Reducing rate of Australian <i>Eucalyptus</i> insects invading New Zealand

Abstract

Trees in the introduced genus Eucalyptus form an important part of New Zealands flora Since the 1860s Australian insects have steadily colonised this resource in this novel habitat There are now 28 specialist eucalypt insect species and approximately another 30 more polyphagous insect species that may feed on Eucalyptus spp established in New Zealand Throughout the 1990s the rate at which these insects had invaded New Zealand reached a peak of one insect every 18 months This study shows how the invasion rate appears to have dropped to one insect every five years Since 2000 only two new eucalyptus pests have established both being psyllids first identified in 2002 Creiis liturata (Froggatt) and Anoeconeossa communis Taylor The eucalyptspecific insect invaders are now dominated by sapsucking bugs particularly psyllids It may be that this group of insects is being dispersed the 1800 km by aerial flight a natural pathway that will not be able to be closed