University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln U.S. Department of Agriculture: Forest Service -- USDA Forest Service / UNL Faculty Publications National Agroforestry Center 2008 Biology and Biological Control of Exotic True Thistles Rachel Winston MIA Consulting Rich Hansen USDA Animal and Plant Health Inspection Service Mark Schwarzlander University of Idaho Eric Coombs Oregon Department of Agriculture–Plant Division Carol Bell Randall USDA Forest Service See next page for additional authors Follow this and additional works at: https://digitalcommons.unl.edu/usdafsfacpub Part of the Forest Sciences Commons Winston, Rachel; Hansen, Rich; Schwarzlander, Mark; Coombs, Eric; Randall, Carol Bell; and Lym, Rodney, "Biology and Biological Control of Exotic True Thistles" (2008). USDA Forest Service / UNL Faculty Publications. 114. https://digitalcommons.unl.edu/usdafsfacpub/114 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Forest Service -- National Agroforestry Center at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA Forest Service / UNL Faculty Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Rachel Winston, Rich Hansen, Mark Schwarzlander, Eric Coombs, Carol Bell Randall, and Rodney Lym This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/ usdafsfacpub/114 Forest Health Technology Enterprise Team TECHNOLOGY TRANSFER Biological Control BIOLOGY AND BIOLOGICAL CONTROL OF EXOTIC T RU E T HISTL E S RACHEL WINSTON , RICH HANSEN , MA R K SCH W A R ZLÄNDE R , ER IC COO M BS , CA R OL BELL RANDALL , AND RODNEY LY M FHTET-2007-05 U.S. Department Forest September 2008 of Agriculture Service FHTET he Forest Health Technology Enterprise Team (FHTET) was created in 1995 Tby the Deputy Chief for State and Private Forestry, USDA, Forest Service, to develop and deliver technologies to protect and improve the health of American forests. This book was published by FHTET as part of the technology transfer series. http://www.fs.fed.us/foresthealth/technology/ On the cover: Italian thistle. Photo: ©Saint Mary’s College of California. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410 or call 202-720-5964 (voice and TDD). USDA is an equal opportunity provider and employer. The use of trade, firm, or corporation names in this publication is for information only and does not constitute an endorsement by the U.S. Department of Agriculture. Federal Recycling Program Printed on recycled paper. BIOLOGY AND BIOLOGICAL CONTROL OF EXOTIC T HISTL E S Rachel Winston Dr. Rich Hansen Environmental Consultant Entomologist MIA Consulting, LLC USDA Animal and Plant Health Inspection Boise, ID Service National Weed Management Laboratory Dr. Mark Schwarzländer Fort Collins, CO Associate Professor Department of Plant, Soil, and Eric Coombs Entomological Sciences Biological Control Entomologist University of Idaho Oregon Department of Agriculture–Plant Moscow, ID Division Salem, OR Carol Bell Randall Entomologist Dr. Rodney G. Lym USDA Forest Service Professor Forest Health Protection Department of Plant Sciences Coeur d’Alene, ID North Dakota State University Fargo, ND For additional copies of this publication, contact: Richard Reardon Carol Bell Randall Mark Schwarzländer USDA Forest Service USDA Forest Service University of Idaho 180 Canfield Street 3815 Schreiber Way Moscow, ID 83844 Morgantown, WV 26505 Coeur d’Alene, ID 83815 (208) 885-9319 (304) 285-1566 (208) 765-7343 [email protected] [email protected] [email protected] ACKNOWL E DGM E NTS We would like to thank all of the county weed superintendents and land managers that we have worked with through the years for encouraging us to develop our series of biol- ogy and biological control manuals. We would like to thank Jennifer Andreas (Washington State University Extension), Richard Old (XID Services, Inc.), and other excellent photographers who contributed many of the photographs in this manual. We also wish to acknowledge Jennifer Andreas for her extensive help in gathering species distribution information. Some of the material in this manual was adapted from the manual for the Biology and Biological Control of Leafy Spurge. We wish to acknowledge the authors of the adapt- ed material (Drs. Rob Bourchier and Andrew Norton). Finally, we would like to thank Mark Riffe, ITX/USDA Forest Service-Forest Health Technology Enterprise Team (FHTET), for editing, layout, and graphics; and Richard Reardon, FHTET, for producing this book. __________________________________________BIOLOGY AND BIOLOGICAL CONTROL OF EXOTIC T RU E T HISTL E S CONT E NTS CHAPTER 1: INTRODU C T I ON ......................................................................1 Overview 1 Classical Biological Control of Weeds .............................................................................. 2 International Code of Best Practices for Classical Biological Control of Weeds ................. 4 International Code of Best Practices for Classical Biological Control of Weeds ............ 4 Biological Control of Exotic Thistles ................................................................................. 5 Integrated Weed Management .......................................................................................... 6 Is Biological Control of Exotic Thistles Right For You? ....................................................... 6 About This Manual ........................................................................................................... 8 CHAPTER 2: GETT I N G TO KNOW EXOT ic TRUE TH I STLES ...................................9 Plant Life Cycle ................................................................................................................ 9 Taxonomic Classification of Exotic True Thistles ............................................................. 13 Species Descriptions of Exotic True Thistles .................................................................... 13 Bull Thistle ................................................................................................................. 14 Canada Thistle ........................................................................................................... 16 Italian Thistle ............................................................................................................. 18 Marsh Thistle ............................................................................................................. 20 Milk Thistle ................................................................................................................ 22 Musk Thistle ............................................................................................................... 24 Plumeless Thistle ........................................................................................................ 26 Scotch Thistle ............................................................................................................. 28 Slenderflower Thistle .................................................................................................. 30 Native True Thistles ........................................................................................................ 33 Cainville Thistle ......................................................................................................... 36 Clustered Thistle ........................................................................................................ 36 Cobwebby Thistle ...................................................................................................... 37 Edible Thistle ............................................................................................................. 37 Eaton’s Thistle ............................................................................................................ 38 Flodman’s Thistle ....................................................................................................... 39 Jackson Hole Thistle ................................................................................................... 39 Gray-Green Thistle ..................................................................................................... 40 Meadow Thistle ........................................................................................................ 41 Mountain Thistle ........................................................................................................ 41 New Mexico Thistle ................................................................................................... 42 Palouse Thistle ........................................................................................................... 42 Prairie Thistle ............................................................................................................