New season of Bag-shelter moths and processionary caterpillars has started

Tree-hugger and ground nesting Ochrogaster lunifer (Bag-shelter) moths are emerging from their over-wintering places in the ground, and mated females are laying eggs on host trees. The eggs are laid on the bark and then covered with scales from the female’s body. The egg masses (photos below) look like small cotton wool balls because of the covering of scales. The scales are very urticating (itchy), and if they come in contact with your skin you may instantly get a rash and an allergic reaction.

White egg mass of a ground-nesting form of Ochrogaster lunifer (the Bag-shelter moth) laid at the base of the trunk on an Acacia salicina host tree.
Egg mass of the tree-hugger nesting form of O. lunifer laid on a twig in the canopy of an Acacia salicina (which is not normally a host of this form). Tree-hugger, trunk and canopy -nesting forms of the Bag-shelter moth have golden-coloured egg masses.
Newly emerged female tree-hugger moth with a piece of pupal case attached to her wing

It will take approximately 3-4 weeks for an egg to develop and hatch into a first instar larva.

NOW is a good time to search for egg masses and destroy or remove them before they develop into a nest of caterpillars. We have found a sharp chisel is effective at scraping egg-masses from trunks, any remaining eggs can be picked off with tweezers. Egg masses in the canopy can be easily removed with pruners. Don’t remove egg masses in windy weather. Cover up completely and particularly protect eyes from the scales covering the eggs. Work upwind even in light breeze conditions. Once removed, egg masses need to be contained and buried or completely incinerated in an appropriate facility so the scales do not contaminate the environment. Wash all implements well.

Acacias (wattles) and some species of Eucalypt and Corymbia (gum) trees are the main host trees to check.


See our gallery of images for more photos of moths and egg masses here.