Adult: Shiny black or green with yellow hairs, legs, and head; black eyes. About 1/5 inch long. Larva: Yellowish-white, stiff, legless, up to 1/3 inch long. Eggs are laid in the crown of carrots.
Carrot, celery, parsley and parsnip.
Larva feeds on roots, destroys fibrous roots.
In northeast, coastal Washington and Oregon.
Carrot rust flies overwinter as pupae. First generation eggs are deposited in spring, singly or in groups, in soil around carrot plants. The carrot fly's three instars feed on lateral and taproots of carrot plants. In about three to four weeks from the egg stage mature larvae move into the soil where they pupate. Multiple generations occur in Virginia annually.
Delay seeding until mid-May and harvest early in June before second generation flies appear. Harvest in blocks rather than selectively. Destroy all volunteer umbelliferous plants as they may serve as alternate hosts and possible sources of infestation. Deep plowing in fall or spring as well as crop rotation will help reduce populations of this pest. Carrot rust fly infestations can be thwarted by placing cones made of window screen over individual plants. Cones can be stacked, stored and used in subsequent years. These same cones can be used to protect young cruciferous plants from attack by cabbage maggots.
Sprinkle rock phosphate around the base of plants.
Apply a registered insecticide in granular form in the seed furrow at planting time.
Notice: Because pesticide labels can change rapidly, you should read the label directions carefully before buying and using any pesticides. Regardless of the information provided here, you should always follow the latest product label when using any pesticide. If you have any doubt, please contact your local Extension agent or pesticide dealer for the latest information on pesticide label changes.
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Prepared by Alexandra Spring and Eric Day (Modified from a publication by the USDA)