Blackleg, caused by L. maculans, is of major economic importance in the canola growing areas of Australia. The aim of this research was to gain information about factors affecting the epidemiology of blackleg in south - eastern Australia. The effect of temperature on a number of aspects of the life cycle of L. maculans was studied in a controlled environment. Germination of ascospores was greater on agar and cotyledons than on leaves, on susceptible cultivars than resistant cultivars, and at 15 and 20 °C than at 5 and 10 °C. Elongation of germ tubes was greater at higher than lower temperatures and generally greater on cotyledons than on leaves of the cultivars after incubation for 24 h at 10 - 20 ° C. Temperature had a greater influence than plant organ or cultivar on ascospore germination and the elongation of germ tubes. Temperature, wetness duration, cultivar and leaf position ( leaves 1 - 3 ) influenced the incubation period of L. maculans on canola. Ascospores infected six canola cultivars over 10 - 20 ° C following leaf wetness duration of 16 - 72 h. Incubation period ( from inoculation to the appearance of first lesions ) was generally shorter at higher temperatures and following longer wetness periods. Incubation period decreased with increasing leaf age, regardless of the blackleg - resistance rating of the cultivars. Pseudothecia developed on naturally infested canola stubble incubated at 5 - 20 ° C under continuous wetness and a 12 h photoperiod. The time taken for pseudothecia to mature after harvest, ranged from 58.3 days at 5 ° C to 22.2 days at 15 ° C. Fewer pseudothecia developed on stubble incubated in darkness at 15 ° C than in light. Pseudothecia took longer to mature when wetness was interrupted than continuous. More ascospores were released at 20 ° C than 5 - 15 ° C, although peak sporulation occurred earlier at 5 - 10 ° C. Discharge of ascospores continued for 8 h at 5 - 10 ° C, for 10 h at 15 ° C, and for 12 h at 20 ° C. The effect of burial of infested canola stubble in sand and field soil ( in pots ) on pathogen survival, pathogenicity and stubble - associated fungi was studied over 13 months in ambient conditions. The isolation frequency of L. maculans from stubble decreased by 63.3 % after 13 months of burial, regardless of soil type. Although the frequency of isolation of L. maculans and Alternaria spp. from stubble decreased over time, that of Stachybotrys chartarum, Fusarium spp. and Coprinus sp. increased substantially over the sampling period. Stubble buried in field soil underwent more decay than in sand over the 13 months. Pseudothecium formation on buried stubble decreased with increasing duration of burial and ceased after 11 months in the field soil and 13 months in sand. The time required for pseudothecia to mature was 25 days for stubble retrieved after one month and 30 days when retrieved 10 months after burial, regardless of soil type. Ascospores from the stubble recovered from burial caused typical Phoma leaf spots on canola over the first 9 months of burial. Over the year, 16 genera of fungi and 12 colony types of bacteria were isolated from the field soil on peptone - rose bengal agar ( PRA ) and on crystal violet agar ( CVA ), respectively. Populations of fungi and bacteria isolated on soil - extract agar were markedly greater than those on PRA and on CVA, respectively. Growth and sporulation of L. maculans on agar media and on infested canola stubble was affected by a variety of fungi obtained from stubble buried in soil or from field soil. Antagonistic activities observed included lysis, deformation, overgrowth and inhibition of L. maculans hyphae, and reduction of pseudothecium density on stubble to one - third or less than that on controls following inoculation with F. equiseti, Gliocladium roseum, Trichoderma aureoviride, Sordaria sp. and an unknown Coelomycete. S. chartarum and Coprinus sp. reduced the mass of canola stubble in vitro. Findings will contribute to a better understanding of blackleg and to the development of more effective control measures. / Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2006.

Thesis (Ph. D.)--University of Adelaide, 1987. / Includes bibliographical references (leaves 169-185).

Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2003. / "November 2003." Bibliography: p. 214-244.

Thesis (Ph.D.)--University of Adelaide, School of Agriculture, Food and Wine, Discipline of Wine and Horticulture, 2007. / Includes Addenda (2 sheets) attached to back pages. Bibliography: leaves 170-183. Also available in print form.

Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Faculty of Health Sciences. Includes bibliographical references (leaves 243-296)

Thesis (Ph. D.)--University of Wisconsin--Madison, 1961. / Typescript. eContent provider-neutral record in process. Description based on print version record. Vita. Includes bibliographical references (leaves 75-82).

Thesis (doctoral)--Rijksuniversiteit te Utrecht, 1931. / Bibliography: p. [91]-93.

