What's eating my celeriac?

Celeriac is a slow-growing crop most threatened by celery leaf miner, which tunnels through its large leaves and weakens the swelling root. Slugs attack seedlings and young roots, and carrot root fly can occasionally target the root. Aphids colonise growing tips. A long growing season (up to 200 days) means sustained vigilance is needed.

Pale brown blistered mines on leaves; heavily mined leaves die back, significantly reducing energy to the developing celeriac bulb. Cover with fine insect mesh from transplanting. Remove and destroy mined leaves as soon as seen. Two generations occur — check from late spring through early autumn.

Seedlings eaten entirely; crevices in the irregular surface of the swelling root provide shelter and feeding sites, causing extensive scarring. Use iron phosphate pellets around plants. Transplant into warm, dryer conditions where possible; avoid wet, heavy soils where slug pressure is highest.

Colonies on growing tips and leaf undersides; leaves curl and plants are checked during the critical late-summer bulking phase. Squash or hose off colonies. Encourage aphid predators with flowering umbellifers (dill, fennel). Use insecticidal soap if colonies are persistent.