PestFacts south-eastern Hoverfly larvae feed on aphids and adult hoverflies are pollinators. These are good grubs, but they are often misidentified as diamondback moth larvae or other pest caterpillars.
Where have they been reported?
Green legless grubs have been found in sweep net catches within legume and canola crops within the Victorian Wimmera and Mallee, as well as the NSW Riverina.
These have been identified as hoverfly larvae, a beneficial insect that feeds on aphids in it’s juvenile stage.
They are often found in crops during spring in response to aphids colonising crops.
In many instances people misidentify hoverfly larvae as pest grubs, often diamondback moth caterpillars.
About hoverflies
Hoverflies are flies from the family Syrphidae.
The adults have large eyes and a flattened body with black and yellow/orange markings; hence they are easily confused with bees. Adults are pollinators; they feed on pollen and nectar.
The larvae are maggot-like, legless grubs with a tapering head region and no eyes.
Larvae can grow to up to 10 mm long and they vary in colour from cream to green or brown; many have a white stripe down the centre of their back.
Our advice
It is important that grubs are correctly identified before deciding on control strategies.
Hoverfly larvae are a very reliable form of control during the warmer days of spring when low to moderate numbers of aphids are present.
Acknowledgements
Source of field reports of hoverflies
Simon Craig – Agronomist, Agronomise Pty Ltd. (Victorian Mallee)
Andrew Reardon – Agronomist, AGnVET (NSW Riverina)
John Robertson – Agronomist, Agwise Services Pty Ltd. (Victorian Wimmera)
Justin Tidd – Agronomist, Landmark (NSW Riverina)
Nick Zordan – Agronomist, Western Ag (Victorian Wimmera)
Cover image: Photo by Andrew Weeks, Cesar Australia
