Pest profile

Mimosa Webworm

Homadaula anisocentra · Lepidoptera: Galacticidae[2]

Mimosa webworm caterpillars web and skeletonize the leaves of honeylocust and Persian silk trees.[1]

Mimosa webworm moth, a small gray moth with black dots on its narrow forewings, on a leaf
Mimosa webworm moth, a small gray moth with black dots on its narrow forewings, on a leaf. Photo: Dennis White, public domain (CC0), via iNaturalist

How to identify it

  • Mature caterpillars are up to 1 inch, gray to dark brown with five white stripes; they wriggle and drop on silk when disturbed.[1]
  • Adults are small steel-gray moths with tiny black dots on the forewings.[1]

Where it lives

Native to China and Japan, it reached Washington, D.C., in the 1940s and has spread through the eastern US west to Texas and Nebraska.[1]

US map: public records from 25 states since 1990 (GBIF).

Biology and life cycle

Pennsylvania has two generations: first-generation larvae feed from late June, second-generation larvae in August and early September.[1]

Larvae spin webs around leaflets and feed inside them.[1]

Damage and signs

  • Foliage turns brown and can be fully webbed by September; the 'Sunburst' honeylocust is especially vulnerable.[1]
  • Mature larvae sometimes wander into homes looking for overwintering spots.[1]

Health risk

It feeds on plants; Penn State Extension mentions no risk to people.[1]

Control

Prevention

Plant less susceptible honeylocust cultivars such as 'Moraine', 'Shademaster' or 'Imperial', and clean up webbed debris.[1]

Biological control

Bt applied while caterpillars are small and webbing is light works; avoid broad-spectrum sprays that hit parasitoids.[1]

Common questions

Why is my honeylocust brown and webbed in late summer?
Mimosa webworm caterpillars web and skeletonize the leaflets.[1]
Will mimosa webworm kill my honeylocust?
Healthy trees withstand a few years of defoliation, but stressed trees can be seriously harmed.[1]

Sources

  1. Penn State Extension, “Mimosa Webworm.” extension.psu.edu/mimosa-webworm (accessed 2026-10-06)
  2. iNaturalist, “Homadaula anisocentra taxon page (order and family).” www.inaturalist.org/taxa/416957 (accessed 2026-10-06)

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