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Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach
Thesis (PhD (Plant Pathology))--University of Pretoria, 2018.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613679413886976 |
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| access_status_str | Open Access |
| author2 | Korsten, Lise |
| author_browse | Korsten, Lise |
| author_facet | Korsten, Lise |
| collection | Thesis |
| description | Thesis (PhD (Plant Pathology))--University of Pretoria, 2018. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110182 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:58.958Z |
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| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
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| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110182 Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach Korsten, Lise achakwiya@gmail.com van der Linde, Elna J. Chakwiya, Alinesi Cobweb disease Mushroom Hypomyces Thesis (PhD (Plant Pathology))--University of Pretoria, 2018. There are about 50 species of Cladobotryum which represent a genus that is fungicolous both on the wild and cultivated mushrooms. Several species affect white button mushrooms (Agaricus bisporus (Lange) Imbach) and are recently among the most commonly encountered fungal pathogens in mushroom growing regions of the World. In recent years, cobweb has emerged as one of the major fungal diseases of cultivated mushrooms causing losses due to brown spotting and premature termination of the crop. Losses of 40-90% have been reported in some countries where cobweb disease has been prevalent. Due to the importance of cobweb disease to the industry around the world it has become increasingly necessary to understand the pathogen in terms of different species of Cladobotryum that cause disease, the importance of each species with regards to aggressiveness and adaptation to fungicide use, and for future more effective development of control methods. In order to achieve this aim four key objectives were covered which included; a) investigation of the morphological diversity of different C. mycophilum associated with cobweb disease for rapid identification and control; b) using proteomic characteristics through Mass Adsorption Laser/Desorption Time Of Flight (MALDI TOF MS) to identify Cladobotryum spp. separate isolates and species and understand their relatedness; c) examination of the host-pathogen interactions between A. bisporus and Cladobotryum spp. in cobweb disease development and; d) determination of in vitro sensitivity of C. mycophilum and C. dendroides to prochloraz manganese and carbendazim, the commonly used fungicides. A database was established using the isolates that were identified as C. x mycophilum (NCBI) and also C. dendroides, using the ITS, RPB1 and RPB2, alpha translation elongation factor 1 genes for use in the comparison between/among isolates and species. Among the isolates under study, it was observed that three distinct proteins were common in the genus Cladobotryum. Only one isolate represented C. dendroides while the rest were recognised as C. mycophilum, by its teleomorph – H. odoratus. Conidial and cultural morphology on malt extract agar were used to identify colony characteristics of both the known Cladobotryum and unknown species. Most of the conidia were ellipsoidal, oblong and cylindrical. Determination of the isolates’ interaction with the host was conducted for all the isolates to estimate the different relations exhibited between the isolates/strains. The isolates under study produced different levels of infection on basidioms, but similar characteristics with mushroom mycelia. Neither necrosis nor any penetration structures were observed. All isolates were exposed to fungicide treatment using the poison plate method. Isolates from the USA were used as a standard for comparison in terms of prochloraz manganese as it is not registered for use in the country. Varying levels of sensitivity to the two fungicides were noted among the Cladobotryum spp. examined. Identification using MALDI TOF MS repeatability showed 100% identification for the isolates matched against the data base. Different textures of colony morphology were expressed by C. mycophilum with the most prevalent being yellow/pinkish cotton fluffy with extensive dry conidia. Cladobotryum dendroides culture morphology was consistently observed as white cotton fluffy compact mycelia turning purple on the underside after more than 96 h. In conclusion, identification of the isolates under investigation can effectively be achieved using different standard and molecular methods. The technology platform developed in this thesis can now be used to rapidly identify different species in mushroom production systems. Monitoring for resistance development is encouraged as this study revealed that naturally occurring isolates with less sensitivity to the test fungicides are present within the mushroom growing farms in South Africa. Plant and Soil Sciences PhD (Plant Pathology) 2026-05-15T17:26:35Z 2026-05-15T17:26:35Z 18/07/25 2018 Thesis http://hdl.handle.net/2263/110182 en application/pdf |
| spellingShingle | Cobweb disease Mushroom Hypomyces Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach |
| title | Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach |
| title_full | Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach |
| title_fullStr | Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach |
| title_full_unstemmed | Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach |
| title_short | Identification and resistance profiles of Cladobotryum spp. pathogenic on Agaricus bisporus (Lange) Imbach |
| title_sort | identification and resistance profiles of cladobotryum spp pathogenic on agaricus bisporus lange imbach |
| topic | Cobweb disease Mushroom Hypomyces |
| url | http://hdl.handle.net/2263/110182 |