Identification

The larval forms of the rust fly are stiff white maggots about 0.33 inch long. Adults are small flies.

Damage

Carrot rust fly larvae cause surface tunnels in roots. Tunnels are filled with a rusty mush and the stiff white maggots. There are no aboveground symptoms.

Solutions

Plant carrots to avoid the egg-laying periods of the fly. In cold areas, plant in early summer. In more mild areas, plant in late winter or late summer. Covering seedbeds with row cover or individual plants with protective cones may help prevent infestations. Harvest carrots as soon as possible and in blocks rather than selectively. Before using carrots, peel off damaged areas. Do not store carrots in ground through winter. Carrot rust fly also attacks parsley, celery, and other related plants. Remove these sources of infestation also.