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ThesisItem Open Access Studies on Leaf Blight of Bt Cotton Caused by Alternaria spp.(UAS, Dharwad, 2013) Anil G. H; S. A. AshtaputreCotton is a major fibre crop of global importance and has high commercial value next to food grains. Among the various diseases, Alternaria leaf blight disease is gaining importance due to its increased incidence. A survey was carried out during kharif 2012 in North Karnataka. The maximum disease was recorded in Raichur, Belgaum and Bellary districts. Morphological variability test showed that conidia of different isolates were septated by 1-7 vertical and 3-9 horizontal septe, the isolates from Shaktinagar and Raladoddi showed maximum size of 34.60 × 7.40 and 33.55 × 9.10 μm, respectively. The least size of the conidia was recorded in Dharwad (11.29 × 2.56 μm) followed by Agsikoppa (14.45 × 3.62 μm). Among the twelve isolates, eight isolates showed resemblance with conidial measurements of Alternaria macrospora descried by Ellis M. B. and remaining four isolates were found to be different from Alternaria macrospora morphologically. Maximum width of mycelia was observed in Tagalladoddi (1.99 μm) followed by Navali (1.85 μm) isolates on potato dextrose agar. Five isolates showed irregular and seven isolates showed smooth colony margin. Chicknasbi, Kadagammanadoddi and Tagalladoddi isolates showed excellent sporulation on PDA. All the isolates inoculated on healthy cotton plant showed symptoms. More variability was observed between Tagalladoddi and Raladoddi isolates and less variability was observed between Annigeri and Dharwad through molecular variability test. Among the 199 cotton genotypes screened, 50 genotypes showed moderate resistant, 69 genotypes showed moderate susceptible and 80 genotypes were found highly susceptible and among 14 commercial Bt cotton hybrids screened, nine hybrid were found moderately susceptible and the remaining five hybrids were highly susceptible to Alternaria leaf blight disease. In field evaluation of nine different fungicides, propineb (0.2%) showed better control of the disease with maximum yield.ThesisItem Open Access Studies on Seed Borne Diseases of Cotton in Northern Karnataka(UAS, Dharwad, 2013) Pushpa S. Hanasi; M. S. L. RaoThirty eight seed samples of cotton (Both Bt and Non-Bt) collected from different private companies and research institute in northern Karnataka were subjected to initial seed health testing by standard blotter method. The results of this investigation revealed the predominance of Fusarium moniliforme, Alternaria alternata followed by species of Curvularia and Aspergillus. For detecting seed-borne bacterial infection, semi selective MSSXAN media and XAN-D media was used. Investigation on standardization of seed health testing methods in diagnosing seed-borne fungal infection in cotton, revealed the efficacy of standard blotter method in diagnosing Alternaria and Curvularia, whereas 2,4-D blotter method was found to be good for detecting Fusarium in cotton seed samples. The pathogenic ability of seed borne fungi viz. A. alternata, Fusarium sp. and Xanthomonas axonopodis pv malvacearum was proved in transmission studies. Study on the location of seed borne fungi in the infected cotton seeds revealed that Alternaria alternata, Aspergillus spp. and Curvularia sp. was noticed on the pericarp, where as Fusarium sp was noticed in both pericarp and endosperm. Among the six seed dressing fungicides tested against seed borne fungal infections by rolled towel method, carboxin + thiram @ 0.2% was found most effective. Out of the eight plant extracts tested, Azadirachta indica was found to be most effective @ 10%. Among the four bioagents tested, Pseudomonas fluorescens showed least seed infection @ 0.8%. Among the four priming agents tested, Pseudomonas fluorescens + jelly was found to be most effective. Under field experiments, Seed treatment with acid delinted + imidacloprid + (carboxin + thiram) @ 0.2% along with foliar spray with hexaconazole @ 0.1% at 40 DAS was found to be most effective against Alternaria blight and for bacterial blight, seed treatment with streptocycline (500 ppm) + Imidacloprid was found to be good followed by carboxin + thiram @ 0.2%.ThesisItem Open Access Studies on Seed-Borne Fungal Diseases of Sesame with Special Reference to Alternaria Sesami (Kawamura) Mohanty and Behera(UAS, Dharwad, 2013) Radha P.L.; S.N. ChattannavarSesamum or otherwise called as sesame, (Sesamum indicum L.) locally called as til, belongs to family Pedaliaceae, originated from East Africa. Sesame oil is known for its excellent nutritional, medicinal, cosmetic and cooking qualities for which it is considered as 'the queen of oils' in the West and in Tamil as ‘nallennai’ meaning good oil. A large proportion of sesame is used for producing