Carrot Rust Fly

Psila rosae
Also known as Carrot Root Fly

Carrot rust fly larvae leave rusty brown castings on the roots

Carrot rust fly damage on carrot

Carrot rust fly larva tunnel into roots

Carrot rust fly damage on parsnip

Carrot rust fly larva

Carrot rust flies lay eggs just under the soil surface

Host Plants:

On Crops: Caraway, carrots, celery, dill, fennel, parsley, parsnips

Where Found:

Most temperate climates where carrots are grown

Description:

Fast and hard to catch, carrot fly adults are slender, metallic, greenish-black flies with yellow legs and head. Larvae are creamy white, tapering maggots found in tunnels in roots.

Damage:

The root maggots eat fine root hairs, and then tunnel into the roots. The tunnels are filled with rusty brown castings, or may be excavated grooves. Plants are stunted but seldom killed, and roots are deformed. Injuries to the roots can then allow disease organisms to enter. After harvest, maggots feed in stored roots.

Preventing Problems:

To provide excellent protection, cover seed beds with floating row covers before seedlings emerge, and make sure to bury the edges under the soil and leave crop covered until harvest. Or, enclose the carrot bed with a vertical fence of window screening, which keeps the adult flies from finding plants. Harvest fall carrots early, and avoid leaving carrots in the ground over winter. Clean up and discard any carrots that may still be around, and any other plants that carrot rust flies like.