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Deepa ¹, Gururaj Sunkad ¹, M. R. Govindappa ¹, M. K. Naik ¹, S. R. Suresh ²

Affiliations
1 Department of Plant Pathology, University of Agricultural Sciences, RAICHUR (KARNATAKA), IN
2 Department of Plant Pathology, University of Agricultural Sciences, DHARWAD (KARNATAKA), IN

Abstract

An experiment was carried out to assess the crop loss due to sunflower leaf curl virus (SuLCV) disease. The crop loss assessment in terms of growth and yield components was recorded at first appearance of symptoms of SuLCV at 30 days to 90 days during the crop growth. The SuLCV disease infection in sunflower significantly affected the plant height (72.60 to 157cm), size of the head (8.60 to 18.78cm), 100 seed weight (2.20 to 6.32g), oil content (31.24% to 38.26%), and weight of seeds/10 heads (77.20 to 372.2g) as compared to the healthy control plants. In the plants, first appearance of symptoms at 30 DAS was recorded the seed yield loss of 79.25 per cent.

Keywords

Sunflower, SuLCV, Yield Loss Estimation, Yield Components.

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Meghashree Meti ¹, Mallikarjun Kenganal ¹, Gururaj Sunkad ¹, D. S. Aswathanarayana ¹, U. K. Shanwad ²

Affiliations
1 Department of Plant Pathology, University of Agricultural Sciences, Raichur (Karnataka), IN
2 Department of Agronomy, University of Agricultural Sciences, Raichur (Karnataka), IN

Abstract

Mungbean a protein rich legume has high demand but, supply is hindered due to poor production and productivity due to mungbean yellow mosaic virus (MYMV) disease. The North Eastern Karnataka being the pulse bowl of the state annually suffers from MYMV incidence. In order to control this whitefly transmitted virus, knowledge and information about its distribution across the region is essential to formulate the strategies of management. In the present study a roving survey was undertaken to know the incidence and present status of MYMV in mungbean among the six districts of North Eastern Karnataka (NEK) region viz., Bellary, Bidar, Koppal, Kalaburgi, Raichur and Yadgir during Kharif 2016, when the crop was at 30 to 45 days old. The GPS position and MYMV incidence in each location were recorded and used to develop GIS map to know the spatial distribution of MYMV in different talukas of six districts. The results showed varied incidence of MYMV across many locations. Highest disease incidence was recorded at Koppal district with 33.33 per cent followed by Bellary (21.45 %), Raichur (19.70 %), Kalaburgi (17.44 %) and Yadgir (15.76 %) districts. The least disease incidence was noticed at Bidar district (5.66%). Higher MYMV incidence in Koppal was mainly due to favourable weather for multiplication and survival of whitefly population which spreads the virus. The virus inoculum in summer crop and weed hosts were found acting as source of inoculum. Findings of the study revealed that higher incidence in Koppal would provide suitable disease pressure for screening of genotypes developed against the MYMV infection and also develop management strategies in each district based on the disease incidences recorded.

Keywords

MYMV, Mungbean, Kharif, PDI (% Disease Incidence), Survey, NEK, GPS.

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Poornima ¹, Gururaj Sunkad ²

Affiliations
1 Department of Plant Pathology, AICRP (Sunflower), MARS, Raichur (Karnataka), IN
2 Department of Plant Pathology, University of Agricultural Sciences, Raichur (Karnataka), IN

Abstract

A technique was standardized to screen for resistance to stem rot (Sclerotium rolfsii Sacc.) in groundnut (Arachis hypogaea L.). A total of seven different inoculation techniques were screened by using susceptible genotype TMV-2. The techniques involved inoculation of 10 day old groundnut plants raised in pots by spreading mycelial propagules of S. rolfsii grown on sorghum grain medium (SGM) on soil surface, Inoculum spread on the soil surface and covered with groundnut leaf debris, Inoculum placed around the collar region, Inoculum placed around the collar region and covered with groundnut leaf debris, Inoculum mixed in the soil, Inoculum mixed in the soil and covered with groundnut leaf debris, Agar disc method. Among these techniques inoculum spread on the soil surface and covered with groundnut leaf debris was found to be most efficient in getting highest per cent incidence of stem rot (84.86%) and pod rot (70.48%).

Keywords

Groundnut, Stem, Pod Rot, S.rolfsii.

