Interim profile, incomplete information
Taxonomic name: Icerya purchasi Maskell, 1878
Common names: cottony cushion scale
Organism type: insect
The cottony cushion scale insect Icerya purchasi causes the decline of indigenous plants on the Galapagos Islands, Ecuador.
The cottony cushion scale Icerya purchasi causes the premature loss of fruits and leaves, dieback of branches and death of some Galapagos plants and threatens valuable natural habitats particularly mangrove stands. I. purchasi also produces large quantities of honeydew which may encourage the growth of black sooty moulds that cover the leaves of the plant preventing photosynthesis (Charles Darwin foundation 2006b).
Native range: The cottony cushion scale insect originates from Australia (Charles Darwin foundation 2006b).
Known introduced range: The cottony cushion scale insect has spread throughout the Galapagos Islands including 15 islands (Charles Darwin foundation 2006b).
The Australian ladybug Rodalia cardinalis Mulsant (Coleoptera: Coccinellidae) has been under investigation as a potential and safe biocontrol agent for the cottony cushion scale insect in the Galapagos Islands (Hoddle 2004; Causton et al, 2004). Preliminary results appear positive. Before the release of R. cardinalis, the mangrove stands of the town of Puerto Ayora on Santa Cruz Island were blackened and dying from the effects of the cottony cushion scale. These mangroves are now green and thriving (Charles Darwin foundation 2006a).
The cottony cushion scale insect feeds on plant sap (Charles Darwin foundation 2006b).
Compiled by: IUCN SSC Invasive Species Specialist Group (ISSG) with support from the EU-funded South Atlantic Invasive Species project, coordinated by the Royal Society for the Protection of Birds (RSPB)
Last Modified: Tuesday, 28 April 2009