Walnut in the West Death by a Thousand Cankers

Walnut in the West Death by a Thousand Cankers Colorado State University Ned Tisserat, Whitney Cranshaw, Curtis Utley, Emily Freeland, Bill Jacobi Boulder County CO Kathleen Alexander CO State Forest Service David Leatherman USFS California Steven Seybold UC Davis Andy Graves; Chuck Leslie Institute Perennial Plants for Food and Bioenergy (IPPFB), UT T. Ford, R. Funk USFS Purdue Keith Woeste U Missouri Mark Coggeshall U Tennessee Scott Schlarbaum Oregon State Jay Pscheidt Czech Republic Miroslav Kolarik Funding USFS, USDA CSREES

Black Walnut (Juglans nigra) Not native to western USA Not a major component of urban landscape but it is a tough tree Street trees Backyards Farmsteads Trees can grow to very large sizes in Oregon Also have hybrids

Black Walnut Decline and Mortality in Utah in 90 s Walnut twig beetle collected near Salt Lake City UT in 1988; but walnut mortality not reported until 1990 s "If I get a little personal and even a little sentimental, I hope you will forgive me," President Hinckley said as he began to describe the origin of the pulpit. "Every year at this season we planted trees," he said. "Well, some 36 years ago I planted a black walnut. It was in a crowded area where it grew straight and tall to get the sunlight. A year ago (1999?), for some reason, it died." "The first time I saw the wood was when Brad had the log in the back of his pickup truck, (Intermountain Wood Products of Salt Lake UT) Walnut pulpit in Mormon Conference Center

Black Walnut Decline and Mortality in Oregon (1990 s?) Always associated with presence of twig beetle Progression slower than in Colorado? Reasons? Walnut hybrids common? Larger trees? Thicker bark? Different weather (less stress)? Note symptomless walnut at end of row

Extensive Mortality In New Mexico Elimination of black walnut near Santa Fe 2001 Walnut twig beetle found Reports of dieback in Albuquerque 2009 Thousand cankers disease (TCD) confirmed in 2010

Black Walnut Mortality in CO Walnut decline first observed in Colorado Springs and Boulder around 2001 2002 May have been years earlier in western Colorado (90 s) Substantial mortality in Colorado Springs and Boulder by 2004 Walnut twig beetle and drought suspected Black walnut eliminated in Colorado Springs by 2008 Well over 2,000 trees dead in Denver Boulder and surrounding area; few surviving trees in Boulder

Red Areas indicate where Geosmithia and Pityophthorus juglandis have been found since 2008

Initial Symptoms Subtle and Easily Confused With Other Problems

May See Resprouting But Sprouts Also Succumb

September 2008 June 2008 June 2009

Walnut Twig Beetle Pityophthorus juglandis Walnut twig beetle found in Colorado 2003 on black walnut First record of insect on Juglans major in New Mexico (1927) native to the Southwest?, California? Twig beetles normally attack small, weakened twigs Range of Juglans major

Slide courtesy S. Seybold Identification of Walnut Twig Beetle, Pityophthorus juglandis Blackman (Coleoptera: Scolytidae) An Über Vector of TCD OCD: Almost compulsive boring and tasting behavior on host branches Two rows of tubercles Concentric arcs of asperities

The walnut twig beetle is a minute bark beetle. Great picture by Jim LaBonte, OR Dept. Agriculture! It is one of few Pityophthorus species that develop in hardwoods. Pityophthorus bark beetles are collectively known as twig beetles because they normally restrict damage to small diameter twigs.

Walnut Twig Beetle Very aggressive on black walnut Most galleries on branches >1 inch diameter Attacks will occur on main trunk Entrance holes very difficult to see J. regia

Trapping is very inefficient using yellow traps or Lindgren funnels Most beetles caught in late summer 45 Beetle Captures 40 35 30 25 20 15 10 5 0

How Does Such a Small Beetle Kill Such A Big Tree?

Summer 2007- Coalescing cankers consistently noted around beetle galleries

Beetle galleries and cankers not evenly distributed on branches or trunk More damage on lower side of branches More damage on one side of trunk? Often west side of tree more damaged? # galleries and cankers on tree is enormous!! East side of trunk West side of trunk

Cankers Initially Restricted to Phloem and Don t Extend into Cambium Outer bark Phloem

Eventually Cankers Will Kill Cambium

Cankers on Walnut (Left) Differ From Open Faced Cankers (Ash Tree on Right)

Summer and Fall 2007 fungus consistently isolated from cankers

Geosmithia morbida Anamorphic genus (Ascomycota:Hypocreales) No sexual state known Off white to buff in culture, often lobed Dry conidia Unlike Ophiostomatoid and ambrosia fungi (e.g. in Raffaelea in Laurel wilt) Thermotolerant Optimal 25 32 ⁰C Will grow at 37 ⁰C (99 ⁰F) Will survive 42 ⁰C (107 ⁰F)

