Pest profile

Vedalia Beetle

Novius cardinalis (formerly Rodolia cardinalis) · Coleoptera: Coccinellidae[3]

Imported from Australia over the winter of 1888-89, the vedalia beetle wiped out cottony cushion scale in California citrus within months.[2]

Small hairy vedalia lady beetle with red and black markings, walking along a green plant stem
Small hairy vedalia lady beetle with red and black markings, walking along a green plant stem. (c) Michael Berardozzi, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adults are about 1/8 inch long, oval and covered with fine hairs, irregularly marked in red and black.[1][2]
  • Some individuals are mostly black and others mostly red, and the hairs can make them look grayish.[1]
  • Eggs are red and oblong, easiest to see on the white egg sacs of cottony cushion scale.[1]
  • Older larvae are dark pink to bluish gray with black bumps and grow to about 1/4 inch.[1]

Look-alikes

Look-alikeHow to tell them apart
Cottony cushion scale crawlersBoth are small, red and oblong, but scale crawlers have black legs and forward-pointing black antennae; young vedalia larvae have red legs and no obvious antennae.[1]

Where it lives

Vedalia is established in California and Florida and turns up in scattered places in the southern U.S.[2]

US map: public records from 7 states since 1990 (GBIF).

Biology and life cycle

Females lay from about 150 to several hundred eggs over a life of one to three months.[1][2]

Egg to adult takes four to six weeks in warm weather, and coastal California sees about eight generations a year.[1][2]

Egg laying stops and larvae develop slowly when days top 90 degrees F.[1]

Damage and signs

  • It feeds only on cottony cushion scale; young larvae eat the eggs inside the egg sac, and older larvae and adults eat every stage.[2][1]
  • Host plants of the scale include citrus, acacia, boxwood, magnolia, nandina, olive, pittosporum and rose.[2]

Health risk

UC IPM and Cornell describe it only as a scale predator, with no mention of any risk to people.[1][2]

Control

Biological control

Arriving in Central Valley citrus in March or April, adults can clear a serious infestation in four to six weeks if not disrupted.[1]

Pesticide sprays and hot weather are what disrupt it, so avoid broad sprays where cottony cushion scale is under its control.[1]

Along the coast, a tiny parasitic fly, Cryptochaetum iceryae, does much of the work instead, and the two share middle areas.[1]

Common questions

Why is the vedalia beetle famous?
Its 1888-89 release saved California's citrus industry and is considered the start of classical biological control.[2]
What does it eat besides cottony cushion scale?
Almost nothing. Cornell calls it specific to cottony cushion scale.[2]
Why did my vedalia beetles disappear in summer?
Heat slows them: egg laying stops and larvae develop slowly once temperatures pass 90 degrees F.[1]

Sources

  1. University of California Statewide IPM Program, “Vedalia (Natural Enemies Gallery).” ipm.ucanr.edu/natural-enemies/vedalia/ (accessed 2026-10-06)
  2. Cornell University College of Agriculture and Life Sciences, “Biological Control: A Guide to Natural Enemies in North America: Rodolia cardinalis (Vedalia Beetle).” biocontrol.entomology.cornell.edu/predators/Rodolia.php (accessed 2026-10-06)
  3. iNaturalist, “Novius cardinalis taxon page (order and family).” www.inaturalist.org/taxa/1065202 (accessed 2026-10-06)

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