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Leek · Allium ampeloprasum

What is eating my leeks?

Leeks can attract hungry visitors like onion maggots or thrips that damage the leaves and stems. Look closely at the base of the plant and under the leaves to identify the culprit.

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pests on a plant
Photo: Jules Verne Times Two, CC BY-SA 4.0

Check these first

  1. Examine the undersides of the leaves for tiny insects.
  2. Check the base of the stem for soft spots or larvae.
  3. Look for silvery trails or holes in the foliage.

Likely causes

  1. Onion Maggots

    Most likely

    How to tell: The plant suddenly wilts and the base of the stem looks soft or tunneled into.

    What to do: Remove and destroy infested plants immediately to stop the spread. Use floating row covers early in the season to prevent adult flies from laying eggs.

  2. Thrips

    Possible

    How to tell: Small silvery streaks or white spots appear on the leaves, and you might see tiny insects.

    What to do: Spray the leaves with a strong stream of water to knock the insects off. If the infestation is heavy, use an insecticidal soap according to the label.

Pests on other plants

Find out what's wrong with your leek

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

If you see a sudden collapse of the entire plant, it is likely a severe maggot infestation. Take action immediately to save the rest of your crop.

Stopping it coming back

Practice crop rotation and use row covers to physically block pests from reaching your leeks.

Leek: pests? Check yours with a photo

Every plant is a little different. Take a photo of your leek and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Are these pests harmful to humans?
No, they are just garden pests. Simply wash your leeks thoroughly before cooking to remove any insects or debris.
Can I use neem oil?
Yes, neem oil is an effective organic option for many garden pests. Apply it in the evening to avoid harming beneficial pollinators.

Guides to these causes

More problems with Leek

Back to the Leek guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.