Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Geosmithia morbida
(thousand cankers disease)

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Datasheet

Geosmithia morbida (thousand cankers disease)

Summary

  • Last modified
  • 18 December 2019
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Geosmithia morbida
  • Preferred Common Name
  • thousand cankers disease
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Fungi
  •     Phylum: Ascomycota
  •       Subphylum: Pezizomycotina
  •         Class: Sordariomycetes
  • Summary of Invasiveness
  • Thousand Cankers Disease is a disease complex native to the western United States that affects many Juglans and Pterocarya species, i.e. walnut and wingnut trees. It is caused by the fungus Geosmit...

  • Principal Source
  • Draft datasheet under review

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Pictures

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PictureTitleCaptionCopyright
Geosmithia morbida (thousand cankers disease: field symptoms, showing epicormic growth and dieback on a black walnut tree (Juglans nigra). Richmond, Virginia, USA. ca. 2013.
TitleField symptoms
CaptionGeosmithia morbida (thousand cankers disease: field symptoms, showing epicormic growth and dieback on a black walnut tree (Juglans nigra). Richmond, Virginia, USA. ca. 2013.
Copyright©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease: field symptoms, showing epicormic growth and dieback on a black walnut tree (Juglans nigra). Richmond, Virginia, USA. ca. 2013.
Field symptomsGeosmithia morbida (thousand cankers disease: field symptoms, showing epicormic growth and dieback on a black walnut tree (Juglans nigra). Richmond, Virginia, USA. ca. 2013.©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing crown thinning and dieback on a black walnut tree (Juglans nigra). Both symptoms are associated with the end stage of thousand cankers disease. USA. June 2009.
TitleField symptoms
CaptionGeosmithia morbida (thousand cankers disease); field symptoms, showing crown thinning and dieback on a black walnut tree (Juglans nigra). Both symptoms are associated with the end stage of thousand cankers disease. USA. June 2009.
Copyright©Curtis Utley/CSUE/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing crown thinning and dieback on a black walnut tree (Juglans nigra). Both symptoms are associated with the end stage of thousand cankers disease. USA. June 2009.
Field symptomsGeosmithia morbida (thousand cankers disease); field symptoms, showing crown thinning and dieback on a black walnut tree (Juglans nigra). Both symptoms are associated with the end stage of thousand cankers disease. USA. June 2009.©Curtis Utley/CSUE/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing dieback and yellowing. Black walnut (Juglans nigra) in end stages. June 25, 2009, the tree was felled and removed one week later. USA. 2009.
TitleSymptoms
CaptionGeosmithia morbida (thousand cankers disease); symptoms, showing dieback and yellowing. Black walnut (Juglans nigra) in end stages. June 25, 2009, the tree was felled and removed one week later. USA. 2009.
Copyright©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing dieback and yellowing. Black walnut (Juglans nigra) in end stages. June 25, 2009, the tree was felled and removed one week later. USA. 2009.
SymptomsGeosmithia morbida (thousand cankers disease); symptoms, showing dieback and yellowing. Black walnut (Juglans nigra) in end stages. June 25, 2009, the tree was felled and removed one week later. USA. 2009.©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing recently dead black walnut tree (Juglans nigra). USA.
TitleField symptoms
CaptionGeosmithia morbida (thousand cankers disease); field symptoms, showing recently dead black walnut tree (Juglans nigra). USA.
Copyright©Curtis Utley/CSUE/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing recently dead black walnut tree (Juglans nigra). USA.
Field symptomsGeosmithia morbida (thousand cankers disease); field symptoms, showing recently dead black walnut tree (Juglans nigra). USA.©Curtis Utley/CSUE/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing epicormic growth and dieback in a black walnut (Juglans nigra). Richmond, Virginia, USA. September 2010.
TitleField symptoms
CaptionGeosmithia morbida (thousand cankers disease); field symptoms, showing epicormic growth and dieback in a black walnut (Juglans nigra). Richmond, Virginia, USA. September 2010.
Copyright©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing epicormic growth and dieback in a black walnut (Juglans nigra). Richmond, Virginia, USA. September 2010.
Field symptomsGeosmithia morbida (thousand cankers disease); field symptoms, showing epicormic growth and dieback in a black walnut (Juglans nigra). Richmond, Virginia, USA. September 2010.©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing dieback on a Little walnut (Juglans microcarpa) in the end stages of thousand cankers disease. Colorado, Larimer County, Fort Collins, USA. 2018.
TitleField symptoms
CaptionGeosmithia morbida (thousand cankers disease); field symptoms, showing dieback on a Little walnut (Juglans microcarpa) in the end stages of thousand cankers disease. Colorado, Larimer County, Fort Collins, USA. 2018.
Copyright©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing dieback on a Little walnut (Juglans microcarpa) in the end stages of thousand cankers disease. Colorado, Larimer County, Fort Collins, USA. 2018.
Field symptomsGeosmithia morbida (thousand cankers disease); field symptoms, showing dieback on a Little walnut (Juglans microcarpa) in the end stages of thousand cankers disease. Colorado, Larimer County, Fort Collins, USA. 2018.©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing beetle galleries of walnut twig beetle and cankers caused by Geosmithia morbida on a black walnut tree (Juglans nigra). Richmond, Virgiana, USA. September 2010.
TitleField symptoms
CaptionGeosmithia morbida (thousand cankers disease); field symptoms, showing beetle galleries of walnut twig beetle and cankers caused by Geosmithia morbida on a black walnut tree (Juglans nigra). Richmond, Virgiana, USA. September 2010.
Copyright©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); field symptoms, showing beetle galleries of walnut twig beetle and cankers caused by Geosmithia morbida on a black walnut tree (Juglans nigra). Richmond, Virgiana, USA. September 2010.
Field symptomsGeosmithia morbida (thousand cankers disease); field symptoms, showing beetle galleries of walnut twig beetle and cankers caused by Geosmithia morbida on a black walnut tree (Juglans nigra). Richmond, Virgiana, USA. September 2010.©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on a hybrid walnut (Juglans spp.). USA. (Laboratory setting)
TitleSymptoms
CaptionGeosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on a hybrid walnut (Juglans spp.). USA. (Laboratory setting)
Copyright©Ned Tisserat/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on a hybrid walnut (Juglans spp.). USA. (Laboratory setting)
SymptomsGeosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on a hybrid walnut (Juglans spp.). USA. (Laboratory setting)©Ned Tisserat/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on an English walnut (Juglans regia). USA. (Laboratory setting)
TitleSymptoms
CaptionGeosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on an English walnut (Juglans regia). USA. (Laboratory setting)
Copyright©Ned Tisserat/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on an English walnut (Juglans regia). USA. (Laboratory setting)
SymptomsGeosmithia morbida (thousand cankers disease); symptoms, showing canker development around walnut twig beetle (Pityophthorus juglandis) galleries on an English walnut (Juglans regia). USA. (Laboratory setting)©Ned Tisserat/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease): symptoms, showing two cankers coalescing on a black walnut branch (Juglans nigra). Richmond, Virginia, USA. June 2011.
