolates of all the pathogens were obtained during the survey from different locations of northern Karnataka and the disease incidence varied from 3.36 to 36.30 per cent. The study on variability of the causal organisms was undertaken. Isolates of all the pathogens showed marked difference in their growth rate and time taken for sclerotial initiation and spore production. Cultural studies on different media revealed that S. rolfsii and Fusarium sp. grew well on Potato Dextrose Agar and Rhizoctonia sp. grew well on Sabouraud’s Agar. Isolates varied in their growth in all the temperature tested. Maximum growth rate and spore germination was observed at 30ºC while no growth at 40ºC. In vitro studies revealed that Trichoderma viride, Trichoderma harzianum, Azadirachtin, Neem oil, Mancozeb, Carbendazim, Thiophanate methyl, Hexaconazole, Propiconazole, Carbendazim + Mancozeb and Carboxin + Mancozeb were more effective in inhibiting the mycelial growth of all the three pathogens. Glasshouse studies revealed that soil drenching with Carbendazim, Carboxin + Thiram, Thiophanate methyl, Hexaconozole, Neem oil, Nimbicidine, T. harzianum and T. viride helped to manage the disease successfully.ThesisItem Open Access Molecular Characterization of Virus Associated with Chilli (Capsicum annuum L.) Murda Complex(UAS, Dharwad, 2011) Pradeep Manyam; A.S. ByadgiChilli murda complex associated with thrips, mites and a virus is one of the most serious diseases of chilli (Capsicum annuum L.) where the role of virus was poorly understood. The survey was undertaken in four northern districts of Karnataka. Where, Haveri district recorded the maximum average disease incidence (45.86%) followed by Dharwad (39.36%), Belgaum (31.68%) and Gadag (30.81%). Symptomatically murda complex was noticed with severe leaf curling in both upward and downward directions with puckering, crinkling, elongated petiole and complete sterility. Dark green mottling with vein banding symptoms was also observed. The electron microscopic observation of murda infected chilli samples showed the presence of flexuous rod shaped particles. Direct Antigen Coating Enzyme Linked Immuno Sorbant Assay indicated the presence of potyvirus particles in murda samples detected with Tobacco etch virus antiserum. Whereas, begomovirus and tospovirus particles were not detected in murda infected chilli samples. RT-PCR analysis of diseased specimens yielded 1200 bp DNA fragment with the primer set designed to amplify CP gene of Chilli veinal mottle virus. But, murda samples failed to amplify for both degenerate primers of DNA-A component of geminiviruses and primers that amplify the sequences between gL3637 and gL4435c of L RNA of tospoviruses. Whereas, individual plants showing chlorotic and necrotic spots with apical necrosis observed sporadically were amplified for conserved L genes of tospoviruses. Thus, the detection through Electron microscopy and with suitable control included in ELISA and PCR based detection have led to establish the association of a potyvirus with the disease and chilli veinal mottle virus may be the possible causative agent at the species level. Among management practices taken up, Imidacloprid 17.8SL (0.03%) application for 3 sprays at main field found effective against sucking pests and disease incidence.ThesisItem Open Access Studies on Variability and Management of Sclerotium rolfsii Sacc. Causing Wilt of Stevia(UAS, Dharwad, 2011) Shwetha G.S.; Yashoda R. HegdeStevia rebaudiana is a perennial herbaceous medicinal plant belonging to family Asteraceae .Wilt caused by Sclerotium rolfsii is major constraint in stevia production. Ten pathogenic isolates of Sclerotium rolfsii were obtained during survey from different locations of Karnataka and per cent disease incidence varied from 8- 40%. The study on variability indicated that all isolates showed marked differences in their growth rate and time taken for sclerotial initiation, colour, size and weight of sclerotial body. Cultural studies on different media revealed that potato dextrose agar and potato dextrose broth were best for growth of all the isolates. The isolates varied in their growth in all temperature and pH. Maximum growth rate of all isolates was observed at 300-350C while, no growth at 400C and optimum pH for isolates varied from 4-5. Present study clearly indicated that the virulence was correlated with many aspects like isolates with small sized sclerotia, high virulence index, more oxalic acid production and least vigour index (SrKAl, SrNID and SrSAI) were highly virulent while, isolates with big sized sclerotia, low virulence index, less oxalic acid production and high vigour index were less virulent viz., SrBEN, SrGAN, SrRIP and SrSIR. Host range studies revealed that coleus, tulsi, shatavari, brahmi, rose mary, patchouli and aloe were collateral host. Aswagandha, lemon grass and basmati were non host. Investigation on sensitivity of isolates to hexaconazole revealed that all isolates except SrSAI, SrNID and SrKAL found sensitive to hexaconazole upto 100 ppb. In chemical studies except carbendazim all were effective. In biological management trial, duranta, eupatorium, cow urine, panchagavya, Trichoderma harzianum and T. viride were effective under in vitro condition. In vivo studies revealed that soil drenching with 0.1 per cent hexaconazole or propiconazole, 10% Eupatorium odoratum and Duranta repens, T. harzianum, T. viride helped to manage the sclerotium wilt successfully.ThesisItem Open Access Studies on Loss Assessment and Management of Common Rust of Maize Caused by Puccinia sorghi Schw.(UAS, Dharwad, 2011) Utpal Dey; S.I. HarlapurCommon rust of maize caused by Puccinia sorghi Schw. is an important disease which results in heavy yield loss. Laboratory and field experiments were carried out to study the loss assessment and management aspects of the disease. Spore germination was maximum within 24 hr at temperature in the range of 20-30°C. The maximum spore germination was recorded at 25°C (66.16%) which is statistically on par at 30°C. Differential spray schedule with Hexaconazole 0.1% revealed that, rust index was least in T5, i.e., five sprays of Hexaconazole (30.25%) and the disease was completely free with T6, i.e., six sprays of Hexaconazole. Maximum grain yield (35.58 q/ha) was obtained with six sprays of Hexaconazole. Highest per cent avoidable grain yield loss was recorded with six sprays of 0.1% Hexaconazole (60.53%) over untreated control. This indicates that common rust disease can cause up to 60.53 % yield loss in susceptible cultivar CM-202. The disease development started on 30 days (22.34% PDI) and increased progressively up to 90 days (88.56% PDI) and later on became stable. Maximum rust severity of 89.82 per cent was observed on 60 days old plants which was on par with 70 days (89.61%) and was significantly superior to rest of the plant age group. Among the inbred lines MI-12 and Indimyt-345 are highly resistant to common rust of maize and among hybrids viz., NK-6240, NK-61, NK-7305, CP-808, GK-3090, 30R77, CP-818, C-1945, JKMH-502, PAC-740, NK-121, Pro-311, DK-984 and Swarna registered resistant reaction under artificial inoculated field condition. A systemic fungicide, Tebuconazole 250 EC and nonsystemic fungicide, Mancozeb + Phyton and botanical product, Neemazol F 5% were most effective which resulted in less per cent germination of uredospore. The ITK’s viz; Jeevamrutha @ 20 per cent concentration caused significantly less per cent germination (22.69%). Among the bio-control agents evaluated, Trichoderma harzianum was found effective against the pathogen. Significantly minimum PDI (19.74%) and maximum grain yield (66.87 q/ha) was recorded in treatment T1, i.e., foliar application of Tebuconazole @ 0.1% at 35 and 50 DAS.