edible oil, while purely white sesame seeds are in demand on conventional markets due to their higher oil content. Sesamum oil is used for manufacturing perfumed oils and for medicinal purposes. Sesamum cake is a rich source of protein, carbohydrates and mineral nutrients such as calcium and phosphorous. The present investigation studies were carried out on seed-borne fungal diseases of sesame with special reference to Alternaria sesami (Kawamura) Mohanty and Behera during 2012-13 which included testing of sesame seed samples for seed borne mycoflora, evaluation of seed health testing methods, seed to plant transmission studies and management of Alternaria leaf spot of sesame. Seed health testing of sesame seed samples collected from different parts of northern Karnataka revealed the dominance 12.94% of Alternaria sesami. Deep freezing method revealed only the presence of saprophytic fungi like Aspergillus sp. and Penicillium sp. Among different seed health testing methods, standard blotter method was found to be good for detecting the seed-borne infection of Alternaria sesami to an extent of 91.63% in sesame. The pathogenic ability of seed borne infection of A. sesami was proved in seed transmission study. Seed dressing fungicide viz., @ 0.2% Hexaconazole and Avatar 0.3% (Hexaconazole + Zineb), bio-agent i.e., Trichoderma harzianum @ 10 g/kg seeds and botanical @ 5 ml of Allium sativum were found as the most effective in eliminating seedborne infection of A. sesami.ThesisItem Open Access Studies on Integrated Management of Powdery Mildew of Blackgram Caused by Erysiphe polygoni DC(UAS, Dharwad, 2013) Channaveeresh T. Sansi; Shripad KulkarniPowdery mildew caused by Erysiphe polygoni DC is one of the major constraints in the production of black gram. Incidence of black gram powdery mildew was maximum in Belgaum district (68.72%) and minimum in Gadag district (20.23%) during study period. The rDNA-ITS sequencing of E. polygoni indicated that Dharwad isolate is having more than 90 per cent homology with reported E.polygoni isolates in NCBI genebank. The per cent reduction of chlorophyll was more in susceptible variety than in resistant cultivar. Higher amount of total sugar, reducing sugar and non-reducing sugar were recorded in susceptible variety compared to resistant cultivar. Non-reducing and total sugar were synthesized at faster rate in susceptible cultivar than in resistant cultivar. Healthy leaves of resistant cultivar had 8.34 mg/g total phenols and it was increased to 16.78 mg/g after infection. Accumulation of total phenols was at faster rate in resistant cultivar (101.19%) compared to susceptible cultivar (33.85%). LBG-17 showed resistant reaction and four genotypes had highly susceptible reaction against powdery mildew under glasshouse condition. Among the 126 genotypes screened under natural condition only three genotypes were resistant, 14 moderately resistant and others had susceptible reaction. Among various fungicides tested in vitro azoxystrobin 250% SC @ 0.1 % was most effective in inhibiting conidial germination. Whereas, azadirachtin @ 5% and Bacillus subtilis @ 6g/L were found most effective among botanicals and bioagents respectively. In field evaluation azoxystrobin 250% SC @ 0.1% (916 kg/ha), azadirachtin 1500 ppm (1:10) @ 5% (591 kg/ha) and B. subtilis @ 6g/L (590 kg/ha) were superior with least PDI and higher seed yield. Host range studies indicated the ability of the E. polygoni to survive on Euphorbia geniculate (Pill pod spurge garden) and serve as collateral host.ThesisItem Open Access Studies on Pearl Millet Blast Caused by Pyricularia grisea (Cooke) Sacc. In Northern Karnataka(UAS, Dharwad, 2013) Bhojya Naik V.K.; M.M. JamadarPearl millet [Pennisetum glaucum(L.)R.Br.] one of the common millets grown as a nutrient-rich food source for human and as a fodder crop for livestock. Among the several diseases, the blast caused by Pyricularia grisea (Cooke) Sacc. has emerged as a serious disease affecting both forage and grain production in pearl millet resulting economic loss. In the present investigation, the roving survey carried out during kharif 2012 revealed that, the highest disease intensity was observed in Koppal district (76.1%) while least was in Bijapur (31.1%) district. The disease appeared as small, water soaked, later developed as spindle shaped spots with grayish white center with a brown margin. Morphologically Pyricularia grisea (Cooke) Sacc., produced hyaline to pale olive, pyriform conidia, 3-celled with 2–septa and measured 17.5–24.0 x 6.5–8.0 μm. Cultural studies indicated carrot and Czapeck's agar (9.0 cm each) among the solid media and Richard's medium (393.0 mg) among different liquid media supported significantly highest mycelial growth while maximum growth of fungus reached on 14th day of incubation. Variability