(one synonym : Prodenia tasmanica Guenée, 1852)
ACRONICTINAE, NOCTUIDAE, NOCTUOIDEA
Initially, the Caterpillars are a translucent green with a dark mark on the thorax.
Later instars are smooth-skinned with a pattern of red, yellow, and green lines, and with a dark patch on the mesothorax.
Initially the caterpillars only eat the flesh of their food leaves, leaving the veins intact. Later, as they grow, they eat whole leaves, and even flowers and fruit. The caterpillars become brown with three thin yellow lines down the back: one in the middle and one each side. A row of black dots run along each side, and a conspicuous row of dark triangles decorate each side of the back.
The caterpillars are an international pest and eat nearly any herbaceous plant, including :
The last instars are very dark, with four prominent yellow triangles on the thorax.
When disturbed, the caterpillar rears up and curls its head under its body.
If further disturbed, it curls into a tight spiral with the head protected in the centre.
When mature, the caterpillar burrows into the soil below the plant for several centimetres and there pupates without a cocoon. As it does so, it produces a quantity of fluid, and will drown in this if it pupates in captivity in an empty glass jar. It will pupate successfully if 0.5 cm. of sand is provided in the container.
The duration of the pupal stage in January in Melbourne is three weeks, but caterpillars that pupate at the end of summer emerge the following spring.
The adult moth is brown with a complex pattern of cream streaks criss-crossing the forewings. The hindwings are silvery white. The moth has a wingspan of about 4 cms.
The males but not the females have a blue-grey band from the apex to the hind margin of each forewing.
The pheromones of this species have been elucidated.
The eggs of this species are normally laid in an irregular furry mass on the underside of a leaf of a foodplant.
For small numbers of plants: the best control is to pick the caterpillars off and deposit the caterpillars somewhere else where they will cause no concern. Also inspect leaf undersides every day and pick off leaves with egg masses on them.
We recommend against using insecticides, which may leave residues in the fruit harmful to to humans, as they reduce the parasite and predator populations next year: so are not a long term solution.
Various other methods of control have been investigated :
The species occurs across south-east Asia and the Pacific, including:
as well as in Australia in
In Sydney, New South Wales, counts were made of the number of adults coming to a nightly ultra-violet light, and the numbers totalled for each month of the year :
These indicate that there is only one brood a year in that area.
Further reading :
Butterflies and Moths,
Collins Eyewitness Handbooks, Sydney 1992, p. 257.
Ian F.B. Common,
Moths of Australia,
Melbourne University Press, 1990, figs. 48.20, 55.14, pp. 34, 34, 38, 65, 461.
Johan Christian Fabricius,
Historiae Natvralis Favtoribvs,
1775, p. 601, No. 50.
Tropical Queensland Wildlife from Dusk to Dawn Science and Art,
LeapFrogOz, Kuranda, 2015, p. 121.
(written 15 August 1996, updated 21 February 2018, 28 September 2019, 15 July 2020, 25 January 2022)