Geosmithia morbida has a yeast phase

Geosmithia species associated with numerous beetles in Europe but has not been reported as plant pathogen Geosmithia species Insect Host G. fassatiae Scolytus intricatus Scolytus rugulosus Quercus spp. Malus G. langdonii Scolytus intricatus Scolytus rugulosus Ernoporicus fagi Scolytus multistriatus Quercus spp. Malus Fagus Ulmus G. obscura Scolytus intricatus Scolytus carpini Quercus Carpinus Geosmithia OTU s Ernoporus tiliae Hylesinus orni Ips typographus Scolytus schevyrewi Trypophloeus Xyloborinus saxeseni Xylosandrus mutilatus Tilia Fraxinus Picea Ulmus Populus Ulmus?

Geosmithia also has been isolated from frass, beetle A galleries, B and beetles Photo courtesy Dr. A. Graves U.C. Davis

0.89 0.1 0.49 0.86 0.92 0.82 0.75 0.78 0.94 0.50 0.88 0.53 0.42 0.74 0.79 0.65 0.82 0.92 0.98 0.70 G. puterillii AF033384 G. sp. 27 RJ0911 AJ578485 OTU2 AJ578487 OTU5 1.00 RJ137m CCF3638 OTU23 AJ578488 OTU3 0.71 0.94 G. rubra AM181464 OTU1 1.00 G. sp. 20 CCF3641 G. adriatica CCF3655 OTU10 G. rufescens MK1803 0.92 G. lavendula AF033385 0.90 0.55 0.70 G. obscura AJ784999 0.97 G. obscura AM181460 G. sp. 8 AM181420 G. microcorthyli CCF3861 G. sp. 16 AM181422 G. sp. 35 RJ167m G. sp. 32 MK1801 G. sp. 30 MK1824 G. sp. 30 RJ156m G. sp. 33 MK1809b G. sp. 34 MK1832 G. sp. 31 MK1793 0.95 G.langdoni AJ578481 G. flava AJ578483 G. fassatiae AJ578482 1247 CO 1217 CO 1234 AZ 0.94 1227 CA 1270 CA 1222 UT 1259 OR 1239 CO 1223 UT 1273 CO 1269 CA 1218 CO G. sp 11 AM181419 G. sp. 29 CCF3753 G. sp. 21 MK592 G. sp. 12 AM181431 G. sp. 13 AM181439 1.0 1226 FortCollins CO G. sp. 40 CCF3563 G. eupagioceri CCF3754 G. sp. 9 CCF3703 G. sp. 25 MK1805 G. sp. 28 RJ278m G. sp. 44 MK1804 0.84 0.69 G. sp. 22 CCF3652 G. sp. 24 MK1822 AJ578486 G.pallida type MK1758 G. morbida Acremonium alternatum AY566992 Isolate from S. schevyrewi from Ulmus G. pallida species complex G.sp. 26 MK1797 Analysis courtesy M. Kolarik Pinaceae Angiosperms + Cupresaceae

It s A a Food Fight! Bark maceration Pityophthorus, ambrosia beetles, other insects Geosmithia, Fusaria & many other fungi B

Fusarium Canker of Walnut Reported in 80 s in Minnesota, Wisconsin, Kansas following harsh winter conditions Associated with ambrosia beetles

Death by a Thousand Cankers Initial beetle attack Cankers form around beetle galleries, but initially localized in phloem Cankers coalesce, eventually penetrate bark to cambium; resulting in branch dieback It may be years between initial beetle attack and visible symptoms The death spiral Tree vigor declines Mass attack by beetles on trunk; many cankers Secondary fungi invade (Fusarium solani and others) Trees are killed

Distribution of 1000 Cankers in Colorado

rdna ITS haplotypes of G. morbida are not geographically or host specific

Where Did 1000 Cankers Originate? Pityophthorus juglandis and Geosmithia morbida widespread on J. major in New Mexico and Arizona But our survey is not complete J. major not in a state of decline in its native range Do isolates vary in aggressiveness to black walnut? not so far

What about the California Walnuts? J. californica J. hindsii

Thousand Cankers Disease: Areas of Interest in CA J. regia J. regia J. regia J. hindsii J. californica Slide Courtesy of A.D. Graves, UC-Davis Dept. Plant Pathology

Thousand Cankers Disease: Areas of Interest in CA J. regia J. regia J. regia J. hindsii J. californica Slide Courtesy of A.D. Graves, UC-Davis Dept. Plant Pathology