studies of P. grisea isolates revealed, maltose and sucrose (396.3 mg each) as the best carbon sources while sodium nitrate (407.1 mg) supported significant maximum growth among the nitrogen sources. Isolates Pg4 (Ilakal) and Pg3 (Sindagi) recorded significantly maximum mycelial growth at 250C whereas temperature range of 20 - 300C and pH range of 6.5 to 7.5 was favourable for growth of all the isolates under study. In vitro bioassay revealed mancozeb75WP (93.30%), captan70+ hexaconazole5 75 WP (93.17%) among the non-systemics and tricyclazole75WP (87.78%) among the systemic fungicides significantly inhibited pathogen. Among botanicals commercial-product; Soldier (71.54%) and tulasi (70.93%) significantly inhibited P. grisea growth while no bioagents were effective. All the 24 genotypes screened were susceptible (Grade 5-6) to highly susceptible (Grade 7-9) to P. grisea under natural infection conditions.ThesisItem Open Access Pearl Millet Rust (Puccinia substriata EII. And Barth. Var. Indica Ramachar and Cummins) and its Integrated Management in Northern Dry Zone of Karnataka(UAS, Dharwad, 2013) Nagaraja H.; P.V. PatilPearl millet [Pennisetum glaucum (L.) R. Br.] is the most drought and heat tolerant crop with highest water use efficiency under drought stress. It is grown as a nutrient rich food source for human and as a fodder crop for livestock. In Karnataka pearl millet is largely cultivated in northern districts comprising Bijapur, Bagalkot, Gulbarga, Raichur, Koppal and Belgaum accounting for 87 per cent of the area and production in the state. Pearl millet in Karnataka presently suffers from many fungal diseases. Among them rust caused by Puccinia substriata var. indica is a potential destructive disease in recent years causing severe yield loss. Hence, the present investigation was carried out with different objectives aiming at the integrated management of this disease. Roving survey conducted during Kharif 2012 in different taluks of Bijapur and Bagalkot districts indicated varying intensities in different taluks. Rust severity was higher in Basavana Bagewadi taluk (42.96 %) followed by Bijapur (40.11 %) and Sindagi (38.88 %) taluks of Bijapur district and in Bagalkot district, Hunagund taluk recorded maximum rust severity (35.18%) followed by Badami (27.15 %) and Bagalkot (17.77 %) taluk. In loss assessment studies among different pearl millet genotypes to rust, irrespective of the fungicidal spray significantly higher per cent disease index was recorded in the genotype MRB 2232 (32.33 %). And higher seed yield (44.83 q ha-1) and 1000 seed weight (12.81 g) was recorded in the genotype GK 1135 compared to other genotypes. Under in vitro condition irrespective of the concentrations, hexaconazole among fungicides, neem oil among botanicals and cow urine among ITK’S recorded maximum inhibition of uredospore germination of 98.18, 88.83 and 82.14 per cent, respectively. In Integrated Disease Management (IDM), the spray schedule hexaconazole @ 0.1% - hexaconazole @ 0.1% recorded least rust severity (15.30 %), higher seed yield (30.50 q ha-1) with higher benefit : cost ratio (1 : 2.40) followed by the spray schedule hexaconazole @ 0.1% - neem oil @ 1.0 %. Among 42 pearl millet genotypes screened against rust, none of the genotype showed immune or highly resistant reaction, four genotypes showed resistant (EBT 10-37, EBLT 10-3, LPRT 10-11 and EMRT 10-17), 18 genotypes each as moderately resistant and susceptible and remaining two genotypes as highly susceptible.ThesisItem Open Access Studies on Banded Leaf and Sheath Blight of Maize Caused by Rhizoctonia Solani f. sp. Sasakil Exner(UAS, Dharwad, 2013) Laxman Singh Rajput; S.I. HarlapurBanded leaf and sheath blight of maize caused by Rhizoctonia solani f.sp. sasakii Exner is an important disease which results in heavy yield loss. The investigations include main aspects viz., survey, variability of pathogen, in vitro evaluation of fungicides, bioagents, botanicals and management of the disease. The results of the investigations are summarized hereunder The roving survey on the disease severity revealed that, maximum disease severity was observed in Kalaghtagi (52.45%) followed by Mundgod (51.54%). Minimum severity was noticed in Bailhongal (15.72%). Highest disease severity observed in black soil under irrigated area on DKC 8101 hybrid in Kalaghtagi taluka of Dharwad district. Six isolates collected from different part of Northern Karnataka were studied for their variability. The isolates showed variability in morphological and cultural characters. Among six isolates, isolate Rsm6 (Kalaghatagi) was found to be fast growing, maximum sclerotial size (3.1mm), oval shape and red brown sclerotia, minimum time took for initiation of sclerotial production (8 days) and highest number of sclerotia per plate (115). The in vitro