Larvae mature in three to four weeks and pupate in the soil. The stake, to which the sticky trap is attached, should be adjusted so that the trap is visible above the foliage. If there is a commercial pest monitoring service functioning in your area, it would be advisable to hire it for this work. Further information on the preparation and use of the traps and fly identification is available from the Crop Protection Branch, B.C. Ministry of Agriculture and Food. Delayed spring seeding of carrots will reduce the severity of rust fly attack.
Cull piles are breeding grounds.
Bury culls or take them to a sanitary land fill. Late carrots must be protected with sprays until early November. The carrot rust fly is found across Canada and in the United States. Besides carrots, the insect attacks parsnips, celery, parsley, dill, caraway and fennel. In severe attacks, the roots are reduced in size, distorted, scarred and riddled with rust-red burrows of the larvae.