Allium Leaf Miner - Phytomyza gymnostoma

The greyish brown flies are 3mm long and show a pale yellow band on the lower abdomen. Larvae attack Allium species, feeding just below the surface, often with several larvae on each plant. The plant becomes often becomes weak and softens due to the damage caused.

See the National Agromyzidae Recording Scheme webpage for this species for further details of puparium and adult insect.

There are other agromyzids that attack Allium species and identification requires detailed examination of the adult fly.

ref.: Warrington, B.P. (2023).  Phytomyza gymnostoma. Accessed at https://agromyzidae.co.uk/species/agromyzidae/phytomyzinae/phytomyza/ph… on 13/12/2023)

Adult leaf mine

Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Gardens, allotments etc. where Allium species, such as leeks, onion, chives, shallot or garlic, are grown.

Click on the 'further details' link in the 'Description' section above.  Then click on the Phenology tab which will provide phenology details for both adult and larval stages.

The adult fly is rarely seen unless reared from the pupae found within the bulbs and stems of affected plants, but may be encountered in most months of the year.

The larvae produce lines of white spots on leaves, then enter the stems and bulbs where they pupate.

First recorded in Britain in 2002, but by 2005 it was distributed across the West Midlands and is now believed to be widespread in central and southern England, although sometimes local in distribution.

Warrington, B. P. 2022. A provisional review of the status of Agromyzidae in Great Britain & Northern Ireland

Infrequently recorded in Leicestershire and Rutland.