Browsing by Author "TOMAR, MANICA"
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ThesisItem Open Access STUDIES ON THE MANAGEMENT OF GLADIOLUS YELLOWS CAUSED BY Fusarium spp.(UHF,NAUNI, 1997) TOMAR, MANICA; GUPTA, V.K.ThesisItem Open Access STUDIES ON THE PREVALENCE AND EPIDEMIOLOGY OF APPLE POWDERY MILDEW IN HIMACHAL PRADESH(UHF,NAUNI, 2022-05) NEGI, RENU; TOMAR, MANICAABSTRACT Powdery mildew of apple was found prevalent in moderate to severe forms in Kalpa and Nichar block of Kinnaur, Himachal Pradesh. Incidence of the disease ranged from 25.42 per cent to 53.80 per cent and severity from 39.75 per cent to 66.25 per cent, respectively. Overall twenty different apple cultivars were screened against powdery mildew planted under field conditions at KVK Sharbo, Kinnaur, H.P. Out of the 20 cultivars 5 cultivars viz. Red Delicious, Royal Delicious, Red Velox, Auvil Early Fuji and Oregon Spur II, were found to be less susceptible to Podosphaera leucotricha, while Granny Smith, Golden Delicious, and Gale Gala were found extremely susceptible. In the pathogenicity test of Podosphaera leucotricha it was observed that the symptoms developed at 12 days after inoculation. Small whitish felt-like patches of fungal growth appeared and quickly covered the entire leaf. According to the present study the disease initiated during first week of May and peaked in the month of July in district Kinnaur. Temperatures between 18-240 C and RH between 50-65 per cent were favourable for the disease development. For the management of the disease, in vitro evaluation of fungitoxicants was done against Podosphaera leucotricha by slide germination method. Boscalid + Pyraclostrobin (100.00), Fluxapyroxad + Difenoconazole (95.91%) and Tebuconazole + Trifloxystrobin (94.78%) were found to be superior over other fungicides in inhibiting the spore germination at all the tested concentrations. The same set of fungicides evaluated in vitro were sprayed under field conditions and maximum disease control (94.04%) was reported in Fluxapyroxad + Difenoconazole treated plots followed by Boscalid + Pyraclostrobin (89.92%). These fungicides were further evaluated under nursery conditions. Here maximum disease control (81.09%) was registered in Fluxapyroxad + Difenoconazole followed by Boscalid + Pyraclostrobin (79.51%). For the perpetuation of fungus Podosphaera leucotricha leaves and twigs were collected from orchards and found that fungus survived and perpetuated in the form of conidia, mycelium and chasmothecia in the dormant buds and twigs of the tree.ThesisItem Open Access STUDIES ON WILT DISEASE OF STRAWBERRY AND ITS BIOLOGICAL MANAGEMENT(UHF ,NAUNI, 2022-10) RANA, AKAHAY; TOMAR, MANICAABSTRACT The present investigation entitled, “Studies on wilt disease of strawberry and its biological management” was carried out in the laboratories and greenhouse of the Department of Plant Pathology during the years 2020-2022. The wilt of strawberry in Northern plains of India is associated with many pathogens viz.’ Fusarium, Sclerotium and Rhizoctonia but Fusarium oxysporum f. sp. fragariae has been found to be the major pathogen causing losses to this crop. The disease was prevalent in all the areas surveyed. The pathogen grows well at 25˚C whereas the maximum sporulation was found at 27˚C under in vitro conditions. Out of the biocontrol agents Trichoderma harzianum significantly arrested the mycelial development in vitro. Whereas in field condition consortium of Pseudomonas chlororaphis and Trichoderma harzianum gave better result to control wilt incidence and also enhance the growth parameters. Therefore, it can be concluded that biocontrol agents specially PGPR not only helps in improving the plant growth parameters but also help in mitigating the loss due to soil borne diseases. .