Thousand Cankers Disease (TCD)

1. Thousand Cankers Disease (TCD) • What is it? • A disease of some walnut trees that is caused by an insect and a fungus • Where is it? • In western and southwestern areas of the United States; in Tennessee (2010), Virginia, Pennsylvania (2011) • Why is it important? • Because as it spreads eastward, it threatens native eastern black walnut • What are we doing? • Prevention, early detection; management Declining black walnut Boulder, Colorado Oct. 2011 K.Kromroy

2. Thousand Cankers Disease: What is it? A disease of walnut trees (Juglans species)… • Two Juglans occur in Minnesota Butternut (Juglans cinerea): Jan. 2012 , Eugene OR - 1st report of natural infection Eastern black walnut (Juglans nigra): Very susceptible www.plantcare.com/.../black-walnut-2127.aspx • www.tree-pictures.com/butternut_tree_photos.html

3. .... caused by a tiny insect that feeds and tunnels in the inner bark of the trunk and branches. Walnut twig beetle (WTB) Pityophthorus juglandis Tunneling Whitney Cranshaw, Colorado State University, Bugwood.org Entry / exit holes W. Cranshaw , Colorado State Univ. www.forestryimages.org

4. Thousand Cankers Disease • The walnut twig beetle introduces a fungus - Geosmithia morbida • that kills the bark and phloem, causing a canker Jim LaBonte, OR Dept. Agric. Whitney Cranshaw, Colorado State University, Bugwood.org “Canker: A visible dead area, usually of limited extent, in the cortex or bark of a plant.” (Tainter & Baker, 1996) Ned Tisserat, Colorado State University

5. Cankers grow together, eventually girdling and killing the branch or trunk Ned Tisserat, Colorado State University

6. Yellowing & wilting foliage, branch dieback; death in susceptible species Whitney Cranshaw, Colorado State University K. Kromroy, MDA. Boulder, Colorado Oct. 2011

7. History of WTB and TCD Prior to 2003 1928 Early 1990’s 2003 2001 Report of black walnut mortality, northern New Mexico; WTB associated. Reports of black walnut decline & mortality in Boulder & Denver, Colorado Original description of WTB, New Mexico Reports of black walnut decline & mortality in Oregon & Utah

8. Thousand Cankers Disease: Where is it now? TCD is in all the red states 2011 2010 Original host: Arizona walnut

9. Why is it important? …because it threatens eastern black walnut in its native range & there is no control

10. Number of Black Walnut Trees > 1” dbh on Forestland 5.9 million

11. Black Walnut in Minnesota • 5.9 million trees on forestland; Winona, Wabasha, Fillmore Counties > 1 million black walnut each • Annual state harvest is 1-2 million board feet; 4% of $75 million total stumpage value for all wood harvested • 40+ mills in Minnesota use walnut; 12% imported (WI, IA) bark on • Almost 300,000 black walnut in urban areas (2010 MN DNR Rapid Assessment data).

12. Black Walnut Through Minnesota – hundreds of logs each year P. Ahlen, MDA

13. Other Values of Black Walnut • Ecologic • Harder to measure • Nuts as food for wildlife – squirrels, beavers, red-bellied woodpeckers • Important species of riparian corridors • Social • Culture around walnuts for food • Bark used for medicine, dye

14. To our knowledge, TCD is still absent from Minnesota Choinski, 9/2011

15. Thousand Cankers Disease: What are we doing? • PREVENTION • Education • Regulation • EARLY DETECTION

16. Prevention: What are the pathways?

17. ………..Wood for hobbyists ESTIMATED APPROACH RATE: ???? Internet sales; mail order companies; friends/acquaintances WTB spread from California to Pennsylvania http://www.furnituredesignidea.com/3729/cool-wooden-furniture-heartwood-design-furniture http://www.primocraft.com/Bar-Features/Walnut-Burl-Inlay.html

