Minnesota First Detectors
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 walnutBoulder, Colorado Oct. 2011
K.Kromroy
Minnesota First Detectors
Thousand Cankers Disease: What is it?
Two Juglans occur in Minnesota
A disease of walnut trees (Juglans species)…
www.plantcare.com/.../black-walnut-2127.aspx www.tree-pictures.com/butternut_tree_photos.html
Eastern black walnut (Juglans nigra): Very susceptible
Butternut (Juglans cinerea): Jan. 2012 , Eugene OR - 1st report of natural infection
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Walnut twig beetle (WTB)Pityophthorus juglandis
Whitney Cranshaw, Colorado State University, Bugwood.org
TunnelingEntry / exit holes
W. Cranshaw , Colorado State Univ. www.forestryimages.org
.... caused by a tiny insect that feeds and tunnels in the inner bark of the trunk and branches.
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The walnut twig beetle introduces a fungus - Geosmithia morbida
that kills the bark and phloem, causing a canker
Ned Tisserat, Colorado State University
Whitney Cranshaw, Colorado State University, Bugwood.org
Jim LaBonte, OR Dept. Agric.
“Canker: A visible dead area, usually of limited extent, in
the cortex or bark of a plant.”(Tainter & Baker, 1996)
Thousand Cankers Disease
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Ned Tisserat, Colorado State University
Cankers grow together, eventually girdling and killing the branch or trunk
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Whitney Cranshaw, Colorado State University
Yellowing & wilting foliage, branch dieback; death in susceptible species
K. Kromroy, MDA. Boulder, Colorado Oct. 2011
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History of WTB and TCD Prior to 2003
Original description of WTB, New Mexico
1928 Early 1990’s
2001 2003
Reports of black walnut decline & mortality in
Oregon & Utah
Report of black walnut mortality, northern New
Mexico; WTB associated.
Reports of black walnut decline & mortality in
Boulder & Denver, Colorado
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Thousand Cankers Disease: Where is it now?
Original host: Arizona walnut
2010
2011
TCD is in all the red states
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…because it threatens eastern black walnut in its native range & there is no control
Why is it important?
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MissouriIowa
WisconsinMinnesota
0
20,000,000
40,000,000
60,000,000
80,000,000
100,000,000
120,000,000
18.5 million
41.9 million
18.5 million
41.9 million
100.9 million
Miles, P.D. Fri. Nov 05 19:16:48 CDT 2010 Forest Inventory EVALIDator web-application version 4.01 beta.
5.9 million
Number of Black Walnut Trees > 1” dbh on Forestland
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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).
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Black Walnut Through Minnesota – hundreds of logs each year
P. Ahlen, MDA
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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
Other Values of Black Walnut
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To our knowledge, TCD is still absent from Minnesota
Choinski, 9/2011
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PREVENTION Education Regulation
Thousand Cankers Disease: What are we doing?
EARLY DETECTION
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Prevention: What are the pathways?PATHWAY ESTIMATED APPROACH RATE
Newton, L. & Fowler, G. 2009. Pathway Assessment: Geosmithia sp. and Pityophthorus juglandis Blackman movement from the western into the
eastern United States. USDA APHIS Rev. 1:10.19.2009. 50 pgs.
Timber Low; little timber shipped from west to east
Firewood Low - moderate; firewood distributors, long distance campers
Wood packing Low to moderateNursery stock Low; no reports of infested nursery plants
Scion wood Low; programs in west revised to prevent spreadNatural spread Low; beetle flies 1-2 miles
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………..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-furniturehttp://www.primocraft.com/Bar-
Features/Walnut-Burl-Inlay.html
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http://www.woodweb.com/cgibin/forums/vawp.pl?read=531138
Black walnut logs, slabs, burls with bark attached.
T. Seeland, MDA. Davis, Nov. 2011
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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
Education
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Regulation
Who regulates?
Infested western states - No APHIS - No
Eastern states - Yes
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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
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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
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Lure
Early Detection: It’s here – a trap with a lure!
S.Seybold, USFS
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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
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Early symptoms
Wilting leaves
Attached brown leaves
Small leaves
J.Juzwik, USFS
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Photo by T. Seeland, MDA, Denver, Colorado, June 2011
Oozing canker on Juglans nigra
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Actively declining symptoms – rapid wilting
Branch cankers below wilting foliage
J.Juzwik, USFS
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Top down dieback
B.Moltzan, USFS
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Many tiny holes on branches >1.5 inches
W. Cranshaw , Colorado State Univ. www.forestryimages.org
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Galleries and meandering tunnels
Whitney Cranshaw, Colorado State University, Bugwood.org
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Small cankers in inner bark
J.Juzwik, USFS
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Old cankers under bark on Juglans nigra lose their color
Photo by T. Seeland, MDA, Denver CO June 2011
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Large dead areas on branches & stems
J.Juzwik, USFS
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What else might be mistaken for TCD?
Anthracnose Fusarium cankerJoseph O'Brien, USDA Forest Service, Bugwood.orgJ.Juzwik, USFS
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Unknown
What else might be mistaken for TCD?
Site stressPhoto by Choinski, 9/2011J.Juzwik, USFS
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Other insects and their damage
Asian ambrosia beetleXyleborinus saxeseni
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
Natasha Wright, Florida Department of Agriculture and Consumer Services, Bugwood.org
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Cossoninae weevilHimatium errans
Weevil holes
Weevil tunnels?
On walnut log, St. Paul rail yard 2011
Photos by J.Juzwik, USFS
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Tree removal Proper disposal
BuryBurn
Sanitation
Management
Disposal site in Boulder, Colorado October 2011, K.Kromroy, MDA
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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
Studies in progress – preliminary results
Management
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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
