PestControlBasics
Menu

Identify

Treat

Local

About

European Holly Leafminer

Phytomyza ilicis[3]

The European holly leafminer is a tiny fly whose larvae mine the leaves of English holly.[1][2]

Group
Insect
Order
Diptera
Family
Agromyzidae
Sources
3 cited
Updated
2026-10-17
Holly leaf with blotch mines made by holly leafminer larvae
Holly leaf with blotch mines made by holly leafminer larvae. (c) Kieran Roy Powell, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • Mines start as narrow, winding trails from the midvein and grow into yellow, brown or reddish blotches where the leaf surfaces separate.[1][2]
  • Adults are tiny grayish-black flies, about 0.06 inch per the PNW handbook or 1/8 inch per UMass.[1][2]
  • Small yellow pits on new leaves mark where females pierced them to feed.[2]

Look-alikes

Look-alikeHow to tell them apart
Native holly leafminerA related leafminer that attacks American holly; the European species reproduces only on English holly.[1][2]

Where it lives

Introduced from Europe and now known in both the eastern and western United States.[1]

Biology and life cycle

Larvae overwinter in their mines and pupate in March or April; adult flies emerge over about six weeks in May.[1][2]

Females lay eggs in the midvein on the underside of leaves, and the larvae mine the midvein slowly until fall, so new mines are easy to miss; there is one generation a year.[1][2]

Damage and signs

  • It feeds and reproduces only on English holly.[1][2]
  • In heavy infestations every leaf may be mined, and leaves with several mines drop early, leaving plants thin until spring growth.[1]

Health risk

None to people or pets.[1][2]

Control

Traps and physical control

Pick and destroy mined leaves in fall or before March.[1][2]

Biological control

Parasitoid wasps may keep it below damaging levels, especially where little or no insecticide is used.[1]

Pesticides

The PNW handbook times control for the egg-laying adults, when small sunken feeding spots appear on the first flush of new leaves.[2]

Common questions

What are the brown blotches in my English holly leaves?
Most likely mines of the European holly leafminer.[1][2]
When should I remove holly leaves with mines?
In fall or late winter, before the flies emerge in spring.[1][2]

Sources

  1. UMass Extension Landscape, Nursery and Urban Forestry Program (Landscape Insect & Mite Guide), “Phytomyza ilicis (Holly Leafminer).” www.umass.edu/agriculture-food-environment/landscape/publications-resources/insect-mite-guide/phytomyza-ilicis (accessed 2026-10-16)
  2. Pacific Northwest Insect Management Handbook (Oregon State, Washington State, University of Idaho), “Holly (Ilex)-Holly leafminer (Hosts and Pests of Landscape Plants).” pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/holly-ilex-holly-leafminer (accessed 2026-10-16)
  3. iNaturalist, “Phytomyza ilicis taxon page (order and family).” www.inaturalist.org/taxa/1709533 (accessed 2026-10-06)

Updated 2026-10-17. Built from sourced records. Spot an error? Tell us.