🥕 Carrot How hard it is to control: ★★★★☆ 4/5

Carrot fly

Larvae of the fly Chamaepsila rosae mine rusty tunnels through carrot roots. It is the worst carrot pest there is — damaged roots will not keep in store.

Symptom photos

Carrot fly — Roots — rusty-brown tunnels and grooves left by feeding maggots — Roots — rusty-brown tunnels and grooves left by feeding maggots Photo: Rasbak, licence CC BY-SA 3.0

Carrot fly — White carrot fly maggot emerging from a tunnel in the root — White carrot fly maggot emerging from a tunnel in the root Photo: Rasbak, licence CC BY-SA 3.0

Carrot fly — Adult carrot fly on the foliage — Adult carrot fly on the foliage Photo: Rasbak, licence CC BY-SA 3.0

Symptoms

Rusty-brown surface tunnels and grooves on the root
Small white larvae in galleries just under the skin
Foliage turning reddish, then yellow, and wilting
Growth checked and roots misshapen
Young plants dying under the first generation

What it does to the crop

Unmarketable roots that will not store
Secondary soft rots entering through the tunnels
Crop losses of up to tens of percent
Having to lift the crop early

What encourages it

First flight in May, second in July and August
Damp, sheltered, shaded sites
Carrots grown near last year's carrot plot
The smell of bruised foliage, for example after thinning, drawing the flies in

Prevention

Cover the crop with fleece or insect mesh all season
Grow alongside onions, which mask the carrot smell
Avoid thinning, or do it in the evening
Sow after 20 May to miss the first flight
Rotate crops and keep distance from last year's plots

⚠️ Before you reach for a spray

This atlas is informational and still growing — different diseases can look almost identical. Confirm the diagnosis and read the product label before applying any plant protection product. If you are unsure, ask your local extension or advisory service.

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📅 When to Sow Carrot? →