Balsam woolly adelgid

Last updated

Balsam woolly adelgid
Balsam woolly adelgid.gif
Adult balsam woolly adelgid
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Sternorrhyncha
Family: Adelgidae
Genus: Adelges
Species:
A. piceae
Binomial name
Adelges piceae
(Ratzeburg, 1844)

The balsam woolly adelgid (Adelges piceae) is small wingless insect that infests and kills firs. In their native Europe they are a minor parasite on silver fir and Sicilian fir, but they have become a threat especially to balsam fir and Fraser fir after they were introduced to the United States around the beginning of the 20th century. Because this species is not native to North America, the Fraser fir has not evolved any type of defense against it.

Contents

Reproduction

These insects typically lay about one hundred eggs and have three generations per year. The adelgid attacks the tree by feeding in fissures within the bark of trees larger than about four centimeters in diameter at breast height. As it feeds, it releases toxins contained within its saliva. These toxins reduce the conductance of sapwood being built, which causes water stress and kills the trees.

Impact

The Great Smoky Mountains National Park, straddling North Carolina and Tennessee in the Southeastern United States, contains about 75% of all southern spruce-fir ecosystems. These ecosystems covered vast portions of the Southeast during the Last Glacial Period, when the climate was cool and moist. Since the retreat of the glaciers, this ecosystem has been confined to the higher elevations in the mountains of the Southeast. The spruce-fir forest has evolved as an ecological island, away from any other ecosystems of its type. This has presented valuable research and a unique habitat. These forests have a very dense canopy and a moist understory.

"Ghost" Fraser firs killed by the balsam woolly adelgid on Clingmans Dome, Great Smoky Mountain National Park GhostFraserFirs.JPG
"Ghost" Fraser firs killed by the balsam woolly adelgid on Clingmans Dome, Great Smoky Mountain National Park

Since the invasion of the balsam woolly adelgid, discovered in 1957, Fraser fir mortality rates have been 90–99%.[ citation needed ] Although some areas are being regenerated by young firs, there is much change in understory composition, including invasion by both woody and herbaceous species. Red spruce, the spruce component of the spruce fir ecosystem, has also been suffering declines. Some researchers attribute these declines to damage from wind, which is usually blocked by the firs.

One concern is that acid rain and ground-level ozone, among other pollutants, are contributing to a weak immune system for the Fraser firs and making them more susceptible to the balsam woolly adelgids.[ citation needed ] The spruce-fir moss spider, which lives on moss mats below the forest canopy, is considered endangered because of the decline of the Fraser fir. [1]

Although the fir population in the Great Smoky Mountains National Park was decimated by woolly adelgids in the 1960s through 1980s, there has been some recovery since then. The number of adult firs has increased over 30 years, with Clingmans Dome having three times as many adult trees as of 2020 as in the 1980s. [2]

The balsam woolly adelgid also has a significant impact on Pacific Northwest forests. Specifically, grand fir, silver fir and subalpine fir in Washington and Oregon can serve as hosts. Extensive mortality by this pest in the Cascade Mountain range was recorded during the 1950s and 1960s. Land area affected by the adelgid in the Pacific Northwest has increased from 83,325 acres (337 km2) in 2004 to 108,128 acres (438 km2) in 2005. [3]

Related Research Articles

<span class="mw-page-title-main">Great Smoky Mountains</span> American mountain range along North Carolina/Tennessee border

The Great Smoky Mountains are a mountain range rising along the Tennessee–North Carolina border in the southeastern United States. They are a subrange of the Appalachian Mountains and form part of the Blue Ridge Physiographic Province. The range is sometimes called the Smoky Mountains, and the name is commonly shortened to the Smokies. The Smokies are best known as the home of the Great Smoky Mountains National Park, which protects most of the range. The park was established in 1934 and, with over 11 million visits per year, is the most visited national park in the United States.

<span class="mw-page-title-main">Mount Rogers</span> Highest point in Virginia, United States

Mount Rogers is the highest natural point in Virginia, United States, with a summit elevation of 5,729 feet (1,746 m) above mean sea level. The summit straddles the border of Grayson and Smyth Counties, Virginia, about 6.45 miles (10.38 km) WSW of Troutdale, Virginia. Most of the mountain is contained within the Lewis Fork Wilderness, while the entire area is part of the Mount Rogers National Recreation Area, which itself is a part of the Jefferson National Forest.

<span class="mw-page-title-main">Spruce-fir moss spider</span> Species of spider

The spruce-fir moss spider is an endangered species of spider found at high elevations in the southern Appalachian Mountains. First identified in 1923, it inhabits moss that grows on rocks underneath the forest canopy.

