Etiology and management of die back disease of mango grafts in nursery (Record no. 27815)
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| fixed length control field | 07114nam a2200193Ia 4500 |
| 003 - CONTROL NUMBER IDENTIFIER | |
| control field | OSt |
| 005 - DATE AND TIME OF LATEST TRANSACTION | |
| control field | 20220323105628.0 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION | |
| fixed length control field | 140128s9999 xx 000 0 und d |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 632.3 |
| Item number | SAN/ET |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Sangeetha C |
| 245 ## - TITLE STATEMENT | |
| Title | Etiology and management of die back disease of mango grafts in nursery |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc. | Vellanikkara |
| Name of publisher, distributor, etc. | Department of Plant Pathology, College of Horticulture |
| Date of publication, distribution, etc. | 2009 |
| 300 ## - PHYSICAL DESCRIPTION | |
| Extent | 118 |
| 502 ## - DISSERTATION NOTE | |
| Degree type | MSc |
| 520 3# - SUMMARY, ETC. | |
| Summary, etc. | A study on "Etiology and management of die back disease of mango grafts in nursery" was carried out in the Department of Plant Pathology, College of Horticulture, Vellanikkara during 2007 - 20008 to study various aspects, particularly the etiology, symptomatology, varietal reaction and management of die back disease. Surveys were conducted at ten different nurseries on the occurrence of die back disease of mango grafts and during the survey different leaf blight diseases were also noticed along with die back incidence. Pathogens associated with these diseases were isolated and proved pathogenicity by artificial inoculation under in vitro and in planta conditions. Isolation of pathogen on PDA medium yielded Colletotrichum sp. and Botryodiplodia sp. from die back symptom and Colletotrichum sp., Pestalotiopsis sp., Cylindrocladium sp., Drechslera sp. and Alternaria sp. from leaf blight symptom. Studies on symptomatology showed that die back and leaf blight symptoms produced by the respective pathogens at different locations were same, but different pathogens produced different type of symptom on mango grafts. The die back caused by Colletotrichum sp. was observed as small necrotic spots on the tip of shoot and at the base of leaf petiole which later coalesced and developed , large brownish black necrotic area. The leaves on the infected shoot dried up and fell down. Black discolouration and darkening of the bark of young green twigs were observed in mango grafts infected by Botryodiplodia sp. This infection spread downwards and resulted in typical die back symptom. In severe infection leaf shedding was also observed. The leaf blight caused by Colletotrichum sp. was also noticed on young leaves and appeared as dark brown circular spot with yellow halo which coalesced to form large blighted area. The pathogen produced the fruiting body, acervulus, on infected area and also showed shot hole symptom. Pestalotiopsis sp. infected matured leaves and produced light brown necrotic area from the leaf tip or margin which later spread towards the midrib with silvery grey coloured area on upper surface of leaf. The other three pathogens viz., Cylindrocladium sp., Drechslera sp. and Alternaria sp. initially produced dark brown spots on leaves. In all these infections, the spots were coalesced and produced large brown coloured blighted area on leaves. Cultural and morphological characters of the six pathogens were studied on PDA medium. Based on the etiological studies and cultural and morphological characters of organisms the pathogens causing die back disease were identified as Colletotrichum gloeosporioides (Penz.) Sacc and Botryodiplodia theobromae Pat and the leaf blight inciting pathogens were identified as Colletotrichum gloeosporioides (Penz.) Sacc, Pestalotiopsis mangiferae (Henn.) Steyaert, Cylindrocladium mangiferae sp. nov, Drechslera australiensis (Bugnicourt) Sub ram & Jain ex M.B.Ellis and Alternaria alternata (Fries) Keissler. There was no earlier report of C. mangiferae on mango and hence it is the first report of this fungus as a leaf blight pathogen on mango. The result of the genetic dissimilarity index computed by the seven different isolates of C. gloeosporioides showed a slight variability among the isolates. An in vitro experiment was conducted to evaluate the effectiveness of fungicides and antagonists against die back and leaf blight pathogens. Among the fungicides, Bordeaux mixture at all the three concentrations recorded cent per cent , inhibition on the growth of all the six pathogens. Carbendazim showed cent per cent inhibition on the growth of C. gloeosporioides, P. mangiferae and C. mangiferae at all the three concentrations but it was not very effective against D. australiensis. Hexaconazole was found effective to control the growth of D. australiensis and recorded more than 85 per cent inhibition over control. The two fungal antagonists viz., T. viride (KAU) and T. harzianum (nSR) showed complete inhibition on the growth of all the six pathogens whereas the bacterial antagonist, P. jluorescens showed more than 50 per cent inhibition on the growth of C. gloeosporioides, B.theobromae, P. mangiferae and D. australiensis. After the in vitro evaluation of fungicides and antagonists, an in planta experiment was conducted two times to know the effect of various treatments on the management of die back and leaf blight diseases. Observations on per cent disease severity of die back and leaf blight disease revealed that all the treatments were superior to control. The data recorded on ten days after the last application of treatments during the first experiment revealed that the highest reduction in disease severity (90.47 per cent) was observed in plants treated with one per cent Bordeaux mixture, 0.3 per cent copper oxychloride, 0.1 per cent carbendazim, 0.15 per cent copper hydroxide. The treatments T9 (P. fluorescens), T10 (T. viride) and T11 (quinalphos) were also on par with the above treatments. The highest reduction in disease severity of leaf blight (79.63 per cent) over control was recorded in plants sprayed with one per cent Bordeaux mixture and was on par with all other treatments except mancozeb and zineb. The results of the second experiment revealed that the highest per cent reduction in disease severity of die back (80.02 per cent) over control was exhibited by one per cent Bordeaux mixture and was on par with all other treatments. Similarly Bordeaux mixture recorded the highest reduction in disease severity of leaf blight (85.64 per cent) over control, and was on par with all other treatments. Hence it is concluded that all the five fungicides viz., one per cent Bordeaux mixture, 0.15 per cent copper hydroxide, 0.3 per cent captan, 0.1 per cent hexaconazole and 0.1 per cent carbendazim and the bioagents viz., T. viride (20 g/ lit) and P. fluorescens (2.0 per cent) were equally effective in the management of die back and leaf blight disease of mango grafts. The data on the screening of mango grafts of different varieties revealed that the two varieties, viz., Alphonso and Mulgoa were highly resistant to die back and leaf blight diseases. The highest total phenol content of 393.69J.lg/g was recorded in Alphonso and was followed by Mulgoa which recorded 283.59 J.lg/ of total phenol per gram of plant sample. . ..; |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Beena S (Guide) |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | http://krishikosh.egranth.ac.in/handle/1/5810135782 |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Koha item type | Theses |
| Withdrawn status | Lost status | Source of classification or shelving scheme | Damaged status | Not for loan | Permanent Location | Current Location | Shelving location | Date acquired | Full call number | Barcode | Date last seen | Price effective from | Koha item type |
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| KAU Central Library, Thrissur | KAU Central Library, Thrissur | Theses | 2014-03-18 | 632.3 SAN/ET | 172875 | 2014-03-18 | 2014-03-18 | Theses |