Carrot Fly

Slender black fly with a yellow head; cream-yellow larvae tunnel through roots of carrots, parsnips, and celery.

Two to three generations per year; adults attracted by the scent of bruised foliage, laying eggs at the base of plants.

Larval tunnels cause rusty-brown scarring and channels in roots, stunted growth, and rot; heavily affected roots are inedible.

Lift and destroy infested roots. No effective rescue treatment once larvae are inside roots.

Grow behind a 60cm barrier or under fine mesh to block low-flying adults; thin plants in the evening to reduce scent release; choose resistant varieties.