Migration and early population development of aphids (Hemiptera: Aphididae) in winter cereals Von der Naturwissenschaftlichen Fakultät der Gottfried Wilhelm Leibniz Universität Hannover zur Erlangung des akademischen Grades Doktor der Gartenbauwissenschaften Dr. rer. hort. genehmigte Dissertation von Dipl.-Ing. agr. A. Michael Klüken, geboren am 15.09.1973 in Krefeld Hannover, Januar 2008 1. Referent: Prof. Dr. B. Hau 2. Referent: Prof. Dr. B. Freier Tag der Promotion (mündlichen Prüfung): 27.02.2008 Soli Dei Gloria Eidesstattliche Erklärung Hiermit erkläre ich an Eides statt, dass ich die vorliegende Arbeit selbstständig angefertigt habe und keine anderen als die angegebenen Quellen und Hilfsmittel verwendet habe, sowie dass diese Arbeit noch keiner anderen Prüfungskommission als Diplomarbeit oder ähnlicher Prüfungsarbeit vorgelegt worden ist. Hannover, 07.01.2008 A. Michael Klüken Table of contents v Table of contents TABLE OF CONTENTS .......................................................................................................... V LIST OF ABBREVIATIONS .................................................................................................XII SUMMARY .......................................................................................................................... XIV RESUME............................................................................................................................... XVI ZUSAMMENFASSUNG...................................................................................................... XIX GLOBAL INTRODUCTION .................................................................................................. 23 IMPORTANCE OF CEREAL APHIDS ....................................................................................................... 23 THRESHOLD LEVEL CONCEPTS AND THEIR PROBLEMS ..................................................................... 24 POPULATION MODELS .......................................................................................................................... 26 MIGRATION .......................................................................................................................................... 27 EVALUATION OF CEREAL APHID POPULATIONS ................................................................................. 30 LANDSCAPE STRUCTURE AND POPULATION GENETICS ..................................................................... 31 HOST PLANT SPECIALISATION ............................................................................................................. 32 OBJECTIVES AND CHAPTER TITLES ............................................................................... 34 CHAPTER 1: COMPARISON AND VALIDATION OF POPULATION MODELS FOR CEREAL APHIDS................................................................................................................... 36 ABSTRACT ............................................................................................................................................. 36 INTRODUCTION .................................................................................................................................... 37 MATERIALS AND METHODS ................................................................................................................. 39 Table of contents vi FIELD EVALUATION ............................................................................................................................... 39 MODEL SIMLAUS ................................................................................................................................ 40 MODEL LAUS ....................................................................................................................................... 41 MODEL GETLAUS01............................................................................................................................ 42 VALIDATION AND STATISTICAL ANALYSIS ............................................................................................ 43 RESULTS ............................................................................................................................................... 44 GENERAL RESULTS ................................................................................................................................ 44 MODEL SIMLAUS ................................................................................................................................ 44 MODEL LAUS ....................................................................................................................................... 47 MODEL GETLAUS01............................................................................................................................ 48 DISCUSSION .......................................................................................................................................... 54 MODEL SIMLAUS ................................................................................................................................ 55 MODEL LAUS ....................................................................................................................................... 56 MODEL GETLAUS01............................................................................................................................ 58 CONCLUSIONS ........................................................................................................................................ 62 Acknowledgements ............................................................................................................................... 62 CHAPTER 2: FORECASTING GRADATION OF CEREAL APHIDS (HEMIPTERA: APHIDIDAE) IN WINTER WHEAT AT EAR EMERGENCE............................................. 64 ABSTRACT ............................................................................................................................................. 64 INTRODUCTION .................................................................................................................................... 65 MATERIALS AND METHODS ................................................................................................................ 67 FIELD DATA EVALUATION ..................................................................................................................... 67 SUCTION TRAP SAMPLES ........................................................................................................................ 67 METEOROLOGICAL PARAMETERS .......................................................................................................... 69 DEFINITION OF VARIABLES .................................................................................................................... 69 STATISTICAL ANALYSES ........................................................................................................................ 69 LOGISTIC REGRESSION ANALYSES (LOG RA) ........................................................................................ 70 LINEAR DISCRIMINANT ANALYSES (L IN DA) ........................................................................................ 71 MODEL VALIDATION .............................................................................................................................. 72 RESULTS ............................................................................................................................................... 73 GENERAL RESULTS ................................................................................................................................ 73 LOGISTIC REGRESSION ANALYSES (LOG RA) ........................................................................................ 74 LINEAR DISCRIMINANT ANALYSES (LIN DA)......................................................................................... 81 EXAMPLES FOR LIN DA AND LOG RA ................................................................................................... 83 MODEL VALIDATION .............................................................................................................................. 84 Table of contents vii DISCUSSION .......................................................................................................................................... 85 GENERAL DISCUSSION ........................................................................................................................... 85 ESTABLISHMENT OF “WINTER CONDITIONS ” AND “REAL MIGRATION ” SUBMODELS ............................ 86 COMPARISONS OF METHODS.................................................................................................................. 87 COMPARISON OF LOCATIONS ................................................................................................................. 89 MODEL CONSTRAINTS ........................................................................................................................... 90 IMPORTANCE OF THRESHOLD LEVELS ................................................................................................... 91 CONCLUSIONS ........................................................................................................................................ 92 Acknowledgements ............................................................................................................................... 92 CHAPTER