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Cochineal Scale

Dactylopius spp. (including D. coccus)[4]

Cochineal scales are small sap-sucking insects that live under white, cottony wax on prickly pear pads; crushing one leaves a deep red stain from the carminic acid used to make carmine dye, and their damage to the cactus is usually minor.[1][2][3]

Group
Insect
Order
Hemiptera
Family
Dactylopiidae
US records
20 states
Sources
4 cited
Updated
2026-10-17
Cochineal scale colonies, white cottony tufts of wax, on a prickly pear pad
Cochineal scale colonies, white cottony tufts of wax, on a prickly pear pad. (c) Alison Northup, 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

  • Look for white, cottony or chalky tufts of wax on the pads; scrape one off and crush it on paper, and a deep red smear confirms cochineal.[1][2][3]
  • The wax shelters the immobile females and their egg masses, while the young crawlers move about before settling.[1][2]

Look-alikes

Look-alikeHow to tell them apart
Fungus or mildewGardeners often take the white patches for a fungus; the red stain when a tuft is crushed shows they are insects.[3][2]

Where it lives

Native to the Americas, where it is associated with prickly pear; common on prickly pear in Arizona landscapes and found as far east as Florida.[1][2]

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

Biology and life cycle

Crawlers feed for about three weeks before settling and becoming immobile, and the crawler stage is when the insects spread among cactus plants; there are several generations a year in warm areas.[1][2]

Damage and signs

  • They suck sap and can reduce a plant's vigor over time, but the damage is usually negligible; a seriously colonized plant can decline.[1][3][2]
  • Cochineal was used by the Aztecs for dye and paint and is still produced in Mexico and India as carmine, a red dye for foods, drinks and cosmetics.[1][2]

Health risk

Cochineal scales are harmless to people and pets.[1][2]

Control

Sanitation

If a plant is badly colonized and declining, prune off the worst pads at the joints and discard them.[1][3]

Traps and physical control

Blast the colonies with a strong stream of water from a hose to expose and weaken them; treating light infestations is optional.[1][3]

Pesticides

After hosing, spray the exposed scales with insecticidal soap, which is gentler on beneficial insects; a 1 percent horticultural oil also works.[1][3]

Common questions

What is the white stuff on my prickly pear cactus?
White, cottony patches on prickly pear pads are usually cochineal scale insects; crush one, and a red stain confirms it.[2][1]
Will cochineal scale kill my prickly pear?
Rarely; the damage is usually minor, though heavy colonies can weaken a plant over time.[1][3]

Sources

  1. University of Arizona Cooperative Extension, Yavapai County, “Cochineal Scale (adapted from Backyard Gardener by J. Schalau; June 18, 2024).” extension.arizona.edu/sites/extension.arizona.edu/files/attachment/CochinealScale.pdf (accessed 2026-10-17)
  2. UF/IFAS Extension Nassau County, “Q: What is this white stuff on my prickly pear cactus? (June 30, 2017).” blogs.ifas.ufl.edu/nassauco/2017/06/30/q-white-stuff-prickly-pear-cactus (accessed 2026-10-17)
  3. Arizona Daily Star, “Garden Sage: chalky-white splotches on prickly pear (P. L. Warren, Pima County Cooperative Extension urban horticulture agent).” tucson.com/lifestyles/gardensage/article_726d4960-84cf-54c6-aabe-72cc1da31a06.html (accessed 2026-10-17)
  4. iNaturalist, “Dactylopius taxon page (order and family).” www.inaturalist.org/taxa/202091 (accessed 2026-10-06)

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