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Laboratories and releasing them at selected sites.
Cinnabar moth caterpillars feed on the leaves and flowers of ragwort.
Description
The moths are about 20 mm in length when the wings are closed. The forewings are black with a red stripe along the anterior wing margin and two red spots close to the outer margin. The hindwings are completely red except for a narrow black margin.
The eggs are globular, yellowish and laid in clusters on the underside of ragwort leaves. They turn a pearly-grey a few days before hatching. Newly emerged caterpillars are yellowish with a black head. However, older caterpillars are distinctly marked with alternating black and orange bands and sparsely covered with long pale hairs. When fully fed the caterpillars range from 25 to 30 mm in length. The pupa is dark brown, about 12 mm long and up to 5 mm wide and is sometimes enclosed in a loosely spun silken cocoon.
Life Cycle
The cinnabar moth has one generation per year. The moths have been recorded from late October until mid-December, during which time they mate and lay their eggs. Each female may produce up to 300 eggs which are laid in large clusters on the underside of ragwort leaves. Hatching of the eggs is temperature dependent and can take about 2 weeks. Newly hatched larvae feed on the underside of leaves in the vicinity of the old egg mass. The caterpillars grow rapidly as they devour plant material. The larger caterpillars are particularly conspicuous and are found all over the plant consuming large quantities of foliage and often feed preferentially on flowers.
 Caterpillars are most evident during January when ragwort is in full flower. The caterpillar stage lasts about 1 month during which time it undergoes 5 moults.
When fully fed the caterpillars crawl away from the plants to pupate in a dry sheltered spot such as among the debris at the base of the plants or into crevices under logs, stones and lumps of earth.
The pupal stage is prolonged lasting about 9 months, and the moths do not emerge again until the following spring.
High losses can occur in winter if pupation sites are waterlogged, as pupae cannot stand prolonged immersion in water, although they can survive considerable desiccation.
Prospects
Previous attempts to establish cinnabar moth in Victoria have been unsuccessful due to heavy caterpillar mortality resulting from the combined effects of disease, insect predators and parasites. One predator, a scorpion fly, caused the most serious mortality. As this predator is not common in Tasmanian ragwort infested areas, it is possible that cinnabar moth may have a better chance of establishing here. Cinnabar moth was first released in Tasmania during the spring and summer of 1993/94. Although it is surviving at several sites it is still uncertain whether populations will become permanently established. The surviving populations will continue to be monitored over the next three years.
If cinnabar moth can be established in Tasmania its flower and foliage feeding activities will place additional stress on ragwort and complement the activities of the other biological control agents. These are the already well established root feeding ragwort flea beetles (Longitarsus spp.) and the more recently established leaf and crown boring moth, Cochylis atricaptana (Stephens). Leaf and crown boring moth has now become permanently established in Tasmania as the result of a mass rearing/release program that commenced for this agent in 1995.
The text and images in this page were supplied by Dr. John Ireson, Senior Entomologist, Tasmanian Institute of Agricultural Research.
 
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