Pest profile

Saltmarsh Caterpillar

Estigmene acrea · Lepidoptera: Erebidae[2]

Saltmarsh caterpillars are hairy, color-variable caterpillars that mostly eat pigweed, sometimes moving onto beans, lettuce, tomatoes and grapes in fall.[1]

Hairy orange-brown saltmarsh caterpillar with long tufts of hair, on a leaf
Hairy orange-brown saltmarsh caterpillar with long tufts of hair, on a leaf. (c) Justin Williams, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Caterpillars are very hairy, with long tufts on colored bumps, in black, brown, gray, orange, white or yellow mixes.[1]
  • They reach about 2-1/4 inches when grown.[1]
  • Adults are white moths with black spots, about 1-1/2 to 2 inches across; males have orange hind wings.[1]

Where it lives

UC IPM calls it an uncommon pest of field and vegetable crops and grapes.[1]

US map: public records from 42 states since 1990 (GBIF).

Biology and life cycle

Mature larvae overwinter and become moths in early spring; females lay egg clusters of up to several hundred under leaves.[1]

Egg to adult takes four to six weeks, with three to four generations a year.[1]

The fall generation is the largest and does the most damage.[1]

Damage and signs

  • Older larvae chew through leaves, leaving ragged foliage on beans, carrots, cole crops, grapes, lettuce and tomatoes.[1]

Health risk

It feeds on plants; UC IPM mentions no risk to people.[1]

Control

Biological control

Tachinid flies and an Ophion wasp parasitize it, often unnoticed.[1]

Pesticides

Only if intolerable, spray leaf undersides with Bt or spinosad; apply spinosad to blooming plants only in the evening.[1]

Common questions

What is the very hairy caterpillar on my lettuce?
Possibly a saltmarsh caterpillar, which is most common in fall.[1]
Do I need to treat?
It's sporadic and uncommonly warrants control.[1]

Sources

  1. University of California Statewide IPM Program, “Saltmarsh Caterpillar (Pests in Gardens and Landscapes).” ipm.ucanr.edu/PMG/GARDEN/VEGES/PESTS/saltmarshcater.html (accessed 2026-10-06)
  2. iNaturalist, “Estigmene acrea taxon page (order and family).” www.inaturalist.org/taxa/121612 (accessed 2026-10-06)

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