Cotesia urabae geographic range expanding
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Formerly known as the Forest Research Institute, Scion has been a leader in research relating to forest health for over 50 years. The Rotorua-based Crown Research Institute continues to provide science that will protect all forests from damage caused by insect pests, pathogens and weeds. The information presented below arises from these research activities.
From Forest Health News 245, February 2014.
Gum leaf skeletoniser (Uraba lugens) is an Australian moth with hairy caterpillars that defoliate eucalypts. It has been in Auckland since at least 2001, and has since spread to many parts of the North Island and Nelson. The specialist parasitoid Cotesia urabae, introduced from Australia, was first released in Auckland by Scion in 2011. Multiple releases in Auckland have resulted in the parasite producing self-sustaining populations that are now spreading throughout the city.
Scion has now also released the biological control agent in Whangarei, Mount Maunganui, Nelson and most recently in Napier. To date, as well as Auckland, establishment has been confirmed in Whangarei and in Mount Maunganui.
On 25 February 2014 Belinda Gresham undertook a release of the parasitoid at the Park Island Recreation Ground in Orotu Park, Napier. Using the same successful method used in previous releases, she attached approximately 450 previously parasitoid-attacked gum leaf skeletoniser larvae to the foliage of two large eucalypt trees. She also released 66 parasitoid wasps – equal numbers of males and females.
Uraba lugens appears to be quite abundant at Park Island and throughout the greater Napier area. Many of the eucalypt trees inspected revealed the caterpillars distinctive feeding damage, and horticultural staff of the Napier City Council have reported unpleasant experiences with these hairy pests at this site in the past. This is because gum leaf skeletoniser caterpillars are covered in urticating hairs that can cause some people to get an itchy skin rash even after the caterpillar has died. This release of the parasitoid was supported by the Hawke’s Bay Regional Council, the Napier City Council and the Department of Conservation. Regional Council pest officer Alice McNatty assisted with locating a suitable release point and the actual release on the day.
Toni Withers and Belinda Gresham
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(Scion is the trading name of the New Zealand Forest Research Institute Limited.)