FAQs related to Gum Leaf Skeletoniser

Gum leaf skeletoniser goes through four different life stages, each looking very different from the other:

Moth

• Eggs are about 1 mm in diameter and are laid in groups of 100 to 200 in parallel rows on young leaves. The eggs are yellow-green at first and turn brown as they develop.
• Caterpillars are hairy and coloured pale yellow with black and grey markings. Older caterpillars have a distinctive 'hat' on their heads.
• Cocoons are usually formed under bark or in leaf litter and are rarely seen.
• Moths are dull grey with silver-grey forewings and a wingspan of 20-30mm.

Two gum leaf skeletoniser life cycles are completed each year, one in summer and one in winter. For more information on the biology of this insect, see the Uraba lugens Factsheet (175 KB).

Caterpillar

Gum leaf skeletoniser caterpillars damage gum trees as they feed on their leaves. The moth's name derives from the young caterpillar's feeding habits. When young caterpillars feed they 'skeletonise' gum leaves by eating the softer parts of leaves, avoiding the veins. Older larvae are capable of eating whole leaves thus increasing damage. This damage can slow tree growth or, in severe cases, even kill younger trees.

Despite its reputation as a eucalypt specialist, gumleaf skeletoniser can also live successfully on other related Australian trees. For more details on its likely impact, see the Factsheet (181 KB).

Gum leaf skeletoniser is found in sub-tropical, Mediterranean, and temperate climates in Australia indicating that it could also be capable of surviving throughout New Zealand, with the exception of alpine areas.

The gum leaf skeletoniser caterpillar is covered with protective spines that sting and may cause irritation. The stiff spines are hollow and contain venom, which can be injected into the human skin upon contact. This often results in local pain (sometimes severe) and welts (swollen patches on the skin) that tend to become itchy. The reaction to gum leaf skeletoniser may last for many days. Note that the spines of dead caterpillars or on shed skin retain their ability to sting.

In case of reaction to gum leaf skeletoniser caterpillars, the following first aid is advisable:

1. Apply ice packs to the exposed area.
2. In case of eye contact, wash area thoroughly and seek medical attention.
3. If ingestion of caterpillar occurs, seek medical attention immediately.
4. If symptoms develop beyond the immediate area of the sting (e.g. widespread rash, shortness of breath or collapse) call an ambulance straight away.

Biosecurity NZ has prepared fact sheets providing more specific public health information:

• Information for schools, kindergartens and childcare facilities (203 KB)
• Information for medical practitioners and other health professionals (105 KB)

For further information, see Derraik JGB. 2006. Erucism in New Zealand: exposure to gum leaf skeletoniser (Uraba lugens) caterpillars in the differential diagnosis of contact dermatitis in the Auckland region. New Zealand Medical Journal 119 (1241)