Turnip Worms & Leaf‑Eating Bugs in Washington State

Washington gardener: wants to keep worms out of turnips, bugs off leaves. Asks about slug killer timing.

Turnip "Worms": Likely Root Maggots (Delia spp.)

• Larvae of flies that lay eggs at base of plants.
• Tunnel in roots.

Leaf Eaters: Flea Beetles, Caterpillars, Slugs

Integrated Approach

1. Row Covers at planting — exclude flies, beetles, moths.
2. Beneficial Nematodes (Steinernema feltiae) applied to soil — kill root maggot larvae.
3. Diatomaceous Earth around plants — deters slugs, beetles.
4. Spinosad (organic) for caterpillars/beetles if needed.
5. Crop Rotation — don't plant brassicas in same spot yearly.

Slug Killer Note

Apply *after* planting if slugs appear. Not a preventative soil drench. Nematodes go in at planting.

Row covers + nematodes + rotation = clean turnips.