18. Black walnut logs, slabs, burls with bark attached. http://www.woodweb.com/cgibin/forums/vawp.pl?read=531138 T. Seeland, MDA. Davis, Nov. 2011

19. Education • Newsletters, websites • Telephone, email, visits • Presentations • TO • Partner organizations • Mill owners, loggers • Landowners • Tree care companies • Nurseries Photos courtesy of Mike Greenheck, Forest Field Day , Gorman Creek Farm, Kellogg, MN, October 2010

20. Regulation • Who regulates? • Infested western states - No • APHIS - No • Eastern states - Yes

21. Thousand Cankers Disease: Regulation Thousand cankers disease occurs Black walnut native range Exterior quarantine, terms vary by state Interior quarantine, by county 2 counties added

22. Early Detection • 2011 • More than 2500 walnut trees visually assessed in urban, rural and industrial communities • 5 suspect trees sampled and examined in lab • NO TCD • 2012 • Visual assessment of walnut trees at or near mills that use walnut • Traps with walnut twig beetle lure hung at 2 sites • Data analyses in progress • 2013 • Farm bill funding for TCD surveys in MN and 16 other states • MN will hang traps at 10 high risk sites • Continue visual assessment

23. Early Detection: It’s here – a trap with a lure! Lure S.Seybold, USFS

24. Visual Assessment: Early symptoms • Thinning crown • Yellow or wilting leaves • Tree may be infested 7 or more years before see crown symptoms J.Juzwik, USFS

25. Early symptoms • Wilting leaves • Attached brown leaves • Small leaves J.Juzwik, USFS

26. Oozing canker on Juglans nigra Photo by T. Seeland, MDA, Denver, Colorado, June 2011

27. Actively declining symptoms – rapid wilting Branch cankers below wilting foliage J.Juzwik, USFS

28. Top down dieback B.Moltzan, USFS

29. Many tiny holes on branches >1.5 inches W. Cranshaw , Colorado State Univ. www.forestryimages.org

30. Galleries and meandering tunnels Whitney Cranshaw, Colorado State University, Bugwood.org

31. Small cankers in inner bark J.Juzwik, USFS

32. Old cankers under bark on Juglans nigra lose their color Photo by T. Seeland, MDA, Denver CO June 2011

33. Large dead areas on branches & stems J.Juzwik, USFS

34. What else might be mistaken for TCD? Anthracnose Fusarium canker Joseph O'Brien, USDA Forest Service, Bugwood.org J.Juzwik, USFS

35. What else might be mistaken for TCD? Site stress Photo by Choinski, 9/2011 Unknown J.Juzwik, USFS

36. Other insects and their damage • Insects found on girdled black walnut in Indiana & Missouri: • Ambrosia beetles – 7 species • Weevils – 5 types • Bark beetles – 2 species 80% of beetles in MO Asian ambrosia beetle Xyleborinus saxeseni Natasha Wright, Florida Department of Agriculture and Consumer Services, Bugwood.org

37. On walnut log, St. Paul rail yard 2011 Cossoninae weevil Himatium errans Weevil holes Weevil tunnels? Photos by J.Juzwik, USFS

38. Management Sanitation • Tree removal • Proper disposal • Bury • Burn Disposal site in Boulder, Colorado October 2011, K.Kromroy, MDA

39. Management Studies in progress – preliminary results • Treatments for wood: Heat, debarking, fumigation • Treatments for trees: Insecticides • Insects • WTB genetics, behavior, cold tolerance • Other insects that may vector pathogen • Fungi • Genetics, aggressiveness • Other canker fungi • Variation in susceptibility/resistance of the host • Role of stress in WTB attraction and in canker development • Time-line of disease progression

40. Acknowledgements • Jenny Juzwik, Paul Castillo- USFS Northern Research Station. • Keith Jacobsen, Don Deckard, Lance Sorenson -MN DNR. • Mike Greenheck - Gorman Creek Farms, Kellogg MN. • Angie Gupta- UM Extension. • Tina Seeland, Bob Koch, Mark Abrahamson - MDA