Elm leaf beetle hitchhiking across Adelaide devouring street trees

The elm leaf beetle is a voracious pest.
Source: News Limited

Image of a elm leaf beetle taken by digital microscope.
Source: News Corp Australia

A VORACIOUS pest is hitchhiking around town on cars and people, devouring whole avenues of heritage trees, gardening writer Jon Lamb says.

Mr Lamb is determined to stop the spread of elm leaf beetle, which first arrived in Adelaide from Victoria four years ago.

“I’m concerned that nobody wants to accept responsibility for the spread of elm leaf beetle in South Australia,” Mr Lamb said.

“SARDI and the Waite entomologists are focused on looking after commercial horticulture and agriculture, and don’t have time or resources to look at the problem and come up with solutions.

“There are a number of issues that need to be addressed, including which is the best form of treatment … Somebody should be looking at that and giving advice. I’m concerned all too often the needs of home gardeners are ignored.”

The problem has been left to councils such as Norwood, Payneham and St Peters Council, which has treated 102 elms on public land with pesticide using the stem injection method. But they won’t touch elms on private land and simply advise owners to contact an arborist.

After treating private trees at Beaumont, horticulturalist Mal Annells was shocked to find that all the elms down Glynburn Rd, Kensington were infested. He stopped to take a look and ended up covered in larvae or “grubs”, the first of two life stages.

“The adult beetle feeds and creates potholes, then lays eggs,” Mr Annells said.

“When the grubs hatch they skeletonise the leaves. So first up you get a whole series of millimetre holes in the tree and then all of a sudden there’s no leaf tissue.”

University of Adelaide entomologist Professor Michael Keller said it was not a biosecurity issue because it was an exotic (foreign) insect attacking an exotic tree.

He said it was “conceivable” beetles could ride on cars or people, but he thought their prevalence along arterial roads might have more to do with water stress, pollution and people moving prunings.

“Trees along those roads tend to be more stressed — you get car fumes, you get less water run-off to the tree — and stressed trees are beyond doubt more susceptible than healthy ones,” he said.

“One of the golden rules of plant protection is the first line of defence have a healthy plant.”

Information about elm leaf beetles can be found on the Norwood, Payneham & St Peters Council website.

 

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Elm leaf beetle hitchhiking across Adelaide devouring street trees