Warning after Aussie's common discovery at base of tree: 'Stay away'

The mum was desperate not to lose the sentimental tree and was worried about the returning infestation.

A woman desperate to keep her backyard tree alive has pleaded for help to find a solution for an unsightly 'infestation' swallowing the trunk of the tree.

The Aussie mum said the native white cedar tree is "very special" as she and her dad planted it before he died, but she's worried the growth on the base of the trunk might eventually kill it.

At first glance, the unusual brown mass appears to be something growing from the base and making its way up the tree. But the frustrated mum revealed the skin-crawling truth — it's an army of hairy caterpillars.

The furry critters are feeding on the tree and its leaves, and despite her efforts to remove them, they "keep coming back" she said.

Left: Caterpillars on a white cedar tree. Right: A white cedar tree at the Australian National University in Canberra.
Caterpillars invaded the woman's white cedar tree (left). Pictured right is a white cedar tree at the Australian National University in Canberra. Source: Facebook/Australian National Botanic Gardens

"It is infested with caterpillars and I mean the trunk is covered in them you can’t see the trunk," she said of the white cedar tree in a post on Facebook. "I’ve tried killing them with bug spray, hosing them but they keep coming back."

The woman said they are "even in my house" and have "devoured every leaf of the tree" pleading for advice. "Will they eventually kill the tree or just eat the leaves?" she asked, desperate to keep it alive.

Gardening enthusiasts react to caterpillar infestation

Keen gardeners were quick to inform the woman that as frustrating as it is, it's actually pretty normal behaviour. "Cedar are notorious for this infestation," one said. "This is really common with white cedar trees and will come back every year," said another.

Identifying the little critters, one guessed the caterpillars were larvae of the White Cedar Moth, which are "are known to attack these trees" and most often harmless — but can be poisonous to pets.

"You can wrap the trunk in hessian and put an insecticide powder on there so they have to crawl through it," they advised. " I’d say now the leaves are gone, they will move on anyway but maybe something to try next year."

White cedar moth caterpillar. Source: CSIRO
White cedar moth caterpillar. Source: CSIRO

Experts warn 'don't touch' caterpillars

Addressing the woman's concerns, Andrew Mitchell, a research scientist from the Australian Museum Research Institute told Yahoo News Australia the caterpillars won't harm the tree because white cedars are deciduous, so lose their leaves in autumn anyway. He advises leaving them alone because "they disappear by themselves" but said people, especially young children, should "stay away from them".

Dr Darrell Kemp, Associate Professor of Biology at Macquarie University, agreed and said "their hairs might cause allergic reactions if brushed against the skin". "I’ve had such an episode which involved a fairly nasty itchy/stinging rash that lasted about a week," he told Yahoo.

Explaining their behaviour, Dr Kemp said the caterpillars are "communal and largely nocturnal". They emerge from their hiding place at dusk and crawl up the tree to feed.

"They are a medium-sized moth but they do consume a great deal of foliage and often defoliate smaller or even medium-sized trees," he explained. "Once they do that, they will go wandering (as a group) to find another cedar to feed on, and this can see them sometimes end up in garages or even in people’s houses."

While a hairy critter such as this one in your home might come as a shock, Dr Kemp said they won’t infest the house. "They are simply looking for another cedar tree," he said.

Do you have a story tip? Email: newsroomau@yahoonews.com.

You can also follow us on Facebook, Instagram, TikTok and Twitter and download the Yahoo News app from the App Store or Google Play.