Genista Broom Moth

How to identify it

• Mature caterpillars are about 1 inch long, tan to greenish-brown with raised black spots, bright yellow patches and sparse long white hairs; the head is black with white dots.^[1][2]
• Moths are light to medium brown with a dark spot on each forewing and yellow or orange hindwings.^[1]
• Young caterpillars are green and feed together, often in silk webbing.^[1][2]

Where it lives

A native species found in southern states and as far north as Iowa, where its shorter season likely limits it to one or two generations.^[1][2]

US map: public records from 29 states since 1990 (GBIF). View the map

Biology and life cycle

Females lay eggs in batches of up to about 70 on host plants.^[1][2]

It overwinters as a pupa in a loose cocoon on or near the host; southern states can see four or more generations a year.^[1][2]

Damage and signs

• Hosts include baptisia (false indigo), brooms, Scotch broom, Texas mountain laurel, lupine and acacia, and it has been reported on crapemyrtle and honeysuckle.^[1][2]
• Feeding in groups, caterpillars can quickly strip a plant, but established plants usually recover; repeated defoliation can stress young plants.^[1][2]

Health risk

The caterpillars store bitter alkaloids from their host plants that make them distasteful or even toxic to birds and mammals, so never eat them.^[1]

Control

Prevention

Because damage is mainly cosmetic and sporadic, many gardeners simply let established plants recover.^[2]

Traps and physical control

Hand-pick caterpillars into soapy water or shake branches to knock them off, especially once they are nearly grown.^[2]

Pesticides

Act while caterpillars are small: Bt, spinosad, insecticidal soap, horticultural oil and neem work best on young caterpillars; fully grown ones have done most of their feeding.^[1][2]

Common questions

What is eating my baptisia?

Often genista broom moth caterpillars, which feed in groups and can strip plants.^[1][2]

Is it too late to spray big caterpillars?

Usually; by the time large caterpillars are found, most damage is done.^[2]

Sources

1. NC State Extension, “Genista Broom Moth (Genista Caterpillar) (PDIC Factsheet).” content.ces.ncsu.edu/genista-broom-moth-genista-caterpillar (accessed 2026-10-16)
2. Iowa State University Extension and Outreach (Yard and Garden), “Genista Broom Moth (Yard and Garden encyclopedia, July 2026).” yardandgarden.extension.iastate.edu/encyclopedia/genista-broom-moth (accessed 2026-10-16)
3. iNaturalist, “Uresiphita reversalis taxon page (order and family).” www.inaturalist.org/taxa/121716 (accessed 2026-10-06)