Gallery of Pests
Regional Lists of Pests
These lists were originally created by The Nature Conservancy's Faith Campbell in September 2004. Subsequent updates by staff of The Nature Conservancy and other partners have been on an as needed basis.
Introduction
Forests cover approximately one-third of the land area in the United States. These forests are comprised of approximately 500 species of trees plus thousands of identified species of terrestrial and aquatic animals and non-woody plants (USDA APHIS and Forest Service, 2000) and likely thousands of undescribed species (http://www.discoverlife.org). Representatives of almost every type of vegetation that occurs worldwide can be found within the United States or its protectorates (cf. USDA APHIS & Forest Service, 2000). Additionally, many exotic plant species are grown for horticulture, Christmas trees, and other uses. Approximately 4,000 exotic plants are established outside cultivation in the United States (Kartesz, 1999; United States Geological Survey, 1998). This combination of native and exotic species across the United States provides ample opportunities for imported pests to find suitable hosts (USDA APHIS and Forest Service, 2000; Niemala & Mattson, 1996). The estimated 4000 exotic insects and 200 pathogens that are permanently established in North America (USDA APHIS & Forest Service, 2000) demonstrate the vulnerability of our natural resources to exotic organisms.
Forest ecosystems vary in their susceptibility to exotic pests. Forest ecosystems comprised of relatively few tree species, e.g., forests dominated by Douglas-fir in the Pacific Northwest, are more affected by species-specific pests than forests which have more diversity. Conversely, the diverse eastern and Californian forests have greater opportunities for exotic pests to find suitable hosts. Damage to host species may range from negligible to potential extinction. The impact of some exotic pests is noticeable in a relatively short period after introduction, e.g., Asian longhorned beetle, or can be delayed as with Asiatic oak weevil (Triplehorn, 1955). Although some generalizations can be made, there is an uncertainty about how an exotic species will react in a new environment, what impact it will have on host species, and when it will be recognized as a problem species (USDA APHIS & Forest Service, 2000).
(view references here)
The Regions
For organizational (and not scientific) reasons, this gallery is divided into a number of geographic regions. On this page we have presented the pests in the Gallery of Pests according to their regions to help users determine what threats might be in their area.
Northeast (and neighboring Canada)
Established exotic forest insects and pathogens with major impacts:
American beech: Beech bark disease
American chestnut and Allegheny chinkapin: Chestnut blight
American chestnut and Allegheny chinkapin: Phytophthora root rot
American chestnut and Allegheny chinkapin: Chestnut gall wasp
American elm and other elm species: Dutch elm disease
Ash species: Emerald ash borer
Butternut: Butternut canker
Eastern hemlock: Hemlock woolly adelgid
Eastern white pine: White pine blister rust
Flowering dogwood: Dogwood anthracnose
Oaks and various hardwood species: European gypsy moth
(Apparently) lesser impacts
Balsam fir: Balsam woolly adelgid
Pine species: Common or larger pine shoot beetle
Tamarack: Larch casebearer
Exotic forest pests and pathogens that could threaten forests in this region if they spread from sites in North America where they are already present
Maple and various hardwood species: Asian longhorned beetle
Oak species and other woody plants: Sudden oak death pathogen (Phytophthora ramorum)
Pines: Red-haired or golden-haired pine bark beetle
Red spruce: Brown longhorned spruce beetle
Viburnum leaf beetle - Pyrrhalta viburni
Walnuts: Twig beetle & Black walnut disease
Exotic forest pests and pathogens that could threaten forests in this region if they are introduced
Alder, birch, willow, other hardwoods and conifers: Pine flat bug
Alders: Alder dieback
Beech, rhododendron, tulip tree, magnolia: Unnamed Phytophthora disease
Hardwood and coniferous species: Eurasian nun moth
Hardwood and coniferous species: Asian gypsy moth
Maples and various hardwood species: Citrus longhorned beetle
Oaks and other hardwoods: European oak bark beetle
Oaks: Oak dieback
Oaks, alder, willows, elms, other hardwoods: Chilean carpenter worm
Pine species: Woodwasp (Sirex noctilio) and its associated fungus
Spruce forests: European spruce beetle
Southeast
Established exotic forest insects and pathogens with major impacts:
American beech: Beech bark disease
American chestnut and Allegheny chinkapin: Chestnut blight
American chestnut and Allegheny chinkapin: Phytophthora root rot
American chestnut and Allegheny chinkapin: Chestnut gall wasp
American elm and other elm species: Dutch elm disease
Bromeliad: Bromeliad weevil
Butternut: Butternut canker
