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Minnesota First Detectors Thousand Cankers Disease What is it? Where is it? Why do we care? What should we do? Kathleen Alexander, Boulder, CO
Minnesota First Detectors
Thousand Cankers Disease
What is it?
Where is it?
Why do we care?
What should we do?
Kathleen Alexander, Boulder, CO
Minnesota First Detectors
Thousand Cankers Disease
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
Why do we care? Because as it spreads eastward, it threatens native eastern black walnut
What should we do? Prevention: reduce risk of introduction
Minnesota First Detectors
Thousand Cankers Disease: What is it?
Two occur in Minnesota
A disease of some walnut trees (Juglans species)
www.plantcare.com/.../black-walnut-2127.aspx
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): Unknown susceptibility
Minnesota First Detectors
….. caused by a tiny insect that feeds and tunnels in the inner bark of the trunk and branches
Walnut twig beetlePityophthorus juglandis
Whitney Cranshaw, Colorado State University, Bugwood.org
TunnelingEntry / exit holes
W. Cranshaw , Colorado State Univ. www.forestryimages.org
Thousand Cankers Disease: What is it?
Minnesota First Detectors
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: What is it?
Minnesota First Detectors
Cankers coalesce, eventually girdling and killing the branch or trunk
Ned Tisserat, Colorado State University
Thousand Cankers Disease: What is it?
Minnesota First Detectors
Kathleen Alexander , City Forester, Boulder, CO Whitney Cranshaw, Colorado State University
Thousand Cankers Disease: What is it?
Crown symptoms: Yellowing & wilting foliage, followed by branch dieback & death may occur in susceptible species
Minnesota First Detectors
2010
Thousand Cankers Disease: Where is it?
States in red & Tennessee
Original host, Arizona walnut Juglans major
Confirmed July 2010
Minnesota First Detectors
Black walnut dieback for 2+ years.
TCD confirmed July 2010. TCD confirmed in 4
counties. Surveys initiated in
neighboring states.
Urban settings news.tennesseeanytime.org/node/5926
1st report in native range
Knoxville, TNSource: M. Mielke NCFPW 2010
Thousand Cankers Disease: Where is it?
KY
NC
GA
VAMO
MS AL
Minnesota First Detectors
…because it threatens eastern black walnut in its native range & there is no control
Thousand Cankers Disease: Why do we care?
Minnesota First Detectors
MissouriIowa
WisconsinMinnesota
0
20,000,000
40,000,000
60,000,000
80,000,000
100,000,000
120,000,000No. Black Walnut Trees > 1” dbh on Forestland
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 In-ventory EVALIDator web-ap-plication version 4.01 beta.
……. black walnut in urban landscapes?
5.9 million
Thousand Cankers Disease: Why do we care?
Minnesota First Detectors
Thousand Cankers Disease: Why do we care?
In Minnesota
• 5.9 million trees (Winona, Wabasha, Fillmore Counties each have > 1 million black walnut trees)
• Annual state harvest – • 1-2 million board feet• 0.1% volume of all wood harvested• $3 million• 5% of $60 million total stumpage value for all
wood harvested
• 30% exported, mainly to Wisconsin, Iowa
• 40+ mills in Minnesota use walnut;12% imported, mainly from Wisconsin and Iowa; bark on.
Minnesota First Detectors
Ecologic Harder to measure Nuts as food for wildlife Important species of
riparian corridors Bark used for medicine, dye
Social Culture around walnuts for
food
Thousand Cankers Disease: Why do we care?Other impacts
Minnesota First Detectors
Minimize the risk of introduction
MOST IMPORTANT PATHWAY=
Wood with bark: • logs for veneer • pieces for woodworking• firewood
Thousand Cankers Disease: What should we do?PREVENTION
Natural spread: Walnut twig beetle can fly 1 – 2 miles, and be carried by wind
Minnesota First Detectors
Regulation
Outreach
Early detection
Thousand Cankers Disease: What should we do?
Tools for prevention
Minnesota First Detectors
Thousand Cankers Disease: What should we do?
Who regulates?
Infested western states No APHIS No
Eastern states Yes
Regulation
Minnesota First Detectors
Source: E.Borchardt, MN Dept. Agric.
Exterior quarantines
Exterior quarantines
Interior quarantine
Thousand Cankers Disease: Regulation
State Quarantines
?In progress
In progress
Minnesota First Detectors
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
Thousand Cankers Disease: What should we do?Outreach!
Minnesota First Detectors
First detector training
MDA/USFS survey for suspect trees:
Thousand Cankers Disease: What should we do?Early Detection
Call Arrest the Pest Hotline651-201-6684 1-888-545-6684
OR follow instructions on survey form to contact
Kathy Kromroy, MDA651-201-6343
Jennifer Juzwik, USFS651-649-5114
Minnesota First Detectors
Early Detection: Does your black walnut have TCD?
Early symptoms (late June to late August)
Area of thinning crown
Yellow or wilting leaves
Leaves smaller than healthy leaves
Attached brown leaves
Tree may be infested 6-8 years before see
crown symptoms
Minnesota First Detectors
Rapid wilting
Early Detection: Does your black walnut have TCD?
Actively declining symptoms
Reduced live crown on trees affected previous season
Cankers on branch below wilting foliage
Minnesota First Detectors
Early Detection: Does your black walnut have TCD?
Late symptomsMany tiny holes on branches >1.5 inches
Galleries and meandering tunnels
Large dead areas on branches & stems
Small cankers in inner bark if scrape away outer bark
Minnesota First Detectors
Early Detection: Does your black walnut have TCD?
What else may be confused with Thousand Cankers Disease?
AnthracnoseFusarium cankers -similar decline
Other beetlesHail injury, storm damage
Squirrel girdling of branches
Nectria cankers
Minnesota First Detectors
Acknowledgements
Jenny Juzwik, Mike Ostry, Paul Castillo. USFS Northern Research Station.
Manfred Mielke. USFS State & Private Forestry.
Keith Jacobsen, Lance Sorenson. MN DNR.
Mike Greenheck. Gorman Creek Farms, Kellogg MN.
Mel Baughman, Angie Gupta. UM Extension.
