Requiem for a Spruce: Spruce Budworm in Michigan

April 11, photo by Michael Koole

April 11, photo by Michael Koole

Garret Ellison of the Grand Rapids Press & mLive writes that the Michigan Department of Natural Resources expects spruce budworm to inflict heavy damage on white spruce and balsam fir trees across the Upper and northern Lower Peninsulas this year:

The budworm is “one of the most destructive native insects” in the northern spruce and fir forests of the eastern U.S. and Canada. The worms drop as caterpillars from treetops on webs and feed on tree growth in the spring.

Repeated budworm defoliation can cause top-kill and death in older and stressed trees. Balsam fir older than 60 and spruce over 70 years are prime targets. Younger trees infested with budworms lose much new growth but generally survive.

Read on for more, including how to protect your trees. The U.S. Forest Service has more about the spruce budworm:

The spruce budworm Choristoneura fumiferana (Clemens) is one of the most destructive native insects in the northern spruce and fir forests of the Eastern United States and Canada. Periodic outbreaks of the spruce budworm are a part of the natural cycle of events associated with the maturing of balsam fir.

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 out breaks 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.

Balsam fir is the species most severely damaged by the bud-worm 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.

If you’re intrigued by the “natural cycle” as I was, head over to Wikipedia’s entry on Choristoneura fumiferana, the Eastern Spruce Budworm for an explanation and some pics of these (for a change) native pests.

View Michael’s photo bigger and see more (including lots of tasty macro) in his Around the Yard slideshow.

PS: Sorry about the Monday morning novel … sometimes I over share. ;)