WSU Extension


Leaf spot 
Root-knot nematode 
Carrot rust fly 

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Caption: Carrot rust fly larval damage
Photo by: A.L. Antonelli
Carrot : Carrot rust fly
(revision date: 6/3/2014)

The carrot rust fly adult is about 1/4" long. The flies are shiny and dark green in color with yellow legs and heads. Females lay eggs around the crowns of host plants, which include carrots, celery, dill, parsley, and related weed species (family Umbelliferae). Upon hatching, the maggots burrow into the roots, where they tunnel in the surface tissues. Tunnels are filled with rust-colored frass (excrement). Larvae may also feed on small fibrous roots. Damaged plants often appear yellow and stunted above ground and may die. Mature larvae are up to 1/3" in length and yellowish to tan in color. The carrot rust fly pupae can overwinter in infested roots or in the soil.
Management Options

Non-Chemical Management
  • Rotate crops. Do not replant susceptible crops in the same area the following year.
  • Cover crops with floating or screen cages immediately after planting to prevent egg-laying. Do not put row covers on soil previously infested with these maggots.
  • Control weeds in and around the garden.
  • Do not leave carrots in the ground through the winter. Early harvest and storage can minimize damage by fall rust fly infestations.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Carrot rust fly larval damage
Photo by: A.L. Antonelli
Caption: Carrot rust fly adult
Photo by: L.W. Getzin