Pest profile

Redhumped Caterpillar

Schizura concinna (iNaturalist: Oedemasia concinna) · Lepidoptera: Notodontidae[2]

Redhumped caterpillars feed side by side in groups and can strip branches of sweetgum, plum and walnut, but spot pruning and parasitic wasps usually keep them in check.[1]

Group of redhumped caterpillars with red heads, red humps and yellow, black and white stripes, feeding on a leaf
Group of redhumped caterpillars with red heads, red humps and yellow, black and white stripes, feeding on a leaf. Red-humped Caterpillar Moth - Schizura concinna, Mason Neck, Virginia by Judy Gallagher — via Flickr, CC BY 2.0

How to identify it

  • Older caterpillars are 1 to 1-1/2 inches long, yellowish orange with black and white lengthwise stripes and a red head.[1]
  • A reddish hump with two black spines rises on the first abdominal segment, and rows of dark bristly bumps run along the body.[1]
  • Larger caterpillars often hold the rear end raised.[1]
  • Eggs are cream to yellow spheres laid in groups of 25 to 100 under leaves.[1]

Where it lives

It occurs through much of the United States; in California, high populations are mostly in the Central Valley.[1]

US map: public records from 41 states since 1990 (GBIF).

Biology and life cycle

Moths emerge in April and May; caterpillars pass through five instars.[1]

In autumn, grown caterpillars spin cocoons in topsoil or litter and overwinter as prepupae.[1]

There are two or more generations a year in California's Central Valley.[1]

Damage and signs

  • Young caterpillars skeletonize the undersides of leaves; older ones eat all but the tough veins and may defoliate small trees.[1]
  • They don't feed on fruit or nuts, though fruit can sunburn and drop after heavy defoliation; healthy trees usually recover.[1]

Health risk

It feeds on tree leaves; UC IPM mentions no risk to people from the caterpillar.[1]

Control

Traps and physical control

Check lower leaves weekly in April and May, and prune out shoots with egg masses or young caterpillar groups.[1]

Biological control

Parasitic wasps such as Cotesia schizurae and Hyposoter fugitivus often prevent outbreaks; if parasitism is common, no further action is needed.[1]

Avoid long-lasting carbamate, organophosphate and pyrethroid sprays, and plant nectar flowers near problem trees.[1]

Common questions

What are the striped caterpillars with red heads on my plum tree?
Probably redhumped caterpillars; look for the red hump with two black spines behind the head.[1]
Do I need to spray?
Usually not; spot pruning and natural parasites are enough in most situations.[1]

Sources

  1. University of California Statewide IPM Program, “Pest Notes: Redhumped Caterpillar (Publication 7474).” ipm.ucanr.edu/PMG/PESTNOTES/pn7474.html (accessed 2026-10-06)
  2. iNaturalist, “Oedemasia concinna taxon page (order and family).” www.inaturalist.org/taxa/1391456 (accessed 2026-10-06)

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