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; managementDeclining black walnut

Boulder, Colorado Oct. 2011K.Kromroy

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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

Tunneling

Entry / 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 moderate

Nursery stock Low; no reports of infested nursery plants

Scion woodLow; programs in west revised to prevent spread

Natural 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