Choose a country to see content specific to your location

Skip to main content

Allium Leaf Miner

Phytomyza gymnostoma

Allium Leaf Miner, Onion Leaf Miner

A bouquet of flowers
The Allium Leaf Miner is a tiny leaf-mining fly, that looks similar to an average housefly. As the name suggests, they're severe pests of Alliums; they're widespread across mainland Europe and the UK. Allium Leaf Miner damage plants by tunnelling through leaves, eating the internal tissue as they move around the foliage. The leaf mines created by an Allium Leaf Miner look like yellow meandering lines, which typically span across the whole leaf. The mines are often accompanied by yellow/white dots, which indicates a female fly has deposited eggs. Other symptoms to look out for include twisted onion leaves and stunted growth in Alliums. Infested leeks become susceptible to secondary bacterial rots.


Leaf mining insects can cause considerable damage to crops from their intrusive way of feeding.


Adults: Small, brown-black flies (3mm) that look a lot like normal house flies. Larvae: The larvae look like small, white, headless maggots. Pupae: Brown, ovular in shape (3mm), located in the within the stems and bulbs of the plant. Leek moths can create similar symptoms in onion plants. The way to distinguish these two insects is by the larvae. Leek moth caterpillars are creamy white, unlike Allium grubs which are white. Leek moth caterpillars possess legs and black heads, both of which are absent in Allium grubs.


Distinctive trail of yellow/white dots on Allium leaves. White/yellow lines (mines) on foliage of plant. Brown, oval shaped pupae found within the bulbs and stems. Stunted growth Dried out or twisted leaves. Secondary rots











Widespread across Europe

Biological treatment

Protect plants with an insect-proof mesh during periods where females are active (March-May and September - November). Rotate crops each year so that when adult females emerge it will be more difficult for them to locate an appropriate host plant. Avoid periods of flight activity by planting Allium later in the year, such as the end of May. Utilise plant companion plants to deter leaf-mining activity. Beets, carrot, celery, lettuce and cabbage have been suggested as useful companion plants for the onion family. It is thought Allium leaf miners dislike the scent of mint, lemon balm and common rue.

Chemical treatment

There are currently no chemical treatments available for home gardeners for this type of plant.


A close up of the white roots of a bunch of green and white leeks.


Allium porrum

A collection of different coloured Onions - some sliced into rings -  sitting on a table


Allium cepa

A close up of some pink Allium schoenoprasum flowers


Allium schoenoprasum


Allium sativum


Be the first to download the app

Help us build a place where community meets knowledge. Try it out and let us know what you think.
Download on the App StoreGet it on Google Play