Carrot fly

What you see

You will not see the fly - a small shiny black insect with orange head that flies low. The evidence is in the root: rusty-brown tunnels just under the skin, packed with fine crumbly frass.

Damage

Foliage takes on a red-bronze tint and wilts in the heat. Roots show rusty tunnels when pulled, worst at the shoulder and tip.

Lifecycle on this coast

Two main generations, roughly May and August. The female finds carrots by SMELL, flying low over the ground.

When to act

Zero practical tolerance - a tunnelled carrot is spoiled. Prevent, do not react.

Months: May, June, July, August, September

Plants it bothers

Carrot, Parsnip, Celery, Hamburg parsley, Celeriac, Florence fennel

Natural enemies

Ground beetle, Rove beetle

Remedies

Insect mesh and fleece barrier, Encourage predators

The thing people get wrong

Carrot fly cruise below about 60 cm and home in on the smell of bruised carrot foliage. Two things follow: a mesh cover is essentially total protection, and thinning your carrots on a still evening - then removing the thinnings from the garden entirely - avoids ringing the dinner bell in the first place.