Carrot and Cabbage Rootfly
Carrot Root Fly - A widespread pest of carrots, parsnips, celery, celeriac & parsley causing tunnels in the roots. Carrot Root Fly can be a particularly problem in old established gardens where the pest builds up each year. It lays eggs in the soil adjacent to the plant, the eggs hatch out and the 9mm yellow/white maggots burrow into the roots. The maggots stay in the ground over winter, pupate and the life cycle starts again in the spring. Two further generations can appear during the year.
Cabbage Root Fly - A pest of all brassicas (cabbages, cauliflowers, etc) and root vegetables (turnip, swede and radishes). The fly lays eggs in the soil near the plants and when the eggs hatch the maggots feed on the plant roots. Older plants may survive an attack, but grow slowly and wilt on sunny days. Cabbages often fail to heart and cauliflowers form a tiny heads. Brassicas are particularly vulnerable as seedlings, as they can be be killed by the maggots. The maggots eat the fine roots and just leave a rotting stump, or when roots are swollen as in radish, swede and turnip, they will bore into the roots leaving an inedible mess.