Exotic scale insects (Hemiptera: Coccoidea) causing severe damage to ornamental pittosporum in London.
During summer 2011, Japanese pittosporum (Pittosporum tobira) hedges in the Squirrel Monkey Exhibit (Zoological Society of London, London Zoo, Regent's Park, London, England) exhibited severe leaf loss, dieback and thinning, with some individual plants being almost killed. Japanese pittosporum was found to be heavily infested with cottony cushion scale, Icerya purchasi, the infestation consisting of dozens of adults and thousands of nymphs. Also present were old ovisacs and hundreds of nymphs of camellia scale, Pulvinaria floccifera. The uppter surface of some of the foliage was covered in honeydew excreted by the scale insects, which served as a medium for the growth of black sooty moulds. I. purchasi is native to Australia and Pulvinaria floccifera to East Asia. A third exotic insect, pittosporum sucker (Trioza vitreoradiata), native to New Zealand, was also present in small numbers, causing pit galls to the foliage. Four species of predatory insect were also observed: Anthocoris sp., Vedalia ladybird (Rodolia cardinalis), unidentified midge larvae (Cecidomyiidae), and unidentified lacewing larvae (Chrysopidae). Also present on the foliage were large numbers of mites (Tydeidae) and bark lice (Ectopsocidae) feeding on the sooty moulds. This is thought to be the first report of I. purchasi and Pulvinaria floccifera causing serious damage to ornamental pittosporum in Britain, and the first occasion that I. purchasi, Pulvinaria floccifera and T. vitreoradiata have been found feeding on the same plants.