TitleSymptoms
CaptionGeosmithia morbida (thousand cankers disease): symptoms, showing two cankers coalescing on a black walnut branch (Juglans nigra). Richmond, Virginia, USA. June 2011.
Copyright©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease): symptoms, showing two cankers coalescing on a black walnut branch (Juglans nigra). Richmond, Virginia, USA. June 2011.
SymptomsGeosmithia morbida (thousand cankers disease): symptoms, showing two cankers coalescing on a black walnut branch (Juglans nigra). Richmond, Virginia, USA. June 2011.©Mary Ann Hansen/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing branch cankers that have developed around twig beetle galleries on a black walnut tree (Juglans nigra). Geosmithia can be seen fruiting (white flecks) in the central gallery. USA. ca. 2009.
TitleSymptoms
CaptionGeosmithia morbida (thousand cankers disease); symptoms, showing branch cankers that have developed around twig beetle galleries on a black walnut tree (Juglans nigra). Geosmithia can be seen fruiting (white flecks) in the central gallery. USA. ca. 2009.
Copyright©Ned Tisserat/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing branch cankers that have developed around twig beetle galleries on a black walnut tree (Juglans nigra). Geosmithia can be seen fruiting (white flecks) in the central gallery. USA. ca. 2009.
SymptomsGeosmithia morbida (thousand cankers disease); symptoms, showing branch cankers that have developed around twig beetle galleries on a black walnut tree (Juglans nigra). Geosmithia can be seen fruiting (white flecks) in the central gallery. USA. ca. 2009.©Ned Tisserat/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); disposal of felled wood by chipping. USA. 2009.
TitleDisposal of felled wood
CaptionGeosmithia morbida (thousand cankers disease); disposal of felled wood by chipping. USA. 2009.
Copyright©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); disposal of felled wood by chipping. USA. 2009.
Disposal of felled woodGeosmithia morbida (thousand cankers disease); disposal of felled wood by chipping. USA. 2009.©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); disposal of felled wood from a black walnut (Juglans niger) by mechanical chipping. Despite this ‘aggressive’ processing of the felled timber, many adults and larvae of the walnut twig beetle (Pityophthorus juglandis) survived in the larger fragments!  USA. 2009.
TitleDisposal of felled wood
CaptionGeosmithia morbida (thousand cankers disease); disposal of felled wood from a black walnut (Juglans niger) by mechanical chipping. Despite this ‘aggressive’ processing of the felled timber, many adults and larvae of the walnut twig beetle (Pityophthorus juglandis) survived in the larger fragments! USA. 2009.
Copyright©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); disposal of felled wood from a black walnut (Juglans niger) by mechanical chipping. Despite this ‘aggressive’ processing of the felled timber, many adults and larvae of the walnut twig beetle (Pityophthorus juglandis) survived in the larger fragments!  USA. 2009.
Disposal of felled woodGeosmithia morbida (thousand cankers disease); disposal of felled wood from a black walnut (Juglans niger) by mechanical chipping. Despite this ‘aggressive’ processing of the felled timber, many adults and larvae of the walnut twig beetle (Pityophthorus juglandis) survived in the larger fragments! USA. 2009.©Whitney Cranshaw/Colorado State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); The disease does not harm the wood quality, so there is a great risk of spread by movement of beetle-infested timber to new locations, e.g. for firewood, wood-turning, etc.  USA. September 2011.
TitleFelled wood
CaptionGeosmithia morbida (thousand cankers disease); The disease does not harm the wood quality, so there is a great risk of spread by movement of beetle-infested timber to new locations, e.g. for firewood, wood-turning, etc. USA. September 2011.
Copyright©Elizabeth Bush/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); The disease does not harm the wood quality, so there is a great risk of spread by movement of beetle-infested timber to new locations, e.g. for firewood, wood-turning, etc.  USA. September 2011.
Felled woodGeosmithia morbida (thousand cankers disease); The disease does not harm the wood quality, so there is a great risk of spread by movement of beetle-infested timber to new locations, e.g. for firewood, wood-turning, etc. USA. September 2011.©Elizabeth Bush/Virginia Polytechnic Institute & State University/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing a canker produced ca.5 weeks after introduction of Geosmithia (isolate 12-181) into a Southern California walnut seedling (Juglans californica). Sporulation of the fungus is occuring and visible at the edges of the wound. USA. ca. 2009. (Laboratory setting).
TitleSymptoms
CaptionGeosmithia morbida (thousand cankers disease); symptoms, showing a canker produced ca.5 weeks after introduction of Geosmithia (isolate 12-181) into a Southern California walnut seedling (Juglans californica). Sporulation of the fungus is occuring and visible at the edges of the wound. USA. ca. 2009. (Laboratory setting).
Copyright©Curtis Utley/CSUE/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); symptoms, showing a canker produced ca.5 weeks after introduction of Geosmithia (isolate 12-181) into a Southern California walnut seedling (Juglans californica). Sporulation of the fungus is occuring and visible at the edges of the wound. USA. ca. 2009. (Laboratory setting).
SymptomsGeosmithia morbida (thousand cankers disease); symptoms, showing a canker produced ca.5 weeks after introduction of Geosmithia (isolate 12-181) into a Southern California walnut seedling (Juglans californica). Sporulation of the fungus is occuring and visible at the edges of the wound. USA. ca. 2009. (Laboratory setting).©Curtis Utley/CSUE/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); asexual spore, showing conidia, cultured on a potato dextrose agar (Fungal Non-selective Media PDA). Laboratory conditions. USA.
TitleAsexual spore
CaptionGeosmithia morbida (thousand cankers disease); asexual spore, showing conidia, cultured on a potato dextrose agar (Fungal Non-selective Media PDA). Laboratory conditions. USA.
Copyright©Alan Windham/University of Tennessee/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); asexual spore, showing conidia, cultured on a potato dextrose agar (Fungal Non-selective Media PDA). Laboratory conditions. USA.
Asexual sporeGeosmithia morbida (thousand cankers disease); asexual spore, showing conidia, cultured on a potato dextrose agar (Fungal Non-selective Media PDA). Laboratory conditions. USA.©Alan Windham/University of Tennessee/Bugwood.org - CC BY 3.0 US
Geosmithia morbida (thousand cankers disease); lateral view of the disease vector, the walnut twig beetle (Pityophthorus juglandis). Adult male. Museum set specimen. USA.
TitleThe disease vector
CaptionGeosmithia morbida (thousand cankers disease); lateral view of the disease vector, the walnut twig beetle (Pityophthorus juglandis). Adult male. Museum set specimen. USA.
Copyright©Steven Valley/Oregon Department of Agriculture/Bugwood.org - CC BY-SA NC 3.0 US
Geosmithia morbida (thousand cankers disease); lateral view of the disease vector, the walnut twig beetle (Pityophthorus juglandis). Adult male. Museum set specimen. USA.
The disease vectorGeosmithia morbida (thousand cankers disease); lateral view of the disease vector, the walnut twig beetle (Pityophthorus juglandis). Adult male. Museum set specimen. USA.©Steven Valley/Oregon Department of Agriculture/Bugwood.org - CC BY-SA NC 3.0 US

