Instruct: Given a question, retrieve relevant documents that answer the question.
Query: What is the wingspan of the eastern spruce budworm?
The moths will emerge from the pupae within 8 to 12 days, during mid-June to August. Adult spruce budworm are medium-sized (15mm in length) and dichromatic, exhibiting gray and rust colors.[12] The wings have silvery patches and are 21mm to 30mm in wingspan.[11] Peak activity occurs during the later afternoon and early evening.[37] After emerging, the adults will mate and lay eggs in July or August.[11][38]
Paleoecological studies suggest the spruce budworm has been breaking out in eastern North America for thousands of years.[43]
For biological methods, birds are important in controlling populations of the eastern spruce budworm below outbreak levels, and the parasitic wasp "Trichogramma minutum" was investigated as a solution as well.
White spruce is also particularly useful for providing evidence of past outbreaks of spruce budworm through radial-growth data. They can provide excellent records from as far back as 200, sometimes 300, years.[23] Although the white spruce is more resistant to budworm attack than balsam fir, heavy defoliation can occur during severe outbreaks, which results in reduction of radial growth. In lesser outbreaks, radial growth is moderately reduced, which often makes it difficult to distinguish if it is caused by random or weather-related fluctuations. Comparisons between radial growth in host trees and non-host trees (especially white and red pines) are used to detect the budworm effect.[47]
Traditionally, the eastern spruce budworm prefers balsam fir over white spruce.[17][18] However, one study showed contradicting evidence. In this study, Bichon sampled spruce budworm populations on branches from the upper mid-crowns of dominant or co-dominant balsam fir and white spruce. This was done at 20 randomly selected points in the Black Sturgeon Lake area near Thunder Bay, Ontario. The number of late-instar larvae captured in water traps was recorded throughout the dispersal period of the late instar larvae. The data indicated that white spruce canopies contained 2 to 3 times more spruce budworm than balsam fir canopies. A similar pattern was found in the understory. Water traps under white spruce trees captured more than 3 times as many larvae as did those under balsam fir trees for most of the dispersal period.[18]
The eastern spruce budworm Choristoneura fumiferana has been called “the most destructive forest insect in North America."[55] Massive budworm epidemics erupt periodically in spruce–fir forests in northern and eastern Canada. Populations of spruce budworm vary in density over several orders of magnitude. Recorded densities in the boreal forest range from less than 0.01[56] to over 100 larvae per 45cm branch tip.[41] Damage to trees in forests can begin even before the buds have flushed. Early instar larvae mine and kill these buds. Late instar larvae are voracious and wasteful feeders, chewing off needles at their bases. In heavy infestations, old foliage is also eaten. Increment loss, tree deformity, and tree mortality follow several years of heavy infestation.[57][58]
The main hosts of the eastern spruce budworm in eastern North America are balsam fir, white spruce, and black spruce,[13][14] but the larvae feed almost exclusively on current-year needles of balsam fir and white spruce.[15] In massive outbreaks, populations of the insect can become so high that the larvae will feed on old foliage after the current-year foliage has been depleted.[16]
Different species use a wide variety of chemical substances to send sexual signals. The first to be described chemically was bombykol, the silkworm moth's sex pheromone, which is a complex alcohol, (E,Z)-10,12-hexadecadienol, discovered in 1959. It is detected in the antennae of the male moth by a pheromone-binding protein which carries the bombykol to a receptor bound to the membrane of a nerve cell.
The chemicals used by other moths are species-specific. For example, the Eastern spruce budworm "Choristoneura fumiferana" female pheromones contain a 95:5 mix of "E-" and "Z" 11-tetradecenal aldehydes, while the sex pheromones of other species of spruce budworm contain acetates and alcohols.
Although sometimes described, e.g., by Switzer (1960), as relatively resistant to attack by insects and disease, white spruce is far from immune to depredation. Important insect pests of white spruce include the spruce budworm ("Choristoneura fumiferana" [Clemens]), the yellow-headed spruce sawfly ("Pikonema alaskensis" Rohwer), the European spruce sawfly ("Gilpinia hercyniae" [Hartig]), the spruce bud moth ("Zeiraphera canadensis)""," and spruce beetle ("Dendroctonus rufipennis" [Kirby]) (Fowells 1965, Rose and Lindquist 1985, Ives and Wong 1988). As well, other budworms, sawflies, and bark beetles, gall formers, bud midges, leaf miners, aphids, leaf eaters, leaf rollers, loopers, mites, scales, weevils, borers, pitch moths, and spittlebugs cause varying degrees of damage to white spruce (Ives and Wong 1988).
Insectivorous birds are a common and major predator of the spruce budworm, mainly preying on the larvae and pupae. Examples of species include sparrows, thrushes, and overstory warblers. Bird distribution will change to reflect budworm density in the forests.[28] A 1989 study found that the highest populations of spruce budworm larvae and pupae occur in June and July. This coincides with the period when some species of birds require maximum food to feed their young. As a result, predation by birds helps control the growth of budworm predation.[9] Other major predators include various invertebrates, primarily spiders.[28]
Fire has an interesting relationship with micro fauna in forests. Damage done to trees by fire hurts the vascular cambium, thus leaving trees more susceptible to insectivorous and fungal attacks. Fungal infections are not as common as insect attacks, but can be just as deadly. The fungus "Amylostereum areolatum" weakens trees and allows insects such as the "Sirex noctilio" (European wood wasp) to take over massive numbers of forests. The most common problems in spruce and fir forests are bark beetles, budworms, and gall-forming insects, to which spruce is extremely susceptible. Several gall-forming insects are present in spruce forests, including the Eastern Spruce gall adelgid and the Cooley's Spruce gall adelgid, which normally would not harm forests, unless the trees are unusually vulnerable to them, as they are after a fire. Budworm larvae feed on the leaves of spruce and fir trees, and can become present in large amounts, which is when they become detrimental to a forest. Bark beetles are the most common insect killer of spruce and fir forests because they can spread quickly, breed rapidly, and can easily devour thousands of acres before actions can be taken against them. During the 1990s, the bark beetles affected almost three million acres (12,000 km²) of spruce forests. The attacks of these insects, in turn, raise the mortality rate of trees in the burn area, which provides even more fuel for the next fire.
