First Record of Pulvinaria urbicola (Hemiptera: Coccidae), a Potentially Damaging Scale Insect, on Christmas Island, Indian Ocean

Pulvinaria urbicola, a pulvinariine soft scale was recorded for the first time on Christmas Island (Indian Ocean) in June 2011. A broad host plant generalist, Pu. urbicola excretes honeydew and is commonly tended by ants, including invasive Anoplolepis gracilipes and Pheidole megacephala. Pu. urbicola is implicated in dieback of forest dominated by Pisonia grandis (Nyctaginaceae) on many Indo-pacific islands. Here we report the first records of Pu. urbicola on Christmas Island, describe the potential impacts of the association of this trophobiont with introduced ants, and outline management options. Pu. urbicola represents a threat to stands of Pi. grandis, potentially threatens the forest dominant Pi. umbellifera, and could exacerbate supercolony formation and impacts of the yellow crazy ant Anoplolepis gracilipes. Christmas Island is now the closest land area with a Pu. urbicola infestation to Cocos (Keeling) Islands and Pulu Keeling National Park and, therefore, it is likely the most probable steppingstone for any future introduction.