The bugs that could soon have an impact on Ballarat’s trees

Infestation: An elm leaf beetle sits on a severely laced leaf on an elm tree near Scott Parade in Ballarat East. Pictures: Peter Kervarec, Ballarat Photography
Infestation: An elm leaf beetle sits on a severely laced leaf on an elm tree near Scott Parade in Ballarat East. Pictures: Peter Kervarec, Ballarat Photography

An elm leaf beetle infestation on V/Line land has Ballarat residents concerned for the safety of the city’s tree population. 

But a local arborculturalist says while an unchecked hotbed of beetles is concerning, most elm trees under siege from the pest will be able to rebound with treatment. 

Photographer Peter Kervarec noticed that trees in the train yard at the apex of Ligar Street and Scott Parade were showing signs of stress. 

“I saw the trees there and I genuinely thought they’d been poisoned,” he said.

“You could see where the elm trees end and different species that weren’t being effected started, because they weren’t brown. 

"I got closer and I saw a beetle, and then more beetles, and after some research on my phone I realised what they were.

“If they get a foothold and infest more trees, it could be a disaster, you think about the implications for a place like Vic Park.”

The elm leaf beetle was first discovered in Australia in 1989, and found its way to Ballarat by 2001.

Munching: Mature elm leaf beetles create 'shot holes' in leaves, while larvae cause skeletonisation of the leaves, eating everything except the leaf veins.

Munching: Mature elm leaf beetles create 'shot holes' in leaves, while larvae cause skeletonisation of the leaves, eating everything except the leaf veins.

Warrenheip arborculturalist Paddy Arnts, known as Paddy the Tree Fella, said while infestations of elm leaf beetles restricted photosynthesis by lacing leaves, they don’t kill elm trees instantly. 

Since Ballarat has come out of a period of drought, trees in the city are fairing well generally, and are less susceptible to pests such as the elm leaf beetle. 

“I haven’t seen any severe infestations generally getting around, but the elm leaf beetles certainly are around,” Mr Arnts said. 

“Worst case scenario would be a severe infestation which skeletonises the leaves, bringing about decline in tree health, over a number of years it sends the tree into decline and death.

“The usual problem is where some will treat for beetles, some trees will be left untreated.”

Brown but not out: Much of the foliage on the Ligar Street trees have been damaged, but arborculturalists say it takes multiple years of infestation to kill trees.

Brown but not out: Much of the foliage on the Ligar Street trees have been damaged, but arborculturalists say it takes multiple years of infestation to kill trees.

Mr Arnts said a simple thing to do was leaving leaf matter around tree trunks, allowing necessary nutrients to re-enter the soil and helping the tree to flourish and be pest-resistant. 

City of Ballarat director of infrastructure and environment Terry Demeo said that Ballarat was home to one of the most significant private an public populations of elm trees in the world. 

“While our elm trees are in a good state of health, most elm trees in the City of Ballarat contain elm leaf beetles,” he said.

“The City of Ballarat has a regular treatment program to manage elm leaf beetle infestation on public land.

“While it is unlikely that we will eradicate the elm leaf beetle, we work to manage its numbers.”

The municipality has a dedicated arborculture team which monitors the health of elm trees. Residents can speak with a member of the team on 5320 5500 for advice.