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Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa
Dissertation (MSc Agric)--University of Pretoria, 2013.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2014
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| _version_ | 1867613520775872512 |
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| access_status_str | Open Access |
| author2 | Van der Waals, Jacqueline Elise |
| author_browse | Van der Waals, Jacqueline Elise |
| author_facet | Van der Waals, Jacqueline Elise |
| collection | Thesis |
| dc_rights_str_mv | © 2013 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc Agric)--University of Pretoria, 2013. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/40339 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:27.661Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/40339 Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa Van der Waals, Jacqueline Elise carlamarais123@gmail.com Espach, Anel Marais, Carla Brown spot and black pit Diseases Potatoes South Africa Fungus Bacteria UCTD Dissertation (MSc Agric)--University of Pretoria, 2013. In recent years two new diseases, brown spot and black pit, have been observed on potatoes in South Africa. Brown spot symptoms appear on the foliage as small brown lesions, whereas black pit symptoms appear on the tubers as small dark sunken lesions. In this study the causal organism of brown spot and black pit of potatoes in South Africa was determined. During initial isolation, one fungus and two bacteria were isolated, which were included in the trial. Only the treatments where the fungal isolate was used in inoculation resulted in the development of brown spot lesions. The causal organism of brown spot and black pit were identified as Alternaria alternata which is consistent with other research. To better understand the spread of Alternaria alternata between the plants and/or tubers a pot trial was conducted. It was observed that when planting an inoculated seed tuber brown spot may develop on foliage. But the daughter tubers harvested from plants infected with A. alternata will not necessarily develop black pit. Daughter tubers are most likely infected by A. alternata during harvesting and black pit lesions develop in high humidity in storage. Cultivar resistance is one of the most important measures in controlling plant diseases. Cultivar susceptibility of thirteen South African potato cultivars (Avalanche, Buffelspoort, BP1, Fabula, Fianna, Frodo, Hertha, Labadia, Lanorma, Mondial, Pentland Dell, Up-To-Date and Van Der Plank) was evaluated. Pot trials showed that all the evaluated cultivars are susceptible to infection by Alternaria alternata. Various crops (tomatoes, cabbage, mustard, wheat, oats, tobacco and maize) were assessed to determine the host range of Alternaria alternata (potato pathotype) in rotation crops in South Africa potato growing regions. Of the crops evaluated, the pathogen was able to infect only tomato crops. Only wheat, maize and oats can safely be used in the crop rotation in South Africa, as various potato pathogens attack cabbage, mustard and tobacco plants. This study will lead to a better understanding of brown spot and black pit diseases of potatoes in South Africa and globally. The study emphasise the need for further research which will help to reduce brown spot and black pit diseases of potato. gm2014 Microbiology and Plant Pathology unrestricted 2014-06-24T09:47:56Z 2014-06-24T09:47:56Z 2014-04-09 2013 Dissertation Marais, C 2013, Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa, MSc (Agric) dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/40339> E14/4/168/gm http://hdl.handle.net/2263/40339 en © 2013 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Brown spot and black pit Diseases Potatoes South Africa Fungus Bacteria UCTD Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa |
| title | Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa |
| title_full | Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa |
| title_fullStr | Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa |
| title_full_unstemmed | Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa |
| title_short | Effect of inoculum source, alternative host and cultivar on development of brown spot and black pit of potatoes in South Africa |
| title_sort | effect of inoculum source alternative host and cultivar on development of brown spot and black pit of potatoes in south africa |
| topic | Brown spot and black pit Diseases Potatoes South Africa Fungus Bacteria UCTD |
| url | http://hdl.handle.net/2263/40339 |