Pest profile

Cycad Aulacaspis Scale

Aulacaspis yasumatsui · Hemiptera: Diaspididae[2]

Cycad aulacaspis scale can coat a king sago in white crust, and heavily infested fronds brown and dry out.[1]

Cycad frond whose midrib is coated in a white crust of cycad aulacaspis scales
Cycad frond whose midrib is coated in a white crust of cycad aulacaspis scales. (c) Ken Puliafico, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Female scales are white, 1.2 to 1.6 mm, pear-shaped or irregular; the insect body and eggs underneath are orange.[1]
  • Male scales are smaller, white and elongate, and usually far more numerous.[1]

Look-alikes

Look-alikeHow to tell them apart
Magnolia white scaleAlso common on cycads, but its body and eggs are yellow and it sits on upper leaf surfaces.[1]

Where it lives

Found in Miami in 1996, it has spread through Florida, the Southeast, California, Hawaii and Puerto Rico, mainly on moved plants.[1]

US map: public records from 6 states since 1990 (GBIF).

Biology and life cycle

Females mature in about 28 days and can lay more than 100 eggs; the scale also infests roots up to 60 cm deep.[1]

Damage and signs

  • Damage starts as yellow spots, then most fronds turn brown and dry; scales crowd the undersides of leaflets.[1]
  • King sago, Cycas revoluta, the most popular cycad planted, was heavily infested from the start.[1]

Health risk

It feeds on plants; UF/IFAS mentions no risk to people.[1]

Control

Traps and physical control

Dead scales cling long after the insects die; hosing the plant helps wash old scales off so you don't keep spraying.[1]

Pesticides

Oil sprays, such as fish oil emulsion or horticultural oil, have been the most consistently effective; spray frond undersides and the stem.[1]

Common questions

What is the white crust on my sago palm?
Often cycad aulacaspis scale, which can coat cycads in white.[1]
Why does the scale stay after I treat it?
Dead scales stay stuck to the leaves and fall off gradually over months.[1]

Sources

  1. University of Florida IFAS Extension (Featured Creatures), “Cycad Aulacaspis Scale, Aulacaspis yasumatsui (EENY-096).” edis.ifas.ufl.edu/publication/IN253 (accessed 2026-10-06)
  2. iNaturalist, “Aulacaspis yasumatsui taxon page (order and family).” www.inaturalist.org/taxa/199419 (accessed 2026-10-06)

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