Help us achieve our goals:
make a donation »
Join the RHS today and
support our charity
Free personalised gardening advice
RHS members get reduced ticket prices
RHS members get free access to RHS Gardens
Reduced prices on RHS Garden courses and workshops
020 3176 5800
Mon – Fri | 9am – 5pm
Make a donation
Join the RHS today and support our charity
I have forgotten my password
Keep me signed in
Register for free to receive our newsletters, add comments to blogs/articles and to save content.
Leek moth is mainly a problem in southern England but it is spreading north. The caterpillars feed within the foliage and stems or bulbs of leeks, onions and related vegetables.
The adult leek moth is an inconspicuous very small (5-6mm) brown moth. Its larvae (caterpillars) feed on leeks and similar crops.
Damage from leek moth caterpillars appears as;
Note that these plants are also attacked in a similar manner by larvae of a fly, known as the allium leaf-mining fly (allium leaf-miner);
The female moths can be prevented from laying eggs by covering susceptible plants with insect-proof mesh. Crop rotation should also be practiced to prevent potential build-up of moth populations under the fleece. Look for the white, net-like silk cocoons on the foliage and squash them.
None of the pesticides currently available to home gardeners for use on leeks and onions will give effective control of leek moth.
Leek moth has two generations during the summer with larvae damaging the plants;
Initially the caterpillars mine the foliage but the older larvae bore into the stems and bulbs.
When fully fed, the caterpillars are 11 mm long. They come out of the plant and pupate within net-like silk cocoons that are spun on the foliage.
Adult moths emerge in autumn and overwinter in sheltered places.
Allium leaf minerInsect-proof meshLeekLeek moth (UK moths)Leek rustOnionsOnion white rot
the RHS today and get 12 months for the price of 9
RHS members can get exclusive individual advice from the RHS Gardening Advice team.
Register for the site or sign in to share your experiences on this topic and seek advice from our community of gardeners.
We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.
Join the RHS today and get 12 months for the price of 9