Identity

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Preferred Scientific Name

  • Geosmithia morbida M. Kolařík, E. Freeland, C. Utley & Tisserat

Preferred Common Name

  • thousand cankers disease

International Common Names

  • English: TCD

Summary of Invasiveness

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Thousand Cankers Disease is a disease complex native to the western United States that affects many Juglans and Pterocarya species, i.e. walnut and wingnut trees. It is caused by the fungus Geosmithia morbida, which is vectored by the walnut twig beetle (Pityophthorus juglandis), and possibly by other insects. The beetle carries fungal spores that are introduced into the tree during gallery construction, and the fungus then causes cankers in the inner bark that disrupt the flow of nutrients throughout the tree, often leading to its death. In recent years the disease has been reported in several eastern states, and also in Italy. Long-distance spread is thought to be a result of the movement of infected and infested wood.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Fungi
  •         Phylum: Ascomycota
  •             Subphylum: Pezizomycotina
  •                 Class: Sordariomycetes
  •                     Subclass: Hypocreomycetidae
  •                         Order: Hypocreales
  •                             Genus: Geosmithia
  •                                 Species: Geosmithia morbida

Description

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The fungus was first described in 2011 by Kolařík et al. (2011). Only the asexual stage has been identified.

Culture

The colony is formed of hyaline mycelia or from yeast-like growth which arises from conidia suspensions. Colonies grown on malt extract agar (MEA) are yellowish to ochre but can also be light brown. Culture morphology is highly lobate with low plane growth. Colonies grown on Czapek year agar (CYA) media have slightly lobate margins, with low plane growth. Colony colour can range from ochre to light brown to darker brown. 

Conidiophore

Conidiophores are verrucose and penicillate with the stipe ranging from 20-200 x 2.5-3 µm in length. The peg foot consists of curved and atypical branched cells or several inflated globose cells. The penicillus ranges from 30-60 µm in size, and can be terverticillate or quaterverticillate, and symmetric or asymmetric. The size of the rami (first branch) ranges from 15-35 x 2-3 µm, and that of the metulae (last branch) from 9-11 x 2-2.5 µm. Phialides range in size from 8-15 x 2.5 µm and there are 3-6 per cluster.