Thesis (Ph.D.) - University of Queensland, 2003. / Includes bibliography.

Fungal diseases of trees are serious impediments to forest expansion and productivity. While the adverse effects of diseases of non-native plantation forest trees are increasingly recognized in Africa, the health of native trees has been virtually ignored. This is especially acute as many commercially propagated trees are related to native woody plants and recurrent movement of pathogens between native and non-native trees is increasingly being recorded. The genus Terminalia accommodates important indigenous tree species in Africa that provide a variety of valuable wood and non-wood products. Despite the importance of Terminalia spp., very little information has been recorded on their health problems. Research for this dissertation aimed at studying some of the fungal diseases of native and non-native Terminalia species in Africa. Special reference was provided to fungi in the Botryosphaeriaceae, a group of pathogens that infect host plants without always producing clear symptoms. A literature review, presented in Chapter One, highlighted the limited information available on the pathogens and pests associated with these trees. Most disease reports include minimal detail. Often the causal agents had been identified based only on morphology and were not classified to the species level. Studies performed in chapter two compared the assemblages of endophytic species of the Botryosphaeriaceae from T. catappa in Cameroon, South Africa and Madagascar. Five species were identified and two of these are new to science and provided with the names N. batangarum and L. mahajangana. The assemblage of the Botryosphaeriaceae varied from one country to another, however, colonization patterns in the three areas were similar. Greenhouse inoculation trials performed on young T. catappa trees showed variation among isolates tested, with L. pseudotheobromae being the most pathogenic. Chapter three represents the first investigation of the Botryosphaeriaceae on native Terminalia trees in Cameroon and Africa. Morphological and DNA sequence data were used to identify these species as L. theobromae, L. pseudotheobromae, L. parva and E. endophytica. Pathogenicity trials performed on young T. mantaly and T. catappa trees revealed that L. pseudotheobromae was the most virulent species. In chapter four, species of Botryosphaeriaceae on native Terminalia spp. in Southern Africa were studied. Nine species were identified from T. sericea and T. sambesiaca. Seven of these, L. crassispora, L. pseudotheobromae, D. alatafructa, P. olivaceum, N. parvum, N. kwambonambiense and N. vitifusiforme represented previously described species and two, L. cryptotheobromae and N. terminaliae, were described as new. The genetic analyses of populations of L. theobromae and L. pseudotheobromae presented in chapter five showed clear genetic divergence between L. theobromae and L. pseudotheobromae supporting their distinction as separate species. Both L. theobromae and L. pseudotheobromae populations possessed high gene diversity, moderate degrees of genotypic diversity, and high levels of gene flow between isolates from T. cacao and Terminalia spp. Both sexual and asexual modes of reproduction were found. The last chapter of this dissertation presents the description of a new genus in the Cryphonectriaceae, Aurifilum marmelostoma, using a combination of molecular and morphological tools. This fungus is the second genus in this family described from Terminalia spp. Pathogenicity tests conducted to assess its ability to cause disease revealed that the fungus is a possible pathogen of this tree. An extensive number of potentially pathogenic fungi, including five new species were found associated with native and non-native Terminalia spp. in Africa. As some of these fungal species could serve as sources of inoculum onto economically important crops, research presented in this dissertation provides a foundation for understanding health issues affecting Terminalia and related genera in selected regions in Africa. Hopefully, results of this study will serve as valuable tools in forestry management in Africa. Copyright / Thesis (PhD)--University of Pretoria, 2010. / Plant Production and Soil Science / Unrestricted

Polyclonal antisera produced against spores, soluble protein and the whole mycelium fractions of Didymella lycopersici reacted with the homologous and heterologous antigens. The most sensitive antiserum was that raised against the whole mycelium, the soluble protein and the spore, in decreasing order of sensitivity. Using the antiserum raised against the whole mycelium it was possible to detect D. lycopersici on diseased plants and infested seeds. Cross reactivity was observed between the antisera produced to D. lycopersici and D. applanata, D. bryoniae and other tomato fungal pathogens including Fusarium spp. and B. cinerea. ELISA was most sensitive and reliable compared to double immunodiffusion, and latex tests. No reactions were obtained using the latex agglutination procedure and no antiserum detected spores in double diffusion tests. Protein profiles on SDS-PAGE revealed that the total number of protein bands decreased with increased age of cultures of D. lycopersici incubated in liquid media. Western blots probed with the antiserum raised against the whole mycelium showed that protein bands from extracts of both D. lycopersici and D. applanata were antigenic. / Land and Food Systems, Faculty of / Graduate