Pest profile

Striped Pine Scale

Toumeyella pini · Hemiptera: Coccidae[3]

Striped pine scale is a soft scale that has greatly increased along Colorado's Front Range and mainly damages Scotch pine.[1]

No licensed photo of this species is available yet; the identification notes below describe what to look for.

How to identify it

  • Adult females are round and wrinkled with tortoise-shell coloring and one or more cream stripes down the middle, about 1/4 inch by late spring.[1]
  • It excretes so much honeydew that twigs and needles turn sticky and dark gray sooty mold grows.[1]

Look-alikes

Look-alikeHow to tell them apart
Pine tortoise scaleA close relative commonly confused with it, with similar life history and controls.[1]
Pine needle scaleA white armored scale on needles; striped pine scale is a soft scale on twigs.[1]

Where it lives

CSU Extension reports it along much of the Front Range on Scotch, pinyon, Austrian and lodgepole pines.[1]

US map: public records from 2 states since 1990 (GBIF).

Biology and life cycle

Fertilized immature females overwinter on current-season twigs; crawlers emerge from early June.[1]

A female can lay hundreds of eggs; there's one generation a year.[1]

Damage and signs

  • Infested trees can decline rapidly, and honeydew draws nuisance bees and wasps.[1]

Health risk

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

Control

Biological control

Birds and lacewing larvae feed on it, but no highly effective natural enemy is known in Colorado.[1]

Pesticides

Horticultural oil in the dormant season or summer can work; crawler sprays are best timed around mid-June.[1]

More from the research literature

A 2020 Chemosphere study found that imidacloprid applied to pines at label rates cut honeydew production by the scale 25-fold within six days, but both imidacloprid and spirotetramat were still excreted in the honeydew, which predators and parasitoids use as food.[2]

Common questions

Why is my Scotch pine sticky and black?
Striped pine scale honeydew and the sooty mold growing on it are a likely cause.[1]
When should I spray for striped pine scale?
Crawler sprays work best around mid-June, when crawlers emerge.[1]

Sources

  1. Colorado State University Extension, “Scale Insects Affecting Conifers (Fact Sheet 5.514).” extension.colostate.edu/resource/scale-insects-affecting-conifers/ (accessed 2026-10-06)
  2. Peer-reviewed literature (PubMed), “Excretion of non-metabolized insecticides in honeydew of striped pine scale (Quesada CR et al., Chemosphere, 2020).” pubmed.ncbi.nlm.nih.gov/32062203/ (accessed 2026-10-15)
  3. iNaturalist, “Toumeyella pini taxon page (order and family).” www.inaturalist.org/taxa/1026333 (accessed 2026-10-06)

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