Giant Willow Aphid - a new aphid on willows in New Zealand

Disna Gunawardana *1, Alan Flynn 1, Heather Pearson 2, Stephanie Sopow 3

1 Ministry for Primary Industries, PO Box 2095, Auckland
2 Ministry for Primary Industries, PO Box 14018, Christchurch
3 SCION (New Zealand Forest Research Institute), Private Bag 3020, Rotorua 3046

Giant Willow Aphid, Tuberolachnus salignus (Hemiptera: Aphididae) was first detected in Central Auckland in late December 2013 on crack willow. At the same time it was reported from Northland and picked up in MPI’s High Risk Site Surveillance programme in South East Auckland. One of the largest aphid species, its hosts are various species of Salicaceae, willow (Salix spp.) and poplar (Populus spp.). Although its distribution is almost cosmopolitan wherever willows are grown, this is the first record in Australasia. Since its first detection in Auckland, T. salignus has been reported from both North and South Islands. New Zealand host records include Salix alba  varieties, S. fragilis, S. matsudana, S. humboldtiana, S. caprea, S. babylonica and Populus nigra. Giant willow aphid forms dense colonies on the trunk and branches of hosts and can adversely impact the growth of trees. Colonies can produce large amounts of honeydew that attracts honeydew feeders such as ants and wasps. As this aphid is a recent arrival, understanding its behaviour in a new environment, host preference and management options are key areas that require study. Its biology, potential pest status, current distribution and hosts in New Zealand will be presented.

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