How can I prevent carrot fly?
Posted by Dobies Staff on 13 August 2014 02:23 pm

A carrot fly is a small black fly that is reputed to be attracted to carrots by their smell. The fly lays its eggs in the soil and the subsequent grubs then gorge themselves on the carrots causing holes and tunnels. The fly is also quite partial to parsnips, celery and parsley.

Flies from the first batch of eggs are most common towards the end of May to early June whereas flies from the later layings 
appear during August and September.

Sowing the seed thinly towards the end of May/beginning of June should mean that you miss the first generation of grubs. Then, harvest as soon as the carrots are ready and before late summer and you should miss the second generation.

It is also a good idea to surround the plants with fine mesh netting such as Enviromesh, ensuring that the edges are buried beneath the surface, or use our Micromesh Carrot Fly Barrier. They are low flying so a height of about 70 cm (30") should be fine. The biological control Nemasys Grow your Own Multiple Pest Killer can be applied from April to July at 14 day intervals to control carrot fly.

As the fly can be attracted by the smell of bruised foliage it is best to do any thinning during the evening when the flies are less active.
Some varieties of carrot show tolerance to carrot fly.

Links to carrot fly tolerant varieties: 

(5 vote(s))
Not helpful customers