Spruce budworms and relatives are a group of closely related insects in the genus Choristoneura. Most are serious pests of conifers, such as spruce. There are nearly forty "Choristoneura" species, and even more subspecies, or forms, with a complexity of variation among populations found throughout much of the United States and Canada, and about again this number in Eurasia. In Eastern North America, "Choristoneura fumiferana" is prevalent, while in Western North America "Choristoneura freemani" has devastated large areas.
It has been hypothesized by Serge Payette that the spruce-moss forest ecosystem was changed into the lichen woodland biome due to the initiation of two compounded strong disturbances: large fire and the appearance and attack of the spruce budworm.[76] The spruce budworm is a deadly insect to the spruce populations in the southern regions of the taiga. J.P. Jasinski confirmed this theory five years later stating “Their [lichen woodlands] persistence, along with their previous moss forest histories and current occurrence adjacent to closed moss forests, indicate that they are an alternative stable state to the spruce–moss forests”.[77]
Balsam fir is the most susceptible host to outbreaks of the spruce budworm. Annual defoliation of current-year growth for 5 to 8 years will kill the host tree.[16] Defoliation by the spruce budworm is most clearly reflected in the fir's radial growth. The population of mature balsam fir in a forest is greatly reduced by a combination of factors: its shorter lifespan and a great vulnerability to lethal budworm attacks.[19][20][21] The dietary preference for balsam fir over white spruce has the potential to alter the structure and composition of spruce-fir forests. Similarly, the next-generation stand of trees are influenced by the late instar larvae that disperse to the understory of the forest and feed on the regeneration of plants.[18] During a 1957 budworm outbreak in Quebec, balsam fir mortality was greater than 75% in stands in which no mortality was reported among the smaller component of white spruce.[22]
Spruce are used as food plants by the larvae of some Lepidoptera (moth and butterfly) species, such as the eastern spruce budworm. They are also used by the larvae of gall adelgids ("Adelges" species).
Dioryctria reniculelloides, the spruce coneworm, is a species of moth of the family Pyralidae. It is found from Nova Scotia to Alaska, south in the east to New York, and south in the west to California and New Mexico. It was recorded from China in 2009. Occasionally abundant, often in conjunction with epidemics of the spruce budworm, the spruce coneworm ("Dioryctria reniculelloides" Mutuura & Munroe) occurs through most or all of the range of spruce in North America, feeding on new foliage and cones of spruce, and often balsam fir (Ives and Wong 1988). When abundant, it can be a serious pest "particularly on white spruce" (Hedlin et al. 1980). 
The wingspan is 9.5–11 mm. The forewings are brownish grey with black zigzag lines, bordered by white. The hindwings are light brownish grey with a pale fringe. Adults are on wing from June to August in one generation per year.
This species is a favoured food of the Cape May warbler, which is therefore closely associated with its host plant, balsam fir. This bird, and the Tennessee and bay-breasted warblers, which also have a preference for budworm, lay more eggs and are more numerous in years of budworm abundance.
In spruce-fir forests throughout Maine, the late-instar spruce budworm larvae is preyed on by eumenid wasps such as the A. adiabatus, and E. leucomelas. This predation is important in controlling populations of the spruce budworm in forest stands.[40]
The eastern spruce budworm is an example of a destructive insect in fir and spruce forests. Birds are a natural form of biological control, but the "Trichogramma minutum", a species of parasitic wasp, has been investigated as an alternative to more controversial chemical controls.
The eastern spruce budworm is one of the most destructive insects of fir and spruce forests throughout Canada and the eastern United States.
The range of the eastern spruce budworm is the largest of all budworms and coincides with the range of its hosts: fir and spruce trees in eastern North America, primarily in Canada.[8][9] It includes the Boreal Forest as well as the Great Lakes-St. Lawrence, Northern, and Acadian forest regions.[10] This range extends westward to Alaska.[11] The spruce budworm is commonly found in boreal and sub-boreal forest regions, specifically those that consist of spruce-fir forests.[12]
In Atlantic Canada, the spruce budworm problem was noted as early as 1910.
Pest management of the eastern spruce budworm is required due to the incompatibility of budworm and human use of the same domain. Management occurs through some manipulation of the environment, which is determined through cultural practice, or by the introduction of a regulatory agent such as a predator or an insecticide. In regard to massive outbreaks, the use of insecticide is a primary practical method of crop protection.
About 90 parasitoids have been collected from spruce budworm in eastern North America. In 1996, Henry found that the suite of parasitoids collected from spruce budworm in isolated white spruce plantations of southern Ontario differed from the usual suite of parasitoids found in the boreal forest.[41]
Choristoneura fumiferana, the eastern spruce budworm, is a species of moth of the family Tortricidae. It is also commonly referred to as the spruce budworm. It is one of the most destructive native insects in the northern spruce and fir forests of the eastern United States and Canada. Its range is also the widest of all the budworm species. Eastern spruce budworm populations can experience significant oscillations. During outbreaks, populations grow to extremely high densities, compared to the relatively low levels that occur in between. These outbreaks are highly destructive and can cause both economic and ecological damage. As a result, methods of control are utilized. Several theories exist regarding these cyclical outbreaks: association with balsam fir maturation, catastrophe theory, dispersal from an epicenter, and oscillations synchronized by entrainment.