| Choristoneura freemani | |
|---|---|
 | |
| Adult | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Lepidoptera |
| Family: | Tortricidae |
| Genus: | Choristoneura |
| Species: | C. freemani |
| Binomial name | |
| Choristoneura freemani | |
| Synonyms | |
| |
Choristoneura occidentalis [or Choristoneura freemani in some schemes], the western spruce budworm, is a species of moth of the family Tortricidae. It is the most destructive defoliator of coniferous forests in western North America.
It is now widely distributed throughout the Rocky and Coast Mountains of Canada and the USA. The first recorded outbreak was in 1909 on the southeastern part of Vancouver Island in British Columbia, Canada. Since that year, infestations have frequently been reported in western Canada. [2]
The Western spruce budworm was first recorded in the United States (for Oregon) in 1914. However, it was not initially recognized as a serious threat to coniferous forests in the western U.S. Aerial spraying apparently terminated some smaller epidemics in the southern and central Rockies; others subsided naturally. The insect then appeared to be dormant in U.S. forests until 1922, when two outbreaks were reported near Priest Lake in northern Idaho. Since then, significant outbreaks in the Rockies and in the Pacific Northwest have caused top-killing with serious economic losses in tree growth. Tree mortality can occur in regeneration, sapling, and pole-sized trees. Trees in mature stands severely defoliated by the western spruce budworm may become susceptible to bark beetles, which kill mature trees. [2]
Considered the most destructive defoliator in British Columbia, sustained outbreaks of the western spruce budworm resulted in defoliation of over 100,000 hectares (250,000 acres) in the Fraser Canyon - Lillooet - Pemberton area from 1949-58. From 1970 -2001 further outbreaks occurred over a much larger area including the area of the previous outbreaks, as well as the Thompson and South Okanagan areas in 1970-2001. [3]
There is no typical pattern for western spruce budworm epidemics. Most of the early epidemics subsided naturally after a few years. Others persisted longer, but without spreading over large areas. An epidemic which began in 1949 in the northern Rocky Mountains has persisted for over 30 years despite insecticidal treatment of more than 6,000,000 acres (24,000 km2) between 1952 and 1966. [2]
Adult moths are about 1/2 inch (12.7 mm) long and have a wing-spread of 7/8 to 11/8 inches (22 to 28mm). Moths of both sexes are similar in appearance, although the females are a bit more robust than males. Both sexes fly. The gray- or orange-brown forewings are banded or streaked, and each usually has a conspicuous white dot on the wing margin. Eggs are oval, light green, and about 3/64 inch (1.2mm) long and overlap like shingles.
Larvae develop through six stages. Newly hatched larvae are yellow-green with brown heads. In the next three stages, larvae have black heads and collars and orange- or cinnamon-brown bodies. In the fifth stage, larvae have reddish-brown heads marked with black triangles, black collars, and pale olive-brown bodies marked with small whitish spots. Mature larvae are 1 to 11/4 inches (25 to 32 mm) long, with tan or light chestnut-brown heads and collars and olive- or reddish-brown bodies with large ivory-colored areas.
Pupae are 1/2 to 5/8 inch (13 to 16 mm) long, broad at the head end, and narrower toward the tail. They are brownish yellow or brownish green at first, and later turn reddish brown.
Throughout most of its range, the western spruce budworm completes one cycle of development from egg to adult within 12 months. Moths emerge from pupal cases usually in late July or early August; in the southern Rockies, adults often begin emerging in early July.
The adults mate, and within 7 to 10 days, the female deposits her eggs and then dies. Each female deposits approximately 150 eggs, usually on the underside of conifer needles. Eggs are laid in one to three-row masses containing a few to 130 eggs, with an average of 25 to 40 eggs per mass.
Larvae hatch from eggs in about 10 days. Larvae do not feed, but seek sheltered places under bark scales or in and among lichens on the tree bole or limbs. Here, they spin silken tents in which they remain inactive through the winter.
