Quick Facts | Spruce Budworm

Spruce Budworm Is….

A native moth

Caterpillars eat needles of fir and spruce trees (hosts), eating some within the bud before the needles expand (budworm)

Spruce budworm is always present in Maine’s spruce-fir forests

Usually hard to find
Every 30-60 years populations outbreak, building to epidemic-levels in sync with maturing hosts
Epidemic-level populations persist for many years

What Happens During a Spruce Budworm Epidemic?

Caterpillars and moths become abundant.
Caterpillars eat conifer needles.
- Favorite foods: primary: balsam fir, white spruce; secondary: red spruce, black spruce, other conifers
Feeding by the caterpillars leads to tree damage and death.
- Damage includes
  - Defoliation
  - Top kill (after several years of heavy feeding)
  - Tree mortality (after about 5 years of heavy feeding)
- Weakened trees not killed by budworm are more vulnerable to other insects (bark beetles and wood borers) and diseases (root rots). This can cause additional loss of wood and tree mortality.
Direct impacts to trees and forests are most severe in northern and Downeast Maine.
- Makeup of the forest is changed (types and ages of trees in the forest)
- Wildlife is affected (some benefit, some lose)
- Forest economy impacted (loss of mature timber; less wood produced; more wood available for the market (lower prices); job loss)

What Can I Expect Outside the Area Where Budworm Feeding Kills and Damages Trees?

Budworm Essentials