Eastern Spruce Budworm
The eastern version of the Spruce Budworm is Choristoneura fumiferana, which is one of the most destructive native insects in the northern spruce and fir forests of the Eastern United States and Canada. According to one common theory, popularized in the 1970s, periodic outbreaks of the spruce budworm are a part of the natural cycle of events associated with the maturing of balsam fir. The catastrophe theory of budworm outbreaks holds that particularly major infestations occur every 40–60 years, as the result of a cusp-catastrophe event, whereby populations jump suddenly from endemic to epidemic levels. An alternative theory holds that outbreaks are the result of spatially synchronized population oscillations that are caused by delayed density-dependent feedback (from various mortality agents) which are synchronized via a process of entrainment.
The first recorded outbreak of the spruce budworm in the United States occurred in Maine about 1807. Another outbreak followed in 1878. Since 1909 there have been waves of budworm outbreaks throughout the Eastern United States and Canada. The States most often affected are Maine, New Hampshire, New York, Michigan, Minnesota, and Wisconsin. These outbreaks have resulted in the loss of millions of cords of spruce and fir. In 20th century eastern Canada, the major outbreaks occurred in the time periods ~1910-20, ~1940-50, and ~1970-80. Longer-term tree-ring studies suggest that spruce budworm outbreaks have been recurring every three decades or so since the 16th century. Paleoecological studies suggest the spruce budworm has been outbreaking in eastern North America for thousands of years.
Balsam Fir is the species most severely damaged by the budworm in the Eastern United States. White, Red, and Black Spruce are suitable host trees and some feeding may occur on tamarack, pine, and hemlock. Spruce mixed with Balsam Fir is more likely to suffer budworm damage than spruce in pure stands.
The range of the spruce bud-worm includes the Northern States east of Montana but the budworm is found wherever host species grow.
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Famous quotes containing the words eastern and/or spruce:
“The Eastern steamboat passed us with music and a cheer, as if they were going to a ball, when they might be going to—Davy’s locker.”
—Henry David Thoreau (1817–1862)
“In some of those dense fir and spruce woods there is hardly room for the smoke to go up. The trees are a standing night, and every fir and spruce which you fell is a plume plucked from night’s raven wing.”
—Henry David Thoreau (1817–1862)