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ABSTRACT 

The genus Terminalia is the second largest genus in the Combretaceae. The family is distributed throughout the tropical and sub-tropical regions of the world and approximately fifty species of Terminalia are naturally distributed throughout western, eastern and southern Africa. Terminalia spp. range from small shrubs or trees to large deciduous forest trees. Some species, such as T. ivorensis and T. superba develop as elements of the canopy or sub-canopy layer in evergreen, semi-deciduous to deciduous, primary and secondary forests, whereas species such as T. sericea, thrive well in open woodlands and mixed deciduous forests. Terminalia spp. can be propagated naturally by seeds or through vegetative methods with wildings, seedlings, stump plants or striplings. Terminalia spp. provide economical, medical, spiritual and social benefits.  Limited information on the pests and diseases affecting Terminalia spp. exists.  Many insect species are associated with Terminalia spp. but no widespread pest problems have been recorded. Nevertheless, some locally common species are potentially dangerous, mostly affecting the early stages of trees. Very few pathogens have been reported from Terminalia spp.  The majority of reports include limited detail, often representing no more than a brief mention.  Often the causal agents were identified based only on morphology and were not classified to species level. Scanty information regarding the pathogens associated with introduced and native Terminalia is a limitation that might be detrimental for the survival and the….

INTRODUCTION

Terminalia (Combretaceae, Myrtales) is a pantropical genus accommodating about 200 species (McGaw et al. 2001). About fifty of these are native to Africa and distributed throughout the sub-saharan region (Lebrun and Stork 1991). Based on both their functional uses and distribution in Africa, the most important are Terminalia ivorensis A. Chev. and T. superba Engl. and Diels. in West and Central Africa and T. prunioides M.A. Lawson and T. sericea Burch : DC in Southern Africa (Irvine 1961; Lamb and Ntima 1971; Coastes-Palgrave 1977; Groulez and Wood 1985; Schmidt et al. 2002; Lawes et al. 2004).
Terminalia trees are planted in several countries in the tropics as a source of high quality solid timber for fine carpentry, joinery, building, flooring and plywood manufacture (Schmidt et al. 2002; Smith et al. 2004).  Terminalia ivorensis and T. superba, especially, form an important component of the forestry industries in many countries (Anonymous 1997).  Terminalia spp. are also commonly planted in mixed crop systems to establish a “taungya” agri-sylvicultural system in which they provide shade and play a major role in increasing soil fertility (Nichols et al. 2001; Norgrove and Hauser 2002a). Furthermore, members of the genus Terminalia are among some of the plants most widely used for medicinal purposes in Africa (Masoko et al. 2005; Kamtchouing et al. 2006).
Despite the importance of Terminalia spp., very little research has been done regarding the fungal diseases affecting these trees.  Evidence of die-back, leaf spot and canker has been reported from Terminalia spp. (Lamb and Ntima 1971; Ofosu Siedu and Cannon 1976; Hodges and Fereira 1981). Gryzenhout et al. (2005), recently reported a serious disease problem that emerged on non-native T. ivorensis in Ecuador, while in South Africa, two Ceratocystis spp. have been reported from T. sericea (Roux et al. 2004; Kamgan et al. 2008).
The last or the 20th Century was marked by an increasing requirement for timber, fuel and medicine from trees. This has resulted in unsustainable logging of native trees in Africa. To supplement this requirement, plantations of non-native trees, including Eucalyptus spp., Pinus spp., Acacia spp. and Cupressus spp. are been established in many parts of the tropics and the southern hemisphere (Turnbull 1991; Wingfield et al. 2002; Anonymous 2007). In Africa, as in most other countries, these non-native trees are established in close proximity to native trees. This close association may in the long run, expose trees to new pests and diseases.  One might thus see the movement of native pests and pathogens onto introduced tree species. This is of great concern since this could provide pathogens with an elevated opportunity to spread to the country of origin of its new host, through reciprocal international trade of wood and wood products, causing large-scale mortality of trees in their native ecosystems (Wingfield 2003; Slippers et al. 2005; Wingfield et al. 2008).  On the other hand, the non-native tree might be the source of non-native pathogens and pests, which may spread to the native trees in its new country, resulting in disease epidemics.  An increasing number of examples for both case scenarios exist.  For example, it has been shown that Chr. austroafricana Gryzenh. & M. J. Wingf., the cause of canker and death of plantation grown Eucalyptus spp. in South Africa, also occurs on native Myrtales in Africa (Heath et al. 2006; Nakabonge et al. 2006). This pathogen is thought to have originated from Africa (Heath et al. 2006). On the other hand, in California, native Monterey pine (Pinus radiata D. Don) are seriously affected by the pitch canker pathogen, Fusarium circinatum Niremberg & O’Donnell, following its introduction with Mexican pines (Gordon et al. 2001). In this respect, knowledge of indigenous tree diseases would be useful to establish firm risk assessment programs.
In Africa, some species of Terminalia generally occur as elements of the canopy or subcanopy layer in evergreen, semi-deciduous to deciduous primary and secondary forests. Other species thrive in open woodlands and littoral areas. Within this natural habitat of Terminalia spp., several non-native tree species are frequently encountered.  There is, therefore, a good chance of introduced pathogens spreading onto native Terminalia trees, or innocuous fungi on Terminalia spp., moving onto the non-native trees.  The objective of this review is to present a summary of knowledge pertaining to Terminalia spp. in Africa. A specific focus is given to their origin and distribution, botanic description, ecology, propagation, management, functional uses and international trade. Also, the limited knowledge regarding pests and diseases on these trees is reviewed, providing a background for the contents of the dissertation that follows this review and that focuses on fungi associated with native and introduced Terminalia spp. on the African continent.