<span class="mw-page-title-main">Fraser fir</span> Species of conifer

The Fraser fir, sometimes spelled" Frasier fir, is an endangered species of fir native to the Appalachian Mountains of the Southeastern United States. They are endemic to only seven montane regions in the Appalachian Mountains.

<span class="mw-page-title-main">Black Mountains (North Carolina)</span> Mountain range in western North Carolina, US

The Black Mountains are a mountain range in western North Carolina, in the southeastern United States. They are part of the Blue Ridge Province of the Southern Appalachian Mountains. The Black Mountains are the highest mountains in the Eastern United States. The range takes its name from the dark appearance of the red spruce and Fraser fir trees that form a spruce-fir forest on the upper slopes which contrasts with the brown or lighter green appearance of the deciduous trees at lower elevations. The Eastern Continental Divide, which runs along the eastern Blue Ridge crest, intersects the southern tip of the Black Mountain range.

<span class="mw-page-title-main">Hemlock woolly adelgid</span> Species of true bug

Adelges tsugae, the hemlock woolly adelgid or HWA, is an insect of the order Hemiptera native to East Asia. It feeds by sucking sap from hemlock and spruce trees. In its native range, HWA is not a serious pest because populations are managed by natural predators and parasitoids and by host resistance. In eastern North America it is a destructive pest that threatens the eastern hemlock and the Carolina hemlock. HWA is also found in western North America, where it has likely been present for thousands of years. In western North America, it primarily attacks western hemlock Tsuga heterophylla and has only caused minor damage due to natural predators and host resistance. Accidentally introduced to North America from Japan, HWA was first found in the eastern United States near Richmond, Virginia, in 1951. The pest is now found from northern Georgia to coastal Maine and southwestern Nova Scotia as well as areas of western Michigan near the eastern Lake Michigan shoreline. As of 2015, 90% of the geographic range of eastern hemlock in North America has been affected by HWA.

The gall adelgid is an adelgid species that produces galls in spruce trees. They infect the new buds of native spruce trees in the foothills of the Rocky Mountains in the spring. They also attack blue spruce to a lesser degree. The insects complete two generations within the year. They require two different trees for its life cycle, the second being the Rocky Mountain Douglas-fir. They may also attack Sitka, Engelmann, or white spruce. The many different species of adelgids produce different galls on different spruce species.

<span class="mw-page-title-main">Appalachian–Blue Ridge forests</span> Temperate broadleaf and mixed forests ecoregion of the United States

The Appalachian–Blue Ridge forests are an ecoregion in the Temperate broadleaf and mixed forests Biome, in the Eastern United States. The ecoregion is located in the central and southern Appalachian Mountains, including the Ridge-and-Valley Appalachians and the Blue Ridge Mountains. It covers an area of about 61,500 square miles (159,000 km2) in: northeast Alabama and Georgia, northwest South Carolina, eastern Tennessee, western North Carolina, Virginia, Maryland, and central West Virginia and Pennsylvania; and small extensions into Kentucky, New Jersey, and New York.

<span class="mw-page-title-main">Adelgidae</span> Family of true bugs

The Adelgidae are a small family of the Hemiptera closely related to the aphids, and often included in the Aphidoidea with the Phylloxeridae or placed within the superfamily Phylloxeroidea as a sister of the Aphidoidea within the infraorder Aphidomorpha. The family is composed of species associated with pine, spruce, or other conifers, known respectively as "pine aphids" or "spruce aphids". This family includes the former family Chermesidae, or "Chermidae", the name of which was declared invalid by the ICZN in 1955. There is still considerable debate as to the number of genera within the family, and the classification is still unstable and inconsistent among competing authors.

<span class="mw-page-title-main">Great Balsam Mountains</span> Mountain range in North Carolina, United States

The Great Balsam Mountains, or Balsam Mountains, are in the mountain region of western North Carolina, United States. The Great Balsams are a subrange of the Blue Ridge Mountains, which in turn are a part of the Appalachian Mountains. The most famous peak in the Great Balsam range is Cold Mountain, which is the centerpiece of author Charles Frazier's bestselling novel Cold Mountain.

<span class="mw-page-title-main">Red-cheeked salamander</span> Species of amphibian

The red-cheeked salamander, also known as the Jordan's salamander, Jordan's redcheek salamander, or Appalachian woodland salamander, is a species of salamander in the family Plethodontidae. It is endemic to the Appalachian Mountains in the southeastern United States.

