Pest profile

Black Pineleaf Scale

Nuculaspis californica (also listed as Dynaspidiotus californicus) · Hemiptera: Diaspididae[3]

Black pineleaf scale is a tiny armored scale insect that settles on pine needles under gray-to-black oval shells; heavy infestations yellow and thin the needles, mostly on stressed trees.[1][2]

Gray-black black pineleaf scales dotting green pine needles
Gray-black black pineleaf scales dotting green pine needles. (c) Hunter Hickok, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adult females are under 1/8 inch, with a round to oval brown-to-black waxy covering and lighter margins.[1][2]
  • Crawlers are tiny (about 3/64 inch), yellow-orange and wingless; settled nymphs look like small adults.[1]
  • Affected needles become blotchy yellow, and crowns thin as needles yellow and brown.[1]

Where it lives

CSU calls it rare in Colorado, on ponderosa pine and blue spruce; Utah State reports it commonly on Austrian, Scotch and mugo pines and on Douglas-fir.[1][2]

Biology and life cycle

Eggs are laid under the female's shell in late June and early July, and crawlers are out from mid to late July.[1]

Crawlers drift to new spots on the wind, then build a shell and stay put; nymphs and adults do the damage.[1]

Damage and signs

  • Serious infestations can cause needle drop or kill trees.[1]
  • It is usually associated with stressful growing conditions.[2]

Health risk

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

Control

Prevention

Keep trees healthy and stress-free.[1][2]

From early to mid July, wrap double-sided tape around twigs to catch crawlers and tell when they are active.[1]

Pesticides

Apply horticultural oil when monitoring shows crawlers are present.[1]

Common questions

What are the small black shells on my pine needles?
Possibly black pineleaf scale, an armored scale under 1/8 inch with a dark, light-edged shell.[1][2]
When should black pineleaf scale be treated?
When crawlers are active, in mid to late July in Utah; catch them on double-sided tape to time it.[1]
Can it kill a pine?
Serious infestations can cause needle drop or tree death, mostly on stressed trees.[1][2]

Sources

  1. Utah State University Extension, “Black Pineleaf Scale (Ornamental Pest Guide).” extension.usu.edu/planthealth/ipm/ornamental-pest-guide/arthopods/scales/black-pineleaf-scale.php (accessed 2026-10-15)
  2. Colorado State University Extension, “Scale Insects Affecting Conifers.” extension.colostate.edu/resource/scale-insects-affecting-conifers/ (accessed 2026-10-15)
  3. iNaturalist, “Dynaspidiotus californicus taxon page (order and family).” www.inaturalist.org/taxa/1037819 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.