Beneficial hoverfly larvae
- Canna
A grower this week found high numbers of hoverfly larvae while sweep netting a wheat crop near Canna. Cereal aphids were present in the crop which are the food source for the predatory maggots.
As aphids increase in numbers as the weather warms in spring, beneficial species can also increase dramatically in numbers.
The hoverfly larva is a small (up to 12mm long) legless maggot that ranges in colour, but is mainly greenish-brown. They have a slug like body that is tapered towards their pointy-head. They can sometimes be incorrectly identified as caterpillars without careful observation.
Hoverfly larvae are beneficial insects as they feed on aphids with a single maggot capable of eating up to 400 aphids in the two-to-three week period before they pupate. The adult hoverfly resembles a bee with black and yellow colouration. They hover over flowers and are commonly seen darting around above flowering canola crops.
The pupal stage of the hoverfly is a smooth, tan coloured, teardrop shaped creature that maybe seen attached to cereal and canola at this time of the year. The pupae are a little larger than a wheat grain (i.e. about 7mm long and 3mm wide).
When spraying, consider spray options that are soft (for example pirimicarb) on predators.
For more information on beneficial insects refer to DPIRD’s Know what beneficials look like in your crop page.
For more information contact Technical Officer Alan Lord, South Perth +61 (0)8 9368 3758 or +61 (0)409 689 468.
Article author: Alan Lord (DPIRD South Perth).