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How to identify it
- The caterpillar is bright yellow-green to lime green, with an unmarked green head and a frosted-looking blue-green underside. Full grown it is about 25 millimeters (1 inch) long.[1][2]
- A white to creamy white stripe runs along each side just below the orange breathing holes and continues onto the rear plate. The stripes higher on the body are faint, light yellow and incomplete, and there are two narrow dark green lines down the middle of the back.[1][2]
- On the upper half of the body, each hair rises from a small pale spot.[1]
Where it lives
It occurs in forests and woodlands across Canada and south in the eastern United States to the mountains of North Carolina. Natural Resources Canada records it in Alberta and British Columbia on western conifers.[1][2]
Biology and life cycle
In the East the caterpillars feed on alder, aspen, blueberry, fir, hemlock, poplar, spruce and willow. In western Canada the recorded hosts are conifers: amabilis, grand and subalpine fir, Engelmann, Sitka and white spruce, mountain and western hemlock, Douglas-fir and western redcedar.[1][2]
It seems to spend the winter as an egg. The caterpillars are new-leaf specialists that hatch just as leaf buds begin to open.[2][1]
In Connecticut there is one generation, with grown caterpillars in May and June. In western Canada caterpillars are present from May to July, pupate in June and July, and the moths fly from July to September.[1][2]
The moths emerge and lay their eggs in late fall in the East.[1]
Damage and signs
- The caterpillars feed alone and move freely about the foliage. Natural Resources Canada describes the green velvet looper as common and on occasion locally abundant, but nondestructive.[2]
Health risk
The sources describe it only as a leaf- and needle-feeding caterpillar; they mention no harm to people.[1][2]
Control
Prevention
Neither source recommends any control; Natural Resources Canada describes this looper as nondestructive.[2][1]
Common questions
- When do autumnal moths fly?
- In the East the moths emerge and lay their eggs in late fall. In western Canada adults are recorded from July to September. The eggs appear to be the stage that spends the winter.[1][2]
- Does the green velvet looper damage conifers?
- Natural Resources Canada calls it a common and on occasion locally abundant, but nondestructive, defoliator in Alberta and British Columbia.[2]
Sources
- USDA Forest Service, Forest Health Technology Enterprise Team, “Geometroid Caterpillars of Northeastern and Appalachian Forests, FHTET-2001-10 (D. L. Wagner, D. C. Ferguson, T. L. McCabe and R. C. Reardon, September 2001; scanned copy).” archive.org/details/geometroidcaterp00wagn (accessed 2026-11-09)
- Natural Resources Canada, Canadian Forest Service, “Green velvet looper, Trees, insects and diseases of Canada's forests.” tidcf.nrcan.gc.ca/en/insects/factsheet/1000007 (accessed 2026-11-09)
- iNaturalist, “Epirrita autumnata taxon page (order and family).” www.inaturalist.org/taxa/173571 (accessed 2026-11-09)