Rodolia

Rodolia is a genus of beetles in the family Coccinellidae, commonly known as lady beetles. The genus includes multiple species, with Rodolia cardinalis being the best known. Rodolia cardinalis is commonly called the vedalia beetle and is native to Australia.

Rodolia cardinalis is notable for its historical role in classical biological control of cottony cushion scale (Icerya purchasi), a widespread pest of citrus and other crops. In the late 19th century, beetles were collected in Australia and released in citrus-growing regions such as California, where they substantially reduced scale populations and helped restore yields. The introductions are cited as an early success in biological control and influenced pest management practices in many parts of the world. The species has since established in warm, coastal, and subtropical to tropical climates where suitable prey is present.

Biology and ecology: Rodolia beetles are small, rounded insects that prey on soft-bodied pests. Both adults and larvae feed on scale insects, particularly cottony cushion scale and related species. The life cycle includes eggs laid near colonies of scale, followed by larval development, pupation, and emergence of adults. In warm climates, Rodolia cardinalis can produce several generations per year, contributing to ongoing pest regulation.

Taxonomy and diversity: Rodolia is a genus within Coccinellidae with several described species, though R. cardinalis is the most historically prominent due to its biocontrol legacy. Members of this genus are typically beneficial predators that help regulate pest populations on crops and ornamental plants.