Itchy caterpillars

Family 

Lymantriidae

Euproctis stenomorpha Turner. Identified by RV Southcott. South Australia.

Food plants

Collected by P. Whelan from Eucalyptus tetrodonta F. Muell. (“Darwin Stringybark”) from a school in Darwin 1974 and forwarded to David Lee at SPHTM Sydney and at Howard Springs, August 1981. Also collected infrequently and at very low density on other trees including mango and black wattle (Acacia auriculiformis).

Appearance

A hairy chocolate brown larvae with black tufts of short hairs in two rows along the body. There is a patch of four larger black tufts just behind the head region with a narrow medial white longitudinal patch centrally on the dorsal abdomen.

The moth has a black appearance, with pale yellow sections at the start of the hind wings and a prominent tuft of orange hair at the terminal end of the abdomen. The female is approximately twice as big as the male.

Biology

The main food plant is the Darwin Stringybark. The larvae are found primarily in the wet season and early to mid dry season on mature trees. During the day, the later larval instars harbour at the base of the Stringybark tree in cracks in the bark, beneath partly shed bark or amongst debris at the base of the tree. 

The last instars pupate in these sites, as well as in the nearby vicinity and have been observed pupating on rafters, under termite caps of houses, under seats, and other sheltered areas near the food trees. The larvae spin a silken cocoon and the last larval skin remains inside the cocoon.

Medical effects

The reaction of urticaria and extreme itch can occur by handling the larvae, the pupal cocoon, or even just touching the bark of the tree. If an affected tree bark is handled, there can be a transfer of hairs via the hands to the other parts of the body. Rubbing and scratching can spread the urticaria affected area.

Dr. Scattini, in Katherine has reported a rash all over the back of a victim after urticaria had subsided (pers com.).
Other reports of reaction with severe swelling of the face, especially around the eyes and swelling of the throat and generalised reactions are believed to be due to this species or the Freshwater Mangrove Itchy Caterpillar.

Remedy

Avoid touching the bark of Darwin Stringybark, caterpillars or moths.

Remove trees in urban sites or destroy larvae at resting stage at the base of the food trees by residual application of insecticide to the trunk or leaves of the tree and by wrapping loose bagging impregnated with insecticide at the base of the tree. Burn the area around the base of tree during the day when the caterpillars are resting.

Do not have outside fluorescent or incandescent white lights on after sundown in problem areas or when moths are active. 

Do not touch the black moths.

Do not sleep or sit under lights when the moths are attracted to the lights.

Wash affected clothes or skin well with soap and water.

Apply ice packs or soothing lotions such as Stingose, Calamine Lotion or papaya creme. Antihistamine medications may be required for severe or generalised reactions. Medical advice should be sought for severe reactions.

Reference

Southcott, R.V., 1978, ‘Lepidopterism in the Australian region’, Records of the Adelaide Children’s Hospital, vol. 2, pp. 87–173.

Southcott R.V. Moths and butterflies in Covacevich J, Davie P, and Pearn J, (editors)1987, ‘Toxic plants and animals, A guide for Australia’ Queensland Museum.