ASPECTS OF THE ECOLOGY AND BEHAVIOUR OF Hylastes ater (Paykull) (Coleoptera: Scolytidae) IN SECOND ROTATION Pinus radiata FORESTS IN THE CENTRAL NORTH ISLAND, New Zealand, AND OPTIONS FOR CONTROL. A thesis submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy in the University of Canterbury by. Stephen David Reay University of Canterbury 2000 II Table of Contents ABSTRACT ..................................................................................................................................................... 1 1. GENERAL INTRODUCTION ............................................................................................................. 3 1.1 INTRODUCTION TO SCOL YTIDAE .......................................................................................................... 3 1.2 LIFE HISTORY ...................................................................................................................................... 6 1.3 THE GENUS HYLASTES ERICHSON ......................................................................................................... 8 1.4 HYLASTES ATER (PAYKULL) ................................................................................................................ 11 1.5 HYLASTES ATER IN NEW ZEALAND ...................................................................................................... 17 1.6 THE OBJECTIVES OF TIDS RESEARCH PROJECT .................................................................................... 23 2. OBSERVATIONS ON ASPECTS OF THE ECOLOGY AND BEHAVIOUR OF H. ATER AND H. LIGNIPERDA IN SECOND ROTATION P. RADIATA FORESTS IN THE CENTRAL NORTH ISLAND, NEW ZEALAND .......................................................................................................................... 25 2.1 A PRELIMINARY INVESTIGATION OF H. ATER AND H. LIGNJPERDA LARVAL POPULATIONS .................. 25 2.1.1 Introduction .............................................................................................................................. 25 2.1.2 Methods ................................................................................................................................... 27 2.13 Results ..................................................................................................................................... 32 2.1.4 Discussion ................................................................................................................................ 36 2.2 A STUDY INVESTIGATING ASPECTS OF THE ECOLOGY AND BEHAVIOUR OF H. ATER AND H LlGNJPERDA ..................................................................................................................... .37 2.2.1 The annual flight activity and colonisation behaviour of H. ater and H. ligniperda ............... 38 2.2.1.1 Introduction ........................................................................................................................................ 38 2.2.1.2 Methods ...................................................... ;....................................................................................... 38 2.2.1.3 Results and Discussion ....................................................................................................................... 43 2.2.2 The larval composition of stump populations .......................................................................... 52 2.2.2.1 Introduction ........................................................................................................................................ 52 2.2.2.2 Methods .............................................................................................................................................. 53 2.2.2.3 Results and Discussion ....................................................................................................................... 53 2.2.3 The emergence of H. ater and H. ligniperda from P. radiata stumps ..................................... 66 2.2.3.1 Introduction ........................................................................................................................................ 66 2.2.3.2 Methods .............................................................................................................................................. 66 2.2.3.3 Results and Discussion ....................................................................................................................... 68 2.3 CONCLUSION ...................................................................................................................................... 70 3. THE PRIMARY EFFECT OF H. ATER ATTACK ON SEEDLINGS ........................................... 75 3.1 THE INCIDENCE OF H. ATER ATTACK AND MORTALITY IN SECOND ROTATION P. RADIATA FORESTS IN THE CENTRAL NORTH ISLAND, NEW ZEALAND ............................................................................................ 75 3.1.1 Introduction .............................................................................................................................. 75 3.1.2 Methods ................................................................................................................................... 77 3.1.3 Results ..................................................................................................................................... 82 III 3.104 Discussion ................................................................................................................................ 90 3.2 THE INFLUENCE OF SUB-LETHAL AIT ACK BY HATER ON THE GROWTH OF SEEDLINGS ...................... 95 3.2.1 Introduction .............................................................................................................................. 95 3.2.2 Methods ................................................................................................................................... 96 3.2.3 Results ................................................................................................................................... 100 3.2.4 Discussion .............................................................................................................................. 115 4. SECONDARY EFFECTS OF H. ATER ATTACK ON P. RADIATA SEEDLINGS ................... 118 4.1 INTRODUCTION ................................................................................................................................ 118 4.2 METHODS ......................................................................................................................................... 120 4.3 RESULTS .......................................................................................................................................... 122 4.4 DISCUSSION ..................................................................................................................................... 126 5. THE RESISTANCE OF P. RADIATA SEEDLINGS TO H. ATER ATTACK. ............................ 136 5.1 INTRODUCTION ................................................................................................................................ 136 5.2 METHODS ......................................................................................................................................... 141 5.3 RESULTS .......................................................................................................................................... 143 504 DISCUSSION ..................................................................................................................................... 149 6. THE ORIENTATION OF H. ATER AND H. LIGNIPERDA TO HOST VOLATILES AND BROAD-SPECTRUM ATTRACTANTS .................................................................................................. 154 6.1 INTRODUCTION ................................................................................................................................ 154 6.2 METHODS ......................................................................................................................................... 160 6.3 RESULTS .......................................................................................................................................... 164 6.4 DISCUSSION ...................................................................... ; .............................................................. 169 7. GENERAL DISCUSSION ................................................................................................................. 174 7.1 INTRODUCTION ................................................................................................................................ 174 7.2 OPTIONS FOR THE CONTROL OF HATER IN NEW ZEALAND .............................................................. 178 7.3 SITE-RISK ASSESSMENT AND DAMAGE FORECASTING ....................................................................... 181 7.4 THE DEVELOPMENT OF A MANAGEMENT STRATEGY TO MINIMISE RISKS TO SEEDLINGS ASSOCIATED WITHH ATERATTACK ............................................................................................................................... 184 7.5 THE DIRECTION OF H. ATER RESEARCH IN NEW ZEALAND ................................................................ 188 ACKNOWLEDGEMENTS ........................................................................................................................ 191 REFERENCES ...........................................................................................................................................