How to Control Against Carrot Fly

How a great harvest can all come to a sad end with the subterranean activities of the carrot fly grub. These pests have led many a hardened gardener to give up growing carrots altogether.

The Carrot Fly is a small white fly that can sniff out and hunt down it's favourite host plant – the carrot. It is however not the fly the causes the damage but it is the fly’s young offspring. The carrot fly starts out life as a larvae or grub, these tiny critters munch munch munch down on carrot roots in an attempt to gain enough energy to go through it’s metamorphosis into an adult fly.

While doing so, the grubs burrow through the carrot leaving a tiny black tunnel which can rot further.

How to Recognise

1.    Rusty brown scar rings on the top of the carrot’s root
2.    Tiny black holes on the outside of the root
3.    Development of rotting around these holes
4.    When the carrot is cut open the small tunnels are revealed

How to Control

Reduce smell
The first line of defence is good plot management practises. Often to control against pests it is good to keep your plot neat and tidy – however in other cases this can encourage pest attacks. In the case of carrot fly it is best to not disturb the carrots and to always remove and clear any carrot thinnings and harvested carrots from the plot

Timing
The carrot fly life cycle is short and if you time your sowing right you can avoid the worst of  the pests.

• Late sowing of carrots after mid-May will avoid the 1st generation
• Early Harvesting of carrots before late August will avoid the 2nd generation

Physical Barriers

There are many options here.
Fine mesh netting can be used to block the fly from landing on or around the carrot crops hence preventing the fly from laying eggs and therefore preventing any larva from living in the soil around your carrots.

Raised beds can also work to prevent the carrot fly from laying eggs around your carrots. So long as the raised beds are 60cm or more in height the carrot ‘fly’ which can actually only hop cannot reach the dizzying heights of 2ft and hence is prevented from laying its eggs on your carrots.

Crop Selection
There is a number of carrot cultivars (man-bred) varities of carrot that are resistant to the carrot fly:

• Maestro
• Fly Away
• Resistafly
• Sytan

All these methods will work to prevent attacks of carrot fly. And remember, with all pests it is important to rotate your crops over a 4 year period to further prevent attacks and build up of pests on your plot.