In early May to late June, larvae leave their hibernacula to search for food. They first mine or tunnel into year-old needles, closed buds, or newly developing vegetative or reproductive buds.
New foliage, which is normally the preferred food, is usually entirely consumed or destroyed before larvae will feed on older needles. Larvae become full grown usually in early July about 30 to 40 days after leaving their overwintering sites.
Larvae pupate in webs of silk they have spun either at the last feeding site or elsewhere on the tree. The pupal stage usually lasts about 10 days.
The species was originally named Choristoneura occidentalis Freeman, 1967. However, this name has been stated as a junior homonym of a proposed recombination for another African species Cacoecia occidentalis Walsingham, 1891 (later Archips occidentalis (Walsingham, 1891), and contentiously Choristoneura occidentalis (Walsingham, 1891)). If adopted, the replacement name for the then later described North American species has been formally proposed as Choristoneura freemani Razowski, 2008. [4] . However, the need for a replacement name for the American species was then questioned, with proposals of alternative ways to revise the taxonomy. [5] Subsequently, the recombination of Razowski, 2008 (and hence the homonym) has been refuted by Brunet et al., 2016 [6] , alongside revision of subspecies with discussion on nomenclatural issues, however without a clear alternative taxonomy for Walsingham's species (which furthermore might be a senior to another African species).
A spruce is a tree of the genus Picea, a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. Picea is the sole genus in the subfamily Piceoideae. Spruces are large trees, from about 20 to 60 m tall when mature, and have whorled branches and conical form.
Choristoneura is a genus of moths in the family Tortricidae. Several species are serious pests of conifers, such as spruce and are known as spruce budworms.
The Tortricidae are a family of moths, commonly known as tortrix moths or leafroller moths, in the order Lepidoptera. This large family has over 11,000 species described, and is the sole member of the superfamily Tortricoidea, although the genus Heliocosma is sometimes placed within this superfamily. Many of these are economically important pests. Olethreutidae is a junior synonym. The typical resting posture is with the wings folded back, producing a rather rounded profile.
Larix laricina, commonly known as the tamarack, hackmatack, eastern larch, black larch, red larch, or American larch, is a species of larch native to Canada, from eastern Yukon and Inuvik, Northwest Territories east to Newfoundland, and also south into the upper northeastern United States from Minnesota to Cranesville Swamp, West Virginia; there is also an isolated population in central Alaska.
Choristoneura fumiferana, the eastern spruce budworm, is a species of moth of the family Tortricidae native to the eastern United States and Canada. The caterpillars feed on the needles of spruce and fir trees. Eastern spruce budworm populations can experience significant oscillations, with large outbreaks sometimes resulting in wide scale tree mortality. The first recorded outbreaks of the spruce budworm in the United States occurred in about 1807, and since 1909 there have been waves of budworm outbreaks throughout the eastern United States and Canada. In Canada, the major outbreaks occurred in periods circa 1910–20, c. 1940–50, and c. 1970–80, each of which impacted millions of hectares of forest. Longer-term tree-ring studies suggest that spruce budworm outbreaks have been recurring approximately every three decades since the 16th century, and paleoecological studies suggest the spruce budworm has been breaking out in eastern North America for thousands of years.
Archips occidentalis [or Choristoneura occidentalis in some schemes] is a species of moth of the family Tortricidae. It is found in the Gambia, and possibly more broadly, such as Democratic Republic of Congo, Tanzania, and South Africa.
The Archipini are a tribe of tortrix moths. Since many genera of these are not yet assigned to tribes, the genus list presented here is provisional.
Coleophora laricella, the western larch case-bearer, is a moth belonging to the family of case-bearing moths Coleophoridae. It is native to Central and Northern Europe, with its original food source being the European larch or Larix decidua. However, it was introduced to North America in the mid-19th century where it has gained a wide range and become an invasive defoliator of several species of the genus Larix, particularly the western larch Larix occidentalis and the tamarack larch Larix laricina.
