Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Discula destructiva
(anthracnose of dogwood)

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Datasheet

Discula destructiva (anthracnose of dogwood)

Summary

  • Last modified
  • 15 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Preferred Scientific Name
  • Discula destructiva
  • Preferred Common Name
  • anthracnose of dogwood
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Fungi
  •     Phylum: Ascomycota
  •       Subphylum: Pezizomycotina
  •         Class: Sordariomycetes
  • Summary of Invasiveness
  • Since there is a very strong presumption that D. destructiva is alien to North America (Trigiano et al. 1995), this pathogen i...

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PictureTitleCaptionCopyright
Discula destructiva (Dogwood anthracnose); foliar symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)
TitleFoliar symptoms
CaptionDiscula destructiva (Dogwood anthracnose); foliar symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)
Copyright©John Hartman/University of Kentucky/Bugwood.org - CC BY-NC 3.0 US
Discula destructiva (Dogwood anthracnose); foliar symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)
Foliar symptomsDiscula destructiva (Dogwood anthracnose); foliar symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)©John Hartman/University of Kentucky/Bugwood.org - CC BY-NC 3.0 US
Discula destructiva (Dogwood anthracnose); floral symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)
TitleFloral symptoms
CaptionDiscula destructiva (Dogwood anthracnose); floral symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)
Copyright©Robert L. Anderson/USDA Forest Service/Bugwood.org - CC BY 3.0 US
Discula destructiva (Dogwood anthracnose); floral symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)
Floral symptomsDiscula destructiva (Dogwood anthracnose); floral symptoms of dogwood anthracnose on flowering dogwood (Cornus florida L.)©Robert L. Anderson/USDA Forest Service/Bugwood.org - CC BY 3.0 US

Identity

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Preferred Scientific Name

  • Discula destructiva Redlin 1991

Preferred Common Name

  • anthracnose of dogwood

EPPO code

  • DISCDE (Discula destructiva)

Summary of Invasiveness

Top of page Since there is a very strong presumption that D. destructiva is alien to North America (Trigiano et al. 1995), this pathogen is clearly very invasive in US deciduous forests, seriously modifying their understorey composition and biodiversity by destroying species of Cornus which form a characteristic element of this ecosystem.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Fungi
  •         Phylum: Ascomycota
  •             Subphylum: Pezizomycotina
  •                 Class: Sordariomycetes
  •                     Subclass: Sordariomycetidae
  •                         Order: Diaporthales
  •                             Family: Valsaceae
  •                                 Genus: Discula
  •                                     Species: Discula destructiva

Notes on Taxonomy and Nomenclature

Top of page No teleomorph is known, but other species of Discula have teleomorphs in the genera Apiognomonia and Gnomoniella. Zhang and Blackwell (2001) confirm from DNA sequence analyses that D. destructive has clear affinity with Diaporthales.

Description

Top of page Conidia are of the typical anthracnose type, 7-12 x 2.5-5.5 µm, hyaline, non-septate, smooth, with a truncate base and often polar guttules (Redlin, 1991; Daughtrey et al., 1996). In mass, they form a slimy, white to beige or pinkish ooze. The conidioma (acervuli) form in leaf or twig tissues, erupting through the surface often around a trichome, typically 30-135 µm diameter and rounded on the underside of leaves, or 90-340 µm long and slightly elongated on twigs. They appear dark in the tissues of overwintered twigs. The teleomorph has not been reported.

Distribution

Top of page D. destructiva was detected in 1995 in the UK on imported Cornus florida from the USA.

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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

North America

CanadaRestricted distributionCABI/EPPO, 2004; EPPO, 2014
-British ColumbiaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-OntarioRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
USAWidespreadCABI/EPPO, 2004; EPPO, 2014
-AlabamaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-CaliforniaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-ConnecticutRestricted distributionIntroduced1983Daughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-DelawareRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-District of ColumbiaRestricted distributionCABI/EPPO, 2004; EPPO, 2014
-GeorgiaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-IdahoRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-IllinoisRestricted distributionIntroduced1995Schwegman et al., 1998; CABI/EPPO, 2004; EPPO, 2014
-IndianaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-KansasRestricted distributionIntroduced1994Daughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-KentuckyRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-MarylandRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-MassachusettsRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-MichiganRestricted distributionIntroduced1993Daughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-MississippiRestricted distributionIntroduced1994Daughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-MissouriRestricted distributionCABI/EPPO, 2004; EPPO, 2014
-New HampshireRestricted distributionIntroduced1991Daughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-New JerseyRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-New YorkRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-North CarolinaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-OhioRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-OregonRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-PennsylvaniaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-Rhode IslandRestricted distributionIntroduced1992Daughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-South CarolinaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-TennesseeRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-VermontRestricted distributionCABI/EPPO, 2004; EPPO, 2014
-VirginiaRestricted distributionIntroduced1987Daughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-WashingtonRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014
-West VirginiaRestricted distributionIntroducedDaughtrey et al., 1996; CABI/EPPO, 2004; EPPO, 2014