Thousand Cankers Disease: Areas of Interest in CA Davis, Yolo Co.: Branch dieback and mortality on Juglans hindsii on city streets and along rural highways, June-Aug., 2008 J. regia J. regia J. regia J. hindsii J. californica Slide Courtesy of A.D. Graves, UC-Davis Dept. Plant Pathology

Thousand Cankers Disease: Areas of Interest in CA Winters, Solano Co.: Northern California black walnut is dying in its native habitat in the lower Sacramento River Valley J. regia J. regia J. regia J. hindsii J. californica Slide Courtesy of A.D. Graves, UC-Davis Dept. Plant Pathology

Thousand Cankers Disease: Areas of Interest in CA J. regia J. regia J. regia J. hindsii J. californica Davis, Yolo Co.: Black walnuts are dying in research germplasm collections, e.g., UCD Walnut Collection and NCGR. Mortality of a 12-13 yr old Juglans californica on Paradox Rootstock, Aug. 11, 2009 Slide Courtesy of A.D. Graves, UC-Davis Dept. Plant Pathology

Thousand Cankers Disease: Areas of Interest in CA Piru Lake, Ventura Co.: Native endemic stands of Juglans californica in the Los Padres National Forest showing crown dieback and tree mortality, Aug. 27, 2008 J. regia J. regia J. regia J. hindsii J. californica Slide Courtesy of A.D. Graves, UC-Davis Dept. Plant Pathology

Thousand Cankers Disease: Areas of Interest in CA Near Glendale, Los Angeles Co: Highly symptomatic native Juglans californica in a residential backyard, Montecito Heights, June, 2009 J. regia J. regia J. regia J. hindsii J. californica Slide Courtesy of A.D. Graves, UC-Davis Dept. Plant Pathology

Black Walnut vs. Pecan

Is Juglans regia at Risk? Two dead Juglans nigra on left, healthy Juglans regia on right Photo courtesy Marion Murray, Utah State University

Juglans regia (Denver) in fall 2008 and June 2010.

Juglans microcarpa in Denver 2010

Butternut (J. cinerea) in Denver area 2010

Susceptibility of other Juglans, Carya species? Juglans microcarpa

Inoculations Juglans major Juglans nigra

Canker Development Following Inoculation With Geosmithia 160 Discolored Area (mm 2 140 120 100 80 60 40 20 0 PDA Aspergillus Geosmithia Isolate 1217 Geosmithia Isolate 1218 Tree Species in Order of Susceptibility to Geosmithia Discolored area 6 wk after inoculation; mean of 6 trees

2,000 ** ** 1,500 % increase in discolored area Inoculated vs. control 1,000 500 0 1,500 1,000 NS NS NS NS NS NS NS ** NS ** NS NS ** ** ** ** ** ** ** ** ** * ** ** ** ** NS ** ** 500 ** 0 * NS NS * NS NS NS NS NS NS C.ovata C.illinoensis J.major J.californicaB J.hindsii J.microcarpa J.californica J.regia J.cinerea J.ailantifolia J.nigra Isolate 1217 Isolate 1218

1000 Cankers Poses Grave Risk to Walnuts Dieback and decline of Juglans spp. in California Rapid mortality of black walnut in numerous regions of the West Disease widespread Very efficient, aggressive vector Aggressive fungus What happens if disease establishes in native range of black walnut? What if it doesn t/ can t cause damage in native range? Can we take that chance by ignoring this?

It Will Be Too Late To Do Anything if TCD Establishes in Native Range Other exotics introduced into native range of susceptible trees Butternut canker Chestnut blight Emerald ash borer Laurel wilt TCD is not yet in native range: we can do something

Can We Contain 1000 Cankers? Do We Have the Will to Contain It? Beetle infested black walnut with bark attached as advertised on the internet

What Should We Do Nationally? Walnut wood harbors the insect and fungus We don t know for how long, but moving wood is a very bad idea! Over 23,000 beetles emerged from these logs

How wood might move

Black Walnut Makes For Great Firewood in Colorado (and elsewhere)

No One in the West Wants to Destroy Infested Logs! Denver Craigslist Postings (10/29/2009) I have a full truckload of black walnut wood We have a straight, tall walnut tree, lost to disease, that needs to come down. We thought we'd offer it up to woodworkers before having it hauled off for firewood. For sale 3 stunning walnut crotch slabs. 1 bookmatched set and one other sequential slab all from the same log. These were recently cut so they are still green, you buy green, you save a pile of green.

Transcontinental Movement of Myth that logs are not shipped from West to East Large Logs

What About Bark Removal? Beetles apparently emerged from wood and then tried to reenter logs Debarking may not be a safe measure Some woodworkers don t like bark removed

What about chipping?

