Interaction of maize root associated fungi and the western corn rootworm Dissertation zur Erlangung des Doktorgrades der Fakultät für Agrarwissenschaften der Georg-August-Universität Göttingen vorgelegt von Benedikt Kurtz geboren in Frankfurt am Main Göttingen, im Mai 2010 D 7 1. Referent: Prof. Dr. Stefan Vidal.............................................. 2. Korreferent: Prof. Dr. Petr Karlovsky...................................... Tag der mündlichen Prüfung: 15.07. 2010 Table of contents 3 Table of contents Summary ........................................................................................................................................... 6 General Introduction ........................................................................................................................ 8 Objectives ....................................................................................................................................... 15 Chapter 1: Effects of soil type and maize cultivar on the development of western corn rootworm larvae.............................................................................................................................. 16 Introduction .................................................................................................................................. 17 Material and Methods................................................................................................................... 18 Soil and plants ......................................................................................................................... 18 Handling of western corn rootworm......................................................................................... 19 Experimental setup .................................................................................................................. 19 Data analysis ........................................................................................................................... 20 Results ......................................................................................................................................... 21 Discussion.................................................................................................................................... 24 Acknowledgements...................................................................................................................... 25 References................................................................................................................................... 25 Chapter 2: Interaction between western corn rootworm (Coleoptera: Chrysomelidae) larvae and root infecting Fusarium verticillioides .................................................................................. 29 Introduction .................................................................................................................................. 30 Material and Methods................................................................................................................... 32 Cultivation of Fusarium verticillioides and handling of western corn rootworm....................... 32 Experimental setup .................................................................................................................. 33 DNA extraction and real-time PCR.......................................................................................... 33 Data analysis ........................................................................................................................... 34 Results ......................................................................................................................................... 35 Fusarium verticillioides root infection....................................................................................... 35 Larval development ................................................................................................................. 37 Discussion.................................................................................................................................... 38 Acknowledgements...................................................................................................................... 41 References................................................................................................................................... 41 Chapter 3: Belowground feeding of western corn rootworm increases aboveground Fusarium verticillioides colonization in maize............................................................................ 45 Introduction .................................................................................................................................. 46 Material and Methods................................................................................................................... 48 Plants, cultivation of Fusarium verticillioides and handling of western corn rootworm ........... 48 Experimental setup .................................................................................................................. 49 Table of contents 4 DNA extraction and real-time PCR.......................................................................................... 49 Analysis of beetle development............................................................................................... 50 Data Analysis........................................................................................................................... 50 Results ......................................................................................................................................... 52 Root colonization ..................................................................................................................... 52 Aboveground colonization ....................................................................................................... 52 Beetle development ................................................................................................................. 54 Discussion.................................................................................................................................... 54 Acknowledgments........................................................................................................................ 57 References................................................................................................................................... 57 Chapter 4: Can western corn rootworm larvae orientate towards, transport and transmit root infecting Fusarium verticillioides? ............................................................................................... 62 Introduction .................................................................................................................................. 63 Material and Methods................................................................................................................... 65 Choice test............................................................................................................................... 65 Transmission experiment......................................................................................................... 67 Results ......................................................................................................................................... 71 Choice test............................................................................................................................... 71 Transmission experiment......................................................................................................... 72 Discussion.................................................................................................................................... 74 Acknowledgements...................................................................................................................... 75 References................................................................................................................................... 76 Chapter 5: Interaction between western corn rootworm (Coleoptera; Chrysomelidae) and the mycorrhiza Glomus intraradices .................................................................................................. 81 Introduction .................................................................................................................................. 82 Material and Methods................................................................................................................... 83 Soil and plants ......................................................................................................................... 83 Experimental setup .................................................................................................................. 85 Microscopical analysis of mycorrhizal colonization ................................................................. 86 Data analysis ........................................................................................................................... 86 Results ......................................................................................................................................... 87 Maize dry weight...................................................................................................................... 87 Western corn rootworm development.....................................................................................