Europe

GermanyPresent, few occurrencesIntroducedStinzing and Lang, 2003; CABI/EPPO, 2004; EPPO, 2014
ItalyRestricted distributionCABI/EPPO, 2004; EPPO, 2014
NetherlandsAbsent, confirmed by surveyEPPO, 2014
SwitzerlandRestricted distributionEPPO, 2014
UKAbsent, intercepted onlyCABI/EPPO, 2004; EPPO, 2014

History of Introduction and Spread

Top of page Dogwood anthracnose was first reported in the USA in 1978 on flowering dogwoods (Cornus florida) in north-eastern states (New York and Connecticut). It was later realized that similar symptoms had also been observed on C. nuttallii on the west coast in 1976. In both cases, the causal agent was identified as D. destructiva in 1991. The disease then spread rapidly and caused serious losses. Genetic studies have revealed a lack of diversity among isolates from the two coasts. Considering the rapid spread around points of entry (New York and Seattle) and the severity of the disease, it is supposed that D. destructiva is an introduced pathogen.

Risk of Introduction

Top of page In the USA, the further spread of D. destructiva poses a strong phytosanitary risk for native Cornus spp. grown both as ornamentals and occurring naturally in forests. Particularly in the eastern states, dogwoods have a strong emblematic value. A 10-point control programme has been developed with the support of a Dogwood Anthracnose Work Group, involving researchers, foresters, nurserymen and regulatory personnel (Daughtrey et al., 1996). Limiting interstate movement of infected host material is recommended. Though there is a general tendency for disease severity to decrease, it remains high at the southern edge where the disease is still spreading. In principle, there is also a risk for other continents where Cornus spp. occur or are grown as ornamentals, particularly Europe. The main hosts Cornus florida and C. nuttallii are not native, but are valuable amenity plants for parks and gardens. Of the two native species, Cornus mas has been found to be resistant, while the susceptibility of the much more abundant C. sanguinea is not known. However, neither wild nor cultivated species in Europe have the particular importance of the dogwoods in North America. Other species of Cornus occur through the remainder of the Palaearctic region. If only by default (as the disease was not previously known in either North America or Europe), it seems possible that D. destructiva originates in Asia, on native species whose resistance has made it inconspicuous.

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial

Hosts/Species Affected

Top of page The North American species Cornus florida (flowering dogwood) and C. nuttallii (Pacific dogwood) are particularly susceptible. Cornus kousa, C. alternifolia and C. amomum are reported as relatively resistant (Sherald et al., 1994). The European Cornus mas is considered resistant in North America (Stinzing and Lam, 2003), but there is no information for C. sanguinea. Nothing appears to be reported concerning Asian species of Cornus.

Host Plants and Other Plants Affected

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Growth Stages

Top of page Flowering stage, Seedling stage, Vegetative growing stage

Symptoms

Top of page Initial symptoms are small leaf spots with a purple margin, which then develop into large necrotic blotches. In many cases, infected mature leaves die prematurely. Sometimes, they remain attached to the stems after normal leaf fall. Infection expands from leaves to small twigs and then branches. Twig and branch dieback start in the lower crown (hence the original name of the disease 'lower branch dieback'). Numerous epicormic shoots often form at the base of the trunk or on branches. D. destructiva causes cankers which can kill the tree. The fungus can kill trees of all sizes, but is more severe on young seedlings and understorey forest dogwoods.

List of Symptoms/Signs

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SignLife StagesType
Leaves / abnormal colours
Leaves / necrotic areas
Leaves / yellowed or dead
Stems / canker on woody stem
Stems / dieback
Stems / witches broom
Whole plant / plant dead; dieback

Biology and Ecology

Top of page D. destructiva persists as cankers on the trunks and branches of its hosts, or in twigs or dead leaves carrying conidiomata. Conidia formed in conidiomata (acervuli) on cankers are rain-splashed to newly expanded leaves in spring, which they infect under humid conditions. Lesions on the leaves may remain as small spots, form larger blotches, or blight the whole leaf, spreading into the petiole and infecting the shoot. At flowering, bracts are also infected. Conidia may infect the current season's shoots directly, forming small cankers which are usually rapidly delimited by callus tissue. However, shoots infected from blighted leaves become more severely cankered and die back. This shoot dieback often results in the development of epicormic shoots on the branches and trunk, which become infected in turn. Heavily infected young trees may be killed but, if conditions become less favourable for disease development in subsequent seasons, branch and trunk cankers may be contained and the tree recovers.

