An identified infestation of elm beetles could pose a serious threat to the district’s elm trees, the Braidwood Community Association heard at its meeting last week.
Braidwood Gardening Club president John Tuckwell noted this was a widespread problem that required an integrated solution. “The infestations do not usually kill the trees, but old trees are at risk,” Mr Tuckwell said, adding he was investigating a range of treatment options.
A Queanbeyan-Palerang Regional Council representative met with Mr Tuckwell and BCA president Sue Murray to inspect trees in Braidwood township and at Mona Farm. QPRC has previously treated trees on council land for elm beetle infestation and is now looking at more treatment options, including ways to assist owners of affected trees on private land.
The BCA meeting determined that the first concern was to get a census of elm trees in the town, and then work with the owners and caretakers to address the issue. Once that process was complete, Mr Tuckwell would provide a summary of options for treatment. He noted at the meeting that while the insecticide that is recommended is licensed in Australia, it has been banned in Europe.
Elm leaf beetles (Pyrrhalta luteola) were accidentally introduced to Australia and were not discovered until they had become well-established.
While they are most prevalent in Victoria, their spread along major traffic routes is inevitable as they are tiny and can ‘hitchhike’ easily on vehicles and clothing without being noticed.
The beetle is described as being “the size of a small pea” and is yellow or olive with black stripes. It lays tiny eggs on the underside of elm leaves and that generation dies.
The eggs are described as a double row of ‘miniature lemons’. They hatch in 7-10 days. At first the larvae are very small and almost black. They feed on the leaves by eating the green matter, leaving a skeleton of leaf veins.