Choristoneura pinus, the jack pine budworm, is a moth of the family Tortricidae. The species was first described by Thomas Nesbitt Freeman in 1953. It is found in jack pine forests in Canada from Atlantic provinces to Cypress Hills on the Alberta-Saskatchewan border as well as northern United States from New England to the lake states.
Zeiraphera canadensis, the spruce bud moth, is a moth of the family Tortricidae. It is a small brown moth mainly found in North America, specifically New Brunswick, Quebec, and the north-eastern United States. The adult moth flutters quickly, and stays low among trees during the day and higher above tree cover after sunset. The spruce bud moth relies primarily on the white spruce tree as a host plant. Both male and female spruce bud moths mate multiply, however males have the ability to secrete accessory gland proteins that prevent female re-mating. The moth is univoltine, meaning only one generation hatches per year, and its eggs overwinter from July to May. The species Z. ratzeburgiana is very similar to Z. canadensis and can only be distinguished by the presence of an anal comb in Z. canadensis.
Acleris semipurpurana is a species in the moth family Tortricidae, and one of several species of moth commonly known as oak leaftier or oak leaf tier. The larvae feed on the leaves of oak trees in the Eastern United States and southeastern Canada which can be a major cause of defoliation. The loss of leaves can kill or damage the affected trees, which are chiefly in the Lobatae or red oak section of Quercus, or oaks.
Archips semiferanus is a species of moth in the family Tortricidae, and one of several species of moth commonly known as oak leafroller or oak leaf roller. The larvae feed on the leaves of oak trees in the eastern United States and southeastern Canada and are a major defoliator of oak trees, which can lead to tree mortality. In Pennsylvania in the late 1960s and early 1970s, oak leafrollers defoliated over 1,045,000 acres (423,000 ha).
Epinotia nanana, the European spruce needleminer, is a moth of the family Tortricidae. It is found from northern and central Europe to Russia and Mongolia.
Argyrotaenia dorsalana is a moth of the family Tortricidae. It is found in western North America from southern British Columbia south to California, Arizona, and New Mexico.
The spongy moth, formerly known as the gypsy moth, was introduced in 1868 into the United States by Étienne Léopold Trouvelot, a French scientist living in Medford, Massachusetts. Because native silk-spinning caterpillars were susceptible to disease, Trouvelot imported the species in order to breed a more resistant hybrid species. Some of the moths escaped, found suitable habitat, and began breeding. The gypsy moth is now a major pest of hardwood trees in the Eastern United States.
Orgyia pseudotsugata, the Douglas-fir tussock moth, is a moth of the subfamily Lymantriinae first described by James Halliday McDunnough in 1921. It is found in western North America. Its population periodically irrupts in cyclical outbreaks. The caterpillars feed on the needles of Douglas fir, true fir, and spruce in summer, and moths are on the wing from July or August to November.
Epinotia radicana, the red-striped needleworm moth, is a species of moth of the family Tortricidae. It is found in western Canada, including British Columbia and Alberta.
Lymantria dispar dispar, commonly known as the gypsy moth, European gypsy moth, LDD moth, or North American gypsy moth or spongy moth, is a species of moth in the family Erebidae. It has a native range that extends over Europe and parts of Africa, and is an invasive species in North America.
Neodiprion abietis, commonly known as the balsam fir sawfly, is a species of insect in the family Diprionidae. It is found in North America from Canada to northern Mexico and is phytophagous, feeding on the needles of coniferous trees.
Choristoneura biennis, the two-year-cycle budworm moth, is a species of moth of the family Tortricidae. It is found in Canada, where it has been recorded from Alberta and British Columbia.
This article incorporates public domain material from David G. Fellin, Jerald E. Dewey. Forest Insect & Disease Leaflet 53: Western Spruce Budworm. United States Forest Service.