Table of Contents

• Abstract
• DEDICATION
  
• LIST OF TABLE
  
• LIST OF FIGURES

Chapter 1: Literature Review: Terminalia spp in Africa with special reference to its health status 
ABSTRACT
1. INTRODUCTION
2. THE GENUS TERMINALIA
2.1. Origin and distribution
2.2. Botanical description and ecology
2.3. Propagation and management
2.3.1. Seed propagation
2.3.2. Vegetative propagation
2.3.3. Tending of trees
2.4. Functional uses of Terminalia trees 25 2.5. Pests and diseases
2.5.1. Insects
2.5.1.1. Fruit Borers
2.5.1.2. Stem Borers
2.5.1.3. Defoliators
2.5.1.4. Termites
2.5.2. Wildlife
2.5.3. Diseases
2.5.3.1. Root diseases
2.5.3.1. Stem diseases
2.5.3.3. Leaf diseases
2.5.3.4. Stain diseases
3. CONCLUSIONS
4. REFERENCES
Chapter 2 Botryosphaeriaceae associated with Terminalia catappa in Cameroon, South Africa and Madagascar
ABSTRACT
1. INTRODUCTION
2. MATERIALS AND METHODS
2.1. Isolates
2.2. Morphology and cultural characteristics
2.3. DNA extraction
2.4. PCR amplification
2.5. DNA Sequencing
2.6. DNA Sequence Analyses
2.7. Pathogenicity
3. RESULTS
3.1. Isolates
3.2. Morphologic characterization
3.3. DNA extraction and PCR amplification
3.4. DNA sequence analyses 57
3.5. Taxonomy
3.6. Distribution of the Botryosphaeriaceae
3.7. Pathogenicity
4. DISCUSSION
5. REFERENCES
Chapter 3  Botryosphaeriaceous fungi as endophytes on Terminalia species in Cameroon
ABSTRACT
1. INTRODUCTION
2. MATERIALS AND METHODS
2.1. Sample collection and fungal isolation
2.2. Morphology and cultural characteristics
2.3. DNA extraction, PCR reactions and DNA sequencing
2.4. Sequence Analyses
2.5. Pathogenicity
3. RESULTS
3.1. Isolates and morphology
3.2. DNA extraction and PCR amplification
3.3. Phylogenetic analyses
3.4. Pathogenicity
4. DISCUSSION
5. REFERENCES
Chapter 4 Phenotypic and molecular characterization of the Botryosphaeriaceae associated with native Terminalia spp. of Southern Africa
ABSTRACT
1. INTRODUCTION
2. MATERIALS AND METHODS
2.1. Sample collection and fungal isolation
2.2. Morphology and culture characteristics
2.3. DNA extraction, PCR reactions and DNA sequencing
2.4. DNA Sequence Analyses
2.5. Pathogenicity
3. RESULTS
3.1. Isolation, morphology and culture characteristics
3.2. DNA extraction and PCR amplification
3.3. Phylogenetic analyses
3.4. Taxonomy
3.5. Pathogenicity
4. DISCUSSION
5. REFERENCES
Chapter 5 Genetic structure of Lasiodiplodia theobromae and L. pseudotheobromae from native and non-native hosts in Cameroon
ABSTRACT
1. INTRODUCTION
2. MATERIALS AND METHODS
2.1. Fungal isolates
2.2. DNA extraction, PCR reactions and DNA sequencin
2.3. Simple sequence repeat (SSR)-PCR and GENESCAN analyses
2.4. Statistical analyses
2.4.1. Bayesian clustering analyses
2.4.2. Gene and genotypic diversity
2.4.3. Genetic differentiation and gene flow
2.4.4. Linkage disequilibrium
3. RESULTS
3.1. Fungal isolates
3.2. Microsatellite PCR amplification
3.3. Statistical analyses
3.3.1. Bayesian clustering analyses
3.3.2. Gene diversity
3.3.3. Genotypic diversity
3.3.4. Genetic differentiation and gene flow
3.3.5. Linkage disequilibrium
4. DISCUSSION
5. REFERENCES
Chapter 6 Aurifilum, a new fungal genus in the Cryphonectriaceae from Terminalia species in Cameroon
ABSTRACT
1. INTRODUCTION
2. MATERIALS AND METHODS
2.1. Survey and specimen collection
2.2. DNA extraction and sequence comparisons
2.3. Morphology
2.4. Pathogenicity
3. RESULTS
3.1. Survey and specimen collection
3.2. DNA sequence comparisons
3.3. Morphology
3.4. Taxonomy
3.5. Pathogenicity
4. DISCUSSION
5. REFERENCES
Summary

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