Conidia

Conidia are cylindrical to ellipsoid, ranging from 4.5-6 x 2 µm in size. They are narrow and can persist in chains up to 200 µm long. These chains tangle, forming a compact crust.

Distribution

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Geosmithia morbida has been found in many western states of the USA, from Washington State to New Mexico; although it has been found in several eastern states, there are many northern and eastern states where it has not yet been found in. In Europe, thousand cankers disease has only been found in Italy.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 23 Apr 2020
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Europe

ItalyPresent, LocalizedIntroduced2013InvasiveCABI and EPPO (2014); Montecchio and Faccoli (2014); EPPO (2020)
LithuaniaAbsent, Confirmed absent by surveyEPPO (2020)
NetherlandsAbsentEPPO (2020)
SloveniaAbsent, Confirmed absent by surveyEPPO (2020)

North America

United StatesPresent, LocalizedInvasiveKolařík et al. (2011); CABI and EPPO (2014); EPPO (2020)
-ArizonaPresent, WidespreadKolařík et al. (2011); CABI and EPPO (2014); EPPO (2020)
-CaliforniaPresent2008InvasiveKolařík et al. (2011); CABI and EPPO (2014); Yaghmour et al. (2014); EPPO (2020)Probably present before 2008. Confirmed from Los Angeles County in the south to Sutter County in the north.
-ColoradoPresent, WidespreadKolařík et al. (2011); CABI and EPPO (2014); EPPO (2020)
-IdahoPresent, WidespreadKolařík et al. (2011); CABI and EPPO (2014); EPPO (2020)
-IllinoisAbsent, Unconfirmed presence record(s)EPPO (2020)
-IndianaPresent, LocalizedInvasiveJuzwik et al. (2015); EPPO (2020)Found on the weevil Stenomimus pallidus
-MarylandPresent, Localized2014Maryland Department of Agriculture (2019); EPPO (2020)
-MinnesotaAbsent, Unconfirmed presence record(s)EPPO (2020)
-NevadaPresent, LocalizedCABI and EPPO (2014); EPPO (2020)
-New MexicoPresent, WidespreadTisserat et al. (2011); CABI and EPPO (2014); EPPO (2020)
-North CarolinaPresent, Localized2014InvasiveCABI and EPPO (2014); Hadziabdic et al. (2014); EPPO (2020)
-OhioPresent, LocalizedInvasiveCABI and EPPO (2014); EPPO (2020)
-OregonPresent, WidespreadKolařík et al. (2011); CABI and EPPO (2014); EPPO (2020)
-PennsylvaniaPresent, LocalizedCABI and EPPO (2014); EPPO (2020)
-TennesseePresent, LocalizedInvasiveGrant et al. (2011); CABI and EPPO (2014); EPPO (2020)
-UtahPresent, WidespreadKolařík et al. (2011); CABI and EPPO (2014); EPPO (2020)
-VirginiaPresentEPPO (2020); CABI and EPPO (2014)
-WashingtonPresent, WidespreadKolařík et al. (2011); CABI and EPPO (2014); EPPO (2020)

History of Introduction and Spread

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Thousand Cankers disease was first reported in western states of the USA in the 1990s, but it was not officially documented until 2009 (Tisserat et al., 2009). The vector, the walnut twig beetle Pityophthorus juglandis, was known to occur in southwestern states including Arizona, New Mexico and Nevada, and in Mexico. More recently, the disease, the fungus and the vector have been found in some eastern states and in Italy. Spread to Italy is thought to have been by movement of infected or infested timber (Montecchio and Faccoli, 2014).

Introductions

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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Italy USA 2014 Timber trade (pathway cause) No No Montecchio and Faccoli (2014); Moricca et al. (2019)

Habitat

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Thousand Cankers Disease affects urban, forest and planted settings (in many areas in the western US, walnut is used as a street tree for urban areas). In the eastern USA too, walnut is a forest and planted tree, and TCD is beginning to affect these areas as well. 

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
Terrestrial – ManagedManaged forests, plantations and orchards Present, no further details Harmful (pest or invasive)
Urban / peri-urban areas Present, no further details Harmful (pest or invasive)
Terrestrial ‑ Natural / Semi-naturalNatural forests Present, no further details Harmful (pest or invasive)
Riverbanks Present, no further details Harmful (pest or invasive)

Hosts/Species Affected

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Geosmithia morbida affects trees in the genera Juglans (walnuts) and Pterocarya (wingnuts).

Host Plants and Other Plants Affected

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Growth Stages

Top of page Vegetative growing stage

Symptoms

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Symptoms of Thousand Cankers Disease include yellowing and thinning of branches, resulting in branch dieback. As the disease progresses, overall thinning of crowns occurs, and death of trees can occur over the course of 2-3 years. With closer observation, exit holes of the walnut twig beetle Pityophthorus juglandis can be observed, and commonly cankers (darkened lesions) are present under the bark layer in the phloem where exit holes are observed (Tisserat et al., 2009). Cankers are usually small and circular at initial infection, but usually grow into oblong shapes around insect galleries. At advanced stages of the disease, basal sprouts will often be developed, but die within one to two years (Tisserat et al., 2009).

Mortality can occur either quickly or more slowly depending on the level of infestation and infection. It is assumed that Geosmithia morbida causes an annual canker and therefore that each site that is infested with Pityophthorus juglandis forms a canker, with death usually occurring from the coalescing of many cankers (Utley et al., 2013).

