Home / Cossid Millers Moths (Cossidae) / Carpenterworm Moth (Prionoxystus robiniae)

Carpenterworm Moth (Prionoxystus robiniae)

The carpenterworm moth is a member of the family of Cossidae moths. It is widely considered a pest because of the larvae’s ability to bore plants like ash and oak into the wood. This moth is found in North America.

Carpenterworm Moth


Scientific Classification

  • Family: Cossidae
  • Genus: Prionoxystus
  • Scientific Name: Prionoxystus robiniae

Description and Identification


The larva’s body ranges from green to red and is covered with black spots. Its head is dark brown, and it even has a hairy appearance.

Carpenterworm Moth Caterpillar



The pupae are fully sclerotized, i.e., they do not spend this stage in a cocoon. They are dark brown, with the female’s length ranging between 3.8 and 5 cm and that of the male being 2.5 cm.

Adult Moth

Sexual Dimorphism: Present. The forewings of the female are more mottled than the male. Also, the yellow color seen in the hindwings of the male is absent in females.

Color and Appearance

Forewing: When the wings are opened, they have a gray mottled pattern. When the wings are closed, the patterns remain observable.

Hindwing: When the wings are opened, they are yellowish-orange with a black border present in the males. When the wings are closed, this color is not visible at all.

Average wingspan: Females: 7.5 cm Males: 5 cm

Flight pattern: Erratic

Season: April-October

Prionoxystus robiniae



The egg is greenish-gray, oval, and 1mm in diameter. Around 200 eggs are laid in clusters inside the crevices of the host plants.

Quick Facts

DistributionSouthern Canada as well as the greater United States
HabitatDeciduous forests
Lifespan of AdultsNot recorded
PredatorsBirds, bats
Host PlantsAsh, chestnut, locust, maple, oak,  poplar, and willow.
Adult DietDoes not feed

Did You Know

  • This species was first described by American naturalist William Dandridge Peck in 1818.
Carpenterworm Moth Image


Carpenterworm Moth Picture


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