How to protect carrots from carrot fly

If you have yet to experience that awful sinking feeling of lifting carrot after carrot riddled with dark crevices, tunnelled out by the dreaded carrot fly larvae, then consider yourself lucky. But for those of you that have, fear not! Haxnicks have been fighting various garden pests for over 15 years, and have picked up a few tricks along the way...

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But first... some facts about carrot fly:

• Carrot fly also affects other vegetables in the parsley family, such as Parsnip, Celery and Celeriac
• They are attracted to the smell of bruised foliage
• The larvae that damage the roots can continue to feed through the autumn into winter, moving between plants
• The adult carrot fly is approximately 8mm long

How can you tell if your carrots are infected? - Check for reddening of the foliage and stunted growth

So now we know a little bit about the pest itself, we can look at some of the ways which we can protect our crops from infestations:

1. Make sure to avoid using previously infested ground. Carrot fly larvae are capable of surviving through the winter, so avoid re-sowing any vegetable from the Parsley family (see above)
2. Avoid sowing during the main egg-laying periods, which are (for most parts of the UK): mid-April to the end of May & Mid-July to the end of August
3. Sow disease and pest resistant varieties such as Fly Away F1 and Resistafly F1, available from garden centres and online seed suppliers.
4. Erect a fine-mesh barrier at the time of sowing – at least 70cm high. Check out our Micromesh Pest & Wind Barrier for an example
5. Sow thinly so as to avoid ‘thinning out’, releasing the smell of bruised foliage
6. Thin out or harvest on a dry evening with no wind – or use scissors so that no bruising of foliage occurs
7. Try companion planting - growing varieties of pungent Rosemary, Sage or Marigold as a deterrent/’smokescreen’
8. Grow your carrots in planters taller than 70cm - for example ‘Veg Trugs’ or Carrot Patio Planters
9. Lift main carrot crops by Winter, especially if any are infected – don’t leave them in the ground to serve as food for overwintering larvae.

Thinning out tip: Use scissors to avoid bruising the foliage (and releasing the carrot-fly attracting scent)

To find out more about carrot fly, why not take a look at this entry on Wikipedia or this in depth factsheet from Garden Organic.

Have you any experience of carrot fly damage? What do you think went wrong? Please let us know your thoughts using the comments section below.

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