In August last year, tree crews treated about 260 trees in streets and parks using insecticide designed to kill the beetles once they ate the leaves.

Mayor Reg Kidd said the worst damage occurred last summer, where leaves were eaten before falling off the trees before autumn. 

But he believed the council was “on top of the problem” and the results would be even more visible by next year as more beetles were killed before they had a chance to lay eggs.

“You’ll still see damage this season in the trees we’ve treated because the insecticide needs to be absorbed by the tree, it goes up into the leaves,” he said.

“The beetles and larvae skeletonising the leaf, chewing these holes in it, absorb the vegetation and that kills them.

“The damage in the street trees isn’t as severe as it was last year.”

Sixty trees required stem injection, involving 20-30 half-centimetre holes bored halfway up the trunk to allow chemicals to travel through the branches and into the leaves. 

The insecticide used cost about $1000 a litre and trees needed up to 100 millilitres injected. 

Tablets were buried at the foot of the remaining 200, with insecticide absorbed through the root system, however the method is only effective in spring.

The insecticide provides protection for up to three years and kills both beetles and larvae. 

Cr Kidd said residents should contact an arborist about damaged garden elms. 

Losing leaves early affects a tree’s ability to store energy to grow and resist disease.

“If it’s defoliating all the time, it’s decreasing its food sources and it puts pressure on the tree and can actually cause die-back,” Cr Kidd said. 

“The big golden elm I have in the front of my yard, I noticed there was damage in that and I’ve treated it.”

Bathurst City Council used a contractor to treat its affected elms, however Cr Kidd did not believe the outlay was money well spent.