Browsing by Author "Naidu, R."
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Item Breeding cardamom for 'Katte' disease resistance(2007-02-08) Subbarao, G.; Naidu, R.' Katte ' or Mosaic disease of small cardamom (E. cardamomum Maton) is an important virus disease transmitted by an aphid (Pentalonia nigronerusa f. caladii Vander Goot). In order to obtain resistant lines, various breeding programmes were initiated at this Research Centre. Evaluation of existing germplasm including high yielders, morphological variants occurring in nature like pinkstemmed, terminal panicle, male sterile and chlorophyll variegants through insect vector has not revealed any resistant types. Seedlings raised after exposing the seeds to physical mutagens at 5, 10, 15 KR of gamma rays and seeds treated with chemical mutagens like Ethyl methane sulpbonate (EMS) and Diethyl sulphate (DES) with different concentrations and treatments has also not yielded positive results in getting a resistant type. Even species of allied genera like Aframomum, Amomum Alpinia have also taken infection. So far the screened material was found to be susceptible.Item Effect of insecticides on transmission and acquisition of katte virus of small cardamom and their use in relation to disease spread and vector control(2007-02-08) Rajan, P.; Naidu, R.; Venugopal, M.N.Thirty four insecticides were evaluated against nonpersistent aphid borne Katte virus to determine their effect on transmission and acquisition under laboratory conditions. Transmission results showed that none of the insecticides tested was effective on acquisition and transmission of virus even on the day of spraying. Investigations were also carried to find out the feasibility of using systemic and contact insecticides for control of vector and disease. Regular application of insecticides such as Phosphamidon, Carbofuran and Phorate resulted in significantly more disease spread than control. But in the Methyl parathion, Dimethoate and Quinalphos treated plots the disease incidence was on par with control. However, suppression of aphid pupulation build up was significantly less in all insecticide treated plots.Item Effect of natural infection of 'Katte' on yield of cardamom: A case study(2007-02-08) Venugopal, M.N.; Naidu, R.Studies on crop loss due to natural infection indicated that virus affected plants yield 38 per cent, 62 per cent and 68 per cent less cardamom in the first, second and third year of infection respectively. The quantity of crop loss is related to the duration over which the plant had been infected. The yield of a well-maintained plot was affected considerably from the very first year of infection. Production of cardamom in the disease-affected plot, experienced a loss of 16 per cent at 37 per cent infection level, 44 per cent at 84 per cent infection level and 59 per cent at 98.5 per cent infection level respectively in the first, second and third year of infection.Item Epidemiology of 'Katte' virus disease of small cardamom-II: Foci of primary disease entry, patterns and gradients of disease entry and spread(2007-02-08) Naidu, R.; Venugopal, M.N.Monitoring of forty nurseries raised through seed and voluntary seedlings and twenty two plantations situated at 6-9 Km from the source of inoculum revealed that voluntary seedings collected from infected plantations and the nurseries located in the vicinity of diseased crop from the primary foci of disease spread. Entry of disease also occurs in contiguous and nearby plantations up to 1,000 m from the external inooulum source. Further centrifugal influx was recorded around primary foci due to secondary spread by the vector. Spatial pattern of spread is concentrated within 40 m radius with occasional introduction of disease up to 90 m distance. Sharp difference in the pattern of spread was observed between the plots with and without roguing. The gradient of the disease decreases steeply near the source of inoculum and less steeply at great distances.Item Epidemiology of 'Katte' virus disease of small cardamom. I. Disease incubation period and role of different host parts as a source of inoculum in disease spread(2007-02-08) Naidu, R.; Venugopal, M.N.The incubation period of 'Katte' virus disease was studied by inoculating grown up clumps under field conditions over a period of three years. The disease incubation period varied from 20 to 114 days during different months of incubation. However, the number of leaves produced during the incubation period remain more or less constant. Symptom expression was directly influenced by the growth of plants as indicated by early expression in the active growing period (May to November) and late expression in dry period (December to April). Higher transmission of the virus was obtained when young growing parts were used as a source of inoculum as against low transmission with mature and old parts. The old leaf sheaths which are the natural breeding sites of the vector were found to be a poor inoculum source. The various forms of aphid found naturally colonising on the old drying parts may not play a significant role in disease spread.Item Increasing Productivity of Cardamom through Large Scale Demonstration of Improved Technology in Farmers Fields in Kodagu District of Karnataka(2007-02) Korikanthimath, V.S.; Venugopal, M.N.; Naidu, R.; Sadanandan, A.K.A High Production Technology (HPT) programme was initiated in 1986 In all the key cardamom growing zones of Kodagu district Kantataka to motivate the grower to increase the per unit production to a level of 650 kg per ha by utilizing the information available at the Cardamom Research Centre, Appangala,collaboration with Spices Board. A series of meetings were held in various field units to enlighten planters for adoption of the HPT programe. Totally 42 farmer, were selected covering area of 94.10 ha by planting 4,70,500 C1-37 seedlings. The preplanting status survey of the HPT cardamom plantations revealed that the yield level ranged from as low as 10 to as high as 125 kg/ha, with the average being 58.0 kg/ha. The establishment of cardamom in all the plots is quite satisfactory (95%). The slots were monitored from time to time by implementing the package of practices as per calender of operations.Item Management of 'Katte' Disease of Small Cardamom(2007-02) Naidu, R.; Venugopal, M.N.Influence of periodical roguing of 'Katte' affected dumps on disease spread was studied for three years in four different plantations with various levels of initial inoculum. Roguing of affected clumps at monthly interval has resulted in reduction of the disease to a manageable level of less than one percent incidence, within three years irrespective of initial level of inoculum in the plantation. However, higher the initial inoculum more is the number of chimps to be rogued and replanted with healthy plants during the first year. Comparison of data on expenditure incurred on roguing of affected clumps one one hand, and production during different years on the other, revealed that roguing was economical. Roguing of diseased chimps at shorter intervals (weekly) only for 3 months, which is an average disease incubation period in host, appeared to be more advantageous fa reducing (he chance of secondary spread before its elimination. Large-scale implentation of 'Katte' eradication programme in growers' plantations revealed that it was possible to extend such programmes whereby the growers pay for technical assistance in tracing and roguing of affected clumps.Item Management of 'Katte' Disease of Small Cardamom(1982) Naidu, R.; Venugopal, M.N.Influence of periodical roguing of 'Katte' affected clumps on disease spread was studied for three years in four different plantations With various levels of initial inoculum. Roguing of affected clumps at monthly interval has resulted in reduction of the disease to a manageable level of less than one percent incidence, within three years irrespective of initial level of ino culum in the plantation. However, higher the initial inoculum more is the number of clumps to be rogued and replanted with healthy plants during the first year. Comparison of data on expenditure incurred on roguing of affected clumps one one hand, and production during different years on the other, revealed that roguing was economical. Roguing of diseased clumps at shorter intervals (weekly) only for 3 months, which is an average disease incubation period in host, appeared to be more advantageous in reducing the chance of secondary spread before its elimination. Large-scale implementation of 'Katte' eradication programme in growers' plantations revealed that it was possible to extend such programmes whereby the growers pay for technical assistance in tracing and roguing of affected clumps.