Hoverflies – cropping’s gift to urban gardens

Invasions of this aphid–devouring insect will help urban IPM and protect all those roses.

Where have they been reported?

There is abundant evidence that hoverflies have arrived en masse in Melbourne and other areas to the east and south of Victoria in the first weeks of October.

Adult hoverflies have been seen flocking around flowering and non-flowering garden plants and weeds alike.

They are often being mistaken for small bees or wasps.

Enquires have even reached Victorian talkback radio.

The good news is that hoverflies are not a plant or household pest; rather an important beneficial insect.

Hoverfly larvae (Melangnya spp.) attack a range of soft-bodied insects and are a particularly voracious predator of aphids. The larvae are often mistaken for pest caterpillars such as diamondback moth.

There is no doubt that hoverflies, and other beneficials, have held back damaging aphid populations in crops, and will continue to do so in urban gardens.

This spring, hoverfly numbers have been very high across large parts of south-eastern Australia.

This is probably because of the consistently large numbers of cereal and canola aphids experienced in crops over winter and early spring, allowing the rapid, ubiquitous growth of hoverfly populations.

In Europe, hoverflies are known migrants, so this is also likely to be the case in Australia.

The Tasmanian Government has also reported much larger than usual immigrations of hoverfly over the Bass Strait from the mainland in early October.

So urban gardeners and horticulturalists are now benefitting from the hoverflies arriving from agricultural and native landscapes. 

About hoverflies

Hoverfly adults are 4-10 mm long and have dark-coloured flattened bodies with black and yellow markings.

As the name suggests, they ‘hover’ over objects and look similar to bees and wasps.

Adults feed on aphid honeydew, nectar and pollen, and can also be a useful pollinator.

Eggs are laid on the vegetation, in close proximity to pests.

Larvae are maggot-like, legless grubs with no eyes and vary in colour from cream to green or brown. Many have white stripes on their upper side, and they can grow up 10 mm long.

Larvae move on the vegetation searching for prey. They grip and pierce their prey with their mouth hooks and suck out the body contents.

Hoverfly larva with tapering head region and no visible legs. Photo by Andrew Weeks, Cesar Australia

Cover image: Photo by Andrew Weeks, Cesar Australia

What is Pestfacts south-eastern?

PestFacts south-eastern keeps growers and advisers informed about invertebrate pests and beneficials in broadacre crops and pastures during the winter-cropping season in Victoria and southern New South Wales.


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Since 2019 PestFacts south-eastern has been running through IPMforGrains: Best Practice Insect Pest Management, a project delivered by the National Pest Information Network (Cesar Australia, DPIRD, QDAF, NSW DPI, and SARDI). This project aims to provide grain growers and advisors with information on invertebrate grain pest occurrence and equip industry with the knowledge needed to implement integrated pest management practices. This initiative is a GRDC investment and includes in-kind contributions from all project partner organisations.

The online PestFacts south-eastern collection also includes a selection of articles published between 2015 – 2018 when the service was run through a previous GRDC investment, The National Pest Information Service.

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