RANGE Operational Field Guide to the propagation and establishment of the bioagent Larinus planus (Canada thistle seed-feeding weevil) May 2001 The contents of this Field Guide may not be cited in whole or in part without the advance written approval of the Director, Forest Practices Branch, Ministry of Forests, Victoria, British Columbia Information contained in this Field Guide is comprised of fact and field observations as of May 2001. Site specific experiences may vary. Compiled and edited by Susan Turner Operational Field Guide to the propagation and establishment of the bioagent Larinus planus (Canada thistle seed-feeding weevil) May 2001 Forest Practices Branch Range Section Noxious Weed Control Program British Columbia Ministry of Forests Larinus planus (Canada thistle seed-feeding weevil) – Operational Field Guide TABLE OF CONTENTS 1. PURPOSE ................................................................................................................... 1 2. INTRODUCTION ...................................................................................................... 1 3. LARINUS PLANUS ..................................................................................................... 2 BIOLOGY ............................................................................................................2 RANGE ................................................................................................................5 Native (European) Range ............................................................................... 5 Adventive North American Distribution ....................................................... 5 HABITAT ............................................................................................................5 4. HISTORY OF INTRODUCTION ............................................................................ 10 SUMMARY OF COLLECTIONS AND RELEASES ...................................... 10 Cariboo Forest Region ................................................................................. 10 Field releases by district ......................................................................... 10 Kamloops Forest Region .............................................................................. 11 Field collections .....................................................................................11 Field releases by district ......................................................................... 11 Nelson Forest Region ................................................................................... 12 Field collections .....................................................................................12 Field releases by district ......................................................................... 12 Prince George Forest Region ....................................................................... 13 Field releases by district ......................................................................... 13 Prince Rupert Forest Region ........................................................................ 14 Field releases by district ......................................................................... 14 Vancouver Forest Region ............................................................................14 Field collections .....................................................................................14 Field releases by district ......................................................................... 14 Other Release Destinations .......................................................................... 15 Field releases by province ...................................................................... 15 5. REDISTRIBUTION ................................................................................................. 15 FIELD COLLECTION ......................................................................................15 What and where to collect ............................................................................ 15 How to collect .............................................................................................. 17 When to collect ............................................................................................ 18 Additional considerations ............................................................................19 SHIPPING ..........................................................................................................20 FIELD RELEASE ..............................................................................................21 Potential release sites ................................................................................... 21 Insect release ................................................................................................22 Additional considerations ............................................................................23 6. MONITORING ......................................................................................................... 23 AGENTS ............................................................................................................24 PLANTS ............................................................................................................25 RESULTS ..........................................................................................................28 Ministry of Forests, Forest Practices Branch (Range Section) i Larinus planus (Canada thistle seed-feeding weevil) – Operational Field Guide List of Photographs Photo 1: Larinus planus (adult) .................................................................................... 3 Photo 2: Larinus planus larvae in seedhead in Peace River ......................................... 4 Photo 3 Large Canada thistle flower heads in Peace River ......................................... 6 Photo 4: Armour Creek Site ......................................................................................... 7 Photo 5: Bachelor Water Reservoir site in 2000 .......................................................... 9 Photo 6: Lower Arrow Lakes ....................................................................................... 9 Photo 7: Sweeping Canada thistle plants for Larinus planus ..................................... 16 Photo 8: Larinus planus on Canada thistle bud .......................................................... 19 Photo 9: Large Canada thistle infestation in Peace River .......................................... 20 Photo 10: Larinus planus larva in seedhead ................................................................. 25 Photo 11: Unexplained exit holes from flower heads of Canada thistle ...................... 26 Photo 12: Canada thistle plant covered in rust ............................................................. 27 Photo 13: Mature Canada thistle plant ......................................................................... 29 Photo 14 Canada thistle flowers with nearly spineless heads ..................................... 30 Photo 15 Male and female flowers of Canada thistle plant – Suskaw River site in Prince Rupert Region (ICH mc 2) ........................................................................... 30 List of Figures Figure 1: Canada Thistle in North America (Moore 1975) ........................................... 5 Appendices APPENDIX A – HOST WEED ..................................................................................... 28 APPENDIC B: KAMLOOPS REGION DISPERSAL MONITORIG RESULTS OF LARINUS PLANUS, 1999 – 2000 ....................................................... 31 APPENDIX C: LITERATURE CITED ......................................................................... 33 APPENDIX D: BIOAGENT RELEASE FORM .......................................................... 34 APPENDIX E: BIOAGENT MOINTIROING FORMS .............................................. 35 Ministry of Forests, Forest Practices Branch (Range Section) ii Larinus planus (Canada thistle seed-feeding weevil) – Operational Field Guide 1. PURPOSE This document summarizes information for the biocontrol agent Larinus planus while it was classified as ‘primary’ and the responsibility of the Forest Practices Branch. The information is a combination of hard facts and field observations. Intended as a ‘field guide’ for those unfamiliar with L. planus, a seed-feeder of Canada thistle (Cirsium arvense), the summary contains pertinent information for field propagation and establishment of the bioagent as well as a historical background of its introduction into British Columbia. 2. INTRODUCTION The goal of the Ministry of Forests Weed Control Program is to reduce target weed populations to ecologically and economically acceptable levels and to prevent their encroachment into new areas. The biological control portion of the program includes biocontrol agent screening, propagation, release, collection and monitoring. Implicit in the use of biocontrol methods is the acknowledgment that weed eradication is not a goal. Rather, bioagent species and host weed species exist in predator-prey relationships with the weeds held at acceptable population levels and the insect populations self-sustaining. The biocontrol program is a cooperative venture between the Ministry of Forests (MOF), Ministry of Agriculture and Food (MAF), Agriculture and Agri-Food Canada (AAFC), Commonwealth Agricultural Bureaux International (CABI) in Switzerland, as well as numerous other provincial and state agencies across western