List of Symptoms/Signs

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SignLife StagesType
Growing point / wilt
Leaves / abnormal colours
Leaves / yellowed or dead
Stems / canker on woody stem
Stems / dieback
Stems / discoloration
Stems / discoloration of bark
Stems / internal discoloration
Stems / internal feeding
Stems / mycelium present
Stems / visible frass
Stems / wilt
Whole plant / discoloration
Whole plant / wilt

Biology and Ecology

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Genetics

Geosmithia morbida has a smaller genome than closely related non-pathogenic species. Genome reduction may be an important adaptive force for specialization to occupy a specific niche, such as beetle-vectored pathogens (Schuelke et al., 2017). High haploid genetic diversity has been described in seven populations of G. morbida identified across the United States (Hadziabdic et al., 2014a).

Reproductive Biology

No sexual stage has been identified. Asexual reproduction is by conidia, produced in conidiophores whose morphology is described in the Description section.

Associations

Geosmithia morbida has been observed with several species of Fusarium (Sitz et al., 2017Montecchio et al., 2015).

Environmental Requirements

Walnut trees (Juglans spp.) in any setting (urban areas, nut production areas or natural forest stands) are at risk from Geosmithia morbida. Typically, Pityophthorus juglandis beetles infest both healthy and stressed walnut. Well-watered trees can be diseased, but it has been suggested that walnuts under drought stress are more susceptible to disease development, and faster progression of disease development is observed.

Climate

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ClimateStatusDescriptionRemark
As - Tropical savanna climate with dry summer Preferred < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
BS - Steppe climate Preferred > 430mm and < 860mm annual precipitation
BW - Desert climate Preferred < 430mm annual precipitation
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cw - Warm temperate climate with dry winter Preferred Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters)
Cf - Warm temperate climate, wet all year Tolerated Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year
Ds - Continental climate with dry summer Preferred Continental climate with dry summer (Warm average temp. > 10°C, coldest month < 0°C, dry summers)
Dw - Continental climate with dry winter Preferred Continental climate with dry winter (Warm average temp. > 10°C, coldest month < 0°C, dry winters)
Df - Continental climate, wet all year Tolerated Continental climate, wet all year (Warm average temp. > 10°C, coldest month < 0°C, wet all year)

Air Temperature

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Parameter Lower limit Upper limit
Mean annual temperature (ºC) 12

Notes on Natural Enemies

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Two natural enemies of the vector, the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana, have been evaluated as biocontrol agents, with some success (Castrillo et al., 2017).

Means of Movement and Dispersal

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Vector Transmission (Biotic)

The primary vector of Geosmithia morbida has been identified as the walnut twig beetle, Pityophthorus juglandis. The weevil Stenomimus pallidus (Boheman) has been found to carry G. morbida in Indiana (Juzwik et al., 2015) and Ohio (Warmund and Sambeek, 2014). Several other insect species have been shown to be associated with walnut trees and so may also be able to vector the pathogen (Daniels et al., 2016).

Accidental Introduction

As well as movement of the vectors, it is likely that Geosmithia morbida is spread though movement of wood, including firewood, pallets and other packing materials.

Pathway Causes

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CauseNotesLong DistanceLocalReferences
HitchhikerWalnut wood or wood products Yes Yes
Timber trade Yes

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Containers and packaging - wood Yes Yes
Host and vector organismsPityophthorus juglandis, in some cases Stenomimus pallidus, and possibly other insects Yes
Plants or parts of plantsWalnut wood Yes Yes

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Wood spores Yes Pest or symptoms usually visible to the naked eye
Plant parts not known to carry the pest in trade/transport
Bark
Bulbs/Tubers/Corms/Rhizomes
Flowers/Inflorescences/Cones/Calyx
Fruits (inc. pods)
Growing medium accompanying plants
Leaves
Roots
Seedlings/Micropropagated plants
Stems (above ground)/Shoots/Trunks/Branches
True seeds (inc. grain)

Wood Packaging

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Wood Packaging liable to carry the pest in trade/transportTimber typeUsed as packing
Solid wood packing material with bark Walnut (Juglans spp.) Yes
Solid wood packing material without bark Walnut (Juglans spp.) Yes

Vectors and Intermediate Hosts

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VectorSourceReferenceGroupDistribution
Pityophthorus juglandisEPPO, 2014. InsectUSA
Stenomimus pallidusJuzwik et al., 2015. InsectOhio

Impact Summary

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CategoryImpact
Economic/livelihood Negative
Environment (generally) Negative

Economic Impact

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There is a high risk of disease caused by Geosmithia morbida in commercial walnut production, for example in California and the American Southwest; impacts on the timber trade are likely; and the social impacts where walnut is used for shade, aesthetics, and wildlife forage in urban areas also have an economic element. In Kansas, the potential economic losses due to Thousand Cankers Disease, if it were to be introduced there, have been estimated at 160 million dollars annually (Treiman et al. 2010). Daniels et al. (2016) also discuss economic impacts. Little has been documented about the potential economic impacts in Europe.  

Environmental Impact

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Impact on Habitats

Where Thousand Cankers Disease has been present for some time, as in areas of Colorado and California, the impact has been high, with most trees succumbing to the disease within 1 to 3 years after infection (Tisserat et al., 2009; Daniels et al., 2016). Further spread could have significant impacts on forests, reducing species richness and the availability of forage for wildlife (Daniels et al., 2016).

