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The tiny white maggots (larvae) of this pest leave crop roots riddled with dark tunnels. Carrot rust flies target carrots and related crops; parsnip, celery, celeriac, and parsley. The flies lay their eggs in the soil near these plants. When the eggs hatch, the maggots tunnel into the roots and crowns, remaining active for about one month. The longer mature crops remain in the soil, the more likely they are to be damaged. The carrot rust fly larvae’s tunneling activity leaves behind a rust-colored stain, which is what gives this pest its name. The tunneling damages the appearance of roots, reduces storage quality and invites disease.
Carrot rust flies spend the winter in the pupa stage, and there are two generations per year. This pest was introduced from Europe over 100 years ago, and has spread through most parts of the northern United States and Canada.
Last updated: 10/24/15
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