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If you have had Carrot Fly (Psila Rosae) in the past, you’ll know that this little pest can completely ruin a whole crop.

Carrots are not the only crop to be affected. Parsnips also suffer, as do other members of the same family such as parsley and celery.


Damage is caused by small white grubs which burrow into developing roots.

These tunnels quickly turn brown and spoil the crop. They also make long-term storage impossible as the roots will quickly rot.


  • Cover growing plants using a horticultural fleece
  • Avoid thinning out crops
  • Grow resistant seeds, such as those available from Gro-Sure


Resolva Bug Killer is perfect for quick and easy control.

Spray plants to kill adult flies before they can lay their eggs. Adult flies are most active late afternoon to early evening, so sprays at these times will be most effective. Any adult flies sprayed will be killed, as will any flies which land on treated foliage for up to 2 weeks after application.

Generally, Carrot Fly appear 3 big waves each year, ready to lay their eggs, mid-May, mid-June and mid-July. However, it can be difficult to know exactly when, as they are just a few millimetres long and therefore difficult to spot.

Therefore, do what the carrot farmers do and find out when adult flies are active by following the advice of horticultural scientists, such as the University of Warwick online. You could also sign up to our e-newsletter, as we send a report out to you when we hear from the university.

Carrots and parsnips can be safely harvested and eaten 14 days after being treated. Celery and parsley can be harvested just 7 days after being treated.

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