Impact on Biodiversity

The loss of Juglans nigra in forests would impact species richness (Daniels et al., 2016).

Social Impact

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Walnut trees are used for shade and aesthetics (Treiman et al. 2010; Daniels et al., 2016), so if many of them die this causes noticeable social impact. Economic impacts can also have social effects.

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Has a broad native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Is a habitat generalist
  • Highly mobile locally
  • Has propagules that can remain viable for more than one year
  • Reproduces asexually
  • Has high genetic variability
Impact outcomes
  • Damaged ecosystem services
  • Ecosystem change/ habitat alteration
  • Host damage
  • Negatively impacts agriculture
  • Negatively impacts forestry
  • Negatively impacts livelihoods
  • Reduced amenity values
  • Reduced native biodiversity
  • Threat to/ loss of native species
  • Negatively impacts trade/international relations
Impact mechanisms
  • Interaction with other invasive species
  • Pathogenic
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult to identify/detect as a commodity contaminant
  • Difficult to identify/detect in the field
  • Difficult/costly to control

Diagnosis

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A molecular protocol for the detection of Geosmithia morbida and its vector Pityophthorus juglandis was recently developed, based on species-specific microsatellite DNA markers; it was found to have a high degree of sensitivity and specificity for the detection of the organisms (Oren et al., 2018).

Detection and Inspection

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The macroscopic symptoms can be observed. Yellowing and dieback commonly move into larger portions of the crown until the whole crown is impacted. With closer observation, beetle exit holes can be observed. Beetle galleries and darkened wood around the galleries are observed upon inspection of the phloem and cambium (Cranshaw and Tisserat, 2010; Tisserat et al., 2009).

For detecting the vector beetles, flight trapping has been conducted using funnel traps baited with the male-produced aggregation pheromone (Seybold et al., 2012). These traps can be deployed from March to November when the beetles are active, and checked every 7-10 days (USDA, 2014).

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Prevention

SPS measures

Few controls have been documented against Geosmithia morbida. The most effective control thus far is the limitation of its spread, typically by limiting the movement of the Pityophthorus juglandis vector. Quarantines that limit the spread of unprocessed walnut wood into new areas have shown some success. Quarantines have been issued in several US states, including Kansas, Missouri, Oklahoma, Iowa, Minnesota, Michigan, Wisconsin, Indiana, West Virginia and Maryland.

Containment/zoning

Containment measures are in place in Veneto, Italy (Regione del Veneto, 2015).

Control

Once a tree is infested with Pityophthorus juglandis or infected with Geosmithia morbida, no effective controls are known. Therefore the best management action for already infected trees is to fell and then chip or burn them.

Physical/mechanical control

Heat treatment of wood at at least 60°C for at least 30 minutes has been found to be 100% effective at killing Pityophthorus juglandis. Chipping wood was 90% effective at controlling it (Sitz et al., 2013).

Movement control

The most effective control thus far identified is limiting the spread of the disease, typically by limiting the spread of the vector, for example by quarantine measures that limit the spread of unprocessed walnut wood.

Biological control

Castrillo et al. (2017) evaluated the use of the entomopathogenic fungi Metarhizium brunneum and Beauveria bassiana as biocontrol agents against the vector beetles. This study found that brood production was reduced when adult beetles were exposed to both pathogens.

Chemical control

Studies examining efficacy of insecticides against the beetles have resulted in limited control strategies. Injections with insecticides such as permethrin, bifenthrin and carbaryl should limit Pityophthorus juglandis infestations of trees.

Host resistance (incl. vaccination)

Host resistance has not yet been identified.

References

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CABI/EPPO, 2014. Geosmithia morbida. [Distribution map]. Distribution Maps of Plant Diseases, No.October. Wallingford, UK: CABI, Map 1158 (Edition 1)

Castrillo, L. A., Mayfield, A. E., Griggs, M. H., Camp, R., Mudder, B., Taylor, A., Vandenberg, J. D., 2017. Mortality and reduced brood production in walnut twig beetles, Pityophthorus juglandis (Coleoptera: Curculionidae), following exposure to commercial strains of entomopathogenic fungi Beauveria bassiana and Metarhizium brunneum. Biological Control, 114, 79-86. https://www.sciencedirect.com/science/article/pii/S1049964417301706 doi: 10.1016/j.biocontrol.2017.08.007

Cranshaw W, Tisserat N, 2010. Thousand cankers disease: a recently recognized threat to North American black walnut. Arborist News, 19(1), 52-56. http://html5.epaperflip.com/Viewer.aspx?docid=921593b0-e018-4be2-97b6-a2bd00e8331d

Daniels DA, Nix KA, Wadl PA, Vito LM, Wiggins GJ, Windham MT, Ownley BH, Lambdin PL, Grant JF, Merten P, Klingman WE, Hadziabdic D, 2016. Thousand Cankers Disease Complex: A Forest Health Issue that Threatens Juglans Species across the U.S. Forests, 7(11), 260. https://doi.org/10.3390/f7110260

EPPO, 2014. PQR database. Paris, France: European and Mediterranean Plant Protection Organization. http://www.eppo.int/DATABASES/pqr/pqr.htm

EPPO, 2019. EPPO Global database. In: EPPO Global database Paris, France: EPPO.https://gd.eppo.int/

Grant JF, Windham MT, Haun WG, Wiggins GJ, Lambdin PL, 2011. Initial assessment of thousand cankers disease on black walnut, Juglans nigra, in Eastern Tennessee. Forests, 2(3):741-748. http://www.mdpi.com/1999-4907/2/3/741/

