As Australians, we take pride in our lush gardens and thriving orchards, which beautify our homes and provide fresh produce and a serene escape.

However, a tiny but formidable foe threatens this green tranquillity, leaving a trail of destruction in its wake and causing concern among garden enthusiasts and farmers alike.

Also known as the red-shouldered leaf beetle, it has been spotted in 'plague proportions' across Australia.


Tim Pickles, a seasoned horticulturist and owner of Tim’s Garden Centre in Campbelltown, has been in the business for over four decades and was taken aback by the sheer number of Monolepta beetle.

'They’re in plague proportions. You can't believe how many there are. There are thousands; as soon as you bump them, they all fly into the air, settle, and start eating again,' he said.


This man thought he'd seen it all, but even he was left stunned by the sudden invasion.

Dr Kayvan Etebari, an entomologist and senior lecturer at the University of Queensland, finds the beetles' southern migration 'somewhat unusual.'

He suggested recent weather patterns like warmer temperatures and increased humidity may have created ideal breeding conditions for these pests.

The availability of food plants and natural dispersal are also factors.


Still, Dr Etebari warned that this could be more than a temporary occurrence—it might signal a broader environmental shift.

The damage caused by these beetles is not to be underestimated.

They skeletonise leaves, leaving them riddled with holes like a tea strainer, and they don't stop there.

Flowers and fruits are also on the menu, leading to a rapid and devastating impact on gardens and crops.

One orchard owner near Taree described the situation as 'overnight devastation,' with her trees stripped bare by the beetles.

For farmers, the financial implications of a Monolepta beetle infestation can be severe.


Dr Etebari notes that these beetles can lead to defoliation, reduced photosynthesis, and compromised plant health.

In certain crops, such as soybeans, mung beans, and navy beans, high populations can shred leaves and damage reproductive structures, resulting in significant yield losses.

Maize crops have suffered up to a 40 per cent loss due to these pests.

Tim advised, acting quickly. Spraying with pyrethrum is effective for non-edible plants, but he cautions against daytime use to protect the bees.

'People just go gung-ho and go out and spray their gardens in the middle of the day, and that's when bees forage nectar from the flowers,' he said.

'You don't want to spray during the day because you'll also be killing the bees.'

Dr Etebari offered additional advice for managing these pests.

Regularly inspect your garden for any signs of damage, remove weeds and alternative host plants that may attract beetles, and consider using protective barriers like mesh netting to shield your plants.

If needed, carefully apply registered insecticides, ensuring they are explicitly targeted at infestations.

Thankfully, there is a glimmer of hope. Dr Etebari pointed out that the population of Monolepta beetles can fluctuate significantly from year to year, suggesting that this may not become an annual problem.

In other news, a Melbourne resident observed thousands of plague soldier beetles gathering at Queens Park in Moonee Ponds for a mating event.

Dr Tom White, an entomologist, reassured that the insects pose no harm to humans and are essential to the ecosystem as pollinators and natural pest controllers. You can read more about it here.
Have you seen any Monolepta beetles in your garden, and how are you protecting your plants? How do you think Australia's changing weather will affect garden pests like these beetles in the future? Let us know in the comments below.