Pest profile

Crowned Slug Caterpillar

Isa textula · Lepidoptera: Limacodidae[3]

The crowned slug is a flat, pale green slug caterpillar ringed with plumes of stinging hairs; it feeds on oak, maple, cherry and other hardwoods in summer and fall and can sting painfully if touched.[1][2]

Pale green, flattened crowned slug caterpillar fringed with spiny plumes, with small red marks on its back
Pale green, flattened crowned slug caterpillar fringed with spiny plumes, with small red marks on its back. (c) Clay Gibbons, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Caterpillars are flattened, oval and pastel green, with plumes of stinging hairs around the edge and shorter stinging hairs on top.[1]
  • Two pale lines run down the back, ending in a pair of “horns” at the front and a pair of stinging plumes at the rear; some have small red dots.[1]
  • Adults are small brown moths about 3/4 inch long with a one-inch wingspan.[1]

Look-alikes

Look-alikeHow to tell them apart
Saddleback caterpillarThe most common slug caterpillar: charcoal gray with a lime-green saddle across the middle.[2]

Where it lives

NC State reports it on hardwoods in North Carolina; slug caterpillars as a group are among the stinging caterpillars of the Southeast.[1][2]

US map: public records from 31 states since 1990 (GBIF).

Biology and life cycle

Caterpillars feed in summer and fall, even as leaves begin to change color, then spin dense, slightly oval cocoons, usually on the host plant.[1]

Moths fly from May to August, and there is probably one generation a year.[1]

Hosts include cherry, elm, hickory, linden, maple, oak, Norway maple and other trees and shrubs.[1]

Damage and signs

  • It is rarely encountered and does little damage to trees.[1][2]

Health risk

The hollow stinging hairs release venom that causes burning pain and inflammation; NC State notes the symptoms can last several days.[1][2]

Control

Prevention

Most stings come from brushing against trees and shrubs during yard work; admire them without touching.[2]

Traps and physical control

Be careful if removing one by hand, since the stings are uncomfortable for days.[1]

Pesticides

No preventive treatment is needed, because the caterpillar is so rarely encountered.[1][2]

Common questions

What should I do if a crowned slug stings me?
Use tape to pull out broken spines, wash the area with warm soapy water and apply an ice pack to reduce swelling and pain.[2]
Is the crowned slug dangerous?
It stings painfully and the symptoms may last several days, but it is rarely encountered.[1]
Do I need to spray my tree?
No. It is so rarely encountered that preventive treatment isn't necessary.[1][2]

Sources

  1. NC State Extension, “Crowned Slug Caterpillar (PDIC Factsheet).” content.ces.ncsu.edu/crowned-slug-caterpillar (accessed 2026-10-15)
  2. Clemson Cooperative Extension, Home & Garden Information Center, “Stinging Caterpillars (HGIC 2482).” hgic.clemson.edu/factsheet/stinging-caterpillars/ (accessed 2026-10-15)
  3. iNaturalist, “Isa textula taxon page (order and family).” www.inaturalist.org/taxa/154469 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.