Hadziabdic D, Vito LM, Windham MT, Pscheidt JW, Trigiano RN, Kolarik M, 2014. Genetic differentiation and spatial structure of Geosmithia morbida, the causal agent of thousand cankers disease in black walnut (Juglans nigra). Current Genetics, 60(2):75-87. http://link.springer.com/article/10.1007%2Fs00294-013-0414-x

Hadziabdic D, Windham M, Baird R, Vito L, Cheng Q, Grant J, Lambdin P, Wiggins G, Windham A, Merten P, Taylor G, 2014. First report of Geosmithia morbida in North Carolina: the pathogen involved in thousand cankers disease of black walnut. Plant Disease, 98(7):992-993. http://apsjournals.apsnet.org/loi/pdis

Juzwik J, Banik MT, Reed SE, English JT, Ginzel MD, 2015. Geosmithia morbida found on weevil species Stenomimus pallidus in Indiana. Plant Health Progress, No.January:PHP-RS-14-0030. http://www.plantmanagementnetwork.org/php/elements/sum2.aspx?id=10798

Kolařík, M., Freeland, E., Utley, C., Tisserat, N., 2011. Geosmithia morbida sp. nov., a new phytopathogenic species living in symbiosis with the walnut twig beetle (Pityophthorus juglandis) on Juglans in USA. Mycologia, 103(2), 325-332. doi: 10.3852/10-124

Maryland Department of Agriculture, 2019. Walnut Twig Beetle and Thousand Cankers Disease. Annapolis, Maryland, USA: Maryland Department of Agriculture.https://mda.maryland.gov/plants-pests/Pages/tcd.aspx

Montecchio L, Faccoli M, 2014. First record of thousand cankers disease Geosmithia morbida and walnut twig beetle Pityophthorus juglandis on Juglans nigra in Europe. Plant Disease, 98(5):696. http://apsjournals.apsnet.org/loi/pdis

Montecchio, L., Faccoli, M., Short, D. P. G., Fanchin, G., Geiser, D. M., Kasson, M. T., 2015. First report of Fusarium solani phylogenetic species 25 associated with early stages of thousand cankers disease on Juglans nigra and Juglans regia in Italy. Plant Disease, 99(8), 1183. http://apsjournals.apsnet.org/loi/pdis doi: 10.1094/PDIS-01-15-0103-PDN

Moricca, S., Bracalini, M., Benigno, A., Ginetti, B., Pelleri, F., Panzavolta, T., 2019. Thousand cankers disease caused by Geosmithia morbida and its insect vector Pityophthorus juglandis first reported on Juglans nigra in Tuscany, Central Italy. Plant Disease, 103(2), 369. http://apsjournals.apsnet.org/loi/pdis doi: 10.1094/PDIS-07-18-1256-PDN

Oren, E., Klingeman, W., Gazis, R., Moulton, J., Lambdin, P., Coggeshall, M., Hulcr, J., Seybold, S. J., Hadziabdic, D., 2018. A novel molecular toolkit for rapid detection of the pathogen and primary vector of Thousand Cankers Disease. PLoS ONE, 13(1), e0185087. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185087 doi: 10.1371/journal.pone.0185087

Regione del Veneto, 2015. (Misure fitosanitarie di controllo di Geosmithia morbida in Regione Veneto. Aggiornamento della zona delimitata). Venice, Italy: Regione del Veneto.2 pp. https://bur.regione.veneto.it/BurvServices/Pubblica/DettaglioDecreto.aspx?id=291936 (Decreto del Dirigente del Settore Servizi Fitosanitari n. 8 del 06 Febbraio 2015)

Schuelke, T. A., Wu GuangXi, Westbrook, A., Woeste, K., Plachetzki, D. C., Broders, K., MacManes, M. D., 2017. Comparative genomics of pathogenic and nonpathogenic beetle-vectored fungi in the genus Geosmithia. Genome Biology and Evolution, 9(12), 3312-3327. https://academic.oup.com/gbe/article/9/12/3312/4653752 doi: 10.1093/gbe/evx242

Seybold, S. J., King, J. A., Harris, D. R., Nelson, L. J., Hamud, S. M., Chen, Y. G., 2012. Diurnal flight response of the walnut twig beetle, Pityophthoms juglandis Blackman (Coleoptera: Scolytidae), to pheromone-baited traps in two northern California walnut habitats. Pan-Pacific Entomologist, 88(2), 231-247.

Sitz R, Luna E, Tisserat N, Cranshaw W, 2013. Sanitation measures to control Walnut Twig Beetle (Pityophthorus juglandis) emergence from felled black walnut logs. [Entomological Society of America Annual Meeting 2013]

Sitz, R. A., Luna, E. K., Caballero, J. I., Tisserat, N. A., Cranshaw, W. S., Stewart, J. E., 2017. Virulence of genetically distinct Geosmithia morbida isolates to black walnut and their response to coinoculation with Fusarium solani. Plant Disease, 101(1), 116-120. http://apsjournals.apsnet.org/loi/pdis doi: 10.1094/PDIS-04-16-0535-RE

Tisserat N, Cranshaw W, Putnam ML, Pscheidt J, Leslie CA, Murray M, Hoffman J, Barkley Y, Alexander K, Seybold SJ, 2011. Thousand cankers disease is widespread in black walnut in the western United States. Plant Health Progress, No.June:PHP-2011-0630-01-BR. http://www.plantmanagementnetwork.org/php/elements/sum.aspx?id=9480&photo=5359

