The Bugs Are Back – Protecting Our Koala Food Trees

October 13, 2025

Spring and summer bring new life across the Mid North Coast – and that includes the return of some less-welcome visitors to our eucalyptus plantations. With warmer weather, insect populations surge, and our plantation teams focus again on insect inspections and treatments. As it warms up, the young crawler stage of these pests emerges, which is the most vulnerable stage to control measures, so it’s the best time of year to manage pests that threaten our vital koala food trees.

These plantations play a critical role in supporting the koalas in our care. They provide a reliable, chemical-free food source for the koalas in our care, and are an essential part of our Wild Koala Breeding Program. Every leaf matters. Protecting the health of these trees is vital to the survival of the koalas who rely on them.

Tiny Pests with a Big Impact

Much like we explored in our earlier blog about the “not-so-boring borers”, not every bug is a villain – in fact, many play an important role in maintaining healthy ecosystems. After the success of last year’s use of lacewings and ladybugs, we’ll revisit this biological control method, and reintroduce the adults and larvae into affected trees, under the expert guidance of Bugs for Bugs. This will help reduce the numbers of these pest insects, because some species can cause real problems when their populations grow unchecked.

This year we’ll also focus on reducing numbers of the black tyrant ant, Iridomyrmex rufoniger. These ants have a symbiotic relationship with the sap sucking insects, by offering protection in exchange for their sweet excretions, known as honeydew. The ants effectively ‘farm’ the other insects. By protecting these insects in exchange for their honeydew, the ants actually help the pests thrive, putting extra stress on the trees.

The ants stimulate the aphids or larvae with their legs to encourage excretion of honeydew, which the ants take back to their nest. These ants typically nest in the soil, under bark or stones, or in fallen timber, although we’ll restrict our control measures to the base of the affected trees only.

Why It Matters

By managing insect pressures, we’re not just protecting individual trees – we’re safeguarding an entire food source that sustains hundreds of koalas each year. The Maria River Plantation, in particular, provides thousands of kilograms of fresh leaf annually, keeping our koalas healthy, well-fed, and ready for release or breeding.

Working with Nature

At Koala Conservation Australia, we take a careful, chemical-free, and nature-based approach to managing our trees and pests. Ensuring our plantation trees are strong and thriving is at the heart of everything we do. By carefully managing pests and supporting our plantations, we’re feeding the koalas in our care, top quality food.

So, the next time you see ants busily marching up a tree trunk, spare a thought for the bigger picture: in our plantations, every small insect interaction has a ripple effect that can reach all the way to the leaf tips – and the koalas who munch on them.