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How to identify it
- The caterpillar is tiny, up to 8 millimeters (about 1/3 inch) long, light brown with an orange tint that is strongest on the back, and narrow orangish bands where the segments meet. Its color varies.[1]
- It has a dark brown head, a dark brown shield behind the head with a light front edge, dark brown legs and a brown plate at the tail end.[1]
- The signs are hollowed-out needles bound loosely together with silk on spruce twigs, and in spring, eaten buds.[1][2]
- The moth is very small, with a wingspan of 10 to 13 millimeters (under half an inch).[2]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Other spruce needle miners | Several other Coleotechnites species mine spruce needles, and so do several leafroller (tortricid) caterpillars. The variable color of the orange spruce needleminer suggests it may itself be a complex of several species.[1] |
Where it lives
Natural Resources Canada records it in eastern Canada, and the USDA Forest Service guide covers it among conifer caterpillars of the northeastern United States.[2][1]
Biology and life cycle
It feeds on spruces, including white and black spruce, and balsam fir is also listed as a host. Caterpillars have been photographed feeding on the pollen of white spruce.[1][2]
There is one generation a year. In summer and fall the caterpillars mine needles, which they tie loosely together with silk.[1]
The partly grown caterpillar spends the winter in a hollowed needle. In spring it eats buds or mines needles formed the year before, again tying them with silk. Grown caterpillars are found in June and July and pupate in a silk cocoon.[1][2]
Damage and signs
Health risk
The sources describe it only as a spruce-feeding caterpillar; they mention no harm to people.[1][2]
Control
Prevention
Neither the USDA Forest Service guide nor Natural Resources Canada recommends any control for the orange spruce needleminer.[1][2]
Common questions
- What makes spruce needles hollow and tied together with silk?
- Needle-mining caterpillars such as the orange spruce needleminer. It hollows out needles, binds them loosely with silk, and even spends the winter inside a mined needle.[1]
- When are orange spruce needleminer caterpillars active?
- They mine needles in summer and fall, pass the winter inside a needle, and feed again in spring on buds and old needles. Grown caterpillars are present in June and July.[1]
Sources
- USDA Forest Service, Forest Health Technology Enterprise Team, “Orange spruce needleminer (Coleotechnites piceaella), from Caterpillars on the Foliage of Conifers in the Northeastern United States, FHTET-2004-01 (C. T. Maier, C. R. Lemmon, J. M. Fengler, D. F. Schweitzer and R. C. Reardon, 2004), Bugwood wiki archive.” wiki.bugwood.org/Archive:Caterpillars/Coleotechnites_piceaella (accessed 2026-11-09)
- Natural Resources Canada, Canadian Forest Service, “Orange spruce needleminer, Trees, insects and diseases of Canada's forests.” tidcf.nrcan.gc.ca/en/insects/factsheet/8322 (accessed 2026-11-09)
- iNaturalist, “Coleotechnites piceaella taxon page (order and family).” www.inaturalist.org/taxa/217384 (accessed 2026-11-09)