What is the wingspan of the eastern spruce budworm?
11479486#24
The moths will emerge from the pupae within 8 to 12 days, during mid-June to August. Adult spruce budworm are medium-sized (15 mm in length) and dichromatic, exhibiting gray and rust colors. The wings have silvery patches and are 21 mm to 30 mm in wingspan. Peak activity occurs during the later afternoon and early evening. After emerging, the adults will mate and lay eggs in July or August.
Choristoneura fumiferana
18823919#0
Hedya nubiferana, the marbled orchard tortrix or green budworm moth, is a moth of the family Tortricidae. It is found in the Palearctic and the Nearctic ecozones.
The wingspan is 15–21 mm. The moth flies from May to August. .
Hedya nubiferana
11479486#0
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.
Choristoneura fumiferana
11479486#45
The eastern spruce budworm "Choristoneura fumiferana" has been called “the most destructive forest insect in North America." 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 to over 100 larvae per 45 cm branch tip. 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.
Choristoneura fumiferana
11479486#6
Traditionally, the eastern spruce budworm prefers balsam fir over white spruce. 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.
Choristoneura fumiferana
11479486#29
Eastern spruce budworm egg masses are immobile and less vulnerable to predation than other stages of the cycle. Small larvae are exposed to predators during dispersal but become safer while bud or needle mining or overwintering in hibernacula. Large larvae actively escape predation by dropping from the tree foliage, which can also attract the attention of other predators. Predators outside of host plants on the forest floor include ants, spiders, beetles, and small mammals. Pupae are vulnerable because the budworm are generally immobile in this state. The adult moths can fly away from predators but are then exposed to various birds, dragonflies, and robber flies. Spruce budworm male and female moths experience increased vulnerability during copulation.
Choristoneura fumiferana
11479486#4
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. It includes the Boreal Forest as well as the Great Lakes-St. Lawrence, Northern, and Acadian forest regions. This range extends westward to Alaska. The spruce budworm is commonly found in boreal and sub-boreal forest regions, specifically those that consist of spruce-fir forests.
Choristoneura fumiferana
11479486#3
Clemens originally named the eastern spruce budworm, "C. fumiferana", in 1865, which was recognized as a Nearctic representative of the genus C"horistoneura". At this time, the name applied to populations in a variety of geographic regions and biotopes. The "C. pinus," a distinct form of the "Choristoneura," was later established as a separate species. However, a large group of this genus in the western part of North America remained taxonomically undefined as the "western complex" until T.N. Freeman established several new species in 1967. Field collections of late instar larvae of "Choristoneura" populations were taken from a range of localities in a wide arc, from the Atlantic seaboard along the edge of the Laurentian Shield to the Mackenzie River area near the Arctic Ocean. From these collections, only points east of the Rocky Mountain foothills yielded "C. fumiferana." The two-year-cycle budworm "C. biennis" occurs only in the subalpine forest region, with alpine fir and interior spruce as hosts. Budworm populations from Rocky Mountain regions south of the area of introgressive hybridization of spruce differ from "C. biennis". Other budworms are of little or no consequence with respect to spruces.
Choristoneura fumiferana
11479486#27
Eastern spruce budworm moths are strong fliers and disperse in exodus in the evening. They can fly at elevations over 100 meters before going to a new site, which is typically only 50 to 100 kilometers downwind, but can sometimes be up to 450 km away. After depositing some eggs at the first dispersion site, female moths may emigrate and lay eggs at multiple sites. Factors controlling budworm flight during dispersal include meteorological conditions and temperature. Moths will not disperse when the temperature is below 14°C or above 30°C. When the temperature drops below 14°C mid-flight, the moth will fold its wings and descend from the sky.
Choristoneura fumiferana
11479486#28
Long distance migration of the spruce budworm does occur as they can disperse across distances ranging from 20 to 450 km. In northern Minnesota, spruce budworm moths emigrate to the east lakeshore of Lake Superior in Ontario, Canada, because of seasonal changes. Dispersal is influenced heavily by temperature as low temperatures can slow down both take off and arrival. Other factors include dispersal direction, precipitation, altitude, and wind flow. It is likely that mass exoduses of the "C. fumiferana" over long distances are a result of food shortage in the local area.
Choristoneura fumiferana