New Zealand is now into the third season with Giant Willow Aphid (GWA) and the New Zealand Poplar and Willow Research Trust have field experiments in place to help evaluate the effect of GWA in New Zealand.

GWA colonises both tree and non-tree willows (shrub and osier) with the rate of colony growth differing between willow species.

Any information on which willow(s) are affected, age of affected trees, potential stressors on the affected willows and impacts such as reduced growth or yellowing or dropping leaves, helps add to the understanding of the impacts of this pest across the country.

Reporting of any situations where insecticide spraying has improved willow health is also useful.

Populations are now on the rise with a few cases of GWA recently reported from kiwifruit orchards in the Nelson region.

Growers are asked to look out for GWA and contact Sylvia Warren at Zespri if they are seeing this pest in their orchards – email sylvia.warren@zespri.com.

Click here for more information on the giant willow aphid.