Eastern & Carolina hemlocks: Hemlock woolly adelgid
Eastern white pine: White pine blister rust
Flowering dogwood: Dogwood anthracnose
Fraser fir: Balsam woolly adelgid
Oaks and various hardwood species: European gypsy moth
Prickly pear cacti: Cactus moth
Wax myrtle, cocoplum, myrsine, tropical woody diots: Lobate lac scale
(Apparently) lesser impacts
Myrtaceae: Ohi'a rust
Oaks, elms, sweetgum, and other hardwoods in NC-LA: Ambrosia beetle, Xylosandrus crassiusculus
Pines, hardwood trees, and shrubs in MS: Ambrosia beetle, Xylosandrus mutilatus
Sassafras, redbay and other Lauraceae: Laurel wilt & Ambrosia beetle, Ophiostoma sp. & Xyleborus glabratus
Soapberry tree: Soapberry borer - Agrilus prionurus
Exotic forest pests and pathogens that could threaten forests in this region if they spread from sites in North America where they are already present
Ash species: Emerald ash borer
Maple and various hardwood species: Asian longhorned beetle
Oak species and other woody plants: Sudden oak death pathogen (Phytophthora ramorum)
Pine species: Common or larger pine shoot beetle
Red spruce: Brown longhorned spruce beetle
Walnuts: Twig beetle & Black walnut disease
Exotic forest pests and pathogens that could threaten forests in this region if they are introduced
Alder, birch, willow, other hardwoods and conifers: Pine flat bug
Alders: Alder dieback
Beech, rhododendron, tulip tree, magnolia: Unnamed Phytophthora disease
Hardwood and coniferous species: Eurasian nun moth
Hardwood and coniferous species: Asian gypsy moth
Maples and various hardwood species: Citrus longhorned beetle
Oaks and other hardwoods: European oak bark beetle
Oaks, alder, willows, elms, other hardwoods: Chilean carpenter worm
Oaks: Oak dieback
Pine species: Woodwasp (Sirex noctilio) and its associated fungus
Midwest
Established exotic forest insects and pathogens with major impacts:
American chestnut and Allegheny chinkapin: Chestnut blight
American chestnut and Allegheny chinkapin: Phytophthora root rot
American chestnut and Allegheny chinkapin: Chestnut gall wasp
American elm and other elm species: Dutch elm disease
Ash species: Emerald ash borer
Butternut: Butternut canker
Eastern white pine: White pine blister rust
Flowering dogwood: Dogwood anthracnose
Oaks and various hardwood species: European gypsy moth
(Apparently) lesser impacts
Balsam fir: Balsam woolly adelgid
Broad range of hardwoods and pines in TX: Shot-hole borer, Xyleborus similis
Oaks, elms, sweetgum, and other hardwoods in TX: Ambrosia beetle, Xylosandrus crassiusculus
Pine species: Common or larger pine shoot beetle
Tamarack: Larch casebearer
Exotic forest pests and pathogens that could threaten forests in this region if they spread from sites in North America where they are already present
American beech: Beech bark disease
Eastern hemlock: Hemlock woolly adelgid
Maple and various hardwood species: Asian longhorned beetle
Oak species and other woody plants: Sudden oak death pathogen (Phytophthora ramorum)
Prickly pear cacti in TX: Cactus moth
Red spruce: Brown longhorned spruce beetle
Walnuts: Twig beetle & Black walnut disease
Exotic forest pests and pathogens that could threaten forests in this region if they are introduced
Alder, birch, willow, other hardwoods and conifers: Pine flat bug
Alders: Alder dieback
Beech, rhododendron, tulip tree, magnolia: Unnamed Phytophthora disease
Hardwood and coniferous species: Eurasian nun moth
Hardwood and coniferous species: Asian gypsy moth
Maples and various hardwood species: Citrus longhorned beetle
Oaks: Oak dieback
Oaks and other hardwoods: European oak bark beetle
Oaks, alder, willows, elms, other hardwoods: Chilean carpenter worm
Pine species: Woodwasp (Sirex noctilio) and its associated fungus
Spruce forests: European spruce beetle
Rocky Mountain States (and neighboring Canada)
Established exotic forest insects and pathogens with major impacts:
Engelmann spruce, Colorado blue spruce: Spruce aphid (Elatobium abietinum)
Various elms: Dutch elm disease
White & 5-needle pines (Pinus subgenus Strobus): White pine blister rust
(Apparently) lesser impacts
Tamarack: Larch casebearer
True firs (Abies): Balsam woolly adelgid
Various elms: Introduced banded elm bark beetle (Scolytus schevyrewi)
Exotic forest pests and pathogens that could threaten forests in this region if they spread from sites in North America where they are already present
Ash species: Emerald ash borer
Maple and various hardwood species: Asian longhorned beetle
Pine species: Common or larger pine shoot beetle
Prickly pear cacti in NM, AZ: Cactus moth
Red spruce: Brown longhorned spruce beetle
Various hardwood species: European gypsy moth
Exotic forest pests and pathogens that could threaten forests in this region if they are introduced
Alders: Alder dieback
Alder, birch, willow, other hardwoods and conifers: Pine flat bug
Hardwood and coniferous species: Eurasian nun moth
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Hardwood and coniferous species: Asian gypsy moth
