Giant willow aphid, Tuberolachnus salignus – now a major pest of willow trees in New Zealand and its impact on other insects, especially the honey bee and the honey industry.  

John McLean *1

1 ApiNZ Science and Research TG

The Giant Willow Aphid (GWA) was first identified in Auckland in 2013.  Detailed surveys over the next six months showed it was widely spread throughout New Zealand.  In those regions with severe soil moisture deficits the GWA thrived by piercing the stems of willows and producing copious amounts of honey dew.   There are only females in the New Zealand population and after the 4th nymphal moult the new adult is ready to birth young at the rate of 3 to 4 per day.  The honeydew is readily consumed by wasps and bees.  In the case of bees, the complex trisaccharide melezitose is carried back to the hive where it crystallizes in the honeycomb when the bees condition and dehydrate the honey prior to capping.  The melezitose crystals block filters and make extraction difficult for the beekeeper. 

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