<span class="mw-page-title-main">Christmas tree pests and weeds</span>

Pine and fir trees, grown purposely for use as Christmas trees, are vulnerable to a wide variety of pests, weeds and diseases. Many of the conifer species cultivated face infestations and death from such pests as the balsam woolly adelgid and other adelgids. Aphids are another common insect pest. Christmas trees are also vulnerable to fungal pathogens and their resultant illnesses such as root rot, and, in the U.S. state of California, sudden oak death. Douglas-fir trees in particular are vulnerable to infections from plant pathogens such as R. pseudotsugae.

<span class="mw-page-title-main">Spruce–fir forests</span> Spruce forest

Spruce–fir forests are type of forest found in the Northern Hemisphere dominated by spruce and fir trees. These forests are often considered to be climax forests, with the two main tree genera able to reproduce in their own shade.

<span class="mw-page-title-main">Richland Balsam</span> Mountain in North Carolina

Richland Balsam is a mountain in the Great Balsam Mountains in the U.S. state of North Carolina. Rising to an elevation of 6,410 feet (1,950 m), it is the highest mountain in the Great Balsam range, is among the 20 highest summits in the Appalachian range, and is the ninth highest peak in the Eastern United States. The Blue Ridge Parkway reaches an elevation of 6,053 feet (1,845 m)—the parkway's highest point—as it passes over Richland Balsam's southwestern slope. The Jackson County-Haywood County line crosses the mountain's summit.

<span class="mw-page-title-main">Southern Appalachian spruce–fir forest</span> Ecoregion of the southern Appalachian Mountains of the eastern United States

The southern Appalachian spruce–fir forest is an ecoregion of the temperate coniferous forests biome, a type of montane coniferous forest that grows in the highest elevations in the southern Appalachian Mountains of the eastern United States. The ecoregion is the highest and coldest forest type in the Appalachian range, thriving in elevations above 5,500 feet (1,700 m) where the climate is too harsh to support the broad-leaved hardwood forest that dominates the region's lower elevations. A relict of the last Ice Age, this forest type covers just over 100 square miles (260 km2) and is considered the second-most endangered ecosystem in the United States.

<span class="mw-page-title-main">Pineapple gall adelgid</span> Species of true bug

The pineapple gall adelgid is a species of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway and Sitka spruce. The adelgids are pear-shaped, soft-bodied green insects with long antennae, closely related to the aphid. Adelges lays up to one hundred eggs at a time, one on each needle. Adelges abietis is one of the most common species; synonyms are A. gallarum-abietis, Chermes abietis and Sacciphantes abietis.

<i>Adelges</i> Genus of true bugs

Adelges is a genus of insects which feed on conifers. They have complex life cycles, some species feeding exclusively on spruce, others feeding on spruce and an alternate conifer. However, galls characteristic of each species are formed only on spruce. Six generations are usually needed to complete the 2-year cycle, and in the case of species having an alternate host, winged adults about 2 mm long are formed only in the generations that move from one host to the other.

<span class="mw-page-title-main">Appalachian temperate rainforest</span> Temperate rainforest in the Appalachian Mountains

The Appalachian temperate rainforest or Appalachian cloud forest is located in the southern Appalachian Mountains of the eastern United States and is among the most biodiverse temperate regions in the world. Centered primarily around Southern Appalachian spruce–fir forests between southwestern Virginia and southwestern North Carolina, it has a cool, mild climate with highly variable temperature and precipitation patterns linked to elevation. The temperate rainforest as a whole has a mean annual temperature near 7 °C (45 °F) and annual precipitation exceeding 140 centimeters, though the highest peaks can reach more than 200 centimeters and are frequently shrouded in fog.

<span class="mw-page-title-main">Forest disturbance by invasive insects and diseases in the United States</span>

Species which are not native to a forest ecosystem can act as an agent of disturbance, changing forest dynamics as they invade and spread. Invasive insects and pathogens (diseases) are introduced to the United States through international trade, and spread through means of natural and human-dispersal. Invasive insects and pathogens are a serious threat to many forests in the United States and have decimated populations of several tree species, including American chestnut, American elm, eastern hemlock, whitebark pine, and the native ash species. The loss of these tree species is typically rapid with both short and long-term impacts to the forest ecosystem.

The Nabisipi River Old Forest is a protected area of old-growth forest in the Côte-Nord region of Quebec, Canada. It is classified as an exceptional forest ecosystem.

References

  1. US Fish & Wildlife Service: Spruce Fir Moss Spider
  2. McDarris, Anne (April 22, 2020). "Earth Day: After decades of devastation, a comeback for WNC forests". Asheville Citizen-Times . Retrieved April 22, 2020.
  3. United States Forest Service. (2005). Forest Health Conditions Report. Available online (Accessed September 11, 2006).