Forest & Grassland Health

Fireweed Hawk Moth/ Hornworm

Fireweed Hornworm

Fireweed hornworms are named for the spine-like horn on their abdomen.  

Hyles galii (Rottenburg)

Primary host(s) in Alaska:

Fireweed and other perennials

Distribution in Alaska: Throughout Alaska

 

Photos

Click on the image for a larger version.

Adult Hawk Moth

Adult hawk moths are one of the largest moths in Alaska. 

Fireweed Hornworm3TN

Fireweed hornworms fed in large numbers in Southeast AK in 2018.

Cute Fireweed HornwormTN

Fireweed hornworms are large and feature a distinctive "horn" on the end of their abdomens.

Fireweed Hornworm2TN

Feeding damage
by fireweed
hornworms.

Current Status in Alaska 

Fireweed hornworms can be found feeding in abundance in late summer throughout Alaska. The large caterpillars can be found on stalks of fireweed and can cause complete defoliation in some areas.          

 

Hornworm FeedingTN

Fireweed hornworm feeding on fireweed foliage. 

Symptoms, Biology & Impacts

Adults are large, grey, with a red band on the hindwing. They can have a wingspan up to 6 cm. Commonly called hawk moths or sphinx moths they are often confused with hummingbirds due to their large size and flight patterns. They are important pollinators and can be found feeding on nectar between May and August. Larvae are called hornworms due to the characteristic "horn" on the eighth abdominal segment.  Larvae are quite large, reaching as long as 8 cm and can be green or black in color with pale spots on the body. They overwinter as pupae in the leaf litter. 

In boreal or montane North America they are referred to as bedstraw hawk moth, as that is their main host there.  


 

Content prepared by Dr. Elizabeth Graham, Forest Entomologist, Forest Health Protection, elizabeth.e.graham@usda.gov.


 

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