Pest profile

Croton Scale

Phalacrococcus howertoni · Hemiptera: Coccidae[2]

Croton scale, first found in the Florida Keys in 2008, threatens croton and native plants like buttonwood with honeydew and sooty mold.[1]

Croton scales, yellow-green oval soft scales, on a plant stem
Croton scales, yellow-green oval soft scales, on a plant stem. (c) Even Dankowicz, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Females are wingless oval sacs about 4 mm long, yellow-green to green with dark lines on the back.[1]
  • Males have wings and orange bodies.[1]

Look-alikes

Look-alikeHow to tell them apart
Other scale insectsCroton scale was different enough to be placed in a new genus.[1]

Where it lives

It has been found in 21 Florida counties, plus Guatemala, Barbados, Guadeloupe and Hawaii; its native home is unknown.[1]

US map: public records from 1 state since 1990 (GBIF).

Biology and life cycle

Females gather densely on the undersides of leaves.[1]

Some 72 host plants have been recorded in Florida, including guava, mango and croton.[1]

Damage and signs

  • Females produce lots of honeydew, which grows sooty mold that blocks sunlight and leads to plant decline.[1]

Health risk

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

Control

Prevention

Watch for ants: follow their trails on the plant to find scale infestations.[1]

Biological control

A lady beetle preys on croton scale and has been recommended for release a few days after an insecticide application.[1]

Common questions

What are the green bumps under my croton leaves?
Possibly croton scales, which crowd on leaf undersides.[1]
Why are ants all over my shrub?
Ants tend scale insects for their honeydew and protect them from natural enemies.[1]

Sources

  1. University of Florida IFAS Extension (Featured Creatures), “Croton Scale, Phalacrococcus howertoni (EENY-768).” edis.ifas.ufl.edu/publication/IN1335 (accessed 2026-10-06)
  2. iNaturalist, “Phalacrococcus howertoni taxon page (order and family).” www.inaturalist.org/taxa/804291 (accessed 2026-10-06)

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