Maples and various hardwood species: Citrus longhorned beetle
Oaks: Oak dieback
Oaks and other hardwoods: European oak bark beetle
Oaks, alder, willows, elms, other hardwoods: Chilean carpenter worm
Pine species: Woodwasp (Sirex noctilio) and its associated fungus
Rhododendron: Unnamed Phytophthora disease
Spruce (especially Picea engelmannii): European spruce beetle
Pacific States (and neighboring Canada)
Established exotic forest insects and pathogens with major impacts:
Conifers, especially Pines (CA): Mediterranean pine engraver beetle
Oak species and other woody plants: Sudden oak death pathogen (Phytophthora ramorum)
Pines (CA-OR): Pine Pitch Canker
Port-Orford-cedar: Port-Orford-cedar root disease (Phytophthora lateralis)
Various elms: Dutch elm disease
Western dogwoods: Dogwood anthracnose
White & 5-needle pines (Pinus subgenus Strobus): White pine blister rust
(Apparently) lesser impacts
Douglas-fir, redwood, grand fir: Sudden oak death pathogen (Phytophthora ramorum)
Larch: Larch casebearer and European larch canker
Sitka spruce (OR, WA): Spruce aphid (Elatobium abietinum)
True firs (Abies): Balsam woolly adelgid
Various elms: Introduced banded elm bark beetle (Scolytus schevyrewi)
Exotic forest pests and pathogens that could threaten forests in this region if they spread from sites in North America where they are already present
Ash species: Emerald ash borer
Maple and various hardwood species: Asian longhorned beetle
Pine species: Common or larger pine shoot beetle
Red spruce: Brown longhorned spruce beetle
Exotic forest pests and pathogens that could threaten forests in this region if they spread from sites in North America where they are already present
Prickly pear cacti in CA: Cactus moth
Exotic forest pests and pathogens that could threaten forests in this region if they are introduced
Alders: Alder dieback
Alder, birch, willow, other hardwoods and conifers: Pine flat bug
Hardwood and coniferous species: Eurasian nun moth
Hardwood and coniferous species: Asian gypsy moth
Maples and various hardwood species: Citrus longhorned beetle
Oaks: Oak dieback
Oaks and other hardwoods: European oak bark beetle
Oaks, alder, willows, elms, other hardwoods: Chilean carpenter worm
Pine species: Woodwasp (Sirex noctilio) and its associated fungus
Rhododendron: Unnamed Phytophthora disease
Spruce (especially Picea sitchensis ): European spruce beetle
Hawaii and other Pacific Islands
Established exotic forest insects and pathogens with major impacts:
Cycads: Cycad aulacaspis scale
Wiliwili: Erythrina gall wasp
Impacts yet to be determined
Metrosideros (ohi'a) and Eugenia: Ohi'a rust
Sources for Introduction Statement
Kartesz, J.T. 1999. A Synonimized Checklist and Atlas with Biological Attributes for the Vascular Flora of the United States, Canada, and Greenland. First Edition. In: Kartesz, J.T. and C.A. Meacham, Synthesis of the North American Flora, Version 1.0, North Carolina Botanical Garden, Chapel Hill.
Niemela P. and W.J. Mattson. 1996. Invasion of North American Forests by European Phytophagous Insects. Bioscience Vol. 46, No. 10 (November 1996), pp. 741-753).
Triplehorn, C. A. 1955. The Asiatic oak weevil in Delaware. J. Econ. Entomol. 48: 289 293.
United States Department of Agriculture Animal and Plant Health Inspection Service and Forest Service, 2000. (Pasek, J.E., H.H. Burdsall, J.F. Cavey, A. Eglitis, R.A. Haack, D.A. Haugen, M.I. Haverty, C.S. Hodges, D.R. Kucera, J.D. Lattin, W.J. Mattson, D.J. Nowak, J.G. O'Brien, R.L. Orr, R.A. Sequeira, E.B. Smalley, B.M. Tkacz, W.W. Wallner) Pest Risk Assessment for Importation of Solid Wood Packing Materials into the United States.
United States Department of Interior. United States Geological Survey 1998. Status and Trends of the Nation's Biological Resources. Washington, D.C.
Sources for Regional Lists
Kartesz, J.T. 1999. A Synonimized Checklist and Atlas with Biological Attributes for the Vascular Flora of the United States, Canada, and Greenland. First Edition. In: Kartesz, J.T. and C.A. Meacham, Synthesis of the North American Flora, Version 1.0, North Carolina Botanical Garden, Chapel Hill.
Niemela P. and W.J. Mattson. 1996. Invasion of North American Forests by European Phytophagous Insects. Bioscience Vol. 46, No. 10 (November 1996), pp. 741-753).
Triplehorn, C. A. 1955. The Asiatic oak weevil in Delaware. J. Econ. Entomol. 48: 289 293.
United States Department of Agriculture Animal and Plant Health Inspection Service and Forest Service, 2000. (Pasek, J.E., H.H. Burdsall, J.F. Cavey, A. Eglitis, R.A. Haack, D.A. Haugen, M.I. Haverty, C.S. Hodges, D.R. Kucera, J.D. Lattin, W.J. Mattson, D.J. Nowak, J.G. O'Brien, R.L. Orr, R.A. Sequeira, E.B. Smalley, B.M. Tkacz, W.W. Wallner) Pest Risk Assessment for Importation of Solid Wood Packing Materials into the United States.
United States Department of Interior. United States Geological Survey 1998. Status and Trends of the Nation's Biological Resources. Washington, D.C.