Gumleaf skeletoniser
Gumleaf skeletoniser larvae can cause severe skin irritation to humans on contact.
Larva of the gum leaf skeletoniser showing typical 'hat' of shed head capsules
© Queensland Government
Hardwood plantation damage caused by the gumleaf skeletoniser
© Queensland Government
The gumleaf skeletoniser is a common pest of eucalypt trees. Periodic outbreaks completely defoliate trees, causing widespread damage. Initially, foliage on affected trees has a typical bronze appearance, as if the tree has been scorched by fire.
Outbreaks often occur during the winter, with most damage in late winter to early spring.
Scientific name
Uraba lugens
Description
- Hairy caterpillars (larvae) with yellow and brown markings and a 'hat' made up of head capsules that are shed after each moult.
- Larvae are 5–20mm long.
- Young larvae usually cluster on the leaf surface, while older larvae disperse and feed individually.
- The adult moth has a 3cm wingspan with light and dark grey wings.
- See high-resolution images of the gumleaf skeletoniser.
Similar species
Can be distinguished from other hairy caterpillars found on eucalypts by the:
- skeleton-like appearance of the damage
- 'hat' formed on the head of the caterpillars.
Distribution
- Widespread across temperate, subtropical and tropical Australia.
Hosts
- Western white gum (Eucalyptus argophloia)
- Narrow-leaved ironbark (E. crebra)
- Forest red gum (E. tereticornis)
- Spotted gum (Corymbia citriodora subsp. variegata)
Damage
- Larvae graze both leaf surfaces, leaving a skeleton of leaf veins. Affected trees have a bronze, scorched appearance from a distance. Older larvae chew entire leaves.
- Damage is usually restricted to several leaves on a few branches per tree and not widespread in a plantation. However, periodic outbreaks can completely defoliate trees.
- Trees usually recover from damage over time, but repeated defoliation can cause abnormal growth or even tree death.
Biology
- Eggs are laid in lines or parallel rows, usually on the underside of a leaf and in large groups of up to 200.
- Younger caterpillars graze in groups for the first several moults, before becoming solitary as they age.
- Pupation occurs in cocoons created within bark or leaf litter.
Control
- Control of caterpillars on trees in the landscape is not feasible.
- Larvae are covered with stinging hairs which can cause severe skin irritation in humans. Caterpillars near houses may be sprayed with household insecticides and surface sprays to prevent entry.
Resources and research
- Berndt, LA, and Allen, GR 2010, Biology and pest status of Uraba lugens Walker (Lepidoptera: Nolidae) in Australia and New Zealand, Australian Journal of Entomology, 49(3):268–277, viewed July 2023.
- Carnegie, A, Lawson, SA, Smith, T, Pegg, GS, Stone, C, and McDonald, J. 2008. Healthy hardwoods: a field guide to pests, diseases and nutritional disorders in subtropical hardwoods. Forest and Wood Products Australia, Victoria.
- Jones, DL, Elliot, WR, Jones, SR. 2015. Pests, Diseases, Ailments and Allies of Australian Plants. Reed New Holland Publishers Pty Ltd, Chatswood, NSW.