studies on fungicides evaluation at various concentration, indicated Propiconazole 25% EC and Carbendazim 50% WP were found most effective in inhibiting the growth of the fungus. The plant extracts viz., nimbicidine and NSKE at 5 and 10 per cent concentrations were effective against the pathogen. Among the biocontrol agents evaluated, Trichoderma harzianum found effective against the pathogen. Field studies on the management of the disease revealed that, seed treatment with Pseudomonas fluorescens @10 g kg-1 seed followed by two sprays of Propiconazole 25 EC @ 0.1% at 30 and 40 DAS found most effective treatment and resulted in lowest PDI (20.40%). This treatment increased grain yield (40.72%) and fodder yield (44.68%) over untreated check.ThesisItem Open Access Studies on Athracnose of Soybean Caused by Colletotrichum (Schw.) Andrus and Moore(UAS, Dharwad, 2013) Nagaraj B.T.; Shamarao JahagirdarThe investigations on soybean anthracnose caused by Colletotrichum truncatum (Schw.) Andrus and Moore included main aspects, viz., survey for disease, variability study of pathogen, identification of susceptible stages of infection, in vitro and field screening of fungicides, integrated management of disease and screening of available genotypes. A roving survey was conducted during kharif 2012; maximum disease severity in Belgaum district (30.56 PDI); minimum severity was noticed in Dharwad (28.98 PDI). During summer 2013, maximum disease severity was observed in Bailhongal (28.24 PDI); minimum severity was noticed in Athani (22.76 PDI). Variability study indicated that, there was much difference in colony colour ranging from cottony white to dark grey, the spore shape was only truncate type and there was no difference with respect to spore size of Colletotrichum truncatum isolates. Molecular variation existed among the isolates of C. truncatum helped to distinguish the isolates of C. truncatum from major soybean growing areas of the country. Study on susceptible stages of infection revealed that the mean maximum disease severity was obtained by inoculating the plants before flowering (40 DAS) followed by 10 DAS and seed inoculated plants. Among the fungicides evaluated, propiconazole, carbendazim, difenconazole, iprodione + carbendazim and trifloxystrobin + tebuconazole at 0.1 per cent were found very effective in inhibiting the growth of mycelium. Field evaluation of fungicides indicated that seed treatment with carboxin+ thiram (2 g/kg) or captan (2 g/kg) + foliar spray of trifloxystrobin + tebuconazole @ 0.1% at 55 DAS was found very effective in reducing the soybean anthracnose and enhancing the seed yield. The genotypes DSb 12 and DSb 20 showed highly resistant reaction while, JS 335 showed highly susceptible reaction against anthracnose both in glasshouse and field conditions.ThesisItem Open Access Organic Management of Purple Blotch of Onion Caused by Alternaria porri (Ellis) Cif.(UAS, Dharwad, 2013) Vinamrata G. Patilkulkarni; M.G. PalashappaOnion is one of the most important commercial vegetable crops of India. The crop is subject to attack by a number of diseases, of which purple blotch caused by Alternaria porri is serious and also a major limiting factor in cultivation of onion. Survey during Kharif 2012- 13 revealed that purple blotch was found in all parts of Northern Karnataka and was severe in Haveri district. Isolation and pathogenicity to onion plants was proved. Trichoderma harzianum was most effective against A. porri, followed by T. koningii. Among the plant extracts maximum inhibition of mycelial growth of A. porri was recorded with Azadirachta indica followed by Ocimum sanctum. Among the organics tested against A. porri, Cow urine followed by Neem cake was highly inhibitory to A. porri. Among the organic combinations with antagonists tested against A. porri, Cow urine plus T. harzianum showed maximum inhibition of mycelial growth. Among the combinations of organics and botanicals tested against A. porri, maximum inhibition of mycelial growth was recorded in Cow urine plus O. sanctum. Combinations of organics and amendments were tested against A. porri; maximum inhibition of mycelial growth was recorded in Cow urine plus Pongamia cake. Influence of weather parameters on purple blotch of onion at different date of sowing revealed that maximum temperature was positively correlated with number of lesions, lesion size and per cent disease index at all four different dates of sowing and in the late sown crop (third week of July), the disease was low compared to early sowing. The field studies on organic management of purple blotch of onion revealed that seed treatment with T. harzianum @ 10g/kg –spray of Panchagavya 5%+ Neem Seed Kernel Extract 5% proved best with least per cent disease index and bulb weight, bulb diameter, yields compared to unsprayed check.