Tisserat, N., Cranshaw, W., Leatherman, D., Utley, C., Alexander, K., 2009. Black walnut mortality in Colorado caused by the walnut twig beetle and Thousand Cankers Disease. Plant Health Progress, (No.August), PHP-2009-0811-01-RS. http://www.plantmanagementnetwork.org/php/elements/sum.aspx?id=8033&photo=4600

Treiman T, Atchison B, McDonnell T, Barden C, Moser WK, 2010. Economic loss associated with the introduction of thousand cankers disease of black walnut in Kansas. Kansas, USA: Kansas Forest Service and Kansas State University.4 pp. https://www.kansasforests.org/forest_health/health_docs/Econ%20Loss%20KS.pdf

USDA, 2014. Thousand Cankers Disease Survey Guidelines for 2014. USA: United States Department of Agriculture: Forest Service (FS) and Plant Protection and Quarantine (PPQ).

Utley, C., Tivonne Nguyen, Roubtsova, T., Coggeshall, M., Ford, T. M., Grauke, L. J., Graves, A. D., Leslie, C. A., McKenna, J., Woeste, K., Yaghmour, M. A., Cranshaw, W., Seybold, S. J., Bostock, R. M., Tisserat, N., 2013. Susceptibility of walnut and hickory species to Geosmithia morbida. Plant Disease, 97(5), 601-607. http://apsjournals.apsnet.org/loi/pdis doi: 10.1094/PDIS-07-12-0636-RE

Warmund M, Sambeek J van, 2014. Thousand cankers disease: Geosmithia morbida spores isolated from a weevil. Missouri Environment & Garden, 20(6), 3. https://www.fs.usda.gov/treesearch/pubs/46063

Yaghmour, M. A., Nguyen, T. L., Roubtsova, T. V., Hasey, J. K., Fichtner, E. J., DeBuse, C., Seybold, S. J., Bostock, R. M., 2014. First report of Geosmithia morbida on English walnut and its paradox rootstock in California. Plant Disease, 98(10), 1441. http://apsjournals.apsnet.org/loi/pdis doi: 10.1094/PDIS-06-14-0569-PDN

Distribution References

CABI, EPPO, 2014. Geosmithia morbida. [Distribution map]. In: Distribution Maps of Plant Diseases, Wallingford, UK: CABI. Map 1158 (Edition 1).

CABI, Undated. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

EPPO, 2020. EPPO Global database. In: EPPO Global database, Paris, France: EPPO.

Grant J F, Windham M T, Haun W G, Wiggins G J, Lambdin P L, 2011. Initial assessment of thousand cankers disease on black walnut, Juglans nigra, in Eastern Tennessee. Forests. 2 (3), 741-748. http://www.mdpi.com/1999-4907/2/3/741/ DOI:10.3390/f2030741

Hadziabdic D, Windham M, Baird R, Vito L, Cheng Q, Grant J, Lambdin P, Wiggins G, Windham A, Merten P, Taylor G, 2014. First report of Geosmithia morbida in North Carolina: the pathogen involved in thousand cankers disease of black walnut. Plant Disease. 98 (7), 992-993. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-06-13-0630-PDN

Juzwik J, Banik M T, Reed S E, English J T, Ginzel M D, 2015. Geosmithia morbida found on weevil species Stenomimus pallidus in Indiana. Plant Health Progress. PHP-RS-14-0030. http://www.plantmanagementnetwork.org/php/elements/sum2.aspx?id=10798

Kolařík M, Freeland E, Utley C, Tisserat N, 2011. Geosmithia morbida sp. nov., a new phytopathogenic species living in symbiosis with the walnut twig beetle (Pityophthorus juglandis) on Juglans in USA. Mycologia. 103 (2), 325-332. DOI:10.3852/10-124

Maryland Department of Agriculture, 2019. Walnut Twig Beetle and Thousand Cankers Disease. Annapolis, Maryland, USA: Maryland Department of Agriculture. https://mda.maryland.gov/plants-pests/Pages/tcd.aspx

Montecchio L, Faccoli M, 2014. First record of thousand cankers disease Geosmithia morbida and walnut twig beetle Pityophthorus juglandis on Juglans nigra in Europe. Plant Disease. 98 (5), 696. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-10-13-1027-PDN

Tisserat N, Cranshaw W, Putnam M L, Pscheidt J, Leslie C A, Murray M, Hoffman J, Barkley Y, Alexander K, Seybold S J, 2011. Thousand cankers disease is widespread in black walnut in the western United States. Plant Health Progress. PHP-2011-0630-01-BR. http://www.plantmanagementnetwork.org/php/elements/sum.aspx?id=9480&photo=5359

Yaghmour M A, Nguyen T L, Roubtsova T V, Hasey J K, Fichtner E J, DeBuse C, Seybold S J, Bostock R M, 2014. First report of Geosmithia morbida on English walnut and its paradox rootstock in California. Plant Disease. 98 (10), 1441. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-06-14-0569-PDN

Links to Websites

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WebsiteURLComment
Thousand cankers diseasehttp://thousandcankers.com

Organizations

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USA: United State Department of Agriculture (USDA), https://www.usda.gov/

Principal Source

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Draft datasheet under review

Contributors

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04/03/19 Original text by:

Jane Stewart, Colorado State University, Fort Collins, Colorado, USA

Distribution Maps

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