ABC News reported on November 12, 2026, that an estimated 800 roses across 33 varieties in Sydney's Centennial Park are being protected from a heavy aphid infestation with ladybirds and parasitic wasps rather than chemical sprays. Senior horticulturalist Tristan Harman said aphids typically gather on new shoots after winter pruning and can distort roses, spread viruses between plants and encourage black mould.

About 1,000 ladybirds and thousands of parasitic wasps, including eggs, were supplied by a South Australian company and released in five batches from September to early November. Harman said the insects had won after the second release in late September. He described the wasps as laying eggs inside aphids. The garden was planted in 1909, and the insects are released annually; this year's batch cost about $1,300.

Harman argued the approach is comparable over the growing season to chemicals that can kill bees and other unintended targets. He said about 17 million people visit the park each year, so staff aim to maintain it without spraying unless absolutely necessary.