Bug FAQEuropean Holly Leafminer
Phytomyza ilicis · Order: Diptera · Family: Agromyzidae
Also called: Holly leafminer, Holly Leaf Gall Fly, Holly Leaf Miner
Adults are tiny flies with wings about 2.5 to 3 mm long and red eyes. Their larvae mine the leaves of holly (Ilex aquifolium), leaving pale trails but causing little overall damage. They appear in late spring, lay up to five eggs per leaf, and are univoltine.
Source: Wikipedia
Size
Wing length ranges from 2.5 to 3 mm.
Source: Wikipedia
Is it a pest in the house?
The leaf mines cause little overall effect on holly health, and small plants can have affected leaves manually removed.
Source: Wikipedia
How to get rid of it
Sprays are ineffective because holly leaves are thick and glossy, so manual removal of mined leaves is the best approach.
Source: Wikipedia
Where it lives
They are found across the Holarctic wherever holly grows, especially in Europe and parts of western Canada and the north-west USA.
Source: Wikipedia
What it eats
Larvae are leg-less maggots that tunnel inside holly leaves, creating pale mines.
Source: Wikipedia
Life cycle
The species has one generation per year; adults emerge in late May to June and leave a hole larger than 1 mm when exiting.
Source: Wikipedia
When you see it
Egg-laying can only occur when new holly leaves unfold in April-May.
Source: Wikipedia
Where it comes from
Their natural range is the Holarctic on holly (Ilex aquifolium).
Source: Wikipedia
Where it is found in the US
Recorded in 3 of 51 states and DC. Most records: Washington, Oregon, Alaska.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in Canada; introduced in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Do they damage my holly plant?
They cause only minor leaf mining and have little overall impact on plant health.
Source: Wikipedia
How can I control them?
Because sprays do not penetrate the leaf, the most effective method is to manually remove mined leaves, especially on smaller plants.
Source: Wikipedia
Same family (Agromyzidae)
Jewelweed Leaf-miner FlyPhytoliriomyza melampyga
Agromyza vockerothiAgromyza vockerothiDamages trees, gardens or crops
Calycomyza flavinotumCalycomyza flavinotum
Nemorimyza posticataNemorimyza posticata
Dogwood leaf-mining flyPhytomyza agromyzinaDamages trees, gardens or crops
Ophiomyia mauraOphiomyia mauraSources
- Wikipedia: https://en.wikipedia.org/wiki/Phytomyza_ilicis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.