Fireblight Beetle Larvae

In earlier posts we showed the massive impact that Fireblight Beetles have on the regrowth of some Wattle species following the 2009 fires. This included a massive dieback of Wattles which was most visible in spring followed by a recovery in Summer when the Beetles stopped being active. Well the cycle of dieback has started again and currently the Beetle Larvae are actively chomping away on the new Wattle growth. See this video below for vision of the Larvae in action and let this site know if you can find any activity in a forest near you. This video was taken in the Won Wron State Forest.

Fireblight Beetle Site Summer Recovery

In the Spring time last year this site posted an article on the damage to Wattles that Fireblight Beetle can cause, where thick regrowth of Black Wattle had been completely defoliated by these beetles and their larvae.

Over Summer the Fireblight Beetles have gone to ground and the Wattles have staged a dramatic comeback, with virtually all the wattles that looked dead and gone re-sprouting with fresh new growth along with new seeds germinating. Surely there will be another dramatic change later in the year in the cooler months when the Beetles become active and the Black Wattles will cop another attack. The whole process of the Wattles losing their foliage in spring would benefit other native plants that are fighting for space and light.

Black Wattles recovering form their battle with Fireblight beetles last winter.

This site in September last year had all the Black Wattle (Mid Storey) defoliated by the Fireblight Beetle.

This same area 6 Months later and the Wattle saplings still look quite bare but most have regrowth.

Fresh Black Wattle regrowth with no sign of any Fireblight Beetles (yet)

Eucalypt seedling taking advantage of the Wattle dieback to have a growth spurt.

Not only have the existing Wattle trees resprouted but new seedlings are also popping up.

Are your Wattles dying?

Recently a fairly dramatic change to the understorey has been occurring in some areas affected by the 2009 Bushfires. In some localities where the fires triggered mass germination of either Black Wattle (Acacia mearnsii) or Silver Wattle (Acacia dealbata) widespread defoliation and dieback of these species has become very apparent.

The cause of this dieback is an insect known as the Fireblight Beetle (Peltoschema orphana ). The Beetles lay eggs on the underside of the leaves and the small grub like larvae also feed on the foliage. The species (although native to Australia) has been identified as a significant pest when people have tried to establish Wattle plantations and the thick regrowth after fires of the wattles has mimicked these conditions.

The dieback has resulted in a rapid opening up of the understorey and more light and less competition will enable other species to grow. Look out for weeds taking advantage of this new open space, but hopefully the event can provide an opportunity for other native understorey species to flourish, while retaining enough Black and Silver Wattle trees to continue to provide important habitat for animals such as sugar gliders and various bird species.

The Beetle is thought to avoid summer heat by hibernating in spring. It emerges in Autumn to start eating new foliage and lay its eggs. The hatched larvae then form into new beetles and the cycle continues.

Fireblight- Beetle – Peltoschema Orphana as it munches away on the foliage of a Black Wattle – Acacia mearnsii

Wattle Dieback caused by Fireblight Beetle