Pest profile

Native Holly Leafminer

Phytomyza ilicicola · Diptera: Agromyzidae[2]

The native holly leafminer feeds only on American holly, leaving yellow serpentine or blotch mines in the leaves.[1]

Native holly leafminer damage, yellow-brown serpentine mines in a spiny American holly leaf
Native holly leafminer damage, yellow-brown serpentine mines in a spiny American holly leaf. (c) W Rao, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Mines start slender, rarely over 1.3 cm, then broaden into yellow serpentine or blotch mines.[1]
  • Larvae are yellow maggots, 1.5 mm when grown; adults are tiny black flies.[1]

Look-alikes

Look-alikeHow to tell them apart
Holly leafminerA European species that feeds mainly on English holly rather than American holly.[1]

Where it lives

It's found throughout eastern North America wherever American holly grows.[1]

US map: public records from 20 states since 1990 (GBIF).

Biology and life cycle

Larvae overwinter in the mines, pupate in spring, and adults emerge in May to lay eggs in new leaves.[1]

There's one generation a year, often about three larvae per leaf.[1]

Damage and signs

  • Heavily infested plants may drop leaves early; female egg-laying punctures can stunt and distort leaves.[1]

Health risk

It feeds on plants; Penn State Extension mentions no risk to people.[1]

Control

Sanitation

Gather and destroy leaves that drop early, before adults emerge.[1]

Pesticides

Registered foliar sprays in early May, or systemic soil treatments early in the season, can help.[1]

Common questions

What makes yellow squiggly lines in my holly leaves?
Native holly leafminer larvae feeding between the leaf surfaces.[1]
Should I rake up fallen holly leaves?
Yes; destroying early-dropped leaves reduces adults the next spring.[1]

Sources

  1. Penn State Extension, “Native Holly Leafminer.” extension.psu.edu/native-holly-leafminer (accessed 2026-10-06)
  2. iNaturalist, “Phytomyza ilicicola taxon page (order and family).” www.inaturalist.org/taxa/663729 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.