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Eastern Spruce Budworm

Choristoneura fumiferana[3]

The eastern spruce budworm is a native caterpillar that defoliates balsam fir and spruce across northern North America.[1][2]

Group
Insect
Order
Lepidoptera
Family
Tortricidae
US records
27 states
Sources
3 cited
Updated
2026-10-17
Eastern spruce budworm moth with mottled brown wings
Eastern spruce budworm moth with mottled brown wings. Photo: Trix Niernberger, public domain (CC0), via iNaturalist
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • Look for feeding on new needles from about May; damage shows first at the treetops.[1][2]
  • Despite its name, balsam fir is the most susceptible host and spruces are moderately susceptible.[2]

Look-alikes

Look-alikeHow to tell them apart
Western spruce budwormA related budworm of western conifers.[1]

Where it lives

Native across northern coniferous forests; in New England it is usually a concern only in the north, and it has been active in Minnesota every year since at least 1954.[1][2]

US map: public records from 27 states since 1990 (GBIF).

Biology and life cycle

There is one generation a year; females lay eggs in clusters of 10 to 150 on needles in July and August, and moths can ride winds as far as 50 miles.[1]

First-instar larvae feed little, overwinter as second instars and resume heavy feeding the next spring.[1]

Damage and signs

  • It has historically been one of the most important conifer defoliators in North America, killing vast areas of balsam fir and spruce in outbreaks.[1][2]
  • Dead and dying trees left near homes become a fire hazard.[2]

Health risk

None to people or pets.[1][2]

Control

Prevention

In forests, thinning, avoiding overmature stands and reducing reliance on fir lower outbreak risk.[1][2]

Biological control

Parasitic wasps and flies and bad weather help regulate populations.[1]

Pesticides

Spraying forests is expensive and not very successful, but it is an option for saving yard trees.[2]

Common questions

Is spruce budworm a problem for my yard spruce?
Rarely on landscape trees except during regional outbreaks; yard trees can be protected with sprays.[1][2]

Sources

  1. UMass Extension Landscape, Nursery and Urban Forestry Program (Landscape Insect & Mite Guide), “Choristoneura fumiferana (Spruce Budworm).” www.umass.edu/agriculture-food-environment/landscape/publications-resources/insect-mite-guide/choristoneura-fumiferana (accessed 2026-10-16)
  2. University of Minnesota Extension (Forestry), “Eastern spruce budworm.” extension.umn.edu/natural-resources/forestry-and-wildlife/forestry/forest-pests-and-diseases/eastern-spruce-budworm (accessed 2026-10-16)
  3. iNaturalist, “Choristoneura fumiferana taxon page (order and family).” www.inaturalist.org/taxa/208521 (accessed 2026-10-06)

Updated 2026-10-17. Built from sourced records. Spot an error? Tell us.