A WAVE of leaf-eating beetles is moving through the eastern suburbs, causing damage to century-old trees.
Burnside Council has found elm leaf beetles in trees along Rose Park's memorial avenue.
The beetles' tiny larvae feed on the leaves of elms, destroying their ability to absorb sunlight and produce energy reserves.
Burnside chief executive Paul Deb said 12 trees in Prescott Tce and Alexandra Ave were plagued by the beetle and another eight showed signs of infestation.
He said the council was not aware of any other infestations in the Burnside area.
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David Lawry, director of conservation group Treenet, said the beetle had spread quickly throughout Adelaide after it was first discovered in Malvern in 2011.
"It is now quite widespread," Mr Lawry said.
"We've got this elm leaf beetle for good. It threatens most elm species but the English elm is most affected."
He said older trees that had already suffered through drought were more susceptible to damage.
"Those trees won't survive an elm leaf beetle attack," he said.
Mr Lawry expected the beetles would spread to elm trees in neighbouring properties. "It won't take long for them to go from one tree to another," he said.
Leaves ravaged with tiny holes were a tell-tale sign a tree was infested with the beetle.
"It's looks like you've fired them with a shot gun," Mr Lawry said.
Affected trees could be treated in spring with expensive insecticide treatments, via soil or trunk injections, to destroy the beetles' larvae. "It's too late to do anything now because the beetles will hibernate over winter," he said.
Mr Deb said the council would treat the Rose Park elms with either soil treatment or trunk injections.
"Council takes the matter of elm leaf beetle infestation as a serious threat to our urban character, particularly our war memorial tree avenues in Rose Park," Mr Deb said.
Norwood, Payneham & St Peters Council treated more than 100 elms in March to protect them from the beetle.