Pest profile

Japanese Maple Scale

Lopholeucaspis japonica · Hemiptera: Diaspididae[2]

Japanese maple scale is an invasive armored scale that can cause leaf drop, branch dieback and even death of small trees.[1]

Japanese maple scale, many small white oyster-shaped scale covers crowded on a tree branch
Japanese maple scale, many small white oyster-shaped scale covers crowded on a tree branch. (c) Tyler Ekholm, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • The cover is white, oyster-shaped and just under 2 mm long, with a bronze tip at one end.[1]
  • Flip the cover and you'll find a small purple insect; the eggs are purple too.[1]

Look-alikes

Look-alikeHow to tell them apart
Oystershell scaleJapanese maple scale superficially resembles it; look for the white wax coat and the purple insect underneath.[1]
White peach scaleAnother look-alike UK Extension names; the purple body and eggs point to Japanese maple scale.[1]

Where it lives

In Kentucky it's mostly found in production nurseries; NC State reports it on 45 plant genera in 27 families.[1]

US map: public records from 22 states since 1990 (GBIF).

Biology and life cycle

Central Kentucky has two generations a year, Pennsylvania one; females lay about 25 purple eggs under the cover in May.[1]

Crawlers can start forming wax within three days of hatching, and egg hatch is drawn out, so crawlers appear over a long period.[1]

Damage and signs

  • Infested plants lose vigor, may look water-stressed, and show yellow leaves and twig dieback.[1]

Health risk

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

Control

Traps and physical control

Watch for tiny purple crawlers on twigs, or wrap twigs with sticky-side-out tape from May and replace it every 2 to 3 weeks.[1]

Pesticides

Dormant oil in early spring or fall helps suppress it; crawler sprays and systemic imidacloprid or dinotefuran are nursery options.[1]

Common questions

What are the tiny white specks on my maple twigs?
They may be Japanese maple scale covers, white and under 2 mm long.[1]
Is Japanese maple scale only on Japanese maples?
No; hosts include maple, redbud, dogwood, magnolia, serviceberry and holly, among many others.[1]

Sources

  1. University of Kentucky Entomology (ENTFACT), “Managing Japanese Maple Scale in Kentucky Nurseries (ENTFACT-463).” entomology.mgcafe.uky.edu/ef463 (accessed 2026-10-06)
  2. iNaturalist, “Lopholeucaspis japonica taxon page (order and family).” www.inaturalist.org/taxa/63511 (accessed 2026-10-06)

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