A few, however, may hatch and emerge. An insecticide may be applied as a drench in furrow at planting to control first-generation larvae. Do not apply an insecticide that will not be compatible with planned rotational crops. Only one generation per year in Vermont. Tunnels are much larger than carrot rust fly.
Adults chew on stems and foliage.
Several attack both the root and foliage of carrot. Normally not a field problem, but can be a problem with carrots in storage. Lettuce and celery are especially susceptible, but carrots too are subject to yellows. This is only a minor porblem in Vermont. Expect along Connecticut River Valley and similar areas.