Rodolia cardinalis (Mulsant)
Common name: Vedalia beetle.
Geographical distribution: The vedalia beetle, which is of Australian origin, has been distributed around the world.
Morphology: The female is 3-4 mm long, body purple with black markings on the head and the posterior margin of the elytra.
The body of larva is reddish, head darker, legs with golden hue, length up to 5 mm.
Life cycle: Each female produces about 150-200 eggs, placing them in or near the ovisac of a cottony-cushion scale, Icerya purchasi, female. The emerging larvae initially feed on the underside of the prey, then devouring the eggs and crawlers. They pupate when attached to a leaf or twig. In summer the beetle completes a cycle within 3 weeks, in winter 7 to 12 weeks are required, and it may raise 10-12 annual generations (three times more than the prey). Each beetle may live for several months.
As a natural enemy R. cardinalis has several important attributes. It can rapidly locate and destroy even very small and isolated pest colonies, it increases rapidly (especially in comparison to the prey), it has a broad climatic tolerance and may be stored at 12°C for 7-12 weeks with minimal mortality.
Economic importance: The vedalia beetle is the major predator of cottony-cushion scale, feeding on all stages of the pest, often within the scale’s ovisac.
Quezada, J.R. and DeBach, P. 1973. Bioecological studies of the cottony cushion scale, Icerya purchasi Mask., and its natural enemies Rodolia cardinalis Mul. and Cryptochetum iceryae Will., in southern California. Hilgardia 41: 631-688.
Rivnay, E. 1968. Biological control of pests in Israel (a review 1905-1965). Israel Journal of Entomology 3: 1-156.