Pest profile

Cecropia Moth

Hyalophora cecropia · Lepidoptera: Saturniidae[2]

Cecropia caterpillars are large and colorful, but UF/IFAS says the species isn't a serious pest anywhere in its range.[1]

Large green cecropia caterpillar with colorful knobs on a twig
Large green cecropia caterpillar with colorful knobs on a twig. (c) christine123, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Caterpillars pass five instars about a week each; young ones are black, then yellow, feeding in groups.[1]
  • Eggs are large, mottled reddish brown, laid in small groups on both sides of leaves.[1]

Where it lives

It ranges from Nova Scotia and Maine south to Florida and west to the Rocky Mountains.[1]

US map: public records from 38 states since 1990 (GBIF).

Biology and life cycle

Adults sometimes come to lights in spring and early summer.[1]

Damage and signs

  • Larvae feed on a wide range of hosts such as maples, birches and alders without being serious pests.[1]

Health risk

It's harmless to people; some populations may be declining.[1]

Control

Prevention

No control is needed; it isn't considered a pest.[1]

Common questions

What is the huge green caterpillar with colored knobs?
Possibly a cecropia moth caterpillar.[1]
Is it a pest?
No; it's not considered a serious pest anywhere.[1]

Sources

  1. University of Florida IFAS Extension (Featured Creatures), “Cecropia Moth, Hyalophora cecropia (EENY-478).” edis.ifas.ufl.edu/publication/IN861 (accessed 2026-10-06)
  2. iNaturalist, “Hyalophora cecropia taxon page (order and family).” www.inaturalist.org/taxa/81582 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.