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Subject: Plant Pathology × Author: Anil Kumar, K × End date: 1999 × Start date: 1995 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    STUDIES ON VIRAL DISEASES OF POTATO
    (University of Agricultural Science, Dharwad, 1999) Anil Kumar, K; Patil, S
    "Potato is one of the most important commercial vegetable crops cultivated in Northern Karnataka. The crop is known to suffer from many viral diseases among which mosaic and leaf roll are more common. The studies on survey indicated the mild mosaic incidence ranged from trace (Belvadi) to 22.25 per cent (Mritunjayanagar), severe mosaic ranged from trace (Belvadi) to 36.60 per cent (Rayapura) and leaf roll ranged from trace (Belvadi) to 85.50 per cent (Jafarwadi). The mild mosaic virus (PVX) was sap transmissible to different indicator plants and produced systemic symptoms on tobacco, Nicotiana glutinosa, tomato and local lesions on cowpea and Chenopodium amarantlcolor. Severe mosaic virus (PVY) produced systemic symptoms on tobacco Var.KST 19, white burley and samsun and N.glutinosa. Aphid (Myzus persicae) transmitted severe mosaic and leaf roll viruses in a non -persistent and persistent manner, respectively. The mild mosaic and severe mosaic viruses had a Thermal Inactivation Point (TIP) between 70 - 75°C and 50 - 55°C, a Dilution End Point (DEP) between 105 - 106 and 102 - 103 and the Longevity in Vitro (LIV) of 28 days and 48-72 hours, respectively at room temperature (25-28°C). The mosaic disease had slight effect on yield and yield parameters while the leaf roll infection at early stages resulted in greater yield loss than those infected later. Under field conditions the crop could be protected by spraying systemic insecticide, acephate (0.15%) (5 sprays) followed by bougainvillea leaf extract. Alternate sprays of acephate and bougainvillea/lantana leaf extract reduced the viral disease incidence on potato. Among the different genotypes screened 85-P-670 was moderately resistant to both mosaic and leaf roll diseases. MP/90-94, MS/'87-1192, JX- 114 and OP-1 were found to be the other moderately resistant genotypes against leaf roll disease."