The lilly pilly beetle (Paropsides calypso) is a leaf-chewing pest that targets lilly pilly hedges and trees across Australia, stripping new growth and leaving foliage riddled with holes. Both the adult beetles and their larvae feed on leaves, but the larvae do the most damage, sometimes defoliating entire sections of a plant during peak activity in spring.
What the Beetle Looks Like
Paropsides calypso is a small, rounded leaf beetle in the chrysomelid family. Adults are roughly 6 to 10 mm long with a domed, oval body. The larvae are soft-bodied grubs that cluster on leaves, particularly on fresh new growth. Both life stages chew irregular holes and notches into leaves, stems, and developing shoots. When feeding is severe, they can completely strip a plant of its foliage.
When Damage Is Worst
The beetle follows a predictable seasonal cycle, at least in southeastern Australia. Eggs are likely laid at the end of summer and remain dormant until conditions warm up. In Melbourne, October is prime time for larvae to hatch and spread through the plant. One gardener documented catching 180 larvae in a single week in mid-October.
Through the rest of spring and into summer, adult beetles take over as the dominant life stage. Activity can remain high well into December, with populations tapering off as conditions change. This means lilly pilly owners typically face two overlapping waves of damage: heavy larval feeding in early to mid-spring, followed by ongoing adult beetle feeding through summer.
How to Spot the Damage
Lilly pilly beetle damage shows up as ragged, irregular holes chewed through leaves. Unlike psyllid damage (which causes bumpy, pimpled leaves), beetle damage looks like something has physically eaten the foliage. Fresh pink or red new growth is especially vulnerable, and you may notice entire flushes of new leaves reduced to skeletonized remnants. Check the undersides of leaves and along stems for larvae, particularly during October and November. The beetles themselves feed mostly at night, so daytime inspections may only reveal the grubs.
Chemical Treatment Options
There is no pesticide specifically registered for Paropsides calypso in Australia, which limits official recommendations. That said, gardeners have reported success with several approaches.
Because the beetles and larvae feed at night, foliar spraying during the day is not especially efficient for targeting adults. A more effective strategy combines ground treatment with foliage spraying. Bifenthrin applied to the soil around affected trees targets beetles as they move between the ground and the plant, while an organic oil spray on the foliage can help with larvae and eggs during daylight hours. Synthetic pyrethroids have also been used with reported success. When spraying foliage, target the undersides of leaves where larvae tend to cluster, and spray from inside the canopy outward to reach hidden grubs.
Late September or early October, just before larval hatching peaks, is the best window to begin treatment. Starting early can reduce the population before damage becomes severe. For hedges, drenching each plant thoroughly with spray (roughly a litre per tree) in the early morning tends to catch larvae while they’re still active on the leaves.
Cultural Management and Pruning
Healthy, well-maintained lilly pillies recover faster from beetle damage and produce replacement growth more quickly. Pruning can be done at any time of year, and most lilly pillies will respond with a flush of attractive pink new growth. A light tip prune is the most common approach, though plants can handle a hard cut if needed to remove heavily damaged sections. In cooler climates, avoid hard pruning in winter since regrowth will be slow and the plant will look bare for months.
Keep plants well watered before and after pruning to support recovery. Mulching with sugar cane mulch helps retain soil moisture and suppress weeds. For young plants, apply compost or organic pelletised fertiliser in spring, summer, and autumn to maximize growth. Established hedges only need feeding in spring and autumn. Regular tip pruning on the top and sides encourages dense growth from the base up, which helps the plant tolerate some defoliation without looking patchy.
Timing pruning to avoid the peak beetle season can also help. If you prune in late winter or very early spring, the resulting flush of tender new growth arrives right when larvae are hatching and most hungry. Pruning after the worst of the spring feeding has passed gives new growth a better chance of surviving intact.
Are Any Cultivars Resistant?
Unfortunately, there is very limited data on which lilly pilly cultivars resist beetle attack specifically. Some cultivars like Straight and Narrow (Syzygium australe ‘SAN01’) and Sublime (Acmena smithii ‘DOW30’) are marketed for their strong resistance to psyllids, but psyllid resistance does not necessarily translate to beetle resistance. Anecdotally, beetles seem to target Syzygium species broadly, and no cultivar has been identified as reliably beetle-proof. If you’re planting a new hedge in an area where lilly pilly beetle is common, choosing vigorous, fast-growing cultivars at least ensures the plant can recover quickly from feeding damage even if it can’t avoid it entirely.