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GURURAJ SUNKAD ¹, AKSHATA GOUR ¹, RANJANA JOSHI ², MEGHANA PATIL ¹

Affiliations
1 Department of Plant Pathology, University of Agricultural Sciences, Raichur-584104, India ., IN
2 Department of Plant Pathology, University of Agricultural Sciences, Raichur-584104, India., IN

Abstract

Rice (Oryza sativa L.), as a cereal grain, is the most widely consumed staple food for a large part of the world’s human population, especially in Asia and Africa. Rice production is often subjected to several biotic and abiotic stresses. Rice sheath blight is one of the most destructive diseases causing economic losses in rice yields and affecting quality worldwide. Twenty soil samples were collected from the rhizosphere of rice crop from different regions of Northern Karnataka. Trichoderma spp. were isolated from the rhizospheric soil samples. The antagonistic potential of Trichoderma spp. was studied using dual culture technique. Among twenty strains of Trichoderma the highest inhibition (>50%) was recorded in nine strains which ranged from 54.20 to 65.10 per cent. Trichoderma harzianum recorded highest seed germination (100%), root length (13.73 cm), shoot length (8.64 cm) and seedling vigour index. In pot culture experiment, the Trichoderma strains significantly improved the growth parameters such as root length, shoot length and number of tillers per plant. Among the different treatments, seed treatment + root dipping + foliar spray with T. harzianum strain was highly effective in increasing the shoot length, root length and seedling vigour index at 30, 60 and 90 days after sowing. This strain was found highly effective in inhibiting the pathogen and promoting the growth of rice plants.

Keywords

Plant growth promotion, rice, sheath blight, Trichoderma strains

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GURURAJ SUNKAD ¹, KHADARBI ¹, RANJANA JOSHI ¹, MEGHANA S. PATIL ¹

Affiliations
1 Department of Pathology, University of Agricultural Sciences, Raichur - 584104, Karnataka, India ., IN

Abstract

Stem and pod rot of groundnut is an economically important soil borne disease caused by Sclerotium rolfsii Sacc. The present study aimed to evaluate the indigenous bacterial bio control agent Pseudomonas fluorescens strains having multiple traits related to bio control and plant growth promoting activity. Healthy rhizospheric soil from groundnut field was collected from different North Karnataka districts. Nineteen strains of P. fluorescens were isolated by serial dilution technique on King’s B medium. The antagonistic potential of nineteen strains was tested against S. rolfsii by using dual culture technique. The per cent inhibition was highly variable among the nineteen strains of P. fluorescens ranging from 2.59 to 75.18 per cent. Maximum mycelial inhibition of S. rolfsii was recorded by the strain PF-2 (75.18%) followed by PF-3 (72.96%), PF-6 (69.62%) and least inhibition was recorded by PF-13 (2.59%). Five superior strains of P. fluorescens showed fluorescens under UV light, yellowish green pigmentation, rod shaped cells under microscope. Five superior strains were subjected for various biochemical tests and all the isolates were positive for biochemical characterization such as Gram staining, endospore production, catalase, starch hydrolysis, urease test, casein hydrolysis and gelatin liquefy action and negative for KOH and in dole test. Further, these strains were subjected for plant growth promoting traits such as HCN production, IAA production, siderophore production and volatile compounds production. Among these, the strainsviz., PF-2 and PF-3 were scored as strong with respect to antagonism and growth promotion. The strainsPF-6, PF-7 and PF-10 were scored as moderate with light brown colour. Among the tested strains of P. fluorescens, the isolates PF-2 and PF-3 were recorded higher production of siderophore, isolates PF-6, PF-7 and PF-10 showed moderate production of siderophore. The strain PF-2 of P. fluorescens showed highest per cent of mycelial inhibition of S. rolfsii indicating higher production of volatile compounds, followed by PF-3 and PF-6. Whereas, the least mycelial inhibition was recorded by the isolate PF-10 indicating less production of volatile compounds.

Keywords

Groundnut, management, Pseudomonas, sclerotium rot

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GURURAJ SUNKAD ¹, MEGHANA S. PATIL  ¹, RANJANA JOSHI ¹

Affiliations
1 Department of Plant Pathology,   University of Agricultural Sciences, Raichur – 584104, Karnataka, IN

Abstract

Chickpea (Cicer arietinum L.) is grown in more than 50 countries. India is the largest chickpea-producing country accounting for 64% of the global chickpea production. However, the production is contrained by the dry root rot disease caused by Rhizoctonia bataticola. Considering this problem, the investigation was carried out to isolate, characterize and the antagonistic potential of indigenous endophytic PGPMs for one of the components in the integrated management of dry root rot of chickpeas in eco-friendly manner. Hence, the isolation of thirty endophytic PGPMs was carried from chickpea by using the spread plate technique. The cultural characters and Gram’s staining reaction confirmed that the endophytic PGPMs isolated from chickpea plant tissues were bacteria. Among thirty bacterial strains, eight showed more than 50% of mycelial inhibition of the pathogen. Out of eight strains, five highly superior strains were selected and subjected for 16S rDNA gene sequencing using the universal primers (16Sr DNA F and 16Sr DNA R), which produced amplified products of size 1500 bp. nBLAST results of 16S rDNA gene sequence revealed that all the endophytic bacterial PGPMs showed homology with genus Bacillus but with different species. The five potential strains namely, BEPGPM-5, BEPGPM-9, BEPGPM-27, BEPGPM-28, and BEPGPM-30 were identified and confirmed as B. tropicus, B. pacificus, B. cereus, B. subtilis, respectively, based on molecular technique.

Keywords

Bacillus cereus, B. pacificus, B. subtilis, B. tropicus, chickpea, dry root rot

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