van Epenhuijsen, K.C.W., Henderson, R.C., Carpenter, A., & Burge, G.K. 2000 The rise and fall of manuka blight scale: a review of the distribution of Eriococcus orariensis (Hemiptera: Eriococcidae) in New Zealand.. New Zealand Entomologist 23: 67-70.
Notes: The decline in abundance and distribution of the manuka (Leptospermum scoparium) blight scale insect, E. orariensis [Acanthococcus orariensis], between the 1950s and 1997/99 is described. Manuka blight (which is a combination of the scale insect and an associated sooty mould fungus, Capnodium walteri) was discovered about 1937 in the Orari Gorge, Mid-Canterbury, and by 1958 had become widespread throughout New Zealand. Despite intensive searches in 1997/99, the scale was found on only five out of 27 samples of manuka from 23 sites around New Zealand. A dramatic decline of manuka blight scale, and its displacement by the less noxious species, Eriococcus leptospermi [Acanthococcus leptospermi], in a period of little more than 40 years has occurred. This survey shows that in recent years sooty mould is mainly caused by E. leptospermi rather than E. orariensis.