The rise and fall of manuka blight scale: a review of the distribution of Eriococcus orariensis (Hemiptera: Eriococcidae) in New Zealand

Abstract

The decline in abundance and distribution of the manuka blight scale insect, Eriococcus orariensis Hoy, between the 1950s and 1997/99 is described. Manuka blight 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 (Leptospermum scoparium) from 23 sites around New Zealand. A dramatic decline of manuka blight scale, and its displacement by the less noxious species, Eriococcus leptospermi Maskell, 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.

Keywords:

• Eriococcus leptospermi
• Eriococcus orariensis
• Leptospermum scoparium
• manuka
• manuka blight
• sooty mould