Walnut twig beetles were able to complete development in larger pieces following chipping

Right Now We Need To Prevent Movement of ANY Form of Wood!

What About Chemical Treatments? Not a solution to the long term survival of black walnut in native range May have some use in the West

What About Drenching Sprays? Drenching branch sprays (pyrethroids and others) for walnut twig beetle has not been effective possibly because of poor timing

Soil treatments and Walnut Twig Beetle Imidacloprid (Merit) use in Boulder may have slowed progression, but did not always save diseased trees However, most applications made curatively rather than preventively Need higher rates? Trials planned for Denver in 2010 Imidaclorprid, abamectin, possibly others Dinotefuran may work better for this application, but doesn t have food crop tolerance What about fungicides?

What Needs to Be Done Strong public education on the threat of Thousand Cankers Disease to black walnut in its native range Arborists, Woodworkers, Homeowners http://www.colostate.edu/depts/bspm/extension %20and%20outreach/thousand%20cankers htmlhttp://mda.mo.gov/plants/pests/thousandca nkers.php Information

What Needs to Be Done Immediate restrictions on the movement of walnut wood State quarantines National quarantines We must stop this!

Containment of 1000 Cankers Don t move infested logs or lumber with bark attached Sanitation in infested areas probably won t help Movement of fresh debarked lumber? Movement of wood chips?

Average Geosmithia Canker Size Utah Study Average Canker Area in mm 2 100 90 80 70 60 50 40 30 20 10 0 Geo. Iso. 1222 Geo.Iso. 1223 Juglandaceae Species inoculated

Those who do not remember the past are condemned to repeat it

Black Walnut (Juglans nigra) in the Not native to western US Not a major component of urban landscape Street trees Backyards Farmsteads It s a tough tree! West Oregon

March 2008 Canker formation in black walnut 8 weeks after inoculation with isolates of Fusarium solani and Geosmithia morbida Isolate Number of inoculation sites developing cankers Average and range ( ) of canker lengths (mm) Fusarium solani 917 2/8 19.0 (16-22) Fusarium solani 1179 6/8 21.0 (10-40) Geosmithia 1217 8/8 57.0 (29-130) Geosmithia 1218 8/8 46.5 (31-60) A B F. solani G. morbida

Geosmithia is a bark, and not a vascular pathogen Canker formation 4 weeks after inoculation in field (Utah), original inoculation point 3 mm diam.

Adult twig beetle tunneling on excised stem of Juglans nigra after 24 hours

Canker development 4 weeks after placement of adult twig beetles on excised stem of Juglans nigra

Other Canker Fungi Very long, vertical cankers on trunk during final stages of decline Fusarium solani isolated from cambium in 2006 (but not from around beetle galleries) Other Fusarium species have also been recovered

Walnut twig beetles readily breed in logs Dead Walnut Wood Can Host Bark Beetles and Fungus

Two logs, ca 5 1/2-in diameter, 18-in length

23,040 Beetles/2 logs = 35+ Beetles/inch 2

2006 in Boulder Colorado

Open Faced Cankers Don t Form May see bark cracking around entrance holes, star shaped wounds at leaf scars, and staining on trunk, but these are not diagnostic

Could Walnut Twig Beetle Kill the Tree Without Geosmithia? Geosmithia always associated with insect Does the fungus enhance the ability to attack Pityophthorus to attack bark? Reduced vigor? beneficial to insect?

Where Did G. morbida Come From? 1234 AZ 1263Ventura CA 1264Ventura CA 1261SanJoaquin CA 1276CSUOval CO 1217Boulder CO 1279Wheatridge CO 1224Boulder CO 1249YoloCounty CA 1227Winters CA 1273GoldenCemetery CO 1236Prosser WA 1250Boulder CO 1270SanJoaquin CA 1267SanJoaquin CA 1260 OR 1245Boise ID 1262Ventura CA 3 1223 UT 1268Ventura CA 1274Wheatridge CO 1 1269Ventura CA 1258 OR 1 1228Winters CA 1272Ventura CA 1 1233YoloCounty CA 1256 OR 1266Ventura CA ITS rdna sequencing 1218Boulder CO 1259 OR 1247ColoradoSprings CO 1246ColoradoSprings CO 1285Delta CO 65 1222 UT 1239Westminster CO 1271GoldenCemetery CO Isolates vary slightly in DNA (rdna ITS) sequence Suggests at least some genetic diversity Probably not the result of a single introduction? 0.0002

Juglans Germplasm Collection Positive Isolation of Geosmithia from English Walnut, J. regia, Accession No. DJUG0366.1, Block C, Row?, Tree 1, September 2009 1) Mass attack by walnut twig beetle

Red Areas indicate where Geosmithia and Pityophthorus juglandis have been found