In culture, optimal growth is at 21-24°C, no growth occurs at 27°C. Infection is favoured by cool, wet spring and autumn, but can occur throughout the growing season. Low light intensity and drought stress are predisposing factors (Erbaugh et al., 1995).

See Daughtrey and Hibben (1994) and Daughtrey et al. (1996).

Notes on Natural Enemies

Top of page dsRNA has been detected in isolates of D. destructiva (i.e. a fungal virus; Yao and Tainter, 1996). There is a possibility that this could be associated with a decrease in virulence. By analogy with the control of chestnut blight (Endothia parasitica [Cryphonectria parasitica]), it is conceivable that hypovirulent strains could be used in disease control.

Means of Movement and Dispersal

Top of page Short distance dispersal of conidia probably occurs via rainsplash. Field dispersal by coccinellids (Hippodamia convergens) has been observed. Birds and other animals (Holt et al., 1998) may possibly carry the pathogen, even in fruits or seeds, which have been shown to contain the pathogen (Britton et al., 1993). Trade of infected plants ensures long distance dispersal.

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Leaves hyphae; spores Yes Pest or symptoms not visible to the naked eye but usually visible under light microscope
Stems (above ground)/Shoots/Trunks/Branches hyphae; spores Yes Pest or symptoms not visible to the naked eye but usually visible under light microscope
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
Roots
Seedlings/Micropropagated plants
True seeds (inc. grain)
Wood

Wood Packaging

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Wood Packaging not known to carry the pest in trade/transport
Loose wood packing material
Non-wood
Processed or treated wood
Solid wood packing material with bark
Solid wood packing material without bark

Impact Summary

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CategoryImpact
Animal/plant collections None
Animal/plant products None
Biodiversity (generally) Negative
Crop production None
Environment (generally) Negative
Fisheries / aquaculture None
Forestry production None
Human health None
Livestock production None
Native fauna Negative
Native flora Negative
Rare/protected species None
Tourism None
Trade/international relations None
Transport/travel None

Impact

Top of page In the USA, in addition to the environmental impacts, consecutive years of infection have killed many ornamental Cornus spp. in parks and gardens. The disease now presents a considerable problem for nursery production of healthy plants.

Environmental Impact

Top of page In the USA, a significant proportion of woodland dogwood populations has been killed. In 1984, a survey in a national park in Maryland showed, in a severe case, that only 3% of dogwoods were free from anthracnose and 33% were dead. In 1988, 89% trees were dead and all remaining trees were infected. In the short term, at least, the disease is causing a clear change in forest understorey composition in eastern forests (Jenkins and White, 2002), with a substantial effect on their amenity value for the public. Nevertheless, the impact of the disease varies with site and past history (Chellemi et al., 1992; McEwan et al., 2000), so dogwoods are not seriously endangered. Indeed, the importance of the disease appears to be declining in areas where it was first introduced.

Impact: Biodiversity

Top of page D. destructiva is clearly very invasive in deciduous forests in the USA, seriously modifying their understorey composition and biodiversity by destroying species of Cornus, which form a characteristic element of this ecosystem. It may secondarily affect other forest plants and animals by modifying the canopy structure and the availability of dogwood leaves and fruits as food (Rossell et al., 2001).

Social Impact

Top of page Dogwoods are emblematic plants in the eastern USA, in nature and in gardens (for example, dogwood is the state flower of North Carolina). Their decline has a clear aesthetic impact.

Similarities to Other Species/Conditions

Top of page D. destructiva was initially confused with the anamorph of Glomerella cingulata, already well known on this host. Various other fungi cause leaf spots of Cornus (Elsinoë corni, species of Septoria, Ascochyta cornicola, Botryotinia fuckeliana), but these are easily distinguished microscopically.

