Spruce budworm is a native moth that can have a serious impact on our spruce-fir forests in northern New Hampshire. The larvae feed on spruce and fir needles. Typically the budworm populations increase to a peak and then collapse in a 40-year cycle. The last New Hamsphire outbreak ended in 1983. Recently, populations in Quebec have blossomed—8 million acres were defoliated in 2013 (pictured right). It is likely the budworm population will move south into New Hampshire in the next few years.
The N.H. Division of Forests and Lands is monitoring for the budworm. Though called spruce budworm, it actually prefers balsam fir. We expect to see some fir defoliation in about three years. Forests and Lands recommend you evaluate your fir trees for size and projected harvest time. Identify mature forest stands with more than 50% fir. Harvest to reduce the large-diameter fir component. This is managing the forest for reduced future vulnerability.
Caterpiller Clash: The Budworm Returns- Northern Woodlands, winter 2014
Spruce Budworm in the Eastern US- Forest Service
Spruce Budworm- Maine Forest Service
Lowland Spruce-Fir Forests-Habitat Stewardship Series