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|Authors:||MADALAGI, ARCHANA ANAND|
|Advisor:||KULKARNI, M. S.|
KULAKARNI, BALAJI S.
|Title:||STUDIES ON LEAF SPOT DISEASES OF CHRYSANTHEMUM CAUSED BY Alternaria alternata (Fr.) Keissler AND Cercospora chrysanthemi (Hd.) Wolf|
|Publisher:||K.R.C. COLLEGE OF HORTICULTURE, ARABHAVI (UNIVERSITY OF HORTICULTURAL SCIENCES, BAGALKOT)|
|Keywords:||STUDIES ON LEAF SPOT DISEASES OF CHRYSANTHEMUM CAUSED BY Alternaria alternata (Fr.) Keissler AND Cercospora chrysanthemi (Hd.) Wolf|
|Abstract:||The production of superior quality chrysanthemum flowers is limited by leaf spot disease are quite important. Isolation, identification and pathogenicity studies revealed that Alternaria alternata and Cercospora chrysanthemi were the causal organisms. Severity of leaf spot diseases were observed in all the districts surveyed viz., Belgaum, Bagalkot, Gadag and Dharwad among these, maximum severity was observed in fields of Belgaum district. Cultural studies confirmed that, the highest colony diameter and sporulation of pathogens were recorded in Potato dextrose agar. Among the liquid media tested potato dextrose broth supported maximum mycelial growth. Physiological studies revealed that, the mycelial growth of A. alternata was maximum at a temperature range from 200C and with good sporulation. The maximum mycelial growth of C. chrysanthemi was observed at 300C. One per cent glucose solution supported the highest spore germination of pathogens. Among the carbon sources tested maximum dry mycelial weight of pathogens was recorded when lactose was used as carbon source. Among the nitrogen sources tested leucine supported the best growth of Alternaria alternata, where as ammonium nitrate supported best growth of Cercospora chrysanthemi. Among the different plant extracts, fungicides and bio agents tested under in vitro conditions, with irrespective of concentrations Nerium and Neem leaf extracts (10%), Mancozeb and carbendazim together (0.2%) and Trichoderma viride was more effective in inhibiting the growth of Alternaria and Cercospora. Among the varieties screened Accession No.1 was found resistant to leaf spot diseases. The chlorophyll carotenoid content and catalase activity decreased, while sugars, proteins, phenol content and polyphenol oxidase activity content were increased due to the infection of pathogens. Field evaluation revealed that four sprays of Mancozeb (0.2%), Carbendazim (0.2%) Nerium oleander leaf extract (10%) and Trichoderma harzianum (0.05%) at fifteen days interval showed maximum plant height, more number of flowers, more number of branches and highest yield per hectare throughout the cropping period and these treatments also recorded higher cost benefit ratio.|
|Theme:||STUDIES ON LEAF SPOT DISEASES OF CHRYSANTHEMUM CAUSED BY Alternaria alternata (Fr.) Keissler AND Cercospora chrysanthemi (Hd.) Wolf|
|Appears in Collections:||Theses|
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