Prevention and Control

Top of page Control of the disease is difficult, particularly in forests. In parks and gardens, cultural control (adequate watering and fertilization, pruning, removal of fallen leaves) and chemical control can be used. In the USA, emphasis is given to: optimum fertilization, trickle irrigation, adequate sunlight, mulching, pruning, fungicides, resistant cultivars, limiting movement of nursery material (Daughtrey et al., 1996). Forest management techniques favourable to the survival of understorey dogwoods remain to be worked out, but Britton et al. (1994) suggest that anthracnose is less severe on stands which were clear-cut 30 years ago than on those where timber was only partially harvested.

Phytosanitary measures

No international measures are currently applied for D. destructiva. As the main risk of introduction is by movement of infected plants for planting, it would be appropriate to require such material to come from a pest-free area or pest-free place of production.

References

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Britton KO; Pepper WD; Loftis DL; Chellemi DO, 1994. Effect of timber harvest practices on populations of Cornus florida and severity of dogwood anthracnose in western North Carolina. Plant Disease, 78(4):398-402

Britton KO; Roncadori RW; Hendrix FF, 1993. Isolation of Discula destructiva and other fungi from seeds of dogwood trees. Plant Disease, 77(10):1026-1028

CABI/EPPO, 2004. Discula destructiva. Distribution Maps of Plant Diseases, No. 926. Wallingford, UK: CAB International.

Chellemi DO; Britton KO; Swank WT, 1992. Influence of site factors on dogwood anthracnose in the Nantahala mountain range of western North Carolina. Plant Disease, 76(9):915-918

Daughtrey ML; Hibben CR, 1994. Dogwood anthracnose: a new disease threatens two native Cornus species. Annual Review of Phytopathology Palo Alto, USA; Annual Reviews Inc, 32:61-73

Daughtrey ML; Hibben CR; Britton KO; Windham MT; Redlin SC, 1996. Dogwood anthracnose: understanding a disease new to North America. Plant Disease, 80(4):349-358; 53 ref.

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

Erbaugh DK; Windham MT; Stodola AJW; Auge RM, 1995. Light intensity and drought stress as predisposition factors for dogwood anthracnose. Journal of Environmental Horticulture, 13(4):186-189; 24 ref.

Holt HL; Grant JF; Windham MT, 1998. Incidence of arthropods infested with conidia of the dogwood anthracnose fungus, Discula destructiva Redlin, on flowering dogwoods in the natural environment. Journal of Entomological Science, 33(4):329-335; 17 ref.

Jenkins MA; White PS, 2002. Cornus florida L. mortality and understory composition changes in western Great Smoky Mountains National Park. Journal of the Torrey Botanical Society, 129(3):194-206; 44 ref.

McEwan RW; Muller RN; Arthur MA; Housman HH, 2000. Temporal and ecological patterns of flowering dogwood mortality in the mixed mesophytic forest of eastern Kentucky. Journal of the Torrey Botanical Society, 127(3):221-229; 29 ref.

Redlin SC, 1991. Discula destructiva sp. nov., cause of dogwood anthracnose. Mycologia, 83(5):633-642

Rossell IM; Rossell CRJr; Hining KJ, 2001. Impacts of dogwood anthracnose (Discula destructiva Redlin) on the fruits of flowering dogwood (Cornus florida L.): implications for wildlife. American Midland Naturalist, 146(2):379-387; 24 ref.

Schwegman JE; McClain WE; Esker TL; Ebinger JE, 1998. Anthracnose-caused mortality of flowering dogwood (Cornus florida L.) at the Dean Hills Nature Preserve, Fayette County, Illinois, USA. Natural Areas Journal, 18(3):204-207; 12 ref.

Sherald JL; Stidham TM; Roberts LE, 1994. Evaluation of eight species of Cornus for resistance to dogwood anthracnose. Journal of Environmental Horticulture, 12(2):61-64

Stinzing A; Lang KJ, 2003. Dogwood anthracnose. First detection of Discula destructiva on Cornus florida in Germany. Nachrichtenblatt des Deutschen Pflanzenschutzdienstes, 55(1):1-5; 13 ref.

Trigiano RN; Caetano-Anolles G; Bassam BJ; Windham MT, 1995. DNA amplification fingerprinting provides evidence that Discula destructiva, the cause of dogwood anthracnose in North America, is an introduced pathogen. Mycologia, 87(4):490-500

Yao JM; Tainter H, 1996. Virus-like particles from Discula destructiva. Canadian Journal of Plant Pathology, 18: 433-438.

Zhang N; Blackwell, 2001. Molecular phylogeny of dogwood anthracnose fungus (Discula destructiva) and the Diaporthales. Mycologia, 93: 355-365.

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