STUDIES ON POWDERY MILDEW (Erysiphe polygoni D C) OF URDBEAN [Vigna mungo (L.) Hepper] IN RELATION TO WEATHER, HOST PLANT RESISTANCE AND MANAGEMENT

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dc.contributor.advisorMANOJ KUMAR, V
dc.contributor.authorTULASI, K
dc.date.accessioned2018-05-08T06:32:24Z
dc.date.available2018-05-08T06:32:24Z
dc.date.issued2016
dc.descriptionD5292en_US
dc.description.abstractPowdery mildew disease caused by Erysiphe polygoni D C is one of the serious constraints that afflict cultivation of blackgram in India and other countries. In view of the significance of the disease, investigation was carried out to study the severity of powdery mildew on urdbean (Vigna mungo (L.) Hepper) in relation to weather, host plant resistance and management. Observations were made on different aspects like incidence, severity (PDI), morphological characters and biochemical changes and growth and yield parameters. A roving survey was conducted during rabi 2015-16 in Guntur district of Andhra Pradesh. Disease incidence and severity were recorded in the surveyed villages of Tadikonda, Veticherukuru, Pedanandipadu and Kakumanu mandals of Guntur district. Incidence was ranged from of 13.69% (Pedanandipadu mandal) to 87.01% (Tadikonda mandal) and severity were ranged from 11.61% (Kakumanu mandal) to 88.08% (Tadikonda mandal), respectively. Symptoms first appeared on shaded lower leaves. These white, powdery colonies grew in size and cover both sides of the leaf, petioles and young stems. When disease progressed leaves became smaller and chlorotic with stunting, distortion and premature leaf fall due to infection of E. polygoni. The pathogen was observed to produce amphigenous dirty white hyaline mycelium and barrel shaped conidia measuring 1.089 μm × 0.7131 μm at 40X magnification. Correlation studies with weather parameters and crop age on powdery mildew disease severity revealed that significant positive correlation of disease was recorded with crop age (r=0.984) and maximum temperature (r=0.657). Regression analyses for per cent severity of diseases with weather factors revealed that maximum temperature and wind speed and minimum temperature would influence powdery mildew disease in urdbean up to 86.6 per cent. During kharif, out of 47 genotypes evaluated, KUP-1 was immune, two genotypes were highly resistant, and ten were moderately resistant to powdery mildew, whereas, twenty moderately susceptible and ten were susceptible and four highly susceptible. In rabi, out of eleven genotypes, two were highly resistant against powdery mildew disease, one moderately resistant, one moderately susceptible, other seven genotypes were highly susceptible. Among selected blackgram genotypes, significantly highest leaf thickness was observed in highly resistant genotypes KUP-34 (201.4 μm), KUP-40 (191.3 μm). Significantly lowest stomatal frequency was observed in highly resistant genotypes KUP-34 (88.64/mm2), KUP-40 (99.24/mm2). Higher trichome density was observed in highly resistant genotypes KUP-34 (62.33), KUP-40 (59.11). Significantly higher phenol content was observed in highly resistant genotypes KUP-34 (0.912 mg/100 mg) and KUP-40 (0.861 mg/100 mg) and one moderately resistant genotype KUP-12 (0.678 mg/100 mg). Highly susceptible genotype LBG-623 recorded the lowest total phenol content (0.299 mg/100 mg). Significantly lowest total sugars, reducing sugars and non reducing sugars were recorded in highly resistant genotypes KUP 34 and KUP 40. In field evaluation of different chemicals, two sprays of Myclobutanil @ 0.2 W.P (31.23%), Wettable sulphur @ 0.3 W.P (32.81%) were found superior as they recorded the lowest per cent disease index. Significant increase in shoot length, number of primary branches per plant, number of pods per plant, 100 seed weight, seed yield was recorded with Myclobutanil spraying at 35 and 45 DAS followed by Wettable sulphur. Highest benefit cost ratio was observed in Wettable sulphur (1.82) followed by Myclobutanil (1.17).en_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810044937
dc.keywordsPOWDERY MILDEW (Erysiphe polygoni D C), URDBEAN [Vigna mungo (L.) Hepper]en_US
dc.language.isoen_USen_US
dc.pages99en_US
dc.publisherAcharya N.G. Ranga Agricultural Universityen_US
dc.research.problemSTUDIES ON POWDERY MILDEW (Erysiphe polygoni D C) OF URDBEAN [Vigna mungo (L.) Hepper] IN RELATION TO WEATHER, HOST PLANT RESISTANCE AND MANAGEMENTen_US
dc.subPlant Pathologyen_US
dc.subjectnullen_US
dc.themeSTUDIES ON POWDERY MILDEW (Erysiphe polygoni D C) OF URDBEAN [Vigna mungo (L.) Hepper] IN RELATION TO WEATHER, HOST PLANT RESISTANCE AND MANAGEMENTen_US
dc.these.typeM.Scen_US
dc.titleSTUDIES ON POWDERY MILDEW (Erysiphe polygoni D C) OF URDBEAN [Vigna mungo (L.) Hepper] IN RELATION TO WEATHER, HOST PLANT RESISTANCE AND MANAGEMENTen_US
dc.typeThesisen_US
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