Forest Health Technology Enterprise Team TECHNOLOGY TRANSFER Biological Control Biological Control of Invasive Plants in the Eastern United States Roy Van Driesche Bernd Blossey Mark Hoddle Suzanne Lyon Richard Reardon Forest Health Technology Enterprise Team—Morgantown, West Virginia United States Forest FHTET-2002-04 Department of Service August 2002 Agriculture BIOLOGICAL CONTROL OF INVASIVE PLANTS IN THE EASTERN UNITED STATES BIOLOGICAL CONTROL OF INVASIVE PLANTS IN THE EASTERN UNITED STATES Technical Coordinators Roy Van Driesche and Suzanne Lyon Department of Entomology, University of Massachusets, Amherst, MA Bernd Blossey Department of Natural Resources, Cornell University, Ithaca, NY Mark Hoddle Department of Entomology, University of California, Riverside, CA Richard Reardon Forest Health Technology Enterprise Team, USDA, Forest Service, Morgantown, WV USDA Forest Service Publication FHTET-2002-04 ACKNOWLEDGMENTS We thank the authors of the individual chap- We would also like to thank the U.S. Depart- ters for their expertise in reviewing and summariz- ment of Agriculture–Forest Service, Forest Health ing the literature and providing current information Technology Enterprise Team, Morgantown, West on biological control of the major invasive plants in Virginia, for providing funding for the preparation the Eastern United States. and printing of this publication. G. Keith Douce, David Moorhead, and Charles Additional copies of this publication can be or- Bargeron of the Bugwood Network, University of dered from the Bulletin Distribution Center, Uni- Georgia (Tifton, Ga.), managed and digitized the pho- versity of Massachusetts, Amherst, MA 01003, (413) tographs and illustrations used in this publication and 545-2717; or Mark Hoddle, Department of Entomol- produced the CD-ROM accompanying this book. ogy, University of California at Riverside, (909) 787- All images in the publication are available through 4714, [email protected]; or Bernd Blossey, Dept. Forestry Images (www.forestryimages.org) and of Natural Resources, Cornell University, (607) 255- Invasive.org (www.invasive.org) websites via the 5314, [email protected]; or from Richard Reardon, numbers in the lower right-hand corner of the fig- US Forest Service, Morgantown, West Virginia, (304) ures. The publication is available on the Bugwood 285-1566, [email protected]. website (www.bugwood.org). Additional copies of the CD-ROM can be or- Thanks to Mary Kroll (Kroll Communications, dered from Richard Reardon. Long Prairie, Minn.) for editing and Mark Riffe (Intecs International, Ft. Collins, Colo.) for design and layout. Technical Coordinators • Roy Van Driesche and Suzanne Lyon, Department • Mark Hoddle, Department of Entomology, Uni- of Entomology, University of Massachusetts, versity of California, Riverside, California. Amherst, Massachusetts. • Richard Reardon, Forest Health Technology En- • Bernd Blossey, Biological Control of Non-Indig- terprise Team, USDA Forest Service, enous Plant Species Program, Department of Morgantown, West Virginia. Natural Resources, Cornell University, Ithaca, New York. On the cover: Upper photo set: infestation of Pistia stratiotes L. (waterlettuce) on Torry Island in Lake Okeechoee, Florida, before and after introduction of the weevil Neohydronomus affinis Hustache, pictured at right. (Pho- tographs courtesy of USDA, ARS Invasive Plant Research Laboratory.) Lower photo set: infestation of Euphorbia esula L. (leafy spurge) at Forget-Me-Not Lake, Becker Co., Min- nesota, before and after introduction of Aphthona nigriscutis Foudras (flea beetle), pictured at left. (Photographs by Robert Richard, USDA-APHIS-PPQ.) Table of Contents INTRODUCTION ...................................................................................................................................... 1 SECTION I: WEEDS OF LAKES, PONDS, AND RIVERS .............................................................................. 3 1 ALLIGATORWEED ................................................................................................................................. 5 2 FLOATING FERN (SALVINIA) .............................................................................................................. 17 3 WATER CHESTNUT ............................................................................................................................ 33 4 WATERHYACINTH ............................................................................................................................. 41 5 WATERLETTUCE ................................................................................................................................65 6 EURASIAN WATERMILFOIL ................................................................................................................. 79 7 HYDRILLA ........................................................................................................................................ 91 SECTION II: WEEDS OF WETLANDS ................................................................................................... 115 8 AUSTRALIAN PAPERBARK TREE (MELALEUCA) ................................................................................ 117 9 COMMON REED .............................................................................................................................. 131 10OLD WORLD CLIMBING FERN ......................................................................................................... 139 11 PURPLE LOOSESTRIFE .................................................................................................................... 149 12 JAPANESE KNOTWEED ................................................................................................................... 159 SECTION III: WEEDS OF PRAIRIES AND GRASSLANDS ....................................................................... 167 13 SPOTTED KNAPWEED .................................................................................................................... 169 14 LEAFY SPURGE .............................................................................................................................. 181 15 CYPRESS SPURGE........................................................................................................................... 195 16 SWALLOW-WORTS ........................................................................................................................ 209 17 CANADA THISTLE .......................................................................................................................... 217 18 MUSK THISTLE (NODDING THISTLE) ............................................................................................. 229 19 BULL THISTLE (SPEAR THISTLE) .................................................................................................... 247 20 SLENDERFLOWER THISTLE (WINGED SLENDER OR SEASIDE THISTLE) .............................................. 251 21 PLUMELESS THISTLE (CURLED THISTLE, BRISTLY THISTLE) ............................................................. 255 SECTION IV: WEEDS OF OLD FIELDS AND PASTURES ........................................................................ 263 22 MULTIFLORA ROSE ....................................................................................................................... 265 23 TROPICAL SODA APPLE, WETLAND NIGHTSHADE, AND TURKEY BERRY ......................................... 293 24 BRAZILIAN PEPPERTREE ................................................................................................................. 311 SECTION V: WEEDS OF FORESTS ........................................................................................................ 323 25 KUDZU ......................................................................................................................................... 325 26 MILE-A-MINUTE WEED ................................................................................................................ 331 27 SKUNK VINE ................................................................................................................................. 343 28 COGON GRASS ............................................................................................................................. 353 29 GARLIC MUSTARD ........................................................................................................................ 365 iii Biological Control of Invasive Plants in the Eastern United States SECTION VI: CONCLUSION ................................................................................................................ 373 30 SELECTION OF APPROPRIATE FUTURE TARGET WEEDS FOR BIOLOGICAL CONTROL .......................... 375 Native Weeds vs. Introduced Weeds.................................................................................... 375 Selecting Targets to Minimize Risk to Non-Target Organisms......................................... 376 Selecting Target Weeds to Promote Success ........................................................................ 377 Predicting Successful Biological Control.............................................................................. 378 How Targets Are Selected ...................................................................................................... 379 Future Targets for Biological Control of Weeds.................................................................. 379 References ................................................................................................................................