As well as causing defoliation damage to Eucalyptus and related species, this leaf chewing pest can cause severe skin irritation to humans that come into contact with it.
- Larva of the gum leaf skeletoniser. Note: characteristic 'hat' formed from retained shed head capsules.
- Stand of eucalypt trees defoliated by gumleaf skeletoniser.
- Skeletonising and chewing damage caused by larvae to eucalypt foliage.
The gum leaf skeletoniser (Uraba lugens) is a common native pest of eucalypt trees around Australia. It can periodically develop outbreaks, completely defoliating trees with damage extending over large areas. Foliage on affected trees initially has a characteristic bronze appearance, as if the tree has been scorched by fire, followed by defoliation.
Outbreaks often occur over the winter months, with damage being most prevalent in late winter-early spring.
Narrow-leaved ironbarks (Eucalyptus crebra) as well as other species such as river red gum (E. tereticornis) spotted gum (Corymbia citriodora ssp. variegata) and western white gum (E. argophloia) can be affected.
Larvae are hairy with yellow and brown markings and a ´hat´ made up of head capsules that are shed after each moult.
There are a number of hairy caterpillars that can be found on eucalypt trees, but the skeletonising damage and ´hat´ formed on the head of the caterpillars is characteristic of U. lugens.
Widespread across temperate, subtropical and tropical Australia.
Larvae are 5-20 mm in length.
Young larvae are usually found clustered on the leaf surface, while older larvae disperse and feed individually.
The larvae damage both leaf surfaces leaving a skeleton of leaf veins. Affected trees have a bronze, scorched appearance from a distance. Older larvae chew entire leaves.
Trees usually recover from defoliation over time, but repeated defoliations can result in tree mortality. Control of caterpillars on trees in the landscape is not feasible. The present outbreak (August - October 2010) is nearing completion, with larvae currently pupating.
In Southeast Queensland Eucalyptus crebra (narrow-leaved ironbark) is particularly susceptible, although other species may be affected when population densities are high. Following defoliation, larvae may move onto nearby trees, structures and buildings.
The larvae are covered with urticating hairs and can cause severe skin irritation in humans. Caterpillars near houses may be sprayed with household insecticides and surface sprays to prevent entry.
Carnegie AJ, Lawson SA, Smith TE, Pegg GS, Stone C, McDonald JM (2008) Healthy hardwoods: a field guide to pests, diseases and nutritional disorders in subtropical hardwoods. Forest & Wood Products Australia, Victoria.
Berndt LA, 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.