Fungi, insects and abiotic factors associated with the death of Euphorbia ingens in South Africa Johannes Alwyn van der Linde Fungi, insects and abiotic factors associated with the death of Euphorbia ingens in South Africa By Johannes Alwyn van der Linde Submitted in partial fulfilment of the requirements for the degree Philosophiae Doctor In the Faculty of Natural & Agricultural Sciences, Department of Microbiology and Plant Pathology, DST/NRF Centre of Excellence in Tree Health Biotechnology (CTHB), Forestry and Agricultural Biotechnology Institute (FABI), at the University of Pretoria, Pretoria. 29 January 2018 Supervisor: Prof. Jolanda Roux Co – Supervisors: Prof. Mike Wingfield Prof. Diana Six Declaration I, Johannes Alwyn van der Linde, declare that the thesis, which I hereby submit for the degree of Philosophiae Doctor at the University of Pretoria, is my own work and has not previously been submitted by me for a degree at this or any other tertiary institution. Johannes Alwyn van der Linde 29 January 2018 Table of Contents Acknowledgements .................................................................................................................. 1 Preface ....................................................................................................................................... 3 Chapter 1 .................................................................................................................................. 5 Literature review: Anthropogenic climate change effects on insects and pathogens affecting native and planted forests in the Northern Hemisphere and South Africa ........ 5 Abstract ............................................................................................................................................... 6 1. Introduction ..................................................................................................................................... 7 2. The effect of anthropogenic climate change on tree insects and fungal pathogens ........................ 9 2.1 Insects ..................................................................................................................................... 10 2.1.1 Dendroctonus frontalis .................................................................................................... 10 2.1.2 Dendroctonus rufipennis .................................................................................................. 11 2.1.3 Dendroctonus ponderosae ............................................................................................... 11 2.1.4 Ips typographus ................................................................................................................ 12 2.1.5 Platypus quercivora ......................................................................................................... 13 2.1.6 Thaumetopoea pityocampa .............................................................................................. 13 2.2 Pathogens ................................................................................................................................ 14 2.2.1 Phytophthora cinnamomi ................................................................................................. 15 2.2.2 Phytophthora ramorum .................................................................................................... 15 2.2.3 Dothistroma septosporum ................................................................................................ 16 2.2.4 Botryosphaeriaceae .......................................................................................................... 17 3. Anthropogenic climate change in southern Africa and its potential impact on tree health........... 18 3.1 Pathogens ................................................................................................................................ 19 3.1.1 Fusarium circinatum ........................................................................................................ 19 3.1.2 Botryosphaeriaceae .......................................................................................................... 19 3.1.3 Phytophthora cinnamomi and Armillaria ........................................................................ 20 3.1.4 Austropuccinia psidii ....................................................................................................... 21 3.2 Insects ..................................................................................................................................... 21 4. Conclusions ................................................................................................................................... 23 5. Background and objectives of this thesis ...................................................................................... 23 6. References ..................................................................................................................................... 24 Chapter 2 ................................................................................................................................ 47 Fungi and insects associated with Euphorbia ingens die-off in South Africa ................... 47 Abstract ............................................................................................................................................. 48 1. Introduction ................................................................................................................................... 49 2. Materials and Methods .................................................................................................................. 49 2.1 Estimation of mortality and disease symptoms associated with E. ingens die-off ................. 49 2.2 Fungus and insect collections ................................................................................................. 50 3. Results ........................................................................................................................................... 51 3.1 Estimation of mortality and disease symptoms associated with E. ingens die-off ................. 51 3.2 Fungus and insect collections ................................................................................................. 52 4. Discussion ..................................................................................................................................... 53 5. References ..................................................................................................................................... 56 Chapter 3 ................................................................................................................................ 69 Novel ophiostomatalean fungi from galleries of Cyrtogenius africus (Scolytinae) infesting dying Euphorbia ingens ......................................................................................................... 69 Abstract ............................................................................................................................................. 70 1. Introduction ................................................................................................................................... 71 2. Materials and Methods .................................................................................................................. 72 2.1 Collection of samples and isolations ....................................................................................... 72 2.2 Fungal Morphology and Growth ............................................................................................. 73 2.3 DNA extraction, PCR, Sequencing and Phylogenetic analyses .............................................. 73 2.4 Pathogenicity study ................................................................................................................. 74 3. Results ........................................................................................................................................... 75 3.1 Fungi isolated .......................................................................................................................... 75 3.2 Fungal Morphology and Growth ............................................................................................. 76 3.3 DNA sequence analyses .......................................................................................................... 76 Taxonomy ......................................................................................................................................... 77 3.4 Pathogenicity ........................................................................................................................... 79 4. Discussion ..................................................................................................................................... 79 6. References ..................................................................................................................................... 81 Chapter 4 ................................................................................................................................ 93 Seasonal flight patterns of Curculionidae (Cossoninae and Scolytinae) infesting dying Euphorbia ingens in South Africa ......................................................................................... 93 Abstract ............................................................................................................................................