What are the reddish scabs on my citrus fruit?

They may be California red scale, which shows as small reddish-brown spots.

When is California red scale damage worst?

Late summer and early fall, when populations and tree moisture stress peak.

Adult females look like 1/10-inch reddish-brown spots or scabs on fruit, stems and leaves.^[1]
Females give birth to 100 to 150 yellow crawlers that settle and form hard coverings.^[1]

Look-alike	How to tell them apart
Purple scale	Elongate, slightly curved and purple to dark brown rather than round and reddish.^[1]

HGIC covers it on citrus grown in South Carolina.^[1]

US map: public records from 4 states since 1990 (GBIF).

Crawlers disperse to find a spot, settle to suck nutrients and become immobile adults under hard covers.^[1]

Severe infestations cause leaf yellowing and drop, twig and limb dieback and occasionally tree death.^[1]
Damage peaks in late summer and early fall, when scale numbers and moisture stress are highest.^[1]

It feeds on plants; Clemson HGIC mentions no risk to people.^[1]

Naturally occurring parasitic insects may help control some scales outdoors.^[1]

Horticultural oil kills all scale stages present; it works best before new growth in late winter or early spring, above 45 degrees F.^[1]

What are the reddish scabs on my citrus fruit?: They may be California red scale, which shows as small reddish-brown spots.^[1]
When is California red scale damage worst?: Late summer and early fall, when populations and tree moisture stress peak.^[1]

Clemson Cooperative Extension, Home & Garden Information Center, “Citrus Insects & Related Pests (HGIC 2221).” hgic.clemson.edu/factsheet/citrus-insects-related-pests/ (accessed 2026-10-06)
iNaturalist, “Aonidiella aurantii taxon page (order and family).” www.inaturalist.